Cytochrome P450, family 3, subfamily A enzyme (CYP3A)

Cytochrome P450, family 3, subfamily A (CYP3A) refers to a group of enzymes within the cytochrome P450 superfamily primarily responsible for the oxidative metabolism of a wide variety of endogenous compounds and xenobiotics, including nearly three-quarters of all drugs used clinically. The main members in humans are CYP3A4, CYP3A5, CYP3A7, and CYP3A43, with CYP3A4 being the most abundant and clinically significant isoform. Located predominantly in the liver and intestines, CYP3A enzymes use molecular oxygen and electrons from NADPH to catalyze oxidation reactions, making drugs or toxins more polar for excretion. These enzymes are involved in catabolism of steroids, bile acids, lipids, and the metabolic clearance of many medications. Clinical importance derives from their high variability in expression and activity between individuals and their central role in many drug-drug interactions, pharmacogenomic effects, and variable drug responses. CYP3A activity can be influenced by genetic, physiological, and external factors, presenting significant therapeutic challenges and opportunities for individualizing pharmacotherapy.

Other names

Cytochrome P450 3ACYP3A4CYP3A5CYP3A7CYP3A43Cytochrome P450 IIIANifedipine oxidaseAlbendazole monooxygenaseCholesterol 25-hydroxylaseQuinine 3-monooxygenaseP450PCN1P450C3CYPIIIA3CYPIIIA4HLPNF-25VDDR3CP33CP34

Oxidation and hydroxylation of drugs and xenobiotics to more water-soluble forms for excretion; Activation or inactivation of therapeutic agents; Inhibition or induction can result in significant drug-drug interactions.