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  • 1985-1989  (13,729)
  • Analytical Chemistry and Spectroscopy  (5,836)
  • Biochemistry and Biotechnology  (3,097)
  • Engineering  (2,531)
  • Computational Chemistry and Molecular Modeling  (1,638)
  • Physical Chemistry  (627)
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Years
Year
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  • 201
    Electronic Resource
    Electronic Resource
    Calendar of events (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. i 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030311
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  • 202
    Electronic Resource
    Electronic Resource
    Thin layer chromatography of peptides and proteins: A review (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 95-104 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030302
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  • 203
    Electronic Resource
    Electronic Resource
    Rapid assay of β-galactosidase and sialyltransferase by lectin affinity high performance liquid chromatography with fluorescence detectionThis study was entrusted to the Hohen Oil Company Ltd, by the Science and Technology Agency (STA) using the Special Coordination Funds for Promoting Science and Technology. (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 110-113 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Fluorescein isothiocyanate (FITC)-labelled asialotransferrin and pyridyl aminated oligosaccharides were prepared from asialotransferrin and human milk using affinity chromatography and high performance liquid chromatography (HPLC), respectively. These substances were incubated with galactosidase or sialyltransferase and then examined by lectin affinity HPLC. The elution patterns changed according to the period of incubation and amount of enzyme. This analytical method using lectin affinity HPLC with fluorescence labelled glycoprotein or oligosaccharides as the substrates has great value for detecting these enzyme under the same chromatographic conditions. In addition, differences were noted in the activity of β-galactosidase toward oligosaccharides having the Gal β(1 → 3)GlcNAc or Gal β(1 → 4)GlcNAc structure at reducing termini.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030304
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  • 204
    Electronic Resource
    Electronic Resource
    Lactoferrin from human breast milk and from neutrophil granulocytes. Comparative studies of isolation, quantitation, characterization and iron binding properties (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 121-126 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The isolation and properties of lactoferrin from human breast milk and from neutrophilic granulocytes were investigated. Human breast milk lactoferrin was purified by means of heparin-sepharose or Cibacron Blue affinity chromatography. Quantitative recovery using these two methods was comparable but Cibacron Blue affinity chromatography allowed for isolation of a more homogenous protein. Lactoferrin could only be isolated from human neutrophilic granulocytes by sequential use of antibody affinity followed by non-specific affinity chromatography. Both breast milk lactoferrin and granulocyte lactoferrin were separated into apo and iron-rich species by SDS polyacrylamide gel chromatography. Iron binding is accompanied by a conformational change in tertiary structure associated with more rapid electrophoretic migration. The isoelectric point of both human breast milk lactoferrin and human granulocyte lactoferrin is 5.5 - 6.2. Both types of lactoferrin have similar iron binding properties with release of iron from the one binding site occurring at pH 5.2 - 6.0 while the other binding site holds on to iron down to pH 3.6 - 3.2. Despite the high affinity for iron the percentage saturation of native lactoferrin is low, that for breast milk lactoferrin averaging 12 - 25% and that for granulocyte lactoferrin 〈 10%.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030307
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  • 205
    Electronic Resource
    Electronic Resource
    Evidence for the overestimation of molecular masses of proteins after chemical modification and chemical crosslinks on sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE)This work is the partial fulfilment of the Exchange programs between French Medical Research Council (French INSERM) and Academia Sinica (University of Nanjing). Grants No. CS-RN-739, HN-CP-1.045, and CS-RN-842 during the years of 1984, 1986, 1987 and 1989 for the tenure of four 3 months trips to China by Dr Kia-Ki Han.This work is the partial fulfilment of the short visit of Prof. De-Xu Zhu to Lille, France during the month of September 1988 via French Association Recherche sur le Cancer's Channel (ARC Grant No. 6.715 to Dr Kia-Ki Han). (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 131-135 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Human trypsin inhibitor (home prepared), lactalbumin, trypsinogen, carbonic anhydrase, and bovine serum albumin were submitted to succinylation and their molecular masses were determined by SDS-PAGE according to the method of Weber and Osborn (1969 J. Biol. Chem. 244, 4406) before and after chemical modification. High estimates of their molecular masses were obtained. The monomer and dimer of arrowhead inhibitor proteinase-B (Chinese vegetable legume) obtained after chemical crosslink(s) were also submitted to SDS-PAGE and their apparent molecular masses were also determined and compared to the native arrowhead inhibitor proteinase-B. Abnormally high estimates of their molecular masses were obtained. Our results agree with those in the literature.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030309
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  • 206
    Electronic Resource
    Electronic Resource
    Masthead (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989) 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030301
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  • 207
    Electronic Resource
    Electronic Resource
    Determination of urinary 5-hydroxy-3-indoleacetic acid by an automated HPLC method (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 114-117 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A HPLC method for the quantitative determination of 5-hydroxy-3-indoleacetic acid (5-HIAA) in urine is described. The method is based on ion-pair chromatography, reversed phase (RP) column material and specific fluorimetric detection at 300 nm and 355 nm. Sample preparation and gradient elution were avoided by using a column-switching technique. The sensitivity of the assay was excellent for clinical routine analysis, with a detection limit of 0.2 mg/L 5-HIAA. No endogenous or exogenous interference problems arose. Intra- and interassay precision was good, with observed coefficients of variation of 1.5 to 2.6% and 2.1%, respectively. Recoveries were 93 to 98%. The system described can be used for clinical diagnosis and therapy follow-up of carcinoid tumors. It has been running for over a year without disturbances and with a minimum of technical attendance.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030305
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  • 208
    Electronic Resource
    Electronic Resource
    Purification of rat liver soluble catechol-O-methyltransferase by high performance liquid chromatography (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 127-130 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The soluble form of catechol-O-methyltransferase (EC 2.1.1.6.) from rat liver was purified to homogeneity by high-performance anion-exchange chromatography and high-performance gel-filtration chromatography. The specific activity of the final pool was 270 U/mg protein. The purification was 1180-fold and recovery of the enzyme activity was 15%. During this rapid and gentle purification there were no problems with loss of activity, and the estimated half life of the final purified enzyme pool was 5.5 days at +4°C. The only additive used was phenylmethylsulfonylfluoride in the homogenizing buffer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030308
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  • 209
    Electronic Resource
    Electronic Resource
    High performance liquid chromatographic analysis of time-dependent changes in urinary excretion of indoleamines following tryptophan administration (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 157-160 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Analytical conditions of prepurification extraction and HPLC separation were optimized for determination of urinary serotonin and tryptamine. Under optimal conditions, serotonin, tryptamine and an internal standard were extracted with 15% v/v n-propanol in diethyl ether from urine samples alkalized with a phosphate buffer (0.75 mol/L, pH 10.0), and then they were re-extracted into an HCI solution (0.1 mol/L). Purified indoleamines were simultaneously separated by reversed-phase ion-pair HPLC with native fluorescence detection. Urinary serotonin and tryptamine were selectively determined within about 45 min per sample for the whole procedure. Analytical recovery, reproducibility and detection sensitivity were satisfactory for pursuing time-dependent changes in indoleamine levels. Urinary excretion profiles of serotonin and tryptamine in subjects dosed with L-tryptophan were successfully analyzed by our method.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030404
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  • 210
    Electronic Resource
    Electronic Resource
    Masthead (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989) 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030601
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  • 211
    Electronic Resource
    Electronic Resource
    Reversed phase high performance liquid chromatography of glycopeptides (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 241-245 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A practical procedure for isolating and purifying glycopeptides is described, viz. enzymatic hydrolysis - gel permeation chromatography - ion exchange chromatography - reversed phase HPLC. Using this procedure 28 glycopeptides from hen ovalbumin have been isolated some of which hitherto have not been identified. Water was a suitable mobile phase for preparing pure glycopeptides, and control of column temperature was important for good separations and reproducible retention times. Structural confirmation was by fast atom bombardment mass spectrometry.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030603
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  • 212
    Electronic Resource
    Electronic Resource
    A rapid method for isolation of human hemoglobin benzo[a]pyrene diol epoxide derived adducts using high performance liquid chromatography (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 266-268 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A method is described to isolate rapidly human hemoglobin-benzo[a]pyrene diol epoxide adducts. A combination of 300 Å pore size C4 reversed phase HPLC to effect separation of adducted protein from native protein, and μ-bore C18 reversed phase HPLC to isolate and partially characterize proteolytic peptide adducts (by UV), was used.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030608
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  • 213
    Electronic Resource
    Electronic Resource
    Quantitative determination of itazigrel in rodent diet by reversed-phase HPLC and evaluation of its stability at 20°C (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 180-182 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A simple, accurate and precise procedure for the quantitation of itazigrel (a potent lipophilic inhibitor of collagen and arachidonic acid-induced aggregation being studied for its effects on peripheral vascular disease) from granulated rodent diet is presented. The drug was extracted from rodent diet using methanol + water (80:20) following dissolution of the diet in water. Samples of the supernatant were injected into the HPLC and the eluent was monitored with a fluorescent detector (λex = 320 and λem = 430) to achieve analytical specificity. Interday coefficients of variation of the calibration curve slope were ±6% on standards between 0 and 1000 μg/g. Potency and homogeneity of the drug spiked diet prepared over a 1 year interval at 70,200 and 600 μg/g was 99.3 ± 2.5%, 100 ± 1.8%, and 101 ± 1.9% of label, respectively. Samples prepared for chromatography were stable for 24 h at 20°C, and drug in diet was stable for 102 days when protected from light and stored at 20°C.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030409
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  • 214
    Electronic Resource
    Electronic Resource
    Calendar of events (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. i 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030412
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  • 215
    Electronic Resource
    Electronic Resource
    A high performance liquid chromatography/electrochemical assay for glutamatergic neurotransmitters in the rat brain (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 183-185 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The release and content of the excitatory amino acid neurotransmitters glutamate and aspartate in rat striatum were determined by liquid chromatography/electrochemistry. This determination was based on precolumn off-line derivatization of the amino acids with o-phthaldialdehyde and 2-mercaptoethanol (OPT/2-MCE), and the adducts formed were separated under isocratic conditions and oxidized on a glassy carbon electrode at moderate potential (+0.6 V). The standard and the extracted glutamate when derivatized with OPT/2-MCE produced similar electrochemical and chromatographic characteristics. The detection limit of glutamate was 0.5 pmol. Depolarization induced by the high potassium medium (40 mmol/L) enhanced the release of glutamate and aspartate from superfused rat striatum, whereas the efflux of glutamine remained unchanged. Perfusion (for 60 - 70 min) removed 50 - 80% of the free amino acid content of striatal tissue. The method described here is useful in neurochemical investigations of the brain amino acid neurotransmitters.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030410
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  • 216
    Electronic Resource
    Electronic Resource
    High performance liquid chromatography determination of cyanide in urine by pre-column fluorescence derivatization (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 209-212 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A method for the determination of cyanide in human urine has been developed. The method is based on the reaction of cyanide with 2,3-naphthalenedialdehyde and taurine to give a fluorescent product for reversed-phase HPLC separation and fluorometric detection. After centrifugation followed by dilution of urine samples, the specimens could be analysed directly by this method. The recovery of cyanide added to urine at concentration levels of 50 - 1000 pmol/mL was 85 - 96%. The detection limit of cyanide was 30 pmol/mL in urine. The method was successfully applied to the analysis of urine from smokers and nonsmokers. The mean concentrations of cyanide were found to be 215 pmol/mL for the former and 84 pmol/mL for the latter.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030507
