cytochrome P450 family 24 subfamily A, polypeptide 1 and similar cytochrome P450s
This family is composed of vertebrate cytochrome P450 24A1 (CYP24A1) and similar proteins including several Drosophila proteins such as CYP315A1 (also called protein shadow) and CYP314A1 (also called ecdysone 20-monooxygenase), and vertebrate CYP11 and CYP27 subfamilies. Both CYP314A1 and CYP315A1, which has ecdysteroid C2-hydroxylase activity, are involved in the metabolism of insect hormones. CYP24A1 and CYP27B1 have roles in calcium homeostasis and metabolism, and the regulation of vitamin D. CYP24A1 catabolizes calcitriol (1,25(OH)2D), the physiologically active vitamin D hormone, by catalyzing its hydroxylation, while CYP27B1 is a calcidiol 1-monooxygenase that coverts 25-hydroxyvitamin D3 to calcitriol. The CYP24A1-like family 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.