桑色素与溶菌酶相互作用的荧光光谱法研究

Study on the interaction of morin with lysozyme by fluorescence spectroscopy

在生理酸度(pH7.4)条件下,应用荧光光谱法研究了桑色素与溶菌酶(LYS)相互作用的光谱特性。研究发现,桑色素对溶菌酶的内源荧光产生强烈的猝灭作用,其荧光机理为静态与动态并存的复合猝灭方式。求出了不同温度下桑色素与溶菌酶作用的结合常数和结合位点数。由Van’t Hoff方程式计算了桑色素与溶菌酶反应的热力学参数:焓变(ΔH)和熵变(ΔS)值分别为-30.26kJ/mol和26.76(J/mol·K),表明桑色素与溶菌酶之间的作用力以静电引力为主。根据Frster非辐射能量转移理论,求出了桑色素与溶菌酶色氨酸残基之间的结合距离为4.05nm。同步荧光光谱显示,桑色素使得溶菌酶的构象发生了变化。

The spectroscopic character between morin and lysozyme （LYS）was studied using fluorescence spectroscopy under the simulative physiological condition （pH7.4）. It was observed that there was a strong fluorescence quenching reaction of morin to lysozyme,the quenching mechanism was suggested as both static and dynamic quenching for morin-LYS system.The binding constants K and number of binding sites n of morin with lysozyme were obtained by fluorescence quenching method.The thermodynamic parameters of the interaction between morin and lysozyme were measured according to the Van＇t Hoff equation.The enthalpy change（AH）and the entropy change （AS） were calculated to be -30.26kJ · mol^ -1 ,26.76J · mol^ -1 · K^-1 respectively, which indicated that the interaction of morin with lysozyme was driven mainly by electrostatic interactions.The binding locality was an area 4.05nm away from tryptophan residue in lysozyme based on Forster nonradiation energy transfer mechanism.The results of synchronous fluorescence spectra showed that the binding of morin to lysozyme induced conformational changes in lysozyme.