Essential for the beta oxidation of unsaturated fatty acids. a (3Z)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA a (3E)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA Lipid metabolism; fatty acid beta-oxidation. Homohexamer, dimer of trimers. Interacts with DCI1. This location is DCI1 dependent. By oleate. Belongs to the enoyl-CoA hydratase/isomerase family.