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  • 217
    Electronic Resource
    Electronic Resource
    Calendar of events (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. i 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030512
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  • 218
    Electronic Resource
    Electronic Resource
    Solid phase extraction for an improved assay of physostigmine in biological fluids (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 226-232 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A simple, selective and very sensitive assay is described for the quantification of physostigmine in blood, plasma and urine. The most appropriate solid phase column was selected after a systematic investigation of nine types of phase. The conditions for solid phase extraction were optimized using [3H]physostigmine so that the overall recoveries were 〉90%. Physostigmine was retained on alkaline treated cyanopropyl columns and eluted into the minimum volume of methanol, obviating the need for an evaporation step. Extracted samples were quantified by HPLC with a three electrode coulometric detection system. The limit of detection was 50 pg/mL for a 0.5 mL plasma sample. The precision (CV) for 0.5 mL plasma samples containing 50 pg was 8.1%. Application of the method to plasma, blood and urine samples is presented.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030511
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  • 219
    Electronic Resource
    Electronic Resource
    Identification by gas chromatography/mass spectrometry of long-chain fatty acids and alcohols from hamster meibomian glands using picolinyl and nicotinate derivatives (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 251-254 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Meibomian secretions from the hamster were hydrolysed with base and examined as TMS, [2H9]TMS, methyl ester/TMS, picolinyl ester/TMS and nicotinate/TMS derivatives by capillary GC/MS. Over 90 compounds, representing over 89% of the hydrolysed fraction, were identified. Fatty acids with chain lengths from 10 to 32 carbon atoms were found, the most common of these were in the C15 to C18 and in the C25 to C30 regions. Chain types were predominantly iso or anteiso branched, mono-unsaturated (C16 and C18) and straight. Fatty alcohols were mainly from the iso or anteiso series and tended to have longer chain lengths; the major alcohols had anteiso-25 and 27 and iso-26-chains. In these respects the secretions were similar to those reported earlier from other species, although fewer mono-unsaturated compounds with longer chains (C20 to C30 region) were found than in the rat and human. The steroid fraction was characterized by a larger number of compounds than normally present in secretions of this type. The major compound was cholesterol, in common with that in all other examined species except the rabbit.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030605
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  • 220
    Electronic Resource
    Electronic Resource
    High resolution chromatography of ribonucleosides and its application to RNA analysisAbbreviations used. ψ, pseudouridine; D, 5,6-dihydrouridine; m3C, 3-methylcytidine; m1A, 1-methyladenosine; m5C, 5-methylcytidine; m7G, 7-methylguanosine; Cm, 2′-O-methylcytidine; I, inosine; rT, ribothymidine; Um, 2′-O-methyluridine; m1I, 1-methylinosine; m1G, 1-methylguanosine; m2G, 2-N-methylguanosine; m22G, 2-N,N-dimethylguanosine; m6A, 6-N-methyladenosine; Am, 2′-O-methyladenosine; Gm, 2′-O-methylguanosine; Y, a-amino-b-hydroxy-4,9-dihydro-4,6-dimethyl-9-oxo-1-H-imidazole-1,2-a-purine-7-butylic acid; pG, guanosine 5′-phosphate; Gp, guanosine 3′-phosphate; pGp, guanosine 3′,5′-diphosphate. In abbreviations for oligonucleotides, phosphates between nucleosides are excluded, e.g., AGCUp is ApGpCpUp. (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 246-250 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A simple and precise method was developed for the separation of nucleosides including modified nucleosides and oligonucleotides. Nineteen kinds of nucleosides were completely separated by HPLC using an ODS column (TSK-gel ODS 80TM) and aqueous mobile phases. The RNA molecule was digested by base restrictive RNase (RNase A, RNase T1) and the digests were separated chromatographically into each oligonucleotide. The nucleoside composition of an oligonucleotide was then determined by this analytical system. It is thus possible to fit the oligonucleotide in the original RNA molecule by using modified bases as markers. The reaction site of quinacrine mustard for tRNAPhe (from yeast) could be determined by this analytical system.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030604
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  • 221
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    Simultaneous analysis of furosemide and bumetanide in horse plasma using high performance liquid chromatography (1989)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 3 (1989), S. 262-265 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A high performance liquid chromatographic method is described for the simultaneous determination of furosemide and bumetanide in horse plasma. The C8 (3 μm) reversed phase column (4.8 × 150 mm) provided clear separation of furosemide and bumetanide with other components present in the horse plasma. The detection limit for both the drugs was 10 ng/mL. Both drugs were stable in plasma (at natural or acidic pH) for up to 24 h. The method is sufficiently sensitive to detect furosemide levels in plasma obtained from horses receiving a therapeutic dose of furosemide.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130030607
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  • 222
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    Multicomponent determinations by a membrane-discriminated gas phase analyzer and successive regression in the fiduciary region (1989)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 3 (1989), S. 601-608 
    Details
    ISSN: 0886-9383
    Keywords: Gas phase flow injection analysis ; Membrane-differentiated analysis ; Multicomponent determinations ; Successive linear regression ; Successive regression in fiduciary region ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A membrane-discriminated gas phase analyzer is proposed for multicomponent determinations. Nitrogen gas flows countercurrent through outer and inner channels in a tube-in-tube arrangement. The only communication between the two channels occurs through a 500 μm aperture covered by a porous PTFE membrane. A mixture of organic compounds (up to four components) is injected into the inner channel by a heated backflushed injector and the sample components diffusing into the outer channel are monitored by a flame ionization detector (FID). A calibration set, consisting of pure components, binary, ternary and quaternary mixtures (a total of 64 samples), provides the known data base: temporal profiles of the FID output as a function of sample composition. Although the overall response behavior is not a linearly additive function of individual analyte concentrations, the use of successive inverse multiple linear regression (while continually altering the choice of the calibration samples considered for the forward regression, on the basis of the most recent values of the predicted unknown sample composition) is shown to yield analytical results for unknown samples that are in good agreement with their true values.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180030408
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  • 223
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    Product news (1989)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 3 (1989), S. 609-609 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180030409
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  • 224
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    Rebuilding flavodoxin from Cα coordinates: A test study (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 170-182 
    Details
    ISSN: 0887-3585
    Keywords: modeling ; flavodoxin ; structure prediction ; side chains ; database ; structure analysis ; protein ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The tertiary structure of flavodoxin has been model build from only the X-ray crystallographic α-carbon coordinates. Main-Chain atoms were generated from a dictionary of backbone structures. Side-chain conformations were initially set according to observed statistical distributions, clashes were resolved with reference to other knowledge-based parameters, and finally, energy minimization was applied. The RMSD of the model was 1.7 Å across all atoms to the native structure. Regular secondary structural elements were modeledmore accurately than other regions. About 40%of the ξ1 torsional angles were modeled correctly. Packing of side chains in the core was energetically stable but diverged significantly from the native structure in some regions.The modeling of protein structures is increasing in popularity but relatively few checks have been applied to determine the accuracy of the approach. In this work a variety of parameters have been examined. It was found that close contact, and hydrogen-bonding patterns could identifypoorly packed residues. These tests, however, did not indicate which residues had a conformation different from the native structure or how to move such residues to bring them into agreement. To assist in the modeling of interacting side chains a database of known interactions has been prepared.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340050212
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    The 15 N-terminal amino acids of hexokinase II are not required for in vivo function: Analysis of a truncated form of hexokinase II in Saccharomyces cerevisiae (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 218-223 
    Details
    ISSN: 0887-3585
    Keywords: yeast hexokinase II ; dimerization ; in vivo functions ; glucose repression ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The function of the N-terminal amino acids of Saccharomyces cerevisiae hexokinase II was studied in vivo using strains producing a form of hexokinase II lacking its first 15 amino acids (short form).This short form of hexokinase II was produced from a fusion between the promoter region of the PGK1 gene and the HXK2 coding sequence except the first 15 codons. As expected, the in vitro analysis of the short from protein by gel filtration chromatography indicates that the short protein does not form dimers under conditions where the wild-type protein dimerizes. Kinetic studies show that the enzymatic activities are very similarto wild-type behavior. The physiological experiments performed on the strains containing the fusion allele demonstrate that the short form ofthe enzyme is similar to the wild-type both in terms of phosphorylation of hexoses and glucose repression. We conclude that the N-terminalamino acids of hexokinase II are not required in vivo either for phosporylation of hexoses or for glucose repression.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340050305
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    Electrostatic effects in a large enzyme complex: Subunit interactions and electrostatic potential field of the icosahedral β60 capsid of heavy riboflavin synthase (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 248-257 
    Details
    ISSN: 0887-3585
    Keywords: subunit interactions ; icosahedral capsid ; electrostatic potential ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The role of the electrostatic interactions in the stability of the icosahedral β60 capsid of heavy riboflavin synthase from Bacillus Subtilis has been investigated using an approach based on the theory of Kirkwood and Tanford. The pH dependence of the electrostatic subunit interaction agrees well with experimental data. The electrostatic subunit interaction energy has a pronounced minimum at pH 8.2 for both the ligated and ligand-free capsid. The latter is characterized by a reduction of the magnitude and the pH range of the electrostatic attraction. It is found that only 8 charged groups, which form one cluster and two ion pairs, provide a significant contribution to the capsid stability. The analysis has shown that the aggregation/disaggregation equilibrium seems to be regulated by electrostatic interactions between β-subunits forming dimers, which connect the relatively stable pentamers in the β-60 capsid. The release of the ligand causesareduction of the electrostatic attraction of the dimers, which may induce disaggregation of the capsid. The electrostatic potential field due tothe titratable groups and α-helix macrodipoles has been calculated on the basic of the Coulomb relation. Two different values of the dielectric constant have been used for the protein and the surrounding solvent, respectively. The electrostatic potential shows a radially polardistribution with a positive pole at the inner capsid wall and a negative pole outside the capsid. An interesting feature of the electrostatic field is the formation of the positive potential “channels” that coincide with the channels constituted by the pentameric and trimeric β-subunit aggregates. It is supposed that the electrostatic potential field plays a role in enzyme-substrate recognition.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340050308
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    PKB: A program system and data base for analysis of protein structure (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 233-247 
    Details
    ISSN: 0887-3585
    Keywords: protein folding ; crystallographic data base ; structural analysis ; computer program system ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: PKB is a computer program system that combines a data base of three-dimensional protein structures with a series of algorithms for pattern recognition, data analysis, and graphics. By typing relatively simple commands the user may search the data base for instances of a structural motif and analyze in detail the set of individual structures that are found. The application of PKB to the study of protein folding is illustrated in three examples. The first analysis compares the conformations observed for a short sequential motif, sequences similar to the cell-attachment signal Arg-Gly-Asp. The second compares sequences observed for a conformational motif, a 16-residue βαβ unit. The third analysis considers a population of substructures containing ion-pair interaction, examining the relationship offrequency of occurrence to calculated electrostatic energy.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340050307
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    Masthead (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989) 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060301
