THE ORGANELLES CONTAINING PORCINE 17-BETA-ESTRADIOL DEHYDROGENASE AREPEROXISOMES

Porcine 17 beta-estradiol dehydrogenase was recently purified and clon ed. It catalyzes the NAD(+)-dependent oxidation of estradiol to estron e 360-fold more efficiently than the reverse reaction with NADPH. Immu nogold electron microscopy localizes 17 beta-estradiol dehydrogenase i n organelles of 120 to 500 nm with moderate electron-dense matrices bo unded by single membranes. Antibodies against the peroxisomal markers catalase and acyl-CoA oxidase recognize the same organelles in double- labeling studies. This is the first report on the participation of per oxisomes in the metabolism of estradiol.