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  • Chemistry  (37)
  • Organic Chemistry  (9)
  • Lignin model compounds  (5)
  • ACETALDEHYDE  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Alkyl-phenyl cleavage of the lignin model compounds guaiacylglycol and glycerol-β-guaiacyl ether by Phanerochaete chrysosporium (1980)
    Springer
    Archives of microbiology 128 (1980), S. 190-195 
    Details
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; β-Aryl ether dimers ; Metabolism ; Methoxyhydroquinone ; Alkyl-phenyl cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized guaiacylglycol-β-guaiacyl ether (I) in high nitrogen, shaking and stationary cultures. 2-(o-Methoxyphenoxy) ethanol (X), 2-(o-methoxyphenoxy) acetic acid (IX) and methoxy-phydroquinone (MHQ) were identified as products of the metabolism of (I). P. chrysosporium also metabolized guaiacylglycerol-β-guaiacyl ether (IV) in high nitrogen stationary cultures. 2-(o-Methoxyphenoxy)-1,3 propanediol (XII) and 3-hydroxy, 2-(o-methoxy-phenyxy) propionic acid (XIV) were identified as products of the metabolism of (IV). Finally, P. chrysosporium metabolized α-deoxyguaiacylglycol-β-guaiacyl ether (VI) and α-deoxyguaiacylglycerol-β-guaiacyl ether (VII) in limiting nitrogen cultures. 2-(o-Methoxyphenoxy) ethanol (X) and 2-(o-methoxyphenoxy)-1,3 propanediol (XII) were identified as products of the metabolism of VI and VII respectively indicating α hydroxylation of those substrates with subsequent alkyl-phenyl bond cleavage. Metabolites were identified after comparison with chemically synthesized standards by GLC-mass spectrometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406157
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  • 2
    Electronic Resource
    Electronic Resource
    β-Ether cleavage of the lignin model compound 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether and derivatives by Phanerochaete chrysosporium (1981)
    Springer
    Archives of microbiology 129 (1981), S. 141-145 
    Details
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; Lignin metabolism ; β-aryl ether dimers ; β-ether cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized 4-ethoxy-3-methoxyphenyl-glycerol-β-guaiacyl ether (V) in low nitrogen, stationary cultures under which conditions the ligninolytic enzyme system is expressed. 4-Ethoxy-3-methoxyphenylglycerol XIII, guaicol and 4-ethoxy-3-methoxybenzyl alcohol (II) were isolated as metabolic products. Exogenously added XIII was rapidly converted to 4-ethoxy-3-methoxybenzyl alcohol indicating that it is an intermediate in the metabolism of V. P. chrysosporium also metabolized 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-3-hydroxypropane VI. The degradation pathway for this dimer also included initial β-ether cleavage and α-hydroxylation of the diol product 1-(4′-ethoxy-3′-methoxyphenyl) 2,3 dihydroxypropane (XI) to yield the triol XIII which was cleaved at the α, β bond to yield 4-ethoxy-3-methoxybenzyl alcohol. Finally P. chrysosporium also cleaved the dimer 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-1-hydroxypropane (VIII) at the β-ether linkage yielding 1-(4′-ethoxy-3′-methoxyphenyl) 1,2 dihydroxypropane (IX) which was subsequently cleaved at the α, β bond to yield II. All of the results indicate that oxidative β-ether cleavage is an important initial reaction in the metabolism of β-aryl ether lignin substructure dimeric compounds. Metabolities were identified after comparison with chemically synthesized standards by gas liquid chromatography-mass spectrometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455350
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  • 3
    Electronic Resource
    Electronic Resource
    Direct cleavage of the vicinal diol linkage of the lignin model compound dihydroanisoin by the basidiomycete Phanerochaete chrysosporium (1983)
    Springer
    Archives of microbiology 134 (1983), S. 299-302 
    Details
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Vicinal diol cleavage ; Lignin model compounds ; Dihydroanisoin ; Anlsyl alcohol ; White rot basidiomycete ; Anisaldehyde ; Cytochrome P-450 ; Activated oxygen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized dihydroanisoin (1,2-dianisylethane-1,2 diol) in low nitrogen stationary cultures, conditions under which the ligninolytic system is expressed. Anisyl alcohol was isolated as a metabolic product indicating an initial diol bond cleavage of the substrate. Use of 3H-labeled dihydroanisoin (1,2-dianisylethane-1,2-diol-1,2 3H) indicated that the diol bond was cleaved directly, yielding anisyl aldehyde as the initial product. The metabolically stable ketol anisoin was shown not be an intermediate in the metabolism of dihydroanisoin. The diol cleavage reaction was dependent on the concentration of molecular oxygen but O2 could be replaced by H2O2 under some conditions. The cleavage reaction was inhibited by exogenously-added tyrosine2-Cu2+ complex (TCC). The appearance of the fungal diol cleavage system parallels the appearance of the ligninolytic system under a variety of physiological conditions. In addition, preincubation of ligninolytic cultures with 2.5 mM l-glutamate represses both the ligninolytic and the diol cleavage activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407806
