Abstract
To assess whether catalase-H2O2 is an obligatory component in the microsomal alcoholoxidizing system, various primary alcohols were incubated with hepatic microsomes of both normal and acatalasemic mice in the presence of an NADPH-genenating system. Methanol, ethanol, propanol, butanol, and pentanol were metabolized at striking rates by microsomes of both strains. By contrast, when the NADPH-generating system was replaced by a H2O2-producing one, propanol, butanol, and pentanol were not metabolized, indicating that these higher aliphatic alcohols are not substrates for catalase-H2O2. Furthermore, mild heat treatment of microsomes of acatalasemic mice resulted in inactivation of contaminating catalase and virtually abolished alcohol peroxidation of methanol and ethanol by catalase-H2O2, whereas the rates of the NADPH-mediated alcohol oxidation by the microsomal fraction persisted with methanol, ethanol, propanol, butanol, and pentanol as substrates. In addition, the microsomal alcohol-oxidizing system of both normal and acatalasemic mice was solubilized and isolated from catalase by DEAE-cellulose column chromatography. These findings therefore dissociate the NADPH-dependent microsomal alcohol-oxidizing system from alcohol peroxidation via catalase-H2O2 by difference in substrate specificity and rule out an obligatory involvement of catalase-H2O2 in the microsomal system.
ACKNOWLEDGMENTS The authors thank Miss L. M. DeCarli and Miss N. Lowe for their excellent technical assistance and valuable discussions throughout this study.
- Copyright ©, 1975, by Academic Press, Inc.
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