The role of cytochrome P-450 in the hydroperoxide-catalyzed oxidation of alcohols by rat-liver microsomes.
The organic hydroperoxide cumene hydroperoxide is capable of oxidizing ethanol to acetaldehyde in the presence of either catalase, purified cytochrome P-450 or rat liver microsomes. Other hemoproteins like horseradish peroxidase, cytochrome c or hemoglobin were ineffective. In addition to ethanol, higher alcohols like 1-propanol, 1-butanol and 1-pentanol are also oxidized to their corresponding aldehydes to a lesser extent. Other organic hydroxyperoxides will replace cumene hydroperoxide in oxidizing ethanol but less effectively. The cumene-hydroperoxide-dependent ethanol oxidation in microsomes was inhibited partially by cytochrome P-450 inhibitors but was unaffected by catalase inhibitors. Phenobarbital pretreatment of rats increased the specific activity of the cumene-hydroperoxide-dependent ethanol oxidation per mg of microsomes about seven-fold. The evidence suggests that cytochrome P-450 rather than catalase is the enzyme responsible for hydroperoxide-dependent ethanol oxidation. However, when H2O2 is used in place of cumene hydroperoxide, the microsomal ethanol oxidation closely resembles the catalase system.
D000438:Alcohols / Q000378:metabolism*; D000818:Animals; D001555:Benzene Derivatives; D001593:Benzyl Compounds / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006898:Hydroxylamines / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D008797:Metyrapone / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D010545:Peroxides / Q000494:pharmacology*; D051381:Rats
D000438:Alcohols; D001555:Benzene Derivatives; D001593:Benzyl Compounds; D006898:Hydroxylamines; D010545:Peroxides; D000431:Ethanol; D003577:Cytochrome P-450 Enzyme System; D006735:Horseradish Peroxidase; D002374:Catalase; C007164:cumene hydroperoxide; D008797:Metyrapone