Reaction: a C21-steroid + [reduced NADPH—hemoprotein reductase] + O2 = a 17α-hydroxy-C21-steroid + [oxidized NADPH—hemoprotein reductase] + H2O
Other name(s): steroid 17α-hydroxylase; cytochrome P-450 17α; cytochrome P-450 (P-450 17α,lyase); 17α-hydroxylase-C17,20 lyase; CYP17; CYP17A1 (gene name)
Systematic name: steroid,NADPH—hemoprotein reductase:oxygen oxidoreductase (17α-hydroxylating)
Comments: Requires NADPH and EC 1.6.2.4, 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 1.14.14.32, 7α-hydroxyprogesterone deacetylase). 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.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Lynn, W.S. and Brown, R.H. The conversion of progesterone to androgens by testes. J. Biol. Chem. 232 (1958) 1015-1030. [PMID: 13549484]
2. Yoshida, K.-I., Oshima, H. and Troen, P. Studies of the human testis. XIII. Properties of nicotinamide adenine dinucleotide (reduced form)-linked 17α-hydroxylation. J. Clin. Endocrinol. Metab. 50 (1980) 895-899. [PMID: 6966286]
3. Gilep, A.A., Estabrook, R.W. and Usanov, S.A. Molecular cloning and heterologous expression in E. coli of cytochrome P45017α. Comparison of structural and functional properties of substrate-specific cytochromes P450 from different species. Biochemistry (Mosc.) 68 (2003) 86-98. [PMID: 12693981]
4. Kolar, N.W., Swart, A.C., Mason, J.I. and Swart, P. Functional expression and characterisation of human cytochrome P45017α in Pichia pastoris. J. Biotechnol. 129 (2007) 635-644. [PMID: 17386955]
5. Pechurskaya, T.A., Lukashevich, O.P., Gilep, A.A. and Usanov, S.A. Engineering, expression, and purification of "soluble" human cytochrome P45017α and its functional characterization. Biochemistry (Mosc.) 73 (2008) 806-811. [PMID: 18707589]