CYP21A2
Domain
The leucine-rich hydrophobic amino acid N-terminal region probably helps to anchor the protein to the microsomal membrane.
Function
A cytochrome P450 monooxygenase that plays a major role in adrenal steroidogenesis. Catalyzes the hydroxylation at C-21 of progesterone and 17alpha-hydroxyprogesterone to respectively form 11-deoxycorticosterone and 11-deoxycortisol, intermediate metabolites in the biosynthetic pathway of mineralocorticoids and glucocorticoids (PubMed:10602386, PubMed:16984992, PubMed:22014889, PubMed:25855791, PubMed:27721825). Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (CPR; NADPH-ferrihemoprotein reductase) (PubMed:25855791).
Involvement in disease
Adrenal hyperplasia 3
AH3
A form of congenital adrenal hyperplasia, a common recessive disease due to defective synthesis of cortisol. Congenital adrenal hyperplasia is characterized by androgen excess leading to ambiguous genitalia in affected females, rapid somatic growth during childhood in both sexes with premature closure of the epiphyses and short adult stature. Four clinical types: 'salt wasting' (SW, the most severe type), 'simple virilizing' (SV, less severely affected patients), with normal aldosterone biosynthesis, 'non-classic form' or late-onset (NC or LOAH) and 'cryptic' (asymptomatic).
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the cytochrome P450 family.
Cellular localization
- Endoplasmic reticulum membrane
- Peripheral membrane protein
- Microsome membrane
- Peripheral membrane protein
Alternative names
CYP21, CYP21B, CYP21A2, Steroid 21-hydroxylase, 21-OHase, Cytochrome P-450c21, Cytochrome P450 21, Cytochrome P450 XXI, Cytochrome P450-C21, Cytochrome P450-C21B