Production of hydroxyl radicals and their role in the oxidation of ethanol by a reconstituted microsomal system containing cytochrome P-450 purified from phenobarbital-treated rats

Ethanol oxidation by a reconstituted system composed of cytochrome P-450 purified from liver microsomes of phenobarbital-treated rats, NADPH-cytochrome c reductase, phospholipid and NADPH was inhibited by a series of hydroxyl radical scavenging agents. Inhibition was competitive with respect to ethanol and was specific in the sense that the metabolism of aminopyrine or benzphetamine by the reconstituted system was not affected by the scavengers. The generation of ethylene gas from 2-keto-4-thiomethylbutyric acid in an ethanol-sensitive manner provided chemical evidence consistent with the ability of the reconstituted system to generate hydroxyl radicals. These results suggest that the oxidation of ethanol by the reconstituted system reflects the interaction of ethanol with hydroxyl radicals generated during NADPH oxidation.