This gene encodes a member of the hydratase/isomerase superfamily. The protein encoded is a key mitochondrial enzyme involved in beta-oxidation of unsaturated fatty acids. It catalyzes the transformation of 3-cis and 3-trans-enoyl-CoA esters arising during the stepwise degradation of cis-, mono-, and polyunsaturated fatty acids to the 2-trans-enoyl-CoA intermediates. Alternatively spliced transcript variants have been described.ECI2 (Enoyl-CoA Delta Isomerase 2) is a Protein Coding gene. Diseases associated with ECI2 include Moyamoya Disease. Among its related pathways are Peroxisome and Fatty acid metabolism. GO annotations related to this gene include receptor binding and dodecenoyl-CoA delta-isomerase activity. An important paralog of this gene is CDYL2.