EC - Δ4-3-oxosteroid 5β-reductase

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IntEnz Enzyme Nomenclature


Accepted name:
Δ4-3-oxosteroid 5β-reductase
Other names:
3-oxo-Δ4-steroid 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
4,5β-dihydrocortisone:NADP+ Δ4-oxidoreductase
3-oxo-5β-steroid:NADP+ Δ4-oxidoreductase
Systematic name:
5β-cholestan-3-one:NADP+ 4,5-oxidoreductase



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

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00061
Structural data: CSA , EC2PDB
Gene Ontology: GO:0047787
CAS Registry Numbers: 37255-35-9 9029-08-7


  1. Forchielli, E. and Dorfman, R.I.
    Separation of Δ4-5α- and Δ4-5β-hydrogenases from rat liver homogenates.
    J. Biol. Chem. 223 : 443-448 (1957). [PMID: 13376613]
  2. Brown-Grant, K., Forchielli, E. and Dorfman, R.I.
    The Δ4-hydrogenases of guinea pig adrenal gland.
    J. Biol. Chem. 235 : 1317-1320 (1960). [PMID: 13805063]
  3. Levy, H.R. and Talalay, P.
    Enzymatic introduction of double bonds into steroid ring A.
    J. Am. Chem. Soc. 79 : 2658-2659 (1957).
  4. Tomkins, G.M.
    The enzymatic reduction of Δ4-3-ketosteroids.
    J. Biol. Chem. 225 : 13-24 (1957). [PMID: 13416214]
  5. Sugimoto, Y., Yoshida, M. and Tamaoki, B.
    Purification of 5β-reductase from hepatic cytosol fraction of chicken.
    J. Steroid Biochem. Mol. Biol. 37 : 717-724 (1991). [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 : 110-114 (1987). [PMID: 3828348]
  7. Okuda, A. and Okuda, K.
    Purification and characterization of Δ4-3-ketosteroid 5β-reductase.
    J. Biol. Chem. 259 : 7519-7524 (1984). [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 : 228-235 (2001). [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 : 357-363 (1994). [PMID: 7508385]

[EC created 1961 (EC created 1972, incoporated 2005), modified 2005]