Cytochrome P450 2C9 (CYP2C9)

CYP2C9 encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and its expression is induced by rifampin. The enzyme is known to metabolize many xenobiotics, including phenytoin, tolbutamide, ibuprofen and S-warfarin. The binding mode of warfarin suggests that CYP2C9 may undergo an allosteric mechanism during its function.

The newly discovered binding pocket also suggests that CYP2C9 may simultaneously accommodate multiple ligands during its biologic function, and provides a possible molecular basis for understanding complex drug-drug interactions.