|Superclasses:||Reactions Classified By Conversion Type → Simple Reactions → Chemical Reactions|
|Reactions Classified By Substrate → Small-Molecule Reactions|
EC Number: 220.127.116.11
Supersedes EC numbers: 18.104.22.168, 22.214.171.124
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
Mass balance status: Balanced.
Enzyme Commission Primary Name: steroid 17α-monooxygenase
Enzyme Commission Synonyms: steroid 17α-hydroxylase, cytochrome P-45017α, cytochrome P-450 (P-45017α,lyase), 17α-hydroxylase-C17,20 lyase, CYP17, CYP17A1 (gene name)
Enzyme Commission Summary:
Requires NADPH and EC 126.96.36.199, NADPH--hemoprotein reductase. A microsomal hemeprotein that catalyses two independent reactions at the same active site - the 17α-hydroxylation of pregnenolone and progesterone, which is part of glucocorticoid hormones biosynthesis, and the conversion of the 17α-hydroxylated products via a 17,20-lyase reaction to form androstenedione and dehydroepiandrosterone, leading to sex hormone biosynthesis (EC 188.8.131.52, 7α-hydroxyprogesterone aldolase). The ratio of the 17α-hydroxylase and 17,20-lyase activities is an important factor in determining the directions of steroid hormone biosynthesis towards biosynthesis of glucocorticoid or sex hormones.
Unification Links: KEGG:R02131
Relationship Links: BRENDA:EC:184.108.40.206 , ENZYME:EC:220.127.116.11 , IUBMB-ExplorEnz:EC:18.104.22.168 , UniProt:RELATED-TO:P05093 , UniProt:RELATED-TO:P05185 , UniProt:RELATED-TO:P11715 , UniProt:RELATED-TO:P12394 , UniProt:RELATED-TO:P19100 , UniProt:RELATED-TO:P27786 , UniProt:RELATED-TO:P30437 , UniProt:RELATED-TO:Q64410 , UniProt:RELATED-TO:Q92113
Gilep03: Gilep AA, Estabrook RW, Usanov SA (2003). "Molecular cloning and heterologous expression in E. coli of cytochrome P45017alpha. Comparison of structural and functional properties of substrate-specific cytochromes P450 from different species." Biochemistry (Mosc) 68(1);86-98. PMID: 12693981
Pechurskaya08: Pechurskaya TA, Lukashevich OP, Gilep AA, Usanov SA (2008). "Engineering, expression, and purification of "soluble" human cytochrome P45017alpha and its functional characterization." Biochemistry (Mosc) 73(7);806-11. PMID: 18707589
Yoshida80: Yoshida KI, Oshima H, Troen P (1980). "Studies of the human testis. XIII. Properties of nicotinamide adenine dinucleotide (reduced form)-linked 17 alpha-hydroxylation." J Clin Endocrinol Metab 50(5);895-9. PMID: 6966286
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