Rat liver fatty acid-binding protein (FABP) can function as a fatty acid donor protein for both peroxisomal and mitochondrial fatty acid oxidation, since 14C-labeled palmitic acid bound to FABP is oxidized by both organelles. FABP is, however, not detected in peroxisomes and mitochondria of rat liver by ELISA. Acyl-CoA oxidase activity of isolated peroxisomes was not changed by addition of FABP or flavaspidic acid, an inhibitor of fatty acid binding to FABP, nor by disruption of the peroxisomal membranes. These data indicate that FABP may transfer fatty acids to peroxisomes, but is not involved in the transport of acyl-CoA through the peroxisomal membrane.
