ExplorEnz: EC 1.3.1.3

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1.3.1.3

Accepted name:

Δ⁴-3-oxosteroid 5β-reductase

Reaction:

a 3-oxo-5β-steroid + NADP⁺ = a 3-oxo-Δ⁴-steroid + NADPH + H⁺

For diagram of cholesterol catabolism (rings a, B and c), click here

Other name(s):

3-oxo-Δ⁴-steroid 5β-reductase; 5β-reductase; androstenedione 5β-reductase; cholestenone 5β-reductase; cortisone 5β-reductase; cortisone β-reductase; cortisone Δ⁴-5β-reductase; steroid 5β-reductase; testosterone 5β-reductase; Δ⁴-3-ketosteroid 5β-reductase; Δ⁴-5β-reductase; Δ⁴-hydrogenase; 4,5β-dihydrocortisone:NADP⁺ Δ⁴-oxidoreductase; 3-oxo-5β-steroid:NADP⁺ Δ⁴-oxidoreductase; 5β-cholestan-3-one:NADP⁺ 4,5-oxidoreductase

Systematic name:

3-oxo-5β-steroid:NADP⁺ 4,5-oxidoreductase

Comments:

The enzyme from human efficiently catalyses the reduction of progesterone, androstenedione, 17α-hydroxyprogesterone and testosterone to 5β-reduced metabolites; it can also act on aldosterone, corticosterone and cortisol, but to a lesser extent [8]. The bile acid intermediates 7α,12α-dihydroxy-4-cholesten-3-one and 7α-hydroxy-4-cholesten-3-one can also act as substrates [9].

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 9029-08-7

References:

1.	Forchielli, E. and Dorfman, R.I. Separation of Δ⁴-5α- and Δ⁴-5β-hydrogenases from rat liver homogenates. J. Biol. Chem. 223 (1956) 443–448. [PMID: 13376613]
2.	Brown-Grant, K., Forchielli, E. and Dorfman, R.I. The Δ⁴-hydrogenases of guinea pig adrenal gland. J. Biol. Chem. 235 (1960) 1317–1320. [PMID: 13805063]
3.	Levy, H.R. and Talalay, P. Enzymatic introduction of double bonds into steroid ring A. J. Am. Chem. Soc. 79 (1957) 2658–2659. [DOI]
4.	Tomkins, G.M. The enzymatic reduction of Δ⁴-3-ketosteroids. J. Biol. Chem. 225 (1957) 13–24. [PMID: 13416214]
5.	Sugimoto, Y., Yoshida, M. and Tamaoki, B. Purification of 5β-reductase from hepatic cytosol fraction of chicken. J. Steroid Biochem. 37 (1990) 717–724. [PMID: 2278855]
6.	Furuebisu, M., Deguchi, S. and Okuda, K. Identification of cortisone 5β-reductase as Δ⁴-3-ketosteroid 5β-reductase. Biochim. Biophys. Acta 912 (1987) 110–114. [DOI] [PMID: 3828348]
7.	Okuda, A. and Okuda, K. Purification and characterization of Δ⁴-3-ketosteroid 5β-reductase. J. Biol. Chem. 259 (1984) 7519–7524. [PMID: 6736016]
8.	Charbonneau, A. and The, V.L. Genomic organization of a human 5β-reductase and its pseudogene and substrate selectivity of the expressed enzyme. Biochim. Biophys. Acta 1517 (2001) 228–235. [DOI] [PMID: 11342103]
9.	Kondo, K.H., Kai, M.H., Setoguchi, Y., Eggertsen, G., Sjöblom, P., Setoguchi, T., Okuda, K.I. and Björkhem, I. Cloning and expression of cDNA of human Δ⁴-3-oxosteroid 5β-reductase and substrate specificity of the expressed enzyme. Eur. J. Biochem. 219 (1994) 357–363. [PMID: 7508385]

[EC 1.3.1.3 created 1961 (EC 1.3.1.23 created 1972, incorporated 2005), modified 2005]