Cytochrome P450 family 3 subfamily A enzyme system (CYP3A)

The **Cytochrome P450 family 3 subfamily A enzyme system** (CYP3A) is a major subfamily in the cytochrome P450 superfamily of monooxygenase enzymes, primarily localized to the liver and small intestine[1][2][4]. This family comprises multiple highly homologous isoenzymes—CYP3A4, CYP3A5, CYP3A7, and CYP3A43—that collectively account for the metabolism of approximately half of all marketed drugs[1][2][4]. These enzymes catalyze the oxidation (hydroxylation and epoxidation) of structurally diverse endogenous and exogenous compounds, promoting their detoxification and elimination from the body[2][3][6]. CYP3A enzymes also play critical roles in steroid hormone metabolism, bile acid homeostasis, and vitamin metabolism[2][6]. Substantial genetic and non-genetic variability in CYP3A activity impacts drug efficacy and safety, making the enzyme system essential for pharmacogenetics, personalized medicine, and drug-drug interaction risk assessment in therapeutic contexts[4].

Other names

Cytochrome P450 3ACYP3A4CYP3A5CYP3A7CYP3A43CYP3A enzyme system

Substrate metabolism (hydroxylation/oxidation of drugs and xenobiotics for elimination), Enzyme inhibition (drugs/compounds blocking enzyme activity increasing substrate drug levels), Enzyme induction (compounds increasing enzyme expression/activity reducing substrate drug levels)