溴百里酚蓝与牛血清白蛋白的相互作用研究

在模拟动物体生理条件和不同温度下,用荧光光谱和紫外-可见吸收光谱法研究了溴百里酚蓝(BTB)与牛血清白蛋白(BSA)结合反应的光谱行为。用Stern-Volmer和Lineweaver-Burk方程分别处理试验数据,发现BSA与BTB发生反应生成了新的复合物,属于静态荧光猝灭。求出了反应时复合物的形成常数KLB(2.792×105L.mol-1)、热力学参数(ΔHθ=(20.24 kJ.mol-1,ΔSθ=37.22J.K-1,ΔGθ=(31.25kJ.mol-1)与结合位点数(1.1578)。根据F rster偶极-偶极非辐射能量转移理论计算出结合位置距离212位色氨酸残基2.60nm,证明二者主要靠静电作用力结合。同时用同步荧光光谱和三维荧光光谱法探讨了BTB对BSA构象的影响,表明BTB使色氨酸残基所处微环境的极性减弱、疏水作用增强,为阐明BTB的染色机理、毒理效应和生物学效应提供重要信息。

Study on the interaction of bromothymol blue and bovine serum albumin

Under simulated physiological conditions of animals and at various temperatures,the binding reaction of bromothymol blue (BTB) to bovine serum albumin (BSA) was studied by fluorescence spectrum and ultra-violet spectrum spectroscopy.The fluorescence quenching data were analyzed according to Stern-Volmer equation and Lineweaver-Burk double-reciprocal equation.Studies have shown:BSA had reacted with BTB and formed a certain new compound,the quenching belonged to static fluorescence quenching.The formation constants of the compound K_(LB) (2.792×10~5L·mol~(-1)) ,the thermodynamic parameters (ΔH~θ=-20.24kJ·mol~(-1),ΔS~θ=37.22 J·K~(-1),ΔG~θ=-31.25.09 kJ·mol~(-1)) and the number non-radiation energy transfer,the distance between binding locality and tryptophan residue -212 was2.60 nm.It shows that the binding power between them is mainly the electrostatic acting force.The effect of BTB on the conformation of BSA was analyzed by synchronous fluorescence spectra and three-dimensional fluorescence spectra.It indicates that the polarity microenvironment around Trp residues decreased,hydrophobic forces increased.These provide important information for enucleating the dyeing mechanisms、the toxicity effects and biological effects of BTB.