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    In memoriam: Irving S. Sigal 1953-1988 (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 217-221 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: No abstract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060303
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    Characterization and autoprocessing of precursor and mature forms of human immunodeficiency virus type 1 (HIV 1) protease purified from Escherichia coli (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 139-154 
    Details
    ISSN: 0887-3585
    Keywords: retrovirus ; bacterial expression ; high-performance liquid chromatography ; NH2- and COOH-terminal sequence analysis ; kcat ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A recombinant plasmid encompassing the human immunodeficiency virus type 1 (HIV 1) protease coding sequence and flanking regions (Ala-13 to Gly-185 of the pol open reading frame) has been expressed in two distinct strains of Escherichia coli, AR58 and AR68. In the first strain, AR58, the primary translation product, a 25 kilodalton (kDa) precursor protein, is short-lived and rapidly processes itself to the 11 kDa mature protease in vivo. In the second strain, AR68, the 25 kDa species isonly partially processed, and it, a 13 kDA intermediate, and the mature 11 kDA enzyme accumulate at a ratio of 3:4.5:2.5, respectively. The 11 kDa mature protease from AR58 and the 25 kDa precursor from AR68 have been purified to homogeneity. The yield of 11 kDa enzyme from AR58 is approximately 0.02 mg/g wet weight of E. coli cell pellet. The protease has both the expected NH2- and COOH-terminal sequences. The yield of 25 kDa enzyme from AR68 is approximately 0.1 mg/g wet weight of E. coli cell pellet. In vitro, the 25 kDa precursor enzyme rapidly (t1/2≅ 9 min) processes itself into a species with a mass of ∼13kDa and a species with a mass of ∼11 kDa. Both of these latter species can be separated by RP-HPLC, have the NH2-terminal sequence expected for the mature protease, and are active. The 11 kDa enzyme from AR58 comigrates with the 11 kDa enzyme from AR68 on RP-HPLC and SDS poly acrylamide gel electrophoresis. On extended incubation at 4°C at either neutral or acidic pH all species of the proteinexhibit further autodegradation at defined sequences. The availability of the mature, 11 kDa enzyme and the 25 kDa precursor will allow biochemical and physical studies on this critical viral enzyme.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340060205
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    Editor's Note (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 215-215 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060302
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    Hydrolysis of GTP by the α-chain of Gs and other GTP binding proteins (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 222-230 
    Details
    ISSN: 0887-3585
    Keywords: G proteins ; p21ras ; GTPase ; cholera toxin ; GTPase-activating protein ; amino acid sequence ; protein structure ; conformational change ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The functions of G proteins - like those of bacterial elongation factor (EF) Tu and the 21 kDa ras proteins (p21ras) - depend upon their abilities to bind and hydrolyze GTP and to assume different conformations in GTP- and GDP-bound states. Similarities in function and amino acid sequence indicate that EF-Tu, p21ras, and G protein α-chains evolved from a primordial GTP-binding protein. Proteins in all three families appear to share common mechanisms for GTP-dependent conformational change and hydrolysis of bound GTP. Biochemical and molecular genetic studies of the α-chain of Gs (αs) point to key regions that are involved in GTP-dependent conformational change and in hydrolysis of GTP. Tumorigenic mutations of αs in human pituitary tumors inhibit-the protein's GTPase activity and cause constitutive elevation of adenylyl cyclase activity. One such mutation replaces a Gln residue in αs that corresponds to Gln-61 of p21ras; mutational replacements of this residue in both proteins inhibit their GTPase activities. A second class of the GTPase inhibiting mutations in αs occurs in the codon for an ARG residue whose covalent modification by cholera toxin also inhibits GTP hydrolysis by αs. This Arg residue is located in a domain of αs not represented in EF-Tu or p21ras. We propose that this domain constitutes an intrinsic activator of GTP hydrolysis, and that it performs a function analogous to that performed for EF-Tu by the programmed ribosome and for p21ras by the recently discovered GTPase-activating protein. Owing to their inherited similarities of structure and function, what we learn about αs, p21ras, or EF-tu as individual molecules helps us to understand crucial functions of other members of the super-family.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340060304
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    Genetic analysis of the molecular basis for β-adrenergic receptor subtype specificity (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 267-274 
    Details
    ISSN: 0887-3585
    Keywords: β-adrenergic recepor ; chimeric proteins ; receptor subtypes ; ligand binding ; protein structure-function ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Pharmacological analysis of ligand binding to the β-adrenergic receptor (βAR) has revealed the existence of two distinct receptor subtypes (β1 and β2) which are the products of different genes. The predicted amino acid sequence of the β1 and β2 receptors differ by 48%. To identify the regions of the proteins responsible for determining receptor subtype, chimeras were constructed from domains of the human β1 and hamster β2 receptors. Analyses of the ligand-binding characteristics of these hybrid receptors revealed that residues in the middle portion of the βAR sequence, particularly around transmembrane regions 4 and 5, contribute to the subtype specific binding of agonists. Smaller molecular replacement of regions of the hamster β2AR with the analogous regions from the avian β1AR, however, failed to identify any single residue substitution capable of altering the subtype specificity of the receptor. These data indicate that, whereas sequences around transmembrane regions 4 and 5 may contribute to conformations which influence the ligand-binding properties of the receptor, the subtype-specific differences in amine-substituted agonist binding cannot be attributed to a single molecular interaction between the ligand and any amino acid residue which is divergent between the β1 and β2 receptors.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340060309
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    Structural determinants of the conformations of medium-sized loops in proteins (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 382-394 
    Details
    ISSN: 0887-3585
    Keywords: immunoglobulins ; hydrogen bonding ; hairpin loops ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Loops are integral components of protein structures, providing links between elements of secondary structure, and in many cases contributing to catalytic and binding sites.The conformations of short loops are now understood to depend primarily on their amino acid sequences. In contrast, the structural determinants of longer loops involve hydrogen-bonding and packing interactions within the loop and with other parts of the protein. By searching solved protein structures for regions similar in main chain conformation to the antigen-binding loops in immunoglobulins, we identified medium-sized loops of similar structure in unrelated proteins, and compared the determinants of their conformations.For loops that form compact substructures the major determinant of the conformation is the formation of hydrogen bonds to inward-pointing main chain atoms. For oops that have more extended conformations, the major determinant of their structure is the packing of a particular residue or residues against the rest of the protein.The following picture emerges: Medium-sized lops of similar conformation are stabilized by similar interaction. The groups that interact with the loop have very similar spatial dispositions with respect to the loop. However, the residues that provide these interactions may arise from dissimilar parts of the protein: The conformation of the loop requires certain interactions that the protein may provide in a variety of ways.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060405
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    Effect of protein conformation on rate of deamidation: Ribonuclease A (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 8-12 
    Details
    ISSN: 0887-3585
    Keywords: ribonuclease A ; protein deamidation ; protein conformation ; disulfide bonds ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The effect of the folded conformation of a protein on the rate of deamidation of a specific asparaginyl residue has been determine. Native and unfolded ribonuclease A (RNase A) could be compared under identical conditions, because stable unfolded protein was generated by breaking irreversibly the protein disulfide bonds.Deamidation of the labile Asn-67 residue of RNase A was followedelectrophoretically and chromatographically. At 80°C, similar rates of deamidation were observed for the disulfidebonded form, which is thermally unfolded, and the reduced form. At 37°C and pH 8, however, the rate of deamidation of native RNase A was negligible, and was more than 30-fold slower than that of reduced, unfolded RNase A. This demonstrates that the Asn-67 residue is located in a local conformation in the native protein that greatly inhibits deamidation. This conformation is the β-turn of residues 66-68.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340050103
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    Further studies of the helix dipole model: Effects of a free α-NH3+ or α-COO- group on helix stability (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 1-7 
    Details
    ISSN: 0887-3585
    Keywords: helix stabilization ; helix dipole ; charged group ; pH titration ; electrostatic interaction ; hydrogen bonding ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Interactions between the α-helix peptide dipoles and charged groups close to the ends of the helix were found to be an important determinant of α-helix stability in a previous study.1 The charge on the N-terminal residue of the C-peptide from ribonuclease A was varied chiefly by changing the α-NH2 blocking group, and the correlation of helix stability with N-terminal charge was demonstrated. An alternative explanation for some of those results is that the succinyl and acetyl blocking groups stabilize the helix by hydrogen bonding to an unsatisfied main-chain NH group. The helix dipole model is tested here with peptides that contain either a free α-NH3+ α-COO- groups, and no other charged groups that would titrate with similar pKa's. This model predicts that α-NH3α-COO- groups are helix-destabilizingand that the destabilizing interactions are electrostatic in origin. The hydrogen bonding model predicts that α-NH3 and α-COO- groups are not themselves helix-destabilizing, but that an acetyl or amide blocking group at the N- or C- terminus, respectively, stabilizes the helix by hydrogen bonding to an unsatisfied main-chain NH or CO group.The results are as follows: (1) Removal of the charge from α-NH3 and α-COO- groups by pH titration stabilizes an α-helix. (2) The increase in helix stability on pH titration of these groups is close to the increase produced by adding an acetyl or amide blocking group. (3) The helix-stabilizing effect of removing the charge from α-NH3 and α-COO- groups by pH titration is screened by increasing the NaCl concentration, and therefore the effect is electrostatic in origin. (4) Replacing the C-terminal amide blocking group with a methylester blocking group, which cannot donate a hydrogen bond, causes little change in helix stability.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340050102
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    The construction of new proteins: V. A template-assembled synthetic protein (TASP) containing both a 4-helix bundle and β-barrel-like structureFor Part IV see Ref. 29. (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 13-21 
    Details
    ISSN: 0887-3585
    Keywords: template-assembled synthetic protein (TASP) ; 4-helix bundle ; β-barrel structure ; protein de novo design ; peptide synthesis ; peptide conformation ; orthogonal protection ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The construction of a template-assembled synthetic protein (TASP) designed to contain both a 4-helix bundle and a β-barrel as two folding “domains” is described. For the de novo design of proteins, amphiphilic helices (α) and β-sheets (β) are covalently attached to a template peptide (T) carrying functional side chains suitably oriented to promote intarmolecular folding of the secondary structure blocks into a characteristic packing arrangement, i.e., T8-(4α)(4β). The design of this new macromolecule was assisted by computer modeling, which suggested a low-energy conformation with tight hydrophobic packing of the secondary structure subunits. Solid-phase synthesis of the “two-domain” TASP molecule was achieved using orthogonal protection techniques. The solution properties as well as circular dichroism (CD) and infrared spectroscopy (IR) data under various experimental conditions are consistent with the folded conformation suggested by modeling.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340050104
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    Molecular dynamics effects on protein electrostatics (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 313-321 
    Details
    ISSN: 0887-3585
    Keywords: protein ; electron transfer ; molecular dynamic simulations ; dielectric ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Electrostatic calculations have been carried out on a number of structural conformers of tuna cytochrome c Conformers were generated using molecular dynamics simulations with a range of solvent simulating, macroscopic dielectric formalisms, and one solvent model that explicitly included solvent water molecules. Structures generated using the lowest dielectric models were relatively tight, with-side chains collapsed on the surface, while those from the higher dielectric modelshad more internal and external fluidity, with surface side chains exploring a fuller range of conformational space. The average structure generated with the explicitly solvated model corresponded most closely with the crystal structure. Individual pK values, overall titration curves, and electrostatic potential surfaces were calculated for average structures and along each simulation. Differences between structural conformers within each simulation give rise to substantial changes in calculated local electrostatic interactions, resulting in pK value fluctuations for individual sites in the protein that very by 0.3-2.0 pK units from the calculated time average. These variations are due to the thermal side chain reorientations that produce fluctuations in charge site separations. Properties like overall titration curves and pH dependent stability are not as sensitive to side chain fluctuations within a simulation, but there are substantial effects between simulation due to markeddifferences in average side chain behavior. These findings underscore the importance of proper dielectric formalism in molecular dynamics simulations when used to generate alternate solution structures from a crystal structure, and suggest that conformers significantly removed from the averagestructure have altered electrostatic properties that may prove important inepisodic protein properties such as catalysis.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340050407
