Studies on the Metabolism of Unsaturated Fatty Acids. VIII. Induction of 2,4-Dienoyl-CoA Reductase in Escherichia coli on the Addition of Unsaturated Fatty Acids1

2,4-Dienoyl-CoA reductase has been detected in crude extracts of E. coli. The reductase was shown to be induced many fold when the cells were grown in the presence of linoleic or oleic acid. The activity profile of the reductase on gel filtration was different from those of other enoyl reductases. These results suggest that there are two pathways even in E. coli for the degradation of cis-4-decenoyl-CoA, which is an intermediate in the beta-oxidation of linoleic acid, as recently proposed in rat liver.