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  • 4
    Electronic Resource
    Electronic Resource
    Metabolism of the lignin model compounds veratrylglycerol-β-guaiacyl ether and 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether by Phanerochaete chrysosporium (1980)
    Springer
    Archives of microbiology 125 (1980), S. 227-231 
    Details
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; β-aryl ether dimers ; Metabolism αβ cleavage ; Veratryl alcohol ; 4-ethoxy-3-methoxybenzyl alcohol ; Alkyl-phenyl cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot fungus Phanerochaete chrysosporium metabolized the lignin model compounds veratylglycerol-β-guaiacyl ether I and 4-ethoxy-3-methoxy-phenylglycerol-β-guaiacyl ether V in stationary culture under an atmosphere of 100% oxygen and under nitrogen limiting conditions. 2-(o-methoxyphenoxy)-ethanol VII was identified as a product of the metabolism of both substrates. Veratryl alcohol and 4-ethoxy-3-methoxybenzyl alcohol IV were identified as metabolites of I and V respectively. Metabolites were identified after comparison with chemically synthesized standards by mass spectrometry. These results indicate the existence of an enzyme system capable of directly cleaving the etherated dimers I and V at the α, β bond. The additional identification of 2-(o-methoxyphenoxy)-1,3 propanediol IX as a metabolic product indicates that cleavage of the alkyl-phenyl bond of these dimers or their metabolites also occurs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446881
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  • 5
    Electronic Resource
    Electronic Resource
    Degradation of the diarylpropane lignin model compound 1-(3′,4′-diethoxyphenyl)-1,3-dihydroxy-2-(4′'-methoxyphenyl)-propane and derivatives by the basidiomycete Phanerochaete chrysosporium (1982)
    Springer
    Archives of microbiology 132 (1982), S. 123-130 
    Details
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; Lignin degradation ; Diarylpropane ; α,β cleavage ; Anisyl alcohol ; Lignin ; Basidiomycete
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized 1-(3′,4′-diethoxyphenyl)-1,3(dihydroxy)-2-(4′'-methoxyphenyl)-propane (XII) in low nitrogen stationary cultures, conditions under which the ligninolytic enzyme system is expressed. 3,4-Diethoxybenzyl alcohol (IV), 1,2(dihydroxy)-1-(4′-methoxyphenyl)ethane (XX) and anisyl alcohol were isolated as metabolic products indicating an initial α, β bond cleavage of this dimer. Exogenously added XX was rapidly converted to anisyl alcohol, indicating that XX is an intermediate in the metabolism of XII. Fungal cleavage of the α, β bond of 1-(3′-4′-diethoxyphenyl)-1-(hydroxy)-2-(4′'-methoxyphenyl)ethane (XI) also occurred, indicating that a γ hydroxymethyl group is not a prerequisite for this reaction. P. chrysosporium also metabolized 1-(4′-ethoxy-3′-methoxyphenyl)-2,2(dihydroxy)-2-(4′'-methoxyphenyl)propane-1-ol (XIII). The major products of the degradation of this triol included 4-ethoxy-3-methoxybenzyl alcohol (III) and 2-hydroxy-1-(4′-methoxyphenyl)-1-oxoethane (XXI). The nature of the products formed indicates that this triol is also cleaved directly at the α,β bond. The significant difference in the nature of the products formed from the diaryl propane (XII) and the triol (XIII), however, suggests that XIII is not an intermediate in the major pathway for the degradation of XII. Metabolites were identified after comparison with chemically synthesized standards by GLC-mass spectrometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00508716
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  • 6
    Electronic Resource
    Electronic Resource
    Coagulation Protein Function V (Diminution of Antithrombin III Function by Acetaldehyde) (1998)
    Springer
    Digestive diseases and sciences 43 (1998), S. 1746-1751 
    Details
    ISSN: 1573-2568
    Keywords: ANTITHROMBIN III ; THROMBIN ; ACETALDEHYDE ; ALCOHOL ; ALCOHOLISM ; BLOOD COAGULATION