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    A molecular dynamics analysis of protein structural elements (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 337-354 
    Details
    ISSN: 0887-3585
    Keywords: computer simulation ; fluctuations in proteins ; secondary structural dynamics ; lysozyme ; protein-substrate complex ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The relation between protein secondary structure and internal motions was examined by using molecular dynamics to calculate positional fluctuations of individual helix, β-sheet, and loop structural elements in free and substrate-bound hen egg-white lysozyme. The time development of the fluctuations revealed a general correspondence between structure and dynamics; the fluctuations of the helices and β-sheets converged within the 101 psec period of the simulation and were lower than average in magnitude, while the fluctuations of theloop regions were not converged and were mostly larger than average in magnitude. Notable exceptions to this pattern occurred in the substrate-bound simulation. A loop region (residues 101-107) of the active site cleft had significantly reduced motion due to interactions withthe substrate. Moreover, part of a loop and a 310 helix (residues of 67-88) not in contact with the substrate showeda marked increase in fluctuations. That these differences in dynamics of free and substrate-bound lysozyme did not result simply from sampling errors was established by an analysis of the variations in the fluctuationsof the two halves of the 101 psec simulation of free lysozyme. Concerted transitions of four to five mainchain φ and ψ angles between dihedral wells were shown to be responsible for large coordinate shifts in the loops. These transitions displaced six or fewer residues and took place eitherabruptly, in 1 psec or less, or with a diffusive character over 5-10 psec. Displacements of rigid secondary structures involved longer timescale motions in bound lysozyme; a 0.5 Å rms change in the position of a helix occurred over the 55 psec simulation period. This helix reorientation within the protein appears to be a response to substrate binding. There was little correlation between the solvent accessible surface areaand the dynamics of the different structural elements.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340050409
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    The effects of truncating long-range forces on protein dynamics (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 32-45 
    Details
    ISSN: 0887-3585
    Keywords: long range truncation ; molecular dynamics ; myoglobin ; truncation effects ; protein electrostatics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This paper considers the effects of truncating long-range forces on protein dynamics. Six methods of truncation that we investigate as a function of cutoff criterion of the long-range potentials are (1) a shifted potential; (2) a switching function; (3) simple atom-atom truncation based on distance; (4) simple atom-atom truncation based on a list which is updated periodically (every 25 steps); (5) simple group-group truncation based on distance; and (6) simple group-group truncation based on a list which is updated periodically (every 25 steps). Based on 70 calculations of carboxymyoglobin we show that the method and distance of long range cutoff have a dramatic effect on overall protein behavior. Evaluation of the different methods is based on comparison of a simulation's rms fluctuation about the average coordinates of a no cutoff simulation and from the X-ray structure of the protein. The simulations in which long-range forces are truncated by a shifted potential shows large rms deviations for cutoff criteria less than 14 Å, and reasonable deviations and fluctuations at this cutoff distance or larger. Simulations using a switching function are investigated by varying the range over which electrostatic interactions are switched off. Results using a short switching function that switches off the potential over a short range of distances are poor for all cutoff distances. A switching function over a 5-9 Å range gives reasonable results for a distance-dependent dielectric, but not using a constant dielectric. Both the atom-atom and group-group truncation methods based on distance shows large rms deviations and fluctuation for short cutoff distance, while for cutoff distance of 11 Å or greater, reasonable results are achieved. Although comparison of these to distance-based truncation methods show surprisingly larger rms deviations for the group-group truncation, contrary to simulation studies of aqueous ionic solutions. The results of atom-atom or group-group list-based simulations generally appear to be less stable than the distance-based simulations, and require more frequent velocity scaling or stronger coupling to a heat bath.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340060104
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    Computational and site-specific mutagenesis analyses of the asymmetric charge distribution on calmodulin (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 70-85 
    Details
    ISSN: 0887-3585
    Keywords: Protein electrostatics ; protein kinases ; effector protein ; calciumbinding protein ; α-helix ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Calmodulin's calculated electrostatic potential surface is asymmetrically distributed about the molecule. Concentrations of uncompensated negative charge are localized near certain α-helices and calcium-binding loops. Further calculations suggest that these charge features of calmodulin can be selectively perturbed by changing clusters of phylogenetically conserved acidic amino acids in helices to lysines. When these cluster charge reversals are actually produced by using cassette-based site-specific mutagenesis of residues 82-84 or 118-120, the resulting proteins differ in their interaction with two distinct calmodulin-dependent protein kinases, myosin light chain kinase and calmodulin-ldependent protein kinase II. Each calmodulin mutant can be purified to apparent chemical homogeneity by an identical purification protocol that is based on conservation of its overall properties, including calcium binding. Although cluster charge reversals result in localized perturbations of the computed negative surface, single amino acid changes would not be expected to alter significantly the distribution of the negative surface because of the relatively high density of uncompensated negative charges in the region around residues 82-84 and 118-120. However, this does not preclude the possibility of single amino acid charge perturbations having a functional effect on the more intimate, catalytically active complex. The electrostatic surface of calmodulin described in this report may be a feature that would be altered only by cluster charge reversal mutations. Overall, the results suggest that the charge properties that are important for the efficient assembly of calmodulin-protein kinase signal transduction complexes in eukaryotic cells.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340060107
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    Comparing short protein substructures by a method based on backbone torsion angles (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 155-167 
    Details
    ISSN: 0887-3585
    Keywords: protein structure comparison ; dihedral angles ; protein conformation ; hemoglobin structure ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An efficient algorithm was characterized that determines the similarity in main chain conformation between short protein substructures. The algorithm computes Δt, the root mean square difference in φ and ψ torsion angles over a small number of amino acids (typically 3-5). Using this algorithm, large number of protein substrates comparisons were feasible. The parameter Δt was sensitive to variations in local protein conformation, and it correlates with Δr, the root mean square deviation in atomic coordinates. Values for Δt were obtained that define similarity thresholds, which determine whether two substructure are considered structurally similar. To set a lower bound on the similarity threshold, we estimated the component of Δt due to measurement noise fromcomparisons of independently refined coordinates of the same protein. A sample distribution of Δt from nonhomologous protein comparisons identified an upper bound on the similarity threshold, one that refrains from incorporating large numbers of nonmatching comparisons large numbers of nonmatching comparisons. Unlike methods based on Cα atoms alone, Δt was sensitive to rotations in the peptide plane, shown to occur in several proteins. Comparisons of homologus proteins by Δt showed that the active site torsion angles are highly conserved. The Δt method was applied to the α-chain of human hemoglobin, where it readily demonstrated the local differences in the structures of different ligation states.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060206
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    A computer model to dynamically simulate protein folding: Studies with crambin (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 193-209 
    Details
    ISSN: 0887-3585
    Keywords: protein folding ; simulated annealing ; empirical potentials ; Monte Carlo dynamics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The current work describes a simplified representation of protein structure with uses in the simulation of protein folding. The model assumes that a protein can be represented by a freely rotating rigid chain with a single atom approximately the effect of each side chains. Potentials describing the attraction or repulsion between different types of amino acids are determined directly from the distribution of amino acids in the database of known protein structures. The optimization technique of simulated annealinghas been used to dynamically sample the conformations available to this sample model, allowing the protein to evolve from an extended, random coil into a compact globular structure. Many characteristics expected of true proteins, such as the sequence-dependent formation of secondary structure, the partitioning of hydrophobic residues, and specific disulfide, suggestion the model may accurately simulate the folding process.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060208
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    The carboxyl terminal domain of Escherichia coli DNA topoisomerase I confers higher affinity to DNA (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 249-258 
    Details
    ISSN: 0887-3585
    Keywords: DNA binding domain ; etheno-M13 DNA ; single-stranded DNA affinity chromatography ; proteolytic fragments ; truncated topoisomerase ; protein-DNA interaction ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Limited digestion of E. coli DNA topoisomerase I with trypsin or papain generated a DNA-binding domain of MW 14,000 corresponding to the carboxyl terminal of the enzyme. This fragment binds to single-stranded DNA agarose as tightly as the intact enzyme. It required around 400 mM NaCl for elution. A truncated topoisomerase that lacks this C-terminal domain was purified. It was eluted from the single-stranded DNA agarose column at around 150 mM NaCl. Although the truncated enzyme could relax negatively supercoiled DNA as efficiently as the intact enzyme at low ionic strength, its processivity was more sensitive to increasing salt concentration. Measurement of binding to fluorescent etheno-M13 DNA also demonstrated that the presence of the C-terminal domain confers higher affinity to DNA for the enzyme.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060307
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    Substrate specificities in class A β-lactamases: Preference for penams vs. cephams. The role of residues 237 (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 275-283 
    Details
    ISSN: 0887-3585
    Keywords: mutagenesis ; structure-function relationships ; enzymatic catalysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Site saturation mutagenesis has been carried out at Ala-237 in RTEM-1 β-lactamase to assess the role of this site in modulating differences in specificity of β-lactamases for penams vs. cephams as substrates. (An Ala-237 Thr mutation had previously been shown to increase activity on cephems by about 30-80%.1,2) Screening of all 19 possibles mutants on penams and cephems revealed the even more active Ala-237 Asn mutant. Detailed kinnetic analysis showns that this mutant has about four times the activity toward cephalothin and cephalosporin C as the wild-type enzyme. Both mutations reduce the activity toward penams to about 10% that of RETM-1 β-lactamase and lower by about 5°C the tempreature at which the enzyme denatures. Functional properties of the other mutants have also been surveyed. The most intresting aspect of these results is that two quite disparate amino acids, theronine and asparagine, when intorduced for Ala-237, cause such similar changes in enzyme specificity while more similar residues do not alter the catalytic properties of the enzyme to such a significant degree.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340060310
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    Axial ligand replacement in horse heart cytochrome c by semisynthesis (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 338-340 
    Details
    ISSN: 0887-3585
    Keywords: cytochrome c ; axial ligand ; semisynthesis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Semisynthesis has been employed to replace the axial methionine in horse heart cytochrome c with histidine. The reduction potential of the His-80 protein (cyt c-His-80) is 41 mV vs NHE (0.1 M phosphate; pH 7.0; 25°C). The absorption spectra of oxidized and reduced cyt c-His-80 are very similar to those of the native protein in the porphyrin region, but the 695 nm band is absent in the oxidized His-80 protein.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060316
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    Masthead (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989) 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060401
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  • 248
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    Deletions and replacements of omega loops in yeast iso-1-cytochrome c (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 372-381 
    Details
    ISSN: 0887-3585
