Cytochrome P450 Enzymes: CYP19A1, CYP1A2, CYP1B1, CYP2C9, and CYP3A4 (CYP19A1, CYP1A2, CYP1B1, CYP2C9, CYP3A4)

These five enzymes—CYP19A1 (aromatase), CYP1A2, CYP1B1, CYP2C9, and CYP3A4—are cytochrome P450 monooxygenases that catalyze the oxidative metabolism of endogenous and exogenous compounds. They play pivotal roles in drug metabolism, hormone biosynthesis/breakdown, the generation or detoxification of carcinogens, and are directly implicated in clinically relevant pharmacogenetic variation and disease risk. CYP19A1 is especially critical for estrogen biosynthesis, CYP1A2 and CYP1B1 for carcinogen metabolism, CYP2C9 and CYP3A4 for the metabolism of numerous drugs, with CYP3A4 handling over half of all clinically used drugs. Genetic polymorphisms in these enzymes alter drug efficacy, safety, and disease susceptibility.

Other names

AromataseEstrogen synthetase

Enzyme inhibition (competitive/non-competitive, e.g., azoles, macrolides, aromatase inhibitors); Enzyme induction (notably by some antiepileptics, rifampin, St. John's wort)