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  • 1
    Electronic Resource
    Electronic Resource
    A helix-turn-strand structural motif common in α-β proteins (1990)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 8 (1990), S. 334-340 
    Details
    ISSN: 0887-3585
    Keywords: protein structure ; structural comparison ; α-β barrels ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: By exhaustive structural comparisons, we have found that about one-third of the α-helix-turn-β-strand polypeptides in α-β barrel domains share a common structural motif. The chief characteristics of this motif are that first, the geometry of the turn between the α-helix and the β-strand is somewhat constrained, and second, the β-strand contains a hydrophobic patch that fits into a hydrophobic pocket on the α-helix. The geometry of the turn does not seem to be a major determinant of the α-β unit, because the turns vary in length from four to six residues. However, the motif does not occur when there are few constraints on the geometry of the turn-for instance, when the turns between the α-helix and the β-strands are very long. It also occurs much less frequently in flat-sheet α-β proteins, where the topology is much less regular and the amount of twist on the sheet varies considerably more than in the barrel proteins. The motif may be one of the basic building blocks from which α-β barrels are constructed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340080407
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  • 2
    Electronic Resource
    Electronic Resource
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180607
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  • 3
    Electronic Resource
    Electronic Resource
    The use of alkoxycarbonyl derivatives for the mass spectral analysis of drug-thioether metabolites. Studies with the cysteine, mercapturic acid and glutathione conjugates of acetaminophen (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 637-647 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkoxycarbonyl derivatives of the cysteine-, N-acetylcysteine- and glutathione conjugates of acetaminophen have been prepared in aqueous buffer solutions and their chromatographic and mass spectrometric properties examined. Structurally informative fragmentation patterns of the cysteine- and N-acetylcysteine derivatives were obtained when their methyl esters were subjected to analysis by direct insertion chemical ionization (CH4) mass spectrometry, although field desorption and liquid secondary ion mass spectrometric techniques were required in order to obtain satisfactory spectral data for derivatives of the glutathione adduct. Treatment of ethoxycarbonyl derivatives of the three acetaminophen metabolites with N-methyltrifluoroacetamide-based silylating reagents led to the formation of a common volatile product which was ideally suited to analysis by gas chromatography/electron impact mass spectrometry. A mechanism is proposed for the formation of this novel derivative, which appears to possess a benzo-1,3-thioxalane structure, and its mass spectral characteristics are reported. Finally, the utility of alkoxycarbonyl derivatives for the analysis of drug - thioether conjugates in biological fluids is discussed in terms of their advantages for aqueous phase derivatization, purification by high-performance liquid chromatography and characterization by mass spectrometry.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151202
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  • 4
    Electronic Resource
    Electronic Resource
    Introduction to computer-assisted experimentation. Kenneth L. ratzlaff. Wiley-Interscience: New York, NY, 1987. 438 pp + figs and tables. $44.95 (1987)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 1 (1987), S. iv 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290010213
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  • 5
    Electronic Resource
    Electronic Resource
    Improved detection of glucuronide and glutathione conjugates with thermospray ionization following esterification (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 371-376 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Analysis by thermospray of glucuronide and glutathione conjugates as the corresponding methyl-, propyl-, or hexyl esters is demonstrated to yield a remarkable increase in positive pseudomolecular ion production and to result in a dramatic improvement in detectability of these thermally labile compounds as intact molecular structures. In the most extreme examples a 450-fold increase in the [M + NH4]+ ion intensity was observed for mycophenolic acid glucuronide bis-propyl esters vs. the native conjugate and an 860-fold increase in the [M + H]+ ion intensity was achieved for acetaminophen glutathione bis-hexyl ester vs. the native conjugate. Following esterification, seventeen of the eighteen glucuronide esters analyzed demonstrated an increase in totalion-current yield ranging from 1.1- to 8.3-fold while eighteen of the twenty-one glutathione esters examined demonstrated an increase in totalion-current yield from 2.0- to 26.3-fold. For both types of conjugates a trend in increased relative abundance of the positive pseudomolecular ion intensity is observed as the hydrophobicity of the ester increases from methyl to hexyl. For the glutathione conjugate esters, the [M + H]+ ion represented the base peak in the mass spectra of the majority of samples analyzed. This approach improves the protonated- or ammoniated-molecular-ion abundances of the conjugates to such an extent that it provides a means for unambiguous molecular weight assignments to be made. Although the exact mechanism(s) for the observed phenomenon is not known, it appears that the improvement in sensitivity for the conjugate esters over the corresponding native conjugates involves an increase in pseudomolecular-ion stability and also in part an increased ionization efficiency of the esterified molecule.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290080506
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  • 6
    Electronic Resource
    Electronic Resource
