Involvement of the fatty acid oxidation complex in acetyl-CoA-dependent chain elongation of fatty acids in Escherichia coli

The activity of acetyl-CoA-dependent chain elongation of fatty acids in Escherichia coli was enhanced when the organism was grown on oleic acid as the sole carbon source, but not detected when grown on glucose. Antibodies raised against fatty acid oxidation complex of E. coli inhibited both the reaction catalyzed by crotonase and the chain elongation in a similar manner, showing that the oxidation complex participates in the chain elongation. The activities of condensation and the activities of NADH- and NADPH-dependent 3-ketoacyl reduction in the cell-free extract were precipitated by antibodies to the complex in parallel with those of 3-ketoacyl-CoA thiolase and crotonase. These results together with the presence of NADPH-dependent trans-2-enoyl-CoA reductase in E. coli (Mizugaki, et al. (1982) Chem. Pharm. Bull. 30, 2503-2511) indicate that the acetyl-CoA-dependent chain elongation of fatty acids in E. coli occurs by the reversal of fatty acid oxidation other than the step of enoyl reduction.