Peroxisomal Acyl-Coenzyme A Oxidase Is a Rate-Limiting Enzyme in a Very Long-Chain Fatty Acid β-Oxidation System

Abstract The contents of peroxisomal fatty acid β-oxidation enzymes in three rat hepatoma cell lines, i.e ., H4IIEC3 (H4), N1S1, and McA-RH7777 (H7), were measured by immunoblot analysis, and a significant difference in acyl-coenzyme A oxidase (AOX) content became evident. These cell lines were respectively infected with a recombinant virus to express significant amounts of AOX protein. The expressed AOX mainly localized in organelle, supposing peroxisomes, and was catalytically active. The cDNA-expression in H4, N1S1, and H7 cells enhanced 2.6-, 2.2-, and 1.0-fold β-oxidation activity of lignoceric acid, respectively. The enhancement in H4 and NISI cells suggests that AOX is a rate-limiting enzyme in the very-long-chain fatty acid β-oxidation system, in these cell lines.