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No major difference in inhibitory susceptibility between CYP2C9.1 and CYP2C9.3
Tadaaki Hanatani1, Tsuyoshi Fukuda, Sachi Onishi
1Clinical Evaluation of Medicines and Therapeutics, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
Objective:
CYP2C9 is a polymorphic enzyme, and CYP2C9*3 is associated with decreased metabolic activity. In addition to the impaired metabolism, we investigated whether the CYP2C9*3 exhibited altered inhibitory susceptibility compared with CYP2C9*1.
Method:
In the present study, CYP2C9.1 and CYP2C9.3 were expressed in yeast. Using typical CYP2C9 substrates (diclofenac, tolbutamide and S-warfarin) and a potent CYP2C9 inhibitor (nicardipine), the Ki values for nicardipine on the three metabolisms in CYP2C9*1 and CYP2C9*3 were determined.
Result:
The ratios of Ki(CYP2C9*3)/Ki(CYP2C9*1) on tolbutamide, diclofenac and S-warfarin metabolisms were 1.2, 3.1 and 0.8, respectively.
Conclusion:
In conclusion, there are no significant differences in the inhibitory susceptibility between the two CYP2C9 enzymes.
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