    Keywords: cytochromec ; Saccharomyces cerevisiae ; protein secondary structures ; protein design ; protein engineering ; protein folding ; protein evolution ; modular exchange ; loop swap ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ω(Omega)-loops are protein secondary structural elements having small distance between segment termini. It should be possible to delete or replace certain of these Ω-loops without greatly distorting the overall structure of the remaining portion of the molecule. Functional requirements of regions of iso-1-cytochrome c from the yeast Saccharomyces cerevisiae were in investigated by determining the biosynthesis and activity in vivo of mutant forms in which four different Ω-loops were individually deleted, or in which one Ω-loop was replaced with five different segments. Deletion encompassing amino acid positions 27-33 and79-83 either prevented synthesis of the holoprotein, or produced highly labile iso-1-cytochromes c, whereas deletions encompassing position 42-45 and 48-55 allowed partial synthesis and activity. These two latter regions, therefore, are not absolutely required for any biosynthetic process such as heme attachment, mitochondrial import, or for enzymatic interactions. All replacements in Loop A (residue position 24-33) with the same size (10 amino acid residues), longer (13 and 15 amino acid residues), or shorter segments (6 amino acid residues), resulted in strains having at least partial levels of iso-1-cytochrome c; however, the relative activities ranged from zero to almost the normal level. Thus, Loop A does not appear to be essential for such biosynthetic steps as heme attachment and mitochondrial import. In contrast, the full range of relative activities suggest that this region interacts with physiological partners to carry out efficient electron transport.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340060404
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    The surface area of monomeric proteins: Significance of power law behavior (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 418-423 
    Details
    ISSN: 0887-3585
    Keywords: accessible area ; power law fit ; bootstrap analyses ; fractal structure ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The coefficients in a power low fit of accessible area versus molecular weight for high-reslution monomeric protein structures are assessed with respect to statistical accuracy using bootstrap analyses, and with respect to physical significance using model systems and the concept of roughness or fractal structure of the protein surface.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060408
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    Measurement of mevalonate in human plasma and urine by multiple selected ion monitoring (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 174-176 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma levels and urinary excretion of mevalonate were reported to be correlated with cholesterol biosynthesis. Evaluation of mevalonate concentration in plasma and urine represents therefore a non-invasive method for studying the modifications of cholesterol synthesis. A method is described here by wich mevalonate in plasma and urine is determined by the selected ion monitoring technique after extraction as mevalonolactone and conversion into the trimethylsilyl ether. Linear responses were obtained in the evaluation of mevalonate added to plasma in the 10-100 ng/ml (r 〉 0.995) and to urine in the 50-1000 ng/ml concentration ranges, respectively. Identity of mevalonate in plasma and urine was confirmed by high-resolution mass spectrometry.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180305
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    Fast atom bombardment of metal-pyochelin complexes: Metastable analysis at constant B/E of zinc-pyochelinMention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the US Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 185-191 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fast atom bombardment (FAB) mass spectrometry was used to characterize the pyochelin complexes of iron and zinc. Ferripyochelin readily forms the [M + H]+ and [2M + H]+ ions in a glycerol matrix. The molecular ion was 2.5 fold more abundant when acetic acid was present. Iron was shown to be present in the iron-pyochelin complex as the ferric ion by wet chemical methods. Differentiation between ferric and ferrous ions by FAB was not successful owing to the FAB reducing environment. Ferric ions were reduced by FAB to ferrous ions in the following model salts - ferric chloride, ferric nitrate and ferric sulfate - when dissolved in either glycerol, thioglycerol or the magic bullet matrix. Ferric and ferrous chloride salts gave virtually identical spectra with a glycerol/acetic acid matrix. Zinc-pyochelin readily forms the [M + H]+ and [2M + H]+ ions, but only when acetic acid was present in the glycerol matrix. The FAB mass spectrum of zinc-pyochelin exhibited various fragmentations which can be used in structural analysis. Linked-scan at constant B/E and accurate mass data were used to characterize the fragmentations of the zinc-pyochelin complex. Metastable analysis allowed the fragmentation pathway of zinc-pyochelin to be determined.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180307
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    Electron impact mass spectrometry of BHT and its alteration products (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 207-217 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact (EI) mass spectra of 2,6-di-tert-butyl-4-methylphenol (BHT) and certain of its alteration products are described in detail. Accurate mass measurements confirm the elemental compositions of important fragment ions in the EI spectra. Collisionally activated mass spectra are also used to study fragmentation and suggest common ion structures. The reference spectra provide the basis for identifying various alteration products of BHT by capillary gas chromatography/mass spectrometry (GC/MS) without the necessity of isolating individual components. Application of GC/MS is made to three studies: (i) pyrolysis of hydroperoxy-BHT as a potential pathway to alteration products in food; (ii) GC/MS pyrolysis of hydroperoxy-BHT as a model study; and (iii) alteration of BHT in ethanol/water as a food-simulating solvent.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180310
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    Fast atom bombardment mass spectrometry of the D-aldohexoses and some deoxyaldohexoses (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 363-372 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The MI and CA spectra of selected positive and negative ions generated by fast atom bombardment (FAB) of the stereoisomeric aldohexoses can be used to differentiate among these isomers, without prior derivatization or addition of other substances. The main fragmentation routes were traced and compared to those of some 2- and 6-deoxyaldohexoses, which appeared to be suitable model compounds. In both positive and negative ion FAB mass spectrometry, the OH group at the C-2 position plays an important role in the fragmentation reactions of the pseudomolecular [M + glycerol + H]+ and [M - H]- ions.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180603
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    Rapid identification of calbindin-D28k cyanogen bromide peptide fragments by plasma desorption mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 387-393 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chicken intestinal calbindin-D28k is an intracellular protein which is believed to have a fundamental role in vitamin D-mediated transport of calcium. A mapping approach based on 252Cf plasma desorption mass spectrometry (PD mapping) was used to screen the DNA-deduced sequence of calbindin-D28k for sequence changes and posttranslational modifications. In the PD mapping experiment, purified calbindin-D28k was cleaved with cyanogen bromide and the resulting peptides were subjected to PD mass spectrometric analysis either as a mixture or as high-performance liquid chromatography isolated fractions. The DNA-derived primary structure of calbindin-D28k was confirmed by rapid PD mass spectral identification of the CNBr peptide fragments, and the nature of the N-terminal blocking group was readily determined to be an acetyl group. The relatively non-destructive nature of the PD mass spectrometric analysis allowed the mapping of the N-terminal peptide through an additional in situ V8 protease enzymatic reaction.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180605
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    Rapid determination of sequence variations in actinidin isolated from Actinidia chinensis (var. Hayward) using fast atom bombardment mapping mass spectrometry and gas phase microsequencing (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 424-428 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A current limitation in the use of fast atom bombardment (FAB) mass spectrometric mapping of peptide mixtures, derived from enzymic digestion of proteins, is that most of the hydrophilic peptides are not observed. However, it has been demonstrated from previous work that esterification of the peptide mixture results in the detection of almost all peptides in FAB mass spectrometry. This strategy of FAB mapping was applied to the protein actinidin, isolated from an Italian variety of Actinidia chinensis. Two of the 12 tryptic peptides in FAB mass spectrometry did not exhibit molecular ions predicted from the known sequence of actinidin isolated from the New Zealand variety of A. chinensis. The two peptides were isolated by high-performance liquid chromatography, subjected to Staphylococcus aureus V8 protease digestion and sequenced by gas-phase microsequencing. Nine changes in amino acid composition were detected using the rapid and powerful combination of FAB mass spectrometric mapping and gas-phase microsequencing.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180611
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    Studies on anabolic steroids II - gas chromatographic/mass spectrometric characterization of oxandrolone urinary metabolites in manFor Part I see Ref. 1. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 429-438 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism of 17α-methyl-17β-hydroxy-2-oxa-5α-androstan-3-one (oxandrolone) in man has been investigated by gas chromatography/mass spectrometry. After oral administration of a 10 mg dose to man, five metabolites were detected in the free fraction of the urinary samples. Oxandrolone, the major compound excreted in urine, was detected within 72 h after administration. During this period 35.8 and 8.4% of the administered dose was excreted as unchanged oxandrolone and 17-epioxandrolone, respectively. In addition, minute amounts of 16α- and 16β- hydroxyoxandrolone and a δ-hydroxy acid resulting from the hydrolysis of the lactone group of oxandrolone were detected in the urine samples 8-60 h after administration. Furthermore, the susceptibility of oxandrolone to hydrolysis was investigated under several pH conditions. Extraction and fractionation of steroidal metabolites was achieved by using C18 and silica Sep Pak™ chromatography. The mass spectra of the metabolites are presented and major fragmentation pathways discussed.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180612
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    Gas chromatographic and gas chromatographic/tandem mass spectrometric characterization of precursors on the sesterterpene pathway for steroid biosynthesis (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 572-575 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An increasing amount of evidence is accumulating to support the proposal that steroidogenesis can occur by a sesterterpene pathway as well as the cholesterol pathway. Key intermediates on the sesterterpene pathway are 23,24-dinor-5-cholen-3β-ol (guneribol) and some of its metabolites, e.g. 23,24-dinor-4-cholen-3-one (guneribone). It has been reported that these intermediates are biosynthesized and converted to steroid hormones by a range of endocrine tissues in vitro. Monitoring the pentafluorobenzyloxime derivatives by negative ion chemical ionization mass spectrometry in the electron capture mode provided evidence for the presence of guneribone in extracts of bovine testicular and human adrenal tumour tissue. Complementary evidence was obtained from gas chromatographic/tandem mass spectrometric data generated on a triple-quadrupole instrument by monitoring daughter ions (in the multiple ion detection, MID mode) of the molecular anion of derivatized guneribone in both standards and tissue extracts. The present findings that sesterterpene pathway intermediates are present as endogenous compounds in tissue extracts, together with the previously reported radiochemical data, give further support to the sesterterpene pathway hypothesis.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180811
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    Determination of cyclic butylboronate esters of some 1,2- and 2,3-diols in plasma by high-resolution gas chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 592-597 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic/mass spectrometric analytical procedure is described to determine glycols in plasma as cyclic butyl boronate esters. The method, involving a pre-deproteinization step, required only 0.25 ml of plasma and a short time (20 min) to react with the derivatizing agent (butyl boronic acid). The gas chromatographic separation on a CP Sil 8 CB silica capillary column coupled to a mass detector assured a complete identification of the compounds. The analytical recoveries (〉95%) with low coefficient of variation (4-11%) assured the feasibility of the method over a concentration range from 5 to 1000 μg ml-1 for each glycol. The lower detection limits, namely 1-5 μg ml-1, confirmed the sensitivity of the method.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180814
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    Isotope labelling of lipids using the Favorsky rearrangement (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 603-612 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of tetradeuterated 10-methylundecanoic acid, dideuterated tetracos-2-enoic acid, (1-14C)pristanic acid and (1-14C)tetracos-2-enoic acid using the Favorsky rearrangement are described. They will be used for studies of long-chain fatty acid metabolism in patients. The positions of isotope labelling were determined by mass spectrometry.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180816
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    Structure analysis of modified oligodeoxyribonucleotides by negative ion fast atom bombardment mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 617-619 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Negative ion fast atom bombardment mass spectrometry is used to verify the sequence of oligodeoxyribonucleotides containing a single modified nucleotide. Both the position in the sequence and the molecular weight of the modified nucleotide can be determined from the 3′ and 5′-phosphate sequence ions which are prominent in the mass spectrum.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180818
