Able to isomerize both 3-cis and 3-trans double bonds into the 2-trans form in a range of enoyl-CoA species. a (3Z)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA a (3E)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA (3Z)-octenoyl-CoA = (2E)-octenoyl-CoA (2E)-tetradecenoyl-CoA = (3Z)-tetradecenoyl-CoA Lipid metabolism; fatty acid beta-oxidation. Homotrimer. Expressed in liver (at protein level). Belongs to the enoyl-CoA hydratase/isomerase family.