Cytochrome P450, family 3, subfamily A (CYP3A)

Cytochrome P450, family 3, subfamily A (CYP3A) is a group of enzymes belonging to the cytochrome P450 superfamily, which are monooxygenases that catalyze the metabolism of a wide range of endogenous substrates (such as steroids, bile acids, lipids, and vitamins) and exogenous substances, especially drugs[1][2][5]. The CYP3A subfamily includes four functional genes (CYP3A4, CYP3A5, CYP3A7, CYP3A43) that together are responsible for the metabolism of approximately 30–50% of all drugs in clinical use[2][3][5]. They are highly expressed in the liver and intestine, playing a central role in first-pass drug metabolism and impacting systemic drug exposure[3][6]. CYP3A enzymes exhibit significant inter-individual variability due to genetic polymorphisms, which can lead to differences in drug clearance, efficacy, and risk of adverse effects[2]. Induction or inhibition of CYP3A enzymes can result in major drug-drug interactions, potentially causing toxicity or therapeutic failure[4][6]. CYP3A expression and activity can also be modulated by certain foods (like grapefruit juice), hormones, and disease states. Clinically, genetic testing for CYP3A4/5 variants and monitoring for known drug interactions are important for safe and effective medication use involving CYP3A substrates[2][7].

Other names

Cytochrome P450 3ACYP3A subfamilyCYP3A4CYP3A5CYP3A7CYP3A43Cytochrome P450 3A4Cytochrome P450 3A5

Substrate oxidation (hydroxylation and epoxidation), Competitive inhibition, Non-competitive inhibition, Induction (enzyme upregulation), Inactivation