CONTRIBUTION, EVALUATION AND STEREOCHEMICAL CHARACTERIZATION OF THE HYDROXYL RADICAL DEPENDENT AND CYTOCHROME P450 DEPENDENT PATHWAYS IN MICROSOMAL ALCOHOL OXIDATIONS.
Item
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Title
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CONTRIBUTION, EVALUATION AND STEREOCHEMICAL CHARACTERIZATION OF THE HYDROXYL RADICAL DEPENDENT AND CYTOCHROME P450 DEPENDENT PATHWAYS IN MICROSOMAL ALCOHOL OXIDATIONS.
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Identifier
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AAI8501151
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identifier
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8501151
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Creator
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KRIKUN, GRACIELA.
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Contributor
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A. I. Cederbaum
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Date
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1984
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biophysics, Medical
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Abstract
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Isolated rat liver microsomes can oxidize a variety of alcohols to their corresponding aldehydes. Recent experiments have suggested that microsomes have the potential to oxidize alcohols by two pathways: one dependent on hydroxyl radicals, the other apparently dependent on cytochrome P450.;Studies in this thesis were carried out to determine the loci of each pathway in intact microsomes. As was the case in reconstituted systems, it was seen that the hydroxyl radical dependent pathway was dependent on NADPH-cytochrome-P450 reductase. It was also shown that the cytochrome P450 pathway could be inhibited by levels of carbon monoxide which did not cause anaerobiosis and hence did not inhibit the formation of oxygen radicals.;The role of each pathway was compared for microsomes isolated from chronic alcohol induced rats versus their pair fed controls. It was seen that the increase in ethanol oxidation after alcohol treatment was due to the increase in both pathways and that the percent contribution of each pathway was the same as it was for control rats.;Stereospecificity studies were carried out with microsomes from normal and differently induced rats. Results show that neither pathway was stereospecific with microsomes from control, phenobarbital induced or dextrose pair fed animals. On the other hand, microsomes isolated from ethanol treated rats displayed stereospecificity via the cytochrome P450 pathway for the (+) isomer of 2-butanol. Initial experiments showed that 2-butanol was a particularly good alcohol substrate for the cytochrome P450 pathway, especially with microsomes from ethanol treated rats. 2-Butanol displayed a binding spectrum with microsomes from alcohol induced rats but not with microsomes from control or phenobarbital treated animals. Similar results were observed with dimethyl sulfoxide.;Injecting rats with pyrazole for 3 days seemed to induce a cytochrome P450 isozyme with properties similar to those described for chronic ethanol consumption.;The use of spectra and stereospecificity in conjunction with increased microsomal oxidation of alcohols can therefore be used to study the induction of the alcohol preferring P450 isozyme(s).
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Biomedical Sciences
