Abstract

Hepatic oxidases were studied in rat and monkey liver homogenates and subcellular fractions for their capacity to provide hydrogen peroxide for the catalase-dependent peroxidative oxidation of methanol. Urate oxidase and glycolate oxidase were the most active hepatic hydrogen peroxide-generating enzymes in the rat; much less activity was found in preparations obtained from monkey liver. Supplementation of solubilized hepatic microbodies or cell sap from either species with an exogenous hydrogen peroxide-generating system stimulated methanol oxidation above rates obtained when uric acid or glycolic acid was used to enhance methanol oxidation. Addition of crystalline catalase did not affect the rate of methanol oxidation. These studies indicate that hydrogen peroxide generation is rate-limiting in the peroxidation of methanol in both rat and monkey liver, and the low activity of oxidases in monkey liver may explain the lack of peroxidative oxidation of methanol in this species.