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The anticoagulant activity of antithrombin III(ATIII), as observed in a plasma-free system consistingof thrombin and fibrinogen, is readily reduced byacetaldehyde (AcH) at concentrations of 447, 89.4, and 17.9 mM. Whereas controlthrombin-fibrinogen mixtures clotted in 17.7 ±0.75 sec, ATIII prolonged clotting time to 55.0 ±1.75 sec on preincubation with thrombin for 30 min atroom temperature. On subsequent preincubation of ATIII with theAcH for 30 min at room temperature and passage of themixture through Sephadex G-25 minicolumns to removeexcess AcH, the eluates were tested for anticoagulant activity. Clotting times of 20.9 ± 1.0,32.3 ± 1.0, and 45.3 ± 1.6 sec wereobtained with 447, 89.4, and 17.9 mM AcH-ATIII mixtures,respectively. These data suggest that functional groupson ATIII, such as guanidiniums, aminos, and others aresusceptible to adduct formation with AcH, therebyaltering the shape and charge of the anticoagulant. Asa consequence of this type of reaction, an alteredmolecule of reduced biological activity may be produced.These experimental results may explain, in part, thereduction in ATIII levels reported by others in patientswith alcoholic liver disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018831619359
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  • 7
    Electronic Resource
    Electronic Resource
    Coagulation Protein Function VI (Augmentation of Anticoagulant Function by Acetaldehyde-Treated Heparin) (1999)
    Springer
    Digestive diseases and sciences 44 (1999), S. 1349-1355 
    Details
    ISSN: 1573-2568
    Keywords: ANTITHROMBIN III ; THROMBIN ; HEPARIN ; BLOOD COAGULATION ; ACETALDEHYDE ; ALCOHOL ; ALCOHOLISM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acetaldehyde (AcH) at preincubationconcentrations of 447, 89.4, and 17.9 mM potentiates theeffects of heparin on the clotting time of plasma. Whilecontrol plasma clotted in the range of 12.6 ± 0.1 to 13.8 ± 0.1 sec, and heparin-treatedplasma clotted in a range from 131.5 ± 2.5 to168.2 ± 1.2 sec, heparin that was preincubated atroom temperature for 30 min with 89.4 or 447 mM AcH didnot clot plasma in 300 sec. Heparin exposed to 17.9 mMAcH clotted plasma in 193 ± 1.1 sec. Ethanol ata 404 mM concentration also prolonged the clotting timeof heparin-treated plasma 〉300 sec, while 202 mM ethanol prolonged the clotting time ofheparin-treated plasma from 149.0 ± 2.0 sec to219.5 ± 1.7 sec. It is suggested that AcH altersthe tertiary structure of heparin by adduct formation,possibly by formation of cyclic acetals with iduronicand glucuronic acids, thereby more readily affectingbinding of the glycosaminoglycan to antithrombin IIIand/or thrombin, prolonging clotting time. Ethanol, which does not react covalently with heparin,might affect its conformation as a consequence of anorganic solvent effect. Protamine sulfate prolonged theclotting time of plasma from 13.6 ± 0.1 sec to 17.9 ± 0.2 sec. Protaminesulfate-treated heparin clotted plasma in 21.0 ±0.4 sec relative to heparin-treated plasma (160.4± 1.7 sec). In subsequent experiments,AcH-treated protamine sulfate extended the clotting time of protamine sulfate from17.9 ± 0 sec to 33.7 ± 0.6 sec. Prioraddition of protamine sulfate to AcH- heparin mixturesor heparin to protamine sulfate-AcH mixtures beforeaddition to plasma resulted in clotting times of 22.0± 0.4 sec and 24.1 ± 0.5 sec,respectively, relative to control clotting times of162.3 ± 2.6 sec for plasma-heparin mixtures.These results confirm both the reduction in coagulation time ofheparin-treated plasma by protamine sulfate and theprolongation of clotting time of plasma by protaminesulfate. Furthermore, and importantly, they indicatethat acetaldehyde-treated protamine sulfate is a more effectiveanticoagulant than protamine sulfate. It is suggestedthat reversible adduct formation between acetaldehyde,heparin, and protamine sulfate may occur as a meansexplaining the essentially identical coagulation time ofthese mixtures when added to plasma regardless of theorder of premixing. Ethanol (404 mM) did not influenceprotamine sulfate effects. Lastly, the potentiation of the anticoagulant function of heparin byacetaldehyde suggests that a structural modification ofthe glycosaminoglycan may occur in alcoholics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026635331519
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  • 8
    Electronic Resource
    Electronic Resource
    Coagulation Protein Function VII (Diametric Effects of Acetaldehyde on Factor VII and Factor IX Function) (1999)
    Springer
    Digestive diseases and sciences 44 (1999), S. 2564-2567 
    Details
    ISSN: 1573-2568
