Catalase. Another enzyme, catalase, located in cell bodies called peroxisomes, is capable of oxidizing ethanol in vitro in the presence of a hydrogen peroxide (H2O2)-generating system, such as the enzyme complex NADPH oxidase or the enzyme xanthine oxidase. Quantitatively, however, this is considered a minor pathway of alcohol oxidation, except in the fasted state (Handler and Thurman 1990). Chronic alcohol consumption by rats has been shown to result in increased H2O2 production in pericentral regions of the liver and increased catalase activity (Misra et al. 1992). The role of CYP2E1 and catalase in alcohol metabolism in the brain are described in detail elsewhere (Zimatkin and Deitrich 1997).