Abstract: AIM: To determine the constants of enzyme kinetics and drug inhibition of the three CYP2C19 genotype(CYP2C19^*1, CYP2C19^*2, CYP2C19^*3),and study the impact of CYP2C19 genetic polymorphism in drug metabolism in vitro. METHODS: In the study the CEC (3-cynao-7-ethoxycoumarin) as a CYP2C19-specific fluorescent substrate used for enzymatic reaction and detected CYP2C19 genotype activity, in addition, the nonlinear regression method to calculate the enzymatic kinetic parameters(K_m value, V_max of the value and intrinsicclear rate Clint value).Then, enzyme inhibition reaction analysis the inhibitory effect of 19 kinds of Chinese herbal medicine on the CYP2C19 genotypes, which by combined of fluorescent substrate CEC and herbal material, as well as other experimental conditions in vitro, and calculate the IC₅₀ values.RESULTS: The screening experiment results showed that: CYP2C19 involved in the metabolism of substrates and known inhibitors all were its inhibitor, majority of Chinese medicine monomer weak or no inhibitory effect on CYP2C19; chemical structure or similar drugs with similar therapeutic effects on inhibition of CYP2C19 different;the same drug inhibitied different genotypes were not the same result,evern a larger difference.CONCLUSION: Establish an efficient, stable, and easy fluorescent high-throughput drug screening platform, it bulited a basement applied before the metabolic nature of innovative drugs or new drug lead compounds for clinical screening and predictive for late-stage study,providing experimental basis for the clinical potential drug interactions.

Key words: CYP2C19, gene polymorphism, fluorogenic assay, enzyme kinetics, high throughput drug screen