a very-long-chain (3R)-3-hydroxyacyl-CoA = a very-long-chain (2E)-enoyl-CoA + H2O (3R)-hydroxyhexadecanoyl-CoA = (2E)-hexadecenoyl-CoA + H2O (3R)-hydroxyoctadecanoyl-CoA = (2E)-octadecenoyl-CoA + H2O (3R)-hydroxyeicosanoyl-CoA = (2E)-eicosenoyl-CoA + H2O (3R)-hydroxydocosanoyl-CoA = (2E)-docosenoyl-CoA + H2O (3R)-hydroxytetracosanoyl-CoA = (2E)-tetracosenoyl-CoA + H2O (3R)-hydroxyhexacosanoyl-CoA = (2E)-hexacosenoyl-CoA + H2O Lipid metabolism; fatty acid biosynthesis. May interact with enzymes of the ELO family (including ELOVL1); with those enzymes that mediate condensation, the first of the four steps of the reaction cycle responsible for fatty acids elongation, may be part of a larger fatty acids elongase complex. Expressed at high levels in heart, skeletal muscle and testis, weak expression in kidney and liver. Differentially expressed during embryogenesis. First detected throughout the somites at 8.5 dpc and in the myotome at 11.5 dpc. Expression was observed in muscles ventral to the developing vertebral column of the neck, thorax, abdomen and tail. Expression was maintained in skeletal muscle types well after the terminal differentiation of muscle fibers. During cardiac development, expression was restricted to the myocytes of the primitive heart tube, and by 10.5 dpc, it was expressed in the muscles throughout all the cardiac chambers. At this last stage it is also detected in the hepatic primordia, and later in embryonic liver. By 15.5 expression was also observed in the smooth muscle surrounding the digestive, respiratory and urogenital tracts. N-glycosylated. Belongs to the very long-chain fatty acids dehydratase HACD family. Shares some similarity with tyrosine phosphatase proteins but it has probably no phosphatase activity.