Detection of acyl-CoA beta-oxidation enzymes in peroxisomes (microperoxisomes) of mouse heart

Homogenate of mouse heart was analyzed by using rate-dependent banding followed by density-dependent banding in sucrose density gradients held in zonal rotors. This protocol allowed substantial separation of myocardial microperoxisomes from other organelles. Particulate acyl-CoA oxidase activity was localized in microperoxisomes, while beta-hydroxyacyl-CoA dehydrogenase, carnitine acetyltransferase, carnitine octanoyltransferase and probably enoyl-CoA hydratase were partially localized in these organelles with most of the activity residing in the mitochondria. The specific activity of acyl-CoA oxidase in the peak microperoxisome fraction was at least 1/3 to 1/4 of that in highly purified renal or hepatic peroxisomes from mouse.