| abstract |
cytochrome P450 family 26, subfamily C, polypeptide 1. Cytochrome P450 26C1 (CYP26C1) is a retinoic acid-metabolizing cytochrome that plays key roles in retinoic acid (RA) metabolism. It effectively metabolizes all-trans retinoic acid (atRA), 9-cis-retinoic acid (9-cis-RA), 13-cis-retinoic acid, and 4-oxo-atRA with the highest intrinsic clearance toward 9-cis-RA. RA is a critical signaling molecule that regulates gene transcription and the cell cycle. Loss of function mutations in the CYP26C1 gene cause type IV focal facial dermal dysplasia (FFDD), a rare syndrome characterized by facial lesions resembling aplasia cutis. CYP26C1 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. |