基于二相代谢酶介导胆红素代谢考察不同体系UGT1A1酶动力学参数

发布时间：2019-05-07 13:50

【摘要】：目的基于二相代谢酶UGT1A1酶介导胆红素代谢过程,测定比较不同种属肝微粒体体系中UGT1A1酶动力学参数。方法采用高分辨质谱对胆红素及其葡萄糖醛酸代谢物进行定性鉴别,采用UPLC测定法,分别以胆红素一级、二级和总代谢产物生成量对胆红素底物浓度作图,求得动力学参数。结果实验结果发现,以总代谢产物计,KRLMKHLM≈Kr UGT1A1,VRLM≈VHLMVr UGT1A1,CLHLMCLr UGT1A1≈CLrRLM。r UGT1A1(人重组UGT1A1酶)酶体系中UGT1A1酶Km值最小,表明其与胆红素亲和能力最强,Vmax值最小,不能及时将其代谢转化;与此相反,大鼠肝微粒体(RLM)体系中UGT1A1酶与胆红素的亲和能力最弱,但转化效果最佳;人肝微粒体(HLM)体系中UGT1A1酶对胆红素亲和能力较强,转化能力适中。结论通过3个体系比较发现,人肝微粒体与r UGT1A1体系Km值接近,确证了胆红素在肝微粒体中的葡萄糖醛酸化反应主要由UGT1A1介导,人肝微粒体和大鼠肝微粒体体系差别主要由酶及其环境的种属差异导致,本实验的相关数据为研究因诱导或抑制UGT1A1酶引起的药物相互作用及毒性提供了实验依据。
[Abstract]:Aim based on the bilirubin metabolism mediated by biphasic metabolizing enzyme UGT1A1 enzyme, the kinetic parameters of UGT1A1 enzyme in liver microsomal system of different species were determined and compared. Methods bilirubin and its glucuronic acid metabolites were identified qualitatively by high resolution mass spectrometry (HRMS). UPLC was used to determine the concentration of bilirubin substrate, and the kinetic parameters were obtained by mapping the concentration of bilirubin substrate with the first, second and total metabolites of bilirubin respectively. Results the results showed that the km value of UGT1A1 enzyme was the lowest in KRLMKHLM 鈮，

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