EC - 3β-hydroxysteroid 3-dehydrogenase

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IntEnz Enzyme Nomenclature


Accepted name:
3β-hydroxysteroid 3-dehydrogenase
Other names:
3-keto-steroid reductase
HSD17B7 (gene name)
ERG27 (gene name)
Systematic name:
3β-hydroxysteroid:NADP+ 3-oxidoreductase



The enzyme acts on multiple 3β-hydroxysteroids. Participates in the biosynthesis of zemosterol and cholesterol, where it catalyses the reaction in the opposite direction to that shown. The mammalian enzyme is bifunctional and also catalyses EC, 17β-estradiol 17-dehydrogenase [4].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ERGO , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0000253 , GO:0102176
CAS Registry Number: 42616-29-5
UniProtKB/Swiss-Prot: (29) [show] [UniProt]


  1. Swindell, A.C. and Gaylor, J.L.
    Investigation of the component reactions of oxidative sterol demethylation. Formation and metabolism of 3-ketosteroid intermediates.
    J. Biol. Chem. 243 : 5546-5555 (1968). [PMID: 4387005]
  2. Billheimer, J.T., Alcorn, M. and Gaylor, J.L.
    Solubilization and partial purification of a microsomal 3-ketosteroid reductase of cholesterol biosynthesis. Purification and properties of 3-β-hydroxysteroid dehydrogenase and Δ5-3-ketosteroid isomerase from bovine corpora lutea.
    Arch. Biochem. Biophys. 211 : 430-438 (1981). [PMID: 6946726]
  3. Gachotte, D., Sen, S. E., Eckstein, J., Barbuch, R., Krieger, M., Ray, B. D., Bard, M.
    Characterization of the Saccharomyces cerevisiae ERG27 gene encoding the 3-keto reductase involved in C-4 sterol demethylation.
    Proc. Natl. Acad. Sci. U.S.A. 96 : 12655-12660 (1999). [PMID: 10535978]
  4. Marijanovic, Z., Laubner, D., Moller, G., Gege, C., Husen, B., Adamski, J., Breitling, R.
    Closing the gap: identification of human 3-ketosteroid reductase, the last unknown enzyme of mammalian cholesterol biosynthesis.
    Mol. Endocrinol. 17 : 1715-1725 (2003). [PMID: 12829805]

[EC created 2002, modified 2012]