Kinetics and Control of Alcohol Oxidation in Rats

  • Wen-Sherng Chen
  • Bryce V. Plapp


The rates of oxidation of ethanol and isopropanol by purified rat liver alcohol dehydrogenase were determined in vitro and compared to the rates of metabolism in vivo in order to estimate the extent to which alcohol dehydrogenase activity limits ethanol metabolism. The metabolism of isopropanol and isopropanol-d7 (CD3CDOHCD3) was examined by measuring blood alcohol and acetone levels at various times and apparently proceeds by an irreversible, enzyme-catalyzed pathway: isopropanol → acetone → an unidentified metabolite. The kinetic constants for the metabolism were computed from simultaneous fits to the appropriate differential equations using a nonlinear least-squares program. The relative rates of oxidation of the alcohols, ethanol:isopropanol:isopropanol-d7, at 25 mM were 9.6: 2.3: 1.0 in vitro and 4.1: 2.4: 1.0 in vivo. Since the ratio of rates for isopropanol is about the same in vitro and in vivo it appears that alcohol dehydrogenase activity is the predominant rate-limiting factor in isopropanol metabolism. The relatively slower rate of ethanol oxidation in vivo as compared to in vitro suggests that liver alcohol dehydrogenase is partially (about 40%) limiting for ethanol metabolism.


Alcohol Dehydrogenase Ethanol Oxidation Alcohol Oxidation Ethanol Metabolism Alcohol Dehydrogenase Activity 
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Copyright information

© Springer Science+Business Media New York 1980

Authors and Affiliations

  • Wen-Sherng Chen
    • 1
  • Bryce V. Plapp
    • 1
  1. 1.Department of BiochemistryThe University of IowaIowa CityUSA

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