TM-2????????????????????е?ø??????????о?

Enzyme Kinetics of TM-2 in Rat,Beagle Dog and Human Liver Microsomes

??OBJECTIVE To study the enzymatic kinetics of TM-2 in rat, Beagle dog and human liver microsomes by LC-MS/MS. METHODS TM-2 was incubated with liver microsomal incubation system. LC-MS/MS method was established for quantitative analysis of TM-2 with cabazitaxel as internal standard. The enzyme kinetics parameters V_max and K_m was calculated by the GraphPad Prism 5.0 software. RESULTS A rapid and sensitive LC-MS/MS method was developed to study the enzyme kinetics of TM-2 in rat, Beagle dog and human liver microsome. The corresponding enzymatic kinetic parameters in rat, Beagle dog and human were as follows: V_maxvalues were 16.3, 354.6 and 154.8 nmol??min^-1??mg(protein)^-1, respectively; K_m values were 25.7, 313.8 and 89.4 ??mol??L^-1, respectively; CL_int values were 0.63, 1.13 and 1.73 mL??min^-1??mg(protein)^-1, respectively. CONCLUSION The result indicates that there are species differences in the activity of metabolic enzyme and the affinity of TM-2 to the metabolic enzyme. Enzyme kinetic parameters obtained of TM-2 provide important parameters for the further study.