替硝唑对胃蛋白酶荧光猝灭的机理研究

Mechanism of fluorescence quenching of pepsin by tinidazole

目的探讨硝基咪唑类药物替硝唑对胃蛋白酶内源性荧光猝灭的机理。方法在胃生理酸度pH 2.0(盐酸—氯化钾溶液)条件下,利用荧光光谱法及紫外吸收光谱等方法分析该猝灭现象。结果该相互作用是静态猝灭的过程;根据实验数据计算出不同温度下(288 K、299 K和310 K)荧光猝灭常数和结合位点数,发现荧光猝灭常数随着温度的升高而降低,结合位点数约为1。判断该猝灭过程中发生了非辐射能量转移,并得出胃蛋白酶与替硝唑结合的作用力类型为静电作用力,结合距离约为5.37 nm。结论本研究探索了替硝唑与蛋白质大分子的相互作用机理,为硝基咪唑类药物的临床使用和新药开发提供一定的理论参考。

Objective To investigate the mechanism of endogenous fluorescence quenching of pepsin by tinidazole.Methods The fluorescence quenching of pepsin by tinidazole was analyzed by fluorescence spectrometry and UV absorption spectra,under the condition of gastric physiological pH 2.0(hydrochloric acid-potassium chloride solution).Results The interaction between pepsin and tinidazole was a process of static quenching.The fluorescence quenching constants at different temperatures(288 K,299 K and 310 K)decreased along with the increase of temperature,while the number of binding sites was about 1.It was found that non-radiation energy transfer occurred during the quenching process,and the type of binding force between pepsin and tinidazole was electrostatic force,with a binding distance of about 5.37 nm.Conclusions These findings provide reference for the study of the mechanism of nitroimidazole in vivo and theoretical basis for further exploration of the mechanism of tinidazole and protein in vivo.