Ultrastructural localization of L-alpha-hydroxy acid oxidase in rat liver perioxisomes

Abstract

The localization of L-alpha-hydroxy acid oxidase in rat liver peroxisomes was studied using slight modifications of the Shnitka and Talibi (1971) method. Best results were obtained with formaldehyde fixation and incubation with glycolate as substrate. Following incubation the copper ferrocyanide reaction product was amplified with 3,3'-diamino-benzidine according to Hanker et al. (1972a,b). Dense reaction product was visible in hepatocyte peroxisomes by light and electron microscopy. Some diffusion of enzyme and/or reaction product into the adjacent cytoplasm occurred around the peroxisomes. Apparent non-specific deposits occurred on the plasmalemma, in the nucleus, and occasionally over mitochondria. Glutaraldehyde fixation severely inhibited enzymatic activity, and the enzyme showed less activity toward L-lactate and DL-alpha-hydroxybutyrate.