Intraparticulate localization of some peroxisomal enzymes related to fatty acid beta-oxidation

Male Wistar rats were given a diet containing 0.05% (w/w) LK-903 (alpha-methyl-p-myristyroxycinnamic acid 1-monoglyceride) for 2 weeks. The activities of four hepatic peroxisomal enzymes involved in the fatty acyl-CoA beta-oxidizing system were determined. The activities of fatty acyl-CoA oxidase, crotonase, beta-hydroxybutyryl-CoA dehydrogenase and thiolase were all increased about three times by administration of LK-903. The intraparticulate localizations of the four enzymes were then investigated by treatment of the purified peroxisomes with Triton X-100, by sonication, and by sucrose-density-gradient centrifugation after Triton X-100 treatment. The results suggest that thiolase is localized in the matrix of peroxisomes, that crotonase and beta-hydroxybutyryl-CoA dehydrogenase are located in the core, and that all or at least part of fatty acyl-CoA oxidase is associated with the core, though its association is weak.