IUBMB Enzyme Nomenclature


Accepted name: 17α-hydroxyprogesterone deacetylase

Reaction: (1) 17α-hydroxyprogesterone + [reduced NADPH—hemoprotein reductase] + O2 = androstenedione + acetate + [oxidized NADPH—hemoprotein reductase] + H2O
(2) 17α-hydroxypregnenolone + [reduced NADPH—hemoprotein reductase] + O2 = 3β-hydroxyandrost-5-en-17-one + acetate + [oxidized NADPH—hemoprotein reductase] + H2O

Glossary: androstenedione = androst-4-ene-3,17-dione

Other name(s): C-17/C-20 lyase; 17α-hydroxyprogesterone acetaldehyde-lyase; CYP17; CYP17A1 (gene name); 17α-hydroxyprogesterone 17,20-lyase

Systematic name: 17α-hydroxyprogesterone,NADPH—hemoprotein reductase:oxygen oxidoreductase (17α-hydroxylating, acetate-releasing)

Comments: A microsomal cytochrome P-450 (heme-thiolate) protein that catalyses two independent reactions at the same active site - the 17-hydroxylation of pregnenolone and progesterone, which is part of glucocorticoid hormones biosynthesis (EC, and the conversion of the 17-hydroxylated products via a 17,20-lyase reaction to form androstenedione and 3β-hydroxyandrost-5-en-17-one, leading to sex hormone biosynthesis. The activity of this reaction is dependent on the allosteric interaction of the enzyme with cytochrome b5 without any transfer of electrons from the cytochrome [2,4]. The enzymes from different organisms differ in their substrate specificity. While the enzymes from pig, hamster, and rat accept both 17α-hydroxyprogesterone and 17α-hydroxypregnenolone, the enzymes from human, bovine, sheep, goat, and bison do not accept the former, and the enzyme from guinea pig does not accept the latter [1].

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. 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]

2. Auchus, R.J., Lee, T.C. and Miller, W.L. Cytochrome b5 augments the 17,20-lyase activity of human P450c17 without direct electron transfer. J. Biol. Chem. 273 (1998) 3158-3165. [PMID: 9452426]

3. Mak, P.J., Gregory, M.C., Denisov, I.G., Sligar, S.G. and Kincaid, J.R. Unveiling the crucial intermediates in androgen production. Proc. Natl. Acad. Sci. USA 112 (2015) 15856-15861. [PMID: 26668369]

4. Simonov, A.N., Holien, J.K., Yeung, J.C., Nguyen, A.D., Corbin, C.J., Zheng, J., Kuznetsov, V.L., Auchus, R.J., Conley, A.J., Bond, A.M., Parker, M.W., Rodgers, R.J. and Martin, L.L. Mechanistic scrutiny identifies a kinetic role for cytochrome b5 regulation of human cytochrome P450c17 (CYP17A1, P450 17A1). PLoS One 10 (2015) e0141252. [PMID: 26587646]

5. Bhatt, M.R., Khatri, Y., Rodgers, R.J. and Martin, L.L. Role of cytochrome b5 in the modulation of the enzymatic activities of cytochrome P450 17α-hydroxylase/17,20-lyase (P450 17A1). J. Steroid Biochem. Mol. Biol. (2016) . [PMID: 26976652]

[EC created 1976 as EC, transferred 2016 to EC]

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