    Keywords: ALCOHOL ; COAGULATION ; FACTOR VII ; FACTOR IX ; ACETALDEHYDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The first metabolite of ethanol, acetaldehyde,has the ability to form adducts with proteins and altertheir function. It has been shown that acetaldehydereacts with various proteins of the blood coagulation pathway and, subsequently, produces aprolongation of the clotting time. This study evaluatedthe function of clotting proteins from the extrinsiccoagulation pathway (factor VII) and the intrinsiccoagulation pathway (factor IX) when preincubated withacetaldehyde as compared to a control and compared topreincubation with ethanol. Prior to use in a clottingassay, incubation times with acetaldehyde, ethanol, and the control were the same for both factorsVII and IX. An automatic fibrometer measured theclotting times. Factor VII preincubated withacetaldehyde prolonged the clotting time. However,factor IX preincubated with acetaldehyde actuallydecreased the clotting time. Of interest, both factorsVII and IX preincubated with acetaldehyde producedstatistically significant results when compared to thecontrol and ethanol. This experiment indicates thatacetaldehyde, in forming an adduct with proteins of theblood coagulation pathway, may induce a conformationalchange of factors VII and IX so as to either increase or decrease the clotting time. Therefore, it ispossible that some of the deranged coagulation inalcohol abusers may be a final net result of theinteraction of acetaldehyde and proteins of thecoagulation pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026615928562
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  • 9
    Electronic Resource
    Electronic Resource
    A molecular dynamics study of thermodynamic and structural aspects of the hydration of cavities in proteins (1991)
    New York : Wiley-Blackwell
    Biopolymers 31 (1991), S. 919-931 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure and activity of a protein molecule are strongly influenced by the extent of hydration of its cavities. This is, in turn, related to the free energy change on transfer of a water molecule from bulk solvent into a cavity. Such free energy changes have been calculated for two cavities in a sulfate-binding protein. One of these cavities contains a crystallo graphically observed water molecule while the other does not. Thermodynamic integration and perturbation methods were used to calculate free energies of hydration for each of the cavities from molecular dynamics simulations of two separate events: the removal of a water molecule from pure water, and the introduction of a water molecule into each protein cavity. From the simulations for the pure water system, the excess chemical potential of water was computed to be -6.4 ± 0.4 kcal/mol, in accord with experiment and with other recent theoretical calculations. For the protein cavity containing an experimentally observed water molecule, the free energy change on hydrating it with one water molecule was calculated as -10.0 ± 1.3 kcal/mol, indicating the high probability that this cavity is occupied by a water molecule. By contrast, for the cavity in which no water molecules were experimentally observed, the free energy change on hydrating it with one water molecule was calculated as 0.2 ± 1.5 kcal/mol, indicating its low occupancy by water. The agreement of these results with experiment suggests that thermodynamic simulation methods may become useful for the prediction and analysis of internal hydration in proteins.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360310802
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  • 10
    Electronic Resource
    Electronic Resource
    Design and Synthesis of Potent Macrocyclic Benzolactam Growth Hormone SecretagoguesDedicated to the Memory of Professor Wolfgang Oppolzer.2Deceased March 15, 1996. (1997)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 80 (1997), S. 1244-1259 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a variety of potent macrocyclic growth hormone secretagogues, i.e. 5, 9, 12, and 20-22, based on the known lead structure L-692,429 (1) is described. These conformationally constrained growth hormone secretagogues were prepared by joining the two essential pharmacophores, the amino-acid side chain at the 1H-1-benzazepine moiety and the 1,1′-biphenyl moiety with a variety of linkers. The most potent analog was found to be L-744,080 (21), a derivative in which a 2′-carboxamide moiety at 1,1-biphenyl is N,O-joined to the OH group of the (2-hydroxypropyl)amino-acid side chain by a C4 ester linker. This potent analog may be useful in determining the bound conformation of the benzolactam class of growth hormone secretagogues at the newly identified GHS receptor, L-744,080 (21) with an ED50 of 20 nM was up to fifty times more potent than the seco-acid precursor and 3-fold more potent than the parent 2′-tetrazole compound L-692, 429 (1).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19970800421
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