Cytochrome P450 3A5
Function
A cytochrome P450 monooxygenase involved in the metabolism of steroid hormones and vitamins (PubMed:10681376, PubMed:11093772, PubMed:12865317, PubMed:2732228). 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 (NADPH--hemoprotein reductase). Catalyzes the hydroxylation of carbon-hydrogen bonds (PubMed:10681376, PubMed:11093772, PubMed:12865317, PubMed:2732228). Exhibits high catalytic activity for the formation of catechol estrogens from 17beta-estradiol (E2) and estrone (E1), namely 2-hydroxy E1 and E2 (PubMed:12865317). Catalyzes 6beta-hydroxylation of the steroid hormones testosterone, progesterone, and androstenedione (PubMed:2732228). Catalyzes the oxidative conversion of all-trans-retinol to all-trans-retinal, a rate-limiting step for the biosynthesis of all-trans-retinoic acid (atRA) (PubMed:10681376). Further metabolizes all trans-retinoic acid (atRA) to 4-hydroxyretinoate and may play a role in hepatic atRA clearance (PubMed:11093772). Also involved in the oxidative metabolism of xenobiotics, including calcium channel blocking drug nifedipine and immunosuppressive drug cyclosporine (PubMed:2732228).
Pathway
Steroid hormone biosynthesis.
Cofactor metabolism; retinol metabolism.
Sequence Similarities
Belongs to the cytochrome P450 family.
Cellular localization
- Endoplasmic reticulum membrane
- Peripheral membrane protein
- Microsome membrane
- Peripheral membrane protein
Alternative names
Cytochrome P450 3A5, CYPIIIA5, Cytochrome P450-PCN3, CYP3A5