ALCOHOL-NAD(-LIVER PEROXISOMES() OXIDOREDUCTASE IS PRESENT IN RAT)

Alcohol:NAD(+) oxidoreductase was found in the peroxisomes of animal l iver for the first time as follows. The distribution of alcohol:NAD(+) oxidoreductase activity with nonanol as substrate in the light mitoch ondrial fraction (peroxisome-enriched fraction) of rat liver was exami ned by centrifugation in a sucrose density gradient. Most of the enzym e activity was localized in the mitochondria, with some activity in th e peroxisomes. The administration of clofibrate, a peroxisome prolifer ator, to rats resulted in a marked increase of the enzyme activity in the peroxisomes, but not in the mitochondria. The enzyme was found to be located in the matrix of the peroxisomes. The evidence was obtained that the enzyme differed from alcohol dehydrogenases and alcohol oxid izing systems found previously. The enzyme activity was not affected b y pyrazole, an inhibitor of alcohol dehydrogenase and sodium azide, an inhibitor of catalase. The enzyme was NAD(+)-dependent and oxidized s traight chain aliphatic alcohols with a variety of carbon chains (C-2- C-18), showing the maximum on nonanol. K-m values toward these aliphat ic alcohols decreased with increasing chain length. The major reaction product was identified as the carboxylic acid by using high performan ce liquid chromatography.