头孢克肟与胃蛋白酶相互作用的光谱法研究  

Investigation of interaction between cefixime and pepsin by spectroscopic methods

作　　者：贾悦[1] 杨洪芹[1] 郭刘奇 王庆[1] 黄燕梅[1] 李晖[1] 

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《化学研究与应用》2016年第5期673-680,共8页Chemical Research and Application

基　　金：四川省科技厅应用基础研究项目(2014JY0042)资助

摘　　要：在胃生理酸度pH=2.0(柠檬酸-柠檬酸钠缓冲)条件下,利用荧光和紫外吸收光谱法及分子对接技术,研究了第三代口服头孢菌素--头孢克肟与胃蛋白酶间的相互作用。实验结果表明:头孢克肟对胃蛋白酶荧光猝灭作用明显,且猝灭过程为静态猝灭。298K,304K,310K下,根据Stern-Volmer方程计算的头孢克肟与胃蛋白酶结合常数Ka分别为6.612×10~4,2.740×104,1.024×10~4L·mol^(-1),结合位点数近似为1。ΔG<0表明结合过程是自发进行,ΔH<0,ΔS<0表明头孢克肟与胃蛋白酶间范德华力和氢键作用力是占主导作用。Forster非辐射能量转移实验和理论研究,二者间作用距离r=2.053 nm,能量转移效率E=0.525。头孢克肟与胃蛋白酶相互作用的结果,导致胃蛋白酶构象及微环境的变化。分子模拟对接技术的应用,在分子水平确定了头孢克肟与胃蛋白酶结合的适宜位点。In the stomach physiological conditions of pH2.0(citric acid-sodium citrate buffer solution),the interaction between ce-fixime of the third generation of oral cephalosporins and pepsin was studied using spectrophotometric techniques such as fluorescent spectrometry,UV-vis absorption spectrum,and molecular docking. The experimental results showed that the fluorescence intensity of pepsin was strongly quenched by the addition of cefixime. Spectrophotometric observations were rationalized in terms of a static quenching process. According to the modified Stern-Volmer equation,the binding constants between cefixime and pepsin at different temperatures(298K,304K,310K)were 6. 612×104,2. 740×104,1. 024×104 L·mol-1 respectively,and the number of binding sites were approximately equal to 1,which indicated the strong binding between cefixime and pepsin. The value ofΔG were negative,re-vealed that the binding is a spontaneous process. Negative values for both enthalpy change(ΔH) and entropy change(ΔS) indicate the binding power between cefixime and pepsin is mainly van der Waals force and hydrogen bond. A binding distance ( r=2. 053 nm)and energy transfer efficiency(E=0. 525)was obtained from the F?rster experiment and theory of nonradioactive energy trans-fer. The result of interaction between cefixime and pepsin led to the conformational and micro-environment change of pepsin. At the molecular level,the application of molecular docking method determined that the binding mode of cefixime and pepsin.

关 键 词：头孢克肟 胃蛋白酶 荧光光谱法 相互作用 分子对接 

分 类 号：O633.5[理学—高分子化学]