Document Detail


Ethanol-metabolizing pathways in deermice. Estimation of flux calculated from isotope effects.
MedLine Citation:
PMID:  3294834     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The apparent deuterium isotope effects on Vmax/Km (D(V/K] of ethanol oxidation in two deermouse strains (one having and one lacking hepatic alcohol dehydrogenase (ADH] were used to calculate flux through the ADH, microsomal ethanol-oxidizing system (MEOS), and catalase pathways. In vitro, D(V/K) values were 3.22 for ADH, 1.13 for MEOS, and 1.83 for catalase under physiological conditions of pH, temperature, and ionic strength. In vivo, in deermice lacking ADH (ADH-), D(V/K) was 1.20 +/- 0.09 (mean +/- S.E.) at 7.0 +/- 0.5 mM blood ethanol and 1.08 +/- 0.10 at 57.8 +/- 10.2 mM blood ethanol, consistent with ethanol oxidation principally by MEOS. Pretreatment of ADH- animals with the catalase inhibitor 3-amino-1,2,4-triazole did not significantly change D(V/K). ADH+ deermice exhibited D(V/K) values of 1.87 +/- 0.06 (untreated), 1.71 +/- 0.13 (pretreated with 3-amino-1,2,4-triazole), and 1.24 +/- 0.13 (after the ADH inhibitor, 4-methylpyrazole) at 5-7 mM blood ethanol levels. At elevated blood ethanol concentrations (58.1 +/- 2.4 mM), a D(V/K) of 1.37 +/- 0.21 was measured in the ADH+ strain. For measured D(V/K) values to accurately reflect pathway contributions, initial reaction conditions are essential. These were shown to exist by the following criteria: negligible fractional conversion of substrate to product and no measurable back reaction in deermice having a reversible enzyme (ADH). Thus, calculations from D(V/K) indicate that, even when ADH is present, non-ADH pathways (mostly MEOS) participate significantly in ethanol metabolism at all concentrations tested and play a major role at high levels.
Authors:
J Alderman; T Takagi; C S Lieber
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  262     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1987 Jun 
Date Detail:
Created Date:  1987-07-02     Completed Date:  1987-07-02     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  7497-503     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Acetates / metabolism
Alcohol Dehydrogenase / genetics,  metabolism*
Animals
Carbon Radioisotopes
Deuterium
Ethanol / metabolism*
Kinetics
Liver / metabolism
Male
Peromyscus / metabolism*
Radioisotope Dilution Technique
Rats
Rats, Inbred Strains
Species Specificity
Grant Support
ID/Acronym/Agency:
AA03508/AA/NIAAA NIH HHS; AA05934/AA/NIAAA NIH HHS; AA07275/AA/NIAAA NIH HHS
Chemical
Reg. No./Substance:
0/Acetates; 0/Carbon Radioisotopes; 64-17-5/Ethanol; 7782-39-0/Deuterium; EC 1.1.1.1/Alcohol Dehydrogenase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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