5β-Reductase
5β-Reductase, or Δ4-3-oxosteroid 5β-reductase (EC 1.3.1.3, 3-oxo-Δ4-steroid 5β-reductase, androstenedione 5β-reductase, cholestenone 5β-reductase, cortisone 5β-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) is an enzyme with systematic name 5β-cholestan-3-one:NADP+ 4,5-oxidoreductase.
| Δ4-3-Oxosteroid 5β-reductase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 1.3.1.3 | ||||||||
| CAS no. | 2604034 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| |||||||||
This enzyme catalyses the following chemical reaction:
- (1) 5β-cholestan-3-one + NADP+ cholest-4-en-3-one + NADPH + H+
- (2) 17,21-dihydroxy-5β-pregnane-3,11,20-trione + NADP+ cortisone + NADPH + H+
The human enzyme efficiently acts on progesterone, 17α-hydroxyprogesterone, androstenedione, and testosterone to transform them into 5β-reduced metabolites. It can also act on aldosterone, corticosterone, and cortisol.