3-oxo-5-alpha-steroid 4-dehydrogenase, C-terminal (IPR001104)

Short name: 3-oxo-5_a-steroid_4-DH_C

Overlapping homologous superfamilies


Domain relationships



3-oxo-5-alpha-steroid 4-dehydrogenases, EC: catalyse the conversion of 3-oxo-5-alpha-steroid + acceptor to 3-oxo-delta(4)-steroid + reduced acceptor. The steroid 5-alpha-reductase enzyme is responsible for the formation of dihydrotestosterone, this hormone promotes the differentiation of male external genitalia and the prostate during foetal development [PMID: 1686016]. In humans mutations in this enzyme can cause a form of male pseudohermaphorditism in which the external genitalia and prostate fail to develop normally. A related steroid reductase enzyme, DET2, is found in plants such as Arabidopsis. Mutations in this enzyme cause defects in light-regulated development [PMID: 8602526]. This domain is present in both type 1 and type 2 [PMID: 1944596] forms.

This domain is also found in polyprenol reductase (SRD5A3; EC:, which is reduces the alpha-isoprene unit of polyprenol to form dolichol. Dolichol is required for the synthesis of a dolichol-linked monosaccharide and the oligosaccharide precursor used for N-glycosylation [PMID: 20637498].

Another enzyme with this domain is very-long-chain enoyl-CoA reductase (TECR; EC:, which catalyzes the last of the four reactions of the long-chain fatty acids elongation cycle by reducing the trans-2,3-enoyl-CoA fatty acid intermediate to an acyl-CoA that can be further elongated by entering a new cycle of elongation [PMID: 12482854].

GO terms

Biological Process

GO:0006629 lipid metabolic process

Molecular Function

GO:0016627 oxidoreductase activity, acting on the CH-CH group of donors

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles