IUBMB Enzyme Nomenclature


Accepted name: 3β-hydroxy-Δ5-steroid dehydrogenase

Reaction: a 3β-hydroxy-Δ5-steroid + NAD+ = a 3-oxo-Δ5-steroid + NADH + H+

For diagram click here.

Other name(s): progesterone reductase; Δ5-3β-hydroxysteroid dehydrogenase; 3β-hydroxy-5-ene steroid dehydrogenase; 3β-hydroxy steroid dehydrogenase/isomerase; 3β-hydroxy-Δ5-C27-steroid dehydrogenase/isomerase; 3β-hydroxy-Δ5-C27-steroid oxidoreductase; 3β-hydroxy-5-ene-steroid oxidoreductase; steroid-Δ5-3β-ol dehydrogenase; 3β-HSDH; 5-ene-3-β-hydroxysteroid dehydrogenase; 3β-hydroxy-5-ene-steroid dehydrogenase

Systematic name: 3β-hydroxy-Δ5-steroid:NAD+ 3-oxidoreductase

Comments: This activity is found in several bifunctional enzymes that catalyse the oxidative conversion of Δ5-3-hydroxy steroids to a Δ4-3-oxo configuration. This conversion is carried out in two separate, sequential reactions; in the first reaction, which requires NAD+, the enzyme catalyses the dehydrogenation of the 3β-hydroxy steroid to a 3-oxo intermediate. In the second reaction the reduced cosubstrate, which remains attached to the enzyme, activates the isomerization of the Δ5 form to a Δ4 form (cf. EC, steroid Δ-isomerase). Substrates include dehydroepiandrosterone (which is converted into androst-5-ene-3,17-dione), pregnenolone (converted to progesterone) and cholest-5-en-3-one, an intermediate of cholesterol degradation.

Comments: Acts on 3β-hydroxyandrost-5-en-17-one to form androst-4-ene-3,17-dione and on 3β-hydroxypregn-5-en-20-one to form progesterone.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9044-85-3


1. Cheatum, S.G. and Warren, J.C. Purification and properties of 3-β-hydroxysteroid dehydrogenase and Δ-5-3-ketosteroid isomerase from bovine corpora lutea. Biochim. Biophys. Acta 122 (1966) 1-13. [PMID: 4226148]

2. Koritz, S.B. The conversion of prepnenolone to progesterone by small particle from rat adrenal. Biochemistry 3 (1964) 1098-1102.

3. Neville, A.M., Orr, J.C. and Engel, L.L. Δ5-3β-Hydroxy steroid dehydrogenase activities of bovine adrenal cortex. Biochem. J. 107 (1968) 20P.

[EC created 1972]

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