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目的：研究人重组酶SULT1A3与芹菜素的磺酸化结合反应的动力学特征。方法采用高效液相色谱法，测定芹菜素的消除量及其磺酸化结合反应代谢产物的生成量，并应用LC－MS／MS液质联用技术鉴定其结构。建立芹菜素与重组酶SULT1 A3体外反应体系，测定SULT1A3催化不同浓度芹菜素的磺酸化结合反应代谢速率，采用GraphPad Prism 5软件对其进行酶动力学分析。结果芹菜素在0．15625～30μM范围内线性关系良好，平均回收率大于80％，日内和日间的RSD均小于15％。芹菜素与SULT1A3孵育体系中的代谢产物为单磺酸化结合产物。芹菜素与人重组酶SULT1A3的反应呈底物抑制动力学特征。芹菜素与SULT1A3酶反应的动力学参数Km和Ksi分别为（0．355±1．04）、（23．62±0．06）μM，Vmax为（65．71±1．30） nmol／（min? mg），Vmax／Km为185．10 mL／（min? mg）。结论人重组酶SULT1A3可介导芹菜素的磺酸化结合反应，且其酶动力学特征呈现底物抑制效应。推测由SULT1A3介导的磺酸化结合反应可能在芹菜素的体内II相代谢中发挥重要的作用。“,”Objective To investigate the kinectics characteristics of sulfation of apigenin mediated by SULTIA3.Methods After incubation of apigenin using in vitro SULT1A3 system, high-performance liquid chromatography was utilized to determine the sulfates of apigenin.Mass spectrum(MS) were employed to elucidate the structure of metabolite.The program GraphPad Prism 5 was used to perform the kinetic characterization of SULT1A3 catalyzed metabolism of apigenin.Results A liner calibration curve for the assay of apigenin was validated in the range of 0.15625 ~30 μM with the recoveries of at least 80% and intra-day and inter-day RSD of less than 15%.Metabolic product of apigenin and SULT1A3 in the incubated system was identified one monosulfate.The metabolic behavior of apigenin in SULT1A3 was followed substrate inhibition kinetics.Apparent kinetic parameters of metabolism of apigenin by SULT1A3, Kmwas(0.355 ±1.04) μM and Ksi was(23.62 ±0.06) μM,Vmax was(65.71 ±1.30) nmol/(min? mg),Vmax/Km was 185.10 mL/(min? mg).Conclusion SULT1A3 can mediate the binding of apigenin sulfonated reaction, and the character of enzymatic kinetics shows substrate inhibition.Sulfation of apigenin mediated by SULTIA3 may play an important role in phaseⅡmetabolic in vivo.