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    A comparison of positive ion and negative ion fast atom bombardment mass spectral data for some sulphonyl hydrazones and derivatives (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 620-623 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of sulphonyl hydrazones and derivatives have been synthesized and tested for biological activity as pesticides during the crop protection research programme at the Hatfield Polytechnic. A recent comparative ionization study of some of these compounds using electron impact (EI), fast atom bombardment (FAB) and various chemical ionization methods showed FAB mass spectrometry to be the optimum technique to use in terms of molecular weight information obtained. This study compares the FAB mass spectral data in positive and negative ion mode using an alternating positive and negative ion detection system.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180819
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    Rapid structural analysis of the in vitro and in vivo metabolism of SK&F 95448 by the combined use of thermospray liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 637-644 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermospray liquid chromatography/mass spectrometry (LC/MS) interface has had a major impact on the direct analysis of the metabolic fate of xenobiotics in complex biological media. This paper outlines the rapidity and power of the LC/MS approach, and shows how detailed structural information can be obtained without recourse to individual compound isolation. This provides a great saving in time and effort. The additional specificity of liquid chromatography/tandem mass spectrometry is highlighted in identifying the sites of metabolic transformation. The ability to handle biological samples with little or no clean-up using wide high-performance liquid chromatographic gradients is a key feature of the success of this methodology.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180822
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    Phytochemical studies on the essential oils of species belonging to the Achillea genus by gas chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 629-636 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several populations of Achillea species were collected from Hungarian localities. The characteristic composition cf the essential oils of almost 220 populations were determined by gas chromatography/mass spectrometry. The main component of Achillea asplenifolia, A. setacea and A. collina oils is chamazulene, with a molecular mass of 184. The composition of some A. setacea is different: instead of chamazulene it contains a significant amount of farnesene. Oils of A. distans, A. crithmifolia, A. nobilis, A. pannonica and A. ochroleuca contain some different and specific compounds instead of chamazulene. During the analysis of many essential oils, we found some very interesting differences within species originating from another geographical area.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180821
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    Quantification of urinary 3-hydroxyisovaleric acid using deuterated 3-hydroxyisovaleric acid as internal standard (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 652-656 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deficiency of biotin at the tissue level can be assessed indirectly by measuring the urinary excretion of 3-hydroxyisovaleric acid. This paper describes the application of an improved method of quantifying urinary 3-hydroxyisovaleric acid using unlabeled and uniformly deuterated 3-hydroxyisovaleric acid. These compounds were synthesized by a modification of the lithioacetic acid method for generation of beta-hydroxy acids. Elemental analysis, nuclear magnetic resonance, gas chromatographic and gas chromatographic/mass spectrometric data demonstrated that the compounds are greater than 95% pure. Mass spectrometry confirmed the identity of the unlabeled compound, demonstrated that the deuterated compound is uniformly labeled, and offered insight into the pattern of mass fragmentation. The method for determination of the concentration of 3-hydroxyisovaleric acid in rat urine uses gas chromatographic/mass spectrometric quantification of the di-trimethylsilyl derivative with the deuterated compound as the internal standard. Results provide evidence that this method is more accurate than a previously published method that did not utilize the unlabeled and deuterated standards.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180903
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    Metabolic dissimilarity between (9,12,12-2H)cortisol and natural cortisol in vivo. Can deuterated cortisol be used for the measurement of the urinary cortisol production rate? (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 662-667 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism of deutrated cortisol (9,12,12,-2H)cortisol, (2H3-F) was compared to that of radioactive cortisol (3H2-F) and natural cortisol, when these three compounds were administered simultaneously to an adrenalectomized piglet. The relative isotope dilution of tritium was determined from the specific activities of the main urinary neutral cortisol metabolites, tetrahydrocortisone (THE) and tetrahydrocortisol (THF), normalized to that of the cortisol mixture administered. To obtain a comparison of the isotope dilution of deuterium in the metabolites THE and THF to that in the cortisol mixture, the three steroids were converted to the common oxidation product 11-oxo-aetiocholanolone, and deivatized to the methoxime-tert-butyl-dimethylsilyl ether. The relative 2H-isotope dilution then was measured by gas chromatography/mass spectrometry. It was found that the specific activity of THE in the cumulative urine collections was similar to that of the cortisol mixture administered; the two-day value was, however, less. The specific activity of THF was slightly but significantly smaller than 1 (∼0.9) at all times. The relative 2H-isotope dilution in THE was slightly but significantly larger than one (∼1.1) at all times, whereas that in the THF was larger than 1.0 at 9 and 32 h or equal to 1.0 at 20 and 47 h of urine collection. When comparing the metabolism of the two tracer cortisol species the quotient of the 3H- and the 2H-isotope dilutions in THE and THF was smaller than 1.0. It can be concluded that (2H3)cortisol may be used for the determination of the cortisol production rate.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180905
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    Direct analysis of different classes of surfactants in raw materials and in finished detergent formulations by fast atom bombardment mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 673-689 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characterization of the components of a surfactant mixture is a challenge, since we are dealing with substances inherently difficult to purify or separate by any available chromatographic methods. The results of the present work provide evidence that with fast atom bombardment mass spectrometry it is possible to identify the single constituents of the different clases of tensides - non-ionic, anionic, cationic and amphoteric - directly in the mixture and in detergent formulations (shampoos). The method, which is based on unambiguous molecular weight determination of the single components, allows the definition of the exact distribution of oligomers in the surfactant mixture, and distinction of subtle variations in the detergent composition in finished formulations. The results obtained indicate that this technique is a powerful analytical tool which can be used as a rapid screen test for quality control.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180907
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    Biotransformation of aliphatic formamides: Metabolites of (±)-N-methyl-N-(1-methyl-3,3-diphenylpropyl) formamide in ratsPresented in part at the 35th ASMS Meeting, Denver, Colorado, May 1987. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 690-701 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in vivo biliary and urinary metabolites of (±)-N-methyl-N-(1-methyl-3,3-diphenylpropyl) formamide (1) from male Wistar rats have been characterized by gas chromatography/mass spectrometry. In urine, non-conjugated metabolites included 1,1-diphenyl-3-butanone (4) and 3-methylamino-1,1, diphenylbutane (7). β-Glucuronidase liberated 4, 1,1-diphenyl-3-butanol (5), 1,1-diphenyl-3-butanone oxime (6), N-hydroxymethyl-N-(1-methyl-3, 3-diphenylpropyl) formamide (3), 1-(4-hydroxyphenyl)-1-phenyl-3-butanone (11), 1-(4-hydroxyphenyl)-1-phenyl-3-butanone oxime (12), N-methyl-N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (8), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanone (16), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanol (17), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanone oxime (18), N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (14) and N-methyl-N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (13). Most of the carbinolamide (3) decomposed in the gas chromatograph inlet to N-(1-methyl-3,3-diphenylpropyl) formamide (2) unless stabilized as a trimethylsilyl (TMS) derivative. In bile, compounds 1, 2, 3, 5, 6, 11, 12 and 16 were present as non-conjugated metabolites. β-Glucuronidase also liberated N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (9), and all of the previously listed compounds except 7. Trimethylsilylation of the conjugated bile fraction revealed the presence of an additional two compunds: N-hydroxymethyl-N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (10) and N-hydroxymethyl-N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (15). A stable carbinolamide metabolite standard was synthesized and the mass spectral fragmentations of its TMS derivative studied by tandem mass spectroscopy. This is the first report on stable carbinolamide metabolites of high-molecular-weight formamides.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180908
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    Parent ion spectroscopy in the identification of advanced glycation products (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 713-718 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Advanced glycation products have been investigated by parent ion spectroscopy, employing B2/E = constant linked scans of furoyl ions obtained from hydrolysed glycated albumin and polylysine mixtures, without any extraction procedures. Using such an instrumental approach, together with exact mass measurements and collision spectroscopy, the identification of 2-(2-furoyl)-4-hydroxyl-1H-imidazole and 2-(2-furoyl)-4-carboxy-1H-imidazole among the advanced glycation products has been achieved.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180911
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    Identification of long-chain fatty acids and alcohols from human cerumen by the use of picolinyl and nicotinate esters (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 719-723 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Human cerumen was hydrolysed with base and the constituents were examined as trimethylsilyl (TMS), methyl ester/TMS, picolinyl/TMS and nicotinate/TMS derivatives by gas chromatography and gas chromatography/mass spectrometry. A sample was also reacted with osmium tetroxide for double bond location. The major constituents were cholesterol, squalene and several series of long-chain fatty acids and alcohols. These latter compounds had chain lengths of 12-26 carbon atoms and were predominantly either straight-chain saturated or straight-chain unsaturated compounds. Saturated branched-chain acids with methyl groups predominantly on even-numbered carbon atoms were present but were less abundant. Unsaturated, branched-chain acids were also present. The major unsaturated acids contained unsaturation at the delta-6-position or were derived from these acids by chain elongation. The compounds were similar to those found in vernix caseosa. The mass spectra of picolinyl esters were, for the first time, shown to be capable of determining both the position of unsaturation and methyl branching in the same molecule.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180912
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    Tandem mass spectrometry of leucine enkephalin and physalaemin using a hybrid instrument (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 727-732 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Daughter ion mass spectral data of [M + H]+ ions of leucine enkephalin and physalaemin, which were formed by fast atom bombardment, were obtained using an instrument of EBQQ configuration. In the case of leucine enkephalin, experiments were carried out in which the collision energy was varied and the collision gas pressure kept constant and vice versa. The results show that conditions can be established under which seuqence-relevant ions above m/z 200 are formed, as well as under which mainly immonium and acylium type ions are generated. Of possible interest for characterization of unknown peptides, when using hybrid instruments, are the mid-chain cleavage ions, which, at a constant argon gas pressure of 5 × 10-6 mbat, were found to maximize at around 30 eV collision energy. Daughter ion mass spectral data are also presented for [M + H]+ ions of physalaemin (mol. wt 1264). Compared to data obtained for physalaemin on multisector instruments, our results indicate that the formation of mid-chain cleavage ions is clearly enhanced.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180914
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    Characterization of virus infected cell cultures by pyrolysis/direct chemical ionization mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 757-760 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The supernatants of Vero cell cultures after infection with a herpes simplex virus or a poliomyelitis virus as well as a blank were analysed by pyrolysis/direct chemical ionization mass spectrometry (Py/DCI MS). Informative pyrogrammes were obtained and used for characterization of viral proteins by applying pattern recognition methods. Differentiation of viral proteins was evaluated by analysing ‘blind’ samples. Herpes viruses could be classified correctly but the observed differences between the blank and the polio virus supernatants were too small for reliable classification of the polio viruses. Purification of the samples seems to be a prerequisite for further studies. The potential value of Py/DCI MS as a rapid non-invasive diagnostic method for viral meningoencephalitis is stressed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180919
