DISTRIBUTION AND IMMUNOCHEMICAL PROPERTIES OF RAT KIDNEY L-AMINO-ACID OXIDASE WITH A NOTE ON PEROXISOMES

An amino-acid oxidase in rat kidney cells has been located mainly in peroxisomes and the soluble fraction. The peroxisomes were isolated as a bright yellow pellet from the fraction comprising mitochondria and light mitochondria by sucrose density gradient centrifugation. The particles contained l-amino acid oxidase in the ratio to total peroxisomal protein of 1:4 The enzyme in the subcellular particles could be easily solubilized by treatment with Triton X-100 without causing inactivation or immunochemical changes. The enzyme was found to be essentially the same in all subcellular fractions, as judged by the immunochemical studies and electrophoretic data. No enzyme which catalyzes the dehydrogenation of l-lactate or l-a-hydroxyisocaproate without added NAD+ or flavin cofactors, other than l-amino-acid oxidase, was present in the rat kidney cells. The soluble fraction in rat kidney cells contained an unknown dialyzable activator of l amino acid oxidase. © 1969.