桑色素与牛血清白蛋白结合反应的热力学分析

Thermodynamic Analysis on the Binding Feature Between Morin and Bovine Serum Albumin

应用荧光光谱和紫外可见吸收光谱研究了生理条件下桑色素与牛血清白蛋白(BSA)相互作用的热力学特性,确定静态猝灭和非辐射能量转移是导致桑色素对BSA内源荧光猝灭的主要原因;求得不同温度下桑色素与BSA作用的结合常数分别为1.796×104,9.398×103,2.196×103L.mol-1。根据热力学参数确定它们之间的作用力类型;根据F rster非辐射能量转移理论计算出二者结合时给体(蛋白质)-受体(桑色素)间的距离r=3.313nm。同步荧光光谱和紫外-可见吸收光谱显示,桑色素能够使BSA的二级结构发生变化;同时考察了多种离子对桑色素与BSA作用结合常数的影响。

The thermodynamic feature between morin and bovine serum albumin （BSA） under physiological condition was studied using fluorescence and absorption spectra. It was proved that fluorescence quenching of BSA by morin is deduced by combing static quenching with nonradiative energy transfer. The binding constants obtained by fluorescence quenching method are 1. 796 × 10^4, 9. 398 × 10^3 and 2. 196 × 10^3 L · mol^-1, respectively. The main sorts of binding force were determined according to the thermodynamic parameters. The binding distance r between bovine serum albumin and morin is 3. 313 nm, which was obtained based on the theory of Forster nonradiative energy transfer. The results of synchronous fluorescence the binding of morin to BSA induced conformational changes spectra and UV-vis absorbance spectra showed that in BSA. The effect of ions on the binding constants was also investigated.