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    Fast atom bombardment combined with tandem mass spectrometry for analysis of a complex mixture of lipo-oligopeptides from Nocardia rubra cell wallskeletonPart of the results in this paper have been presented at the 36th ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, USA, p. 1285 (1988). (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 761-766 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Experimental variables in fast atom bombardment combined with tandem mass spectrometry based on low-energy collision-induced dissociation have been systematically invetigated in order to optimize parameters for analysis of synthetic lipo-oligopeptides. The parameters studied were matrix, ion polarity, collision gas, collision gas pressure and collision energy. The optimal parameters recommended in this study have been applied to the N-terminal amino acid seuquence determination of lipopeptide obtained from Nocardia rubra cell wall skeleton. Daughter and parent ion experiments with negative ion fast atom bombardment combined with tandem mass spectrometry have proven to be very useful for structure elucidation of a complex mixture of lipo-oligopeptides.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180920
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    The determination of atmospheric bis (chloromethyl) ether by gas chromatography/tandem mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 775-779 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The technique of gas chromatography/tandem mass spectrometry is applied to the analysis of bis(chloromethyl) ether in laboratory and production environments. A selected reaction monitoring method is shown to yield superior sensitivity and selectivity to previous methods. A detection limit of ∼1 ppt is established even for chemically complex atmospheres which have proved intractable by previous techniques.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180922
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    Fast atom bombardment mass spectra of peptides. Dimer ion studies. Part VIPart V: see Ref. 1; Part IV: see ref. 2. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 281-286 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive ion fast atom bombardment mass spectra of the opioid pentapeptides leucine enkephalin (1) (H-Tyr-Gly-Gly-Phe-Leu-OH or YGGFL), methionine enkephalin (2) (H-Tyr-Gly-Gly-Phe-Met-OH or YGGFM) and leucine enkephalin-2H2 (3) (H-Tyr-2Gly-2H2-Gly-Phe-Leu-OH or YGGFL-2H2) have been recorded in glycerol. The following experiments have been carried out: (i) dimer studies [2M + 1]+; (ii) decompositions of dimers: daughter ions from (YGGFL)2, (YGGFL-YGGFL-2H2) and (YGGFL-2H2)2 as well as (YGGFM-YGGFL) and (YGGFM)2 dimers; (iii) solvation site and pyridine collision-activated dissociation studies for dimer ions; (iv) mechanism of formation of [(2M + 1) - Gly4]+ ions.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180502
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    Practical considerations in the use of stable isotope labelled compounds as tracers in clinical studies (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 321-327 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Increasingly widespread usage of stable isotope tracers to aid clinical diagnosis and support basic research has stemmed from both advances in mass spectrometry and the availability of competitively priced labelled compounds. Stable isotopes have been used generally to investigate normal and abnormal metabolic pathways, to estimate energy expenditure and body composition and to quantitate substrate flux and oxidation rates. Despite the fact that the underlying principles relating to the use of stable isotopes for in vivo studies are straightforward, careful consideration must be given to all aspects of human studies. This review highlights some of these, including choice of label and tracer molecule, mode of tracer administration and sampling site, analytical instrumentation, interpretation of data and ethical constraints.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180507
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    Masthead (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989) 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180601
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    Forthcoming events (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 358-358 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180512
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    Direct liquid inlet liquid chromatographic/mass spectrometric identification and high-performance liquid chromatographic analysis of a benzodiazepine glucuronide (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 359-362 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The glucuronide of N-1-hydroxy-ethyl flurazepam has been analysed by a direct liquid inlet liquid chromatographic/mass spectrometric system using MeOH/H2O (70:30 v/v) as mobile phase, at a flow rate of 0.7 ml min-1. Urine samples were purified by amberlite XAD-2 chromatography; the glucuronide was quantified by highperformance liquid chromatography using a counterion (tetrabutyl ammonium nitrate in methanol). Chromatographic results were validated by an enzymatic method: treatment of the samples with β-glucuronidase and extraction of the parent drug with ethyl ether at pH 9. The biological application of this method was demonstrated by determination of this glucuronide in the urine of healthy human volunteers following a single intravenous administration of 50 mg of N-1-hydroxy-ethyl flurazepam.
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    URL: http://dx.doi.org/10.1002/bms.1200180602
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    Mass spectrometry of domoic acid, a marine neurotoxinNRCC No. 29369. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 373-386 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Domoic acid is a naturally occurring amino acid, formerly available in limited amounts as a natural product of some algae of the family Rhodomelaceae. As the result of a recent incidence of toxicity in cultured blue mussels (Mytilus edulis) from a highly localized region of Atlantic Canada, useful amounts of this substance are likely to become available in the near future. Domoic acid is an important substance for fundamental studies in neurobiology as it possesses the highest affinity amongst known substances for the kainate receptors of the central nervous system. The present work describes fast atom bombardment (FAB) mass spectra of domoic acid, and of some of its isomers present in minor quantities in contaminated mussel extracts. These FAB spectra are subject to interferences from beam-inducced reduction reactions associated with matrices such as glycerol, but not with others such as 3-nitrobenzyl alcohol. Tandem mass spectrometry of the MH+ ions from these compounds is also reported. As a more feasible approach to quantitative analysis at trace levels, formation of the volatile tert-butyldimethylsilyl derivatives has been investigated and shown to be highly promising.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180604
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    Collisional activation mass spectra of M-. ions of azo dyes containing 2-naphthol (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 394-400 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Collisionally activated decomposition mass spectra of M-. ions of azo dyes are presented. The compounds are of general structure Ar(1)—N=N—Ar(2), where Ar(1) is substituted phenyl and Ar(2) is 2-naphthol. Characteristic fragment ions observed include m/z 157, which corresponds to the 2-naphthol substituent with cleavage of the —N=N— bond represented as [Ar(2) - N]-.. Ion of general structure [Ar(1)- NH]- are also observed. Parent ion scans of m/z 157 provide a potential screening technique for 2-naphthol-containing axo dyes. Specific results are reported for the chloroform extract of FD&C Red #8, and capillary gas chromatographic introduction is compared with direct exposure probe introduction for the identification of dyes.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180606
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    Studies on the biotransformation of ketamine. II - quantitative significance of the N-demethylation pathway in rats in vivo determined by a novel stable isotope technique (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 401-404 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to determine the fraction of an intravenous bolus dose of ketamine which is metabolized in vivo to the corresponding N-desmethyl compound, norketamine, a novel stable isotope technique was developed and applied to a study in rats. Co-injection of equimoiar amounts of deuterium-labeled ketamine and unlabeled norketamine to four animals, followed by gas chromatographic/mass spectrometric analysis of both the administered compounds and deuterium-labeled norketamine in plasma yielded pharmacokinetic data from which the fraction of the parent drug subjected to N-demethylation (fm) was calculated from AUC data to be 36.8 ± 2.4%. It is concluded that this stable isotope co-administration technique represents a powerful approach to the determination of fm, in that the pharmacokinetics of the metabolite of interest, given as the preformed compound and generated in vivo, are determined simultaneously. This experimental design thus obviates the influence of time-dependent changes in metabolite clearance which may complicate the interpretation of studies performed using the classical cross-over design.
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    URL: http://dx.doi.org/10.1002/bms.1200180607
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    Profiles in altered metabolism. IV - induction of acute dicarboxylic aciduria following 2-octynoic acid administration to the ratPrevious paper in this series: ‘Profiles in Altered Metabolism III - (Ω-1)-Hydroxyacid Excretion in a Case of Episodic Hypoglycemia’, O. A. Mamer, J. A. Montgomery and E. Colle, Biomed. Mass Spectrom., 7, 53 (1980). (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 416-423 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rats given 2-octynoic acid by intraperitoneal injection excrete elevated amounts of medium-chain dicarboxylic acids and other acidic metabolites usually associated with human medium-chain acyl-CoA dehydrogenase deficiency. Onset of this organic acid profile is immediate and lasts for approximately 24 h. The induced acidosis in this animal model closely, acutely and transiently resembles the human disorder. The 2-octynoate load is also extensively Ω- and Ψ-oxidized, and evidence is presented for the enzymic hydration of 2-octynoate to 3-ketooctanoic acid.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180610
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  • 283
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    High-sensitivity thermospray ionization mass spectrometry of dyes (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 445-449 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of dyes belonging to different chemical classes have been analyzed by thermospray (TSP) ionization mass spectrometry using a modified source containing a wire-repeller. Detection limits were determined and found to be in the range 0.05-20 ng, which are lower by a factor of 10-400 than previously published results. Positive-ion TSP mass spectra of some sulfonated dyes could be recorded for the first time owing to the increased sensitivity. Losses of SO3Na and 2SO3Na as well as losses of Na and 2Na were observed. The losses of each one of these groups involved replacement by a hydrogen atom.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180614
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  • 284
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    Determination of the new aromatase inhibitor CGS 16 949 in biological fluids by capillary gas chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 558-562 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A specific and sensitive gas chromatographic/mass spectrometric method was developed and validated for the quantitative determination of the aromatase inhibitor CGS 16 949 in plasma and urine. A deuterium-labelled analogue of CGS 16 949 was used as internal standard. The analysis of spiked samples demonstrated the good accuracy and precision of the method. For both plasma and urine, the limit of quantification (LOQ: coefficient of variation (CV) = 10%) and the limit of detection (LOD: CV = 100%) were estimated to be 5 and 1 nmol l-1, respectively. The method was applied to the determination of unchanged CGS 16 949 in plasma and urine of a healthy volunteer orally dosed with 1 mg of CGS 16 949 A.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180808
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  • 285
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    Determination of pipecolic acid in serum or plasma by solid-phase extraction and isotope dilution mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 566-571 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of pipecolic acid in serum or plasma by positive chemical ionization gas chromatography/mass spectrometry is assessed. This quantitative method involves stable isotope dilution and cation-exchange solid-phase extraction. Several derivatives of pipecolic acid and its octadeuterated analogue were investigated for their mass spectrometric characteristics. The beptafluorobutyric methyl ester derivatives afford optimal resolution on gas chromatography of biological extracts. Moreover, the derivatizing reagent (methanolic HCl) allows a combined elution and derivatization. Selected ion monitoring is performed on the [M + H]+ ions of both analyte and internal standard, at m/z 340 and 348, respectively. Serum or plasma samples from healthy subjects and patients suspected of peroxisomal diseases have been examined.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180810
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  • 286
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    On the use of laser microprobe mass spectrometry for the analysis of organic biomolecules (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 581-591 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Laser microprobe mass spectrometry has been applied to a variety of organic polyfunctional molecules, covering a wide range of polarity and mass spectrometric behaviour. The technique apparently combines desorption under relatively soft conditions with extensive fragmentation and hence allows much structural information from intactly released thermolabiles to be obtained. The mass spectra appear unfamiliar in comparison to conventional techniques. Interpretation is attempted in a purely empirical way by means of the evidence from our database and tentative hypotheses to rationalize the desorption and ionization by laser microbeam irradiation of organic solids. Selected examples are presented to illustrate the potential and limitations of the method in the field of biomolecules, such as pyridoxine and pyridoxal phosphate, nucleosides, nucleotides and related analogues, drugs and the corresponding N-oxides.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180813
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  • 287
