IUBMB Enzyme Nomenclature


Accepted name: 17α-hydroxyprogesterone aldolase

Reaction: 17α-hydroxyprogesterone = androstenedione + acetaldehyde

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

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

Systematic name: 17α-hydroxyprogesterone acetaldehyde-lyase (4-androstene-3,17-dione-forming)

Comments: A microsomal hemeprotein 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 dehydroepiandrosterone, leading to sex hormone biosynthesis. 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 [2].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 62213-24-5


1. Nowotny, E., Sananez, R.D., Nattoro, G., Yantorno, C. and Faillaci, M.G. Bioconversion of steroids in vitro by testes from autoimmunized rabbits. Hoppe-Seyler's Z. Physiol. Chem. 355 (1974) 716-720. [PMID: 4435747]

2. 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]

3. 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]

4. 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]

[EC created 1976]

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