Progesterone 5alpha-reductase

In enzymology, a progesterone 5alpha-reductase (EC 1.3.1.22) is an enzyme that catalyzes the chemical reaction

5alpha-pregnan-3,20-dione + NADP⁺ ${\displaystyle \rightleftharpoons }$ progesterone + NADPH + H⁺

progesterone 5-alpha-reductase
Identifiers
EC no.	1.3.1.22
CAS no.	72412-84-1
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

Thus, the two substrates of this enzyme are 5alpha-pregnan-3,20-dione and NADP⁺, whereas its 3 products are progesterone, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. It is a C21-steroid hormone that is a 5α-pregnane substituted with a oxo groups at positions 3 and 20. It is an intermediate in the conversion of progesterone to allopregnalone and isopregnanolone, other common forms of neurosteroids. The systematic name of this enzyme class is 5alpha-pregnan-3,20-dione:NADP+ 5-oxidoreductase. Other names in common use include steroid 5-alpha-reductase, and Delta4-steroid 5alpha-reductase (progesterone).