荧光光谱法研究氢化可的松与牛血清白蛋白的结合作用

模拟人体pH值,在不同温度下采用荧光光谱和同步荧光光谱研究了氢化可的松与牛血清白蛋白(BSA)的相互作用及对其同步荧光的影响。结果表明,在pH值7.37的Tris-HCl缓冲溶液中,氢化可的松和BSA彼此扩散和碰撞达到动态平衡导致BSA荧光猝灭,属于动态猝灭机制。计算得到BSA与氢化可的松在25℃和37℃下动态猝灭的猝灭常数分别为1.98105×107 L.mol-1.s-1和2.05933×107 L.mol-1.s-1。根据热力学方程得出氢化可的松与BSA相互作用的参数,ΔH<0、ΔS>0,说明氢化可的松与BSA相互作用以静电引力为主。氢化可的松加入后,BSA同步荧光光谱(Δλ=60nm)的最大发射波长发生红移,表明色氨酸残基所处环境的极性增加。

Study on Binding of Hydrocortisone with Bovine Serum Albumin by Fluorescence Spectroscopy

The binding characteristics of hydrocortisone and bovine serum albumin（BSA） were studied by fluorescence and synchronous fluorescence spectroscopy at different temperatures in simulated human body pH value. The results showed that hydroeortisone had a powerful ability to quench the BSA fluorescence via a diffu- sion and impact energy transfer mechanism in the Tris-HC1 buffer system with a pH value of 7.37. The quench- ing rate constants,the binding constants and the binding sites of the dynamic quenching were calculated at dif- ferent temperatures. And according to the thermodynamic parameters calculated, the binding of BSA at A2 60 nm and hydrocortisone was mainly attributed to the electrostatic attraction force. The maximum emission wavelength of the synchronous fluorescence spectrum of BSA had a red shift in the presence of bydrocortisone, indicating that it enhanced the polarity of the environment in which Trp residues existed.