7alpha-hydroxycholest-4-en-3-one 12alpha-hydroxylase

7alpha-hydroxycholest-4-en-3-one 12alpha-hydroxylase
Identifiers
EC number	1.14.13.95
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

In enzymology, a 7alpha-hydroxycholest-4-en-3-one 12alpha-hydroxylase (EC 1.14.13.95) is an enzyme that catalyzes the chemical reaction

7alpha-hydroxycholest-4-en-3-one + NADPH + H⁺ + O₂ $\rightleftharpoons$ 7alpha,12alpha-dihydroxycholest-4-en-3-one + NADP⁺ + H₂O

The 4 substrates of this enzyme are 7alpha-hydroxycholest-4-en-3-one (7 alpha-hydroxy-4-cholesten-3-one, NADPH, H⁺, and O₂, whereas its 3 products are 7alpha,12alpha-dihydroxycholest-4-en-3-one, NADP⁺, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with NADH or NADPH as one donor, and incorporation of one atom o oxygen into the other donor. The systematic name of this enzyme class is 7alpha-hydroxycholest-4-en-3-one,NADPH:oxygen oxidoreductase (12alpha-hydroxylating).

This enzymatic activity is performed by CYP8B1.^[1]

Other names used include 7alpha-hydroxy-4-cholesten-3-one 12alpha-monooxygenase, CYP12, sterol 12alpha-hydroxylase (ambiguous), and HCO 12alpha-hydroxylase. This enzyme participates in ppar signaling pathway.

References

1. "Entrez Gene: CYP8B1".

• Ishida H, Noshiro M, Okuda K, Coon MJ (1992). "Purification and characterization of 7 alpha-hydroxy-4-cholesten-3-one 12 alpha-hydroxylase". J. Biol. Chem. 267 (30): 21319–23. PMID 1400444.
• Okuda KI, Bjorkhem I (1996). "Molecular cloning and expression of rabbit sterol 12alpha-hydroxylase". J. Biol. Chem. 271 (50): 32269–75. doi:10.1074/jbc.271.50.32269. PMID 8943286.
• Russell DW (2003). "The enzymes, regulation, and genetics of bile acid synthesis". Annu. Rev. Biochem. 72: 137–74. doi:10.1146/annurev.biochem.72.121801.161712. PMID 12543708.