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    Masthead (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989) 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180101
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  • 288
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    Detection of residues of chloramphenicol in crude extracts of fish and milk by tandem mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 5-11 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The collision-induced dissociation mass spectrum, observed with a hybrid tandem instrument, of the ammonia chemical ionization protonated molecular ion of chloramphenicol was used for the detection of residues of the drug in biological samples. The extracted oil from fish was subjected to a rapid clean-up on a pre-packed silica gel cartridge prior to non-chromatographic tandem mass spectral analysis. Fat extracted from milk was analysed directly by on-line combined high-performance liquid chromatography/tandem mass spectrometry with rapid elution of chloramphenicol. Identification was on the basis of agreement of the daughter ion spectra obtained from sample extracts with that of the chloramphenicol standard. Detection was unambiguous at 0.5 mg kg-1. The sensitivity advantage normally expected with multiple reaction monitoring was not achieved owing to the effect of neutral noise phenomena.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180103
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  • 289
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    Isolation, purification and structure elucidation of cyclosporin a metabolites in rabbit and man (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 48-56 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metabolism of cyclosporin A (CsA) was studied in a model of isolated and perfused rabbit liver, and in man. After diethyl ether extraction, CsA metabolites were separated and successfully purified by a combination of two highperformance liquid chromatographic (HPLC) procedures. A normal-phase HPLC methodology was used to separate most of the metabolites, and further separation and purification were optimized with a reversed-phase HPLC method. 27 different CsA metabolites were separated, collected, and characterized by fast atom bombardment mass spectrometry. In addition to several metabolites already described (OL-1, OL-17, OL-18 and OL-21), new compounds (of original molecular weights 1236, 1222 and 1174, and numerous structural isomers of previously reported molecular weights) were isolated from rabbit and human bile. Mass spectral analysis of two of these new metabolites strongly suggests vicinal dihydrodiol (mol. wt 1236) and N-demethylated vicinal dihydrodiol (mol. wt 1222) structures. These two new metabolites most probably derive from an epoxide as a preliminary intermediate.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180107
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  • 290
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    Packed capillary liquid chromatography/mass spectrometry using a moving belt interfacePresented in part at the American Society for Mass Spectrometry 35th Annual Conference, Denver, 1987 and at the 17th Annual Symposium on the Analytical Chemistry of Pollutants, Jekyll Island, 1987. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 77-82 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Packed capillary liquid chromatography/mass spectrometry using a moving belt interface is a practical, versatile technique for the identification of unknowns. The low flow rates (1-2 μl min-1) improve the operation of the moving belt and allow direct deposition of eluates from reversed-phase liquid chromatographic columns containing large proportions of water. Column performance and durability is equivalent to that obtained with conventional or microbore liquid chromatographic columns. Techniques have been developed for analyzing dilute solutions with no loss in column performance and for the detection of radiolabeled metabolites. Applications to analyses of polar, thermally labile compounds and environmental samples are presented.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180111
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  • 291
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    Charge-exchange reactions with water in the detection of perfluorocarbons by thermospray liquid chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 106-109 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Perfluorocarbons (PFCs) can be detected by thermospray liquid chromatography/mass spectrometry (LC/MS) only when the system is operated in the negative ion mode with filament on and some water entering the thermospray source. A new mechanism for PFC ionization is proposed, based on studies of LC/MS detection of the perfluorinated forms of cyclohexane, methyl and dimethyl cyclohexane, decalin, 1-methyl decalin and toluene. The ion evaporation mechanism of Dodd, involving pre-ionization of PFCs in the presence of aqueous NH4OAc, is not operative, nor is chemical ionization of PFCs by the reagent ions as in true thermospray LC/MS. Instead, PFC ionization is attributable to the negative ions formed from the water in the source; these ions undergo prompt charge-exchange reactions with the more electronegative PFCs to form structure-retaining PFC ions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180204
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  • 292
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    Suppression effects in peptide mapping by plasma desorption mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 131-137 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Suppression effects observed in plasma desorption (PD) mass spectrometry have been studied and compared to those found in fast atom bombardment mass spectrometry. A basic difference in the mechanism of suppression in the two techniques is demonstrated. In positive ion mode PD mass spectrometry, peptides carrying net positive charges are preferentially detected when analysed together with peptides carrying net negative charges, and in negative ion mode PD mass spectrometry, the situation is generally reversed. Based on this complementarity, PD mapping carried out by enzymatic digestion of a nitrocellulose-bound sample can in many cases yield almost complete coverage of smaller proteins.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180208
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  • 293
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    Fast atom bombardment and fast atom bombardment collision-activated dissociation/mass-analysed ion kinetic energy analysis of C-glycosidic flavonoids (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 122-130 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fast atom bombardment (FAB) mass spectrometry and FAB tandem mass spectrometry in negative mode can provide molecular weight and very useful structural prior information for C-glycosyl flavonoids without derivatization. Diethanolamine or thioglycerol matrix gave an abundant deprotonated molecular ion for all the studied compounds. Mass-analysed ion kinetic energy (MIKE) and collision-activated dissociation/MIKE spectra provide characteristic fragment ions which permit differentiation of the 6- and/or 8-location, and the position of O-glycosylation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180207
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  • 294
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    Fast atom bombardment mass spectrometric investigation of in vitro degradation within the disulfide-linked core of atrial natriuretic factor (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 12-19 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of high-performance liquid chromatography and fast atom bombardment mass spectrometry are shown to be an efficient combination for investigating protease-mediated digestion of synthetic analogs of the peptide hormone ANF (atrial natriuretic factor). As examples of the reported methodology, rANF5-23-NH2 and rANF7-23-NH2 were digested with the endopeptidase thermolysin. These truncated analogs were selected to investigate metabolism within the disulfide-linked core of ANF, particularly at the Cys7—Phe8 bond. While this position was the site of initial hydrolysis for rANF5-23-NH2 (t1/2 = 0.5 min), the Cys7—Phe8 bond remained intact for all observed degradation products of rANF7-23-NH2 (t1/2 = 16 min). These findings suggest that improved stability towards endopeptidase-mediated core hydrolysis may be conferred to analogs of ANF by removal of the first six residues from the N-terminus.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180104
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  • 295
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    The differentiation of methyl guanosine isomers by laser ionization fourier transform mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 265-277 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Laser ionization of guanosines containing methyl substitutions in the 1-, N2-, 3′-O-, O6- and 7- positions generated two characteristic negative ions: loss of hydrogen to generate [M - H]- and elimination of the sugar ring to form the nucleic base ion. The ions generated by elimination of the sugar ring provided the information necessary to determine whether the methyl group was on the nucleic base or sugar ring. Fourier transform mass spectrometry was used to isolate and collisionally dissociate selected negative ions from these nucleosides. The collisional dissociation spectra indicated daughter ions which were sufficient to differentiate all the isomers with methyl substitution of the nucleic bases. In addition, accurate mass measurement an dsequential collisional dissociation experiments were employed to investigate fragmentation mechanisms.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180410
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  • 296
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    Laser-induced vaporization mass spectrometry of rifamycins (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 301-307 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of many rifamycins cannot be obtained by electron ionization (EI) owing to their thermal decomposition. When a laser beam is used to vaporize the sample through an optic fibre inserted in a hollow probe which reaches the sample cup, decomposition is minimized and the EI spectra show abundant molecular ions and fragments of structurally high diagnostic value. These ionic species are easily observed owing to the lack of chemical noise often present in soft ionization methods, such as direct liquid chemical ionization and fast atom bombardment.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180504
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  • 297
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    Mixed silyl ether-perfluoroacyl ester derivatives for gas chromatography/mass spectrometry of oestrogens. Application to the quantitative determination of oestriol in human plasmaPresented in part at the 11th International Mass Spectrometry Conference, Bordeaux, 29th August-2nd Spetember, 1988. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 314-320 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conversion of oestrogens mixed derivatives comprising a phenolic silyl ether and one or more alcoholic perfluoroactyl ester(s) is described. They are easily formed in quantitative yield and have excellent gas chromatographic and mass spectrometric properties, making them suitable for analysis by selected ion monitoring. Reaction mechanisms are examined which propose explanations for the experimentally observed optimal reaction conditions. The 3-t-butyldimethylsilyl ether-16α 17β-bis(pentafluoropropionate) has been used for the quantitative determination of oestriol in plasma by gas chromatography/mass spectrometry using a stable isotope internal standard. Comparison with the pertrimethylsilyl ether of oestriol indicates higher specificity and better precision for low-level (〈0.5 ng ml-1) estimations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180506
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  • 298
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    On-line generation of fast atom bombardment spectra with particle beam liquid chromatography/mass spectrornetry interfaung (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 355-357 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180511
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  • 299
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    Deuterium-labeled 3-nitrobenzyl alcohol as a matrix for fast atom bombardment mass spectrometry1 (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 1087-1095 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The utility of deuterium-labeled 3-nitrobenzyl alcohol (DNBA) as a fast atom bombardment (FAB) matrix for establishing the number of exchangeable hydrogens present in a molecule is illustrated by the analysis of five selected antitumor agents. A method for the simple preparation of this labeled matrix is described. The use of DNBA may be of value for samples which provide no FAB spectra when deuterium-labeled glycerol is used as a matrix.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200181209
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  • 300
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    Determination of the photodegradation products of basic yellow 2 by thermospray high-performance liquid chromatography and gas chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 1079-1086 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Like most dyes, Basic Yellow 2 (BY-2) fades upon prolonged exposure to light. Light-induced fading is a complex process that is also affected by heat and humidity. In order to better understand the photodegradation process and to identify the various photodegradation products of BY-2, fabric samples and solutions containing BY-2 were exposed to a variety of fading conditions. The analysis of faded BY-2 dyed fabric extracts by high-performance liquid chromatography/mass spectrometry (HPLC/MS) indicated the reduction and hydrolysis of the C=NH2+ group to form primarily benzophenone derivatives, as well as various demethylated products. Due to the absence of fragmentation in the thermospray spectra (only [M + H]+ ions were observed) the dye extracts were analyzed by gas chromatography/mass spectrometry (GC/MS) to confirm the identity of the degradation products. Many of the degradation products were sufficiently volatile for analysis by GC/MS. Mass spectra of the photodegradation products of BY-2 exhibited molecular ions and structurally important fragment ions to complement the thermospray data. The mass spectral data indicated that the most prevalent degradation product formed was ((CH3)2NC6H4)2C=0 (Michler's ketone). Hydrolysis of the C=NH2+ group to C=0 is the main color-destroying reaction in the fading of BY-2. Demethylation products which can alter the shades of color were also detected in the faded BY-2 samples.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200181208
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