    Matrix-assisted laser desorption ionization for rapid determination of the sequences of biologically active peptides isolated from support-bound combinatorial peptide libraries (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 77-81 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A termination synthesis approach has been developed to encode each resin bead in support-bound combinatorial peptide libraries with the information needed to establish the sequence of the full-length products also contained on the beads. Matrix-assisted laser desorption ionization mass spectrometry was then used to rapidly read the appropriate sequences. In addition to rapid peptide sequencing, the technique allows direct assessment of the quality of the synthetic library, since deletion peptides, side-reaction products and incomplete-deprotection products are readily observed. An anti-gp120 monoclonal antibody was screened against a hexapeptide library, and eight active peptides were isolated. Six of the eight peptides were shown to possess the exact recognition sequence for the antibody.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290080115
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  • 7
    Electronic Resource
    Electronic Resource
    Analysis of the interaction between human interleukin-5 and the soluble domain of its receptor using a surface plasmon resonance biosensor (1994)
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 7 (1994), S. 47-55 
    Details
    ISSN: 0952-3499
    Keywords: Cytokine ; Receptor ; Biosensor ; Titration ; Calorimetry ; Association rate ; Dissociation rate ; Equilibrium analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A surface plasmon resonance (SPR) biosensor was used to study the interaction of human interleukin-5 (hIL5) with its receptor. IL5 is a major growth factor in the production and activation of eosinophilis. The receptor for IL5 is composed of two subunits, α and β. The α subunit provides the specificity for IL5 and consist of an extracellular soluble domain, a single transmembrane region and a cytoplasmic tail. We expressed the soluble domain of the human IL5 receptor α subunit (shIL5Rα) and human IL5 (hIL5) in Drosophila. Both hIL5 and shIL5Rα were immobilized separately through amine groups onto the carboxylated dextran layer of sensor chips of the BIAcore™ (Pharmacia) SPR biosensor after N-hydroxysuccinimide/carbodiimide activation of the chip surface. Interactions were measured for the complementary macromolecule, either shIL5Rα or hIL5, in solution. Kinetics of binding of soluble analyst to immobilized ligand were measured and from this the association rate constant, dissociation rate constant and equilibrium dissociation constant (Kd) were derived. With immobilized shIL5Rα and soluble hIL5, the measured Kd was 2 nM. A similar value was obtained by titration calorimetry. The Kd for Drosophila expressed receptor and IL5 is higher than the values reported for proteins expressed in different systems, likely due to differences in the methods of interaction analysis used for differences in protein glycosylation. Receptor-IL5 binding was relatively pH independent between pH 6.5 and 9.5. Outside this range the dissociation rate increased with compressibility little increased in association rate. The values obtained for the interaction of hIL5 and shIL5Rα were found to depend on which component was immobilized; the Kd was 5.5 nM with immobilized hIL5 and soluble shIL5Rα. The SPR biosensor provides a unified methodology to measure the interaction properties of shIL5Rα and hIL5 derivatives, mutants and mimetic as well as to evaluate potential antagonists of the receptor-cytokine interaction.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmr.300070107
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  • 8
    Electronic Resource
    Electronic Resource
    Oxygen-17 nuclear magnetic resonance spectroscopy of organosulfur compounds. Part III. 17O NMR lanthanide-induced shifts (LIS) of diastereotopic oxygen atoms in trans-2- [alkyl(aryl)sulfonyl]cyclohexanolsDedicated to Ernest L. Eliel on the occasion of his seventieth birthday. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 3 (1992), S. 41-50 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 17O NMR diastereotopicity or chemical shift differences of diastereotopic sulfonyl oxygens in a series of trans-2-[alkyl(aryl)sulfonyl]cyclohexanols have been determined. From a comparison of their sulfonyl oxygen 17O NMR lanthanide-induced shifts, equilibrium distributions between diastereomeric sulfonyl oxygen-Eu(fod)3 complexes were determined and found to be sensitive to both the steric size of the -SO2R substituent as well as the proximity of the C1 hydroxyl group.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520030109
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  • 9
    Electronic Resource
    Electronic Resource
    Electrospray tandem mass spectrometry in the diagnosis of organic acidemiasPaper presented in part at the British Mass Spectrometry Society Meeting, Canterbury, 1993. (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 129-133 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A novel procedure based on electrospray tandem mass spectrometry (ESI-MS/MS) has been used in the diagnosis of organic acidemias. The method is based on the determination of acylcarnitine profiles from blood spots collected on Guthrie cards. The acylcarnitines are extracted with methanol, derivatized to their butyl esters and analyzed by ESI-MS/MS. Precursor-ion scanning of the common fragment at m/z 85 of the butyl esters yields highly diagnostic acylcarnitine profiles. Analysis time is one minute per sample and is fully automated. Examples are given of normal profiles, of profiles from two patients with fatty acid oxidation defects, and of a case of propionic acidemia. The technique is simple, rapid and specific, and shows potential for routine application in neonatal screening of organic acidemias.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290080124
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  • 10
    Electronic Resource
    Electronic Resource
    Dynamics of multicomponent polymer mixtures: theoretical models (1992)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Theory and Simulations 1 (1992), S. 333-358 
    Details
    ISSN: 1018-5054
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Theoretical models describing the dynamics of multicomponent polymer mixtures are reviewed. Some detailed derivations are shown to make the basic assumptions clear and to ease the comparison between these models. The effects of random noise and memory functions on the time evolution of dynamical correlation functions are examined. The long-range hydrodynamic interactions or mode-coupling effects are also included. A possible extension of these models to the kinetics of spinodal decomposition in solutions of polymer mixtures is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1992.040010601
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