[An organic peroxide, methyl ethyl ketone peroxide, damage to cytochrome P-450 peroxidase and microsomal enzymes activity].

In vivo, an organic peroxide, methyl ethyl ketone peroxide (MEKP) damaged microsomal cytochrome P-450 and cytochrome P-450 peroxidase in vitamin E deficient rat livers. Dietary vitamin E protected the microsomal enzymes from MEKP damage. Phenobarbital induced liver cytochrome P-450 peroxidase and glutation S-transferase and decreased MEKP damage on microsomal enzymes. MEKP induced production of more lipid peroxides (TBARS) in liver microsomes from vitamin E deficient rats than from vitamin E supplemented rats. Cytochrome P-450 and aminopyrine demethylase from vitamin E deficient rat microsomes were damaged to a greater extent by MEKP than were those from vitamin E supplemented rat microsomes. MEKP markedly inhibited liver microsomal TMPDand NADHperoxidase. In vivo, adequate levels of vitamin E, NADH, and NADPH are probably necessary to provide important protection to the endoplasmic reticulum from damage by organic peroxides.