Cytochrome P450 family 2 subfamily C member 9 (CYP2C9)

Cytochrome P450 2C9 (CYP2C9) is a member of the cytochrome P450 superfamily of enzymes. It functions as a phase I drug-metabolizing enzyme, primarily catalyzing the oxidation of both xenobiotic substances (such as drugs) and endogenous compounds (such as fatty acids and steroid hormones). The enzyme is encoded by the CYP2C9 gene, which is highly polymorphic—meaning genetic variations can significantly affect its metabolic activity. Genetic variants in CYP2C9 can lead to altered metabolism rates for many drugs. This has significant implications for dosing requirements—especially for medications with narrow therapeutic indices like warfarin—and risk assessment for adverse drug reactions or toxicity.

Monooxygenase that introduces an oxygen atom into substrates using electrons from NADPH via cytochrome P450 reductase