Patent ID: 7629140

Claim:
A method for identifying an analyte that inhibits activity of cytochrome P450 isoform 2C9 (CYP2C9), which comprises: (a) providing an aqueous mixture comprising CYP2C9, tritium-labeled diclofenac labeled with tritium at the 4′ position ([4′- 3 H]-diclofenac), NADPH, and the analyte; (b) incubating the aqueous mixture for a time sufficient for the CYP2C9 activity to hydroxylate the tritium-labeled diclofenac at the 4′ position; (c) removing the CYP2C9 from the aqueous mixture; (d) applying the aqueous mixture to a sorbent which preferentially binds non-polar compounds to remove the tritium-labeled diclofenac from the aqueous mixture; and (e) measuring amount of the tritium in the aqueous mixture of step (d) wherein a decrease in the amount of the tritium in the aqueous mixture compared to the amount of tritium in the aqueous mixture from a control mixture comprising CYP2C9, diclofenac labeled with tritium in the 4′ position of the phenyl ring, and NADPH, and not the analyte identifies the analyte as an inhibitor of the CYP2C9.