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cytochrome P450 family 8, subfamily B, polypeptide 1 Cytochrome P450 8B1 (CYP8B1) is also called 7-alpha-hydroxycholest-4-en-3-one 12-alpha-hydroxylase (EC 1.14.18.8) or sterol 12-alpha-hydroxylase. It is involved in the classic (or neutral) pathway of cholesterol catabolism and bile acid synthesis, and is responsible for sterol 12alpha-hydroxylation, which directs the synthesis to cholic acid (CA). It converts 7-alpha-hydroxy-4-cholesten-3-one into 7-alpha,12-alpha-dihydroxy-4-cholesten-3-one, but also displays broad substrate specificity including other 7-alpha-hydroxylated C27 steroids. CYP8B1 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. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",