Cytochrome P450 family 4, subfamily V, polypeptide 2 (CYP4V2) is the most characterized member of the CYP4V subfamily. It is a selective omega-hydroxylase of saturated, medium-chain fatty acids, such as laurate, myristate and palmitate, with high catalytic efficiency toward myristate. Polymorphisms in the CYP4V2 gene cause Bietti's crystalline corneoretinal dystrophy (BCD), a recessive degenerative retinopathy that is characterized clinically by a progressive decline in central vision, night blindness, and constriction of the visual field. The CYP4V subfamily belongs to the large cytochrome P450 (P450, CYP) superfamily of heme-containing proteins that catalyze a variety of oxidative reactions of a large number of structurally different endogenous and exogenous compounds in organisms from all major domains of life. CYPs bind their diverse ligands in a buried, hydrophobic active site, which is accessed through a substrate access channel formed by two flexible helices and their connecting loop.