This family of trans-2-enoyl-CoA reductases, EC:1.3.1.44, carries the the catalytic sites of the enzyme, characterised by the conserved sequence motifs: YNThhhFxK, and YShAPxR. In Euglena where the enzyme has been characterised it catalyses the reduction of enoyl-CoA to acyl-CoA in an unusual fatty acid pathway in mitochondria. the whole path performs a malonyl-CoA independent synthesis of fatty acids leading to accumulation of wax esters, which serve as the sink for electrons stemming from glycolytic ATP synthesis and pyruvate oxidation.

1: Mitochondrial trans-2-enoyl-CoA reductase of wax ester fermentation from Euglena gracilis defines a new family of enzymes involved in lipid synthesis. Hoffmeister M, Piotrowski M, Nowitzki U, Martin W; J Biol Chem. 2005;280:4329-4338. PMID:15569691