荧光光谱法研究间硝基苯胺与牛血清白蛋白的相互作用

Study of Interaction Between m-Nitroaniline and Bovine Serum Albumin Using Fluorospectrophotometry

应用荧光光谱法研究间硝基苯胺与牛血清白蛋白的相互作用。激发波长为280nm,发射波长为342nm,在pH 7.50的Tris-盐酸缓冲溶液中反应150min后,间硝基苯胺对牛血清白蛋白的猝灭效果最为明显。289K,304K和318K下的结合常数分别为1.667×104,1.428×104,1.250×104L·mol-1。根据分子间的相互作用力与相关热力学参数间的相互关系,结合间硝基苯胺与牛血清白蛋白相互作用的焓变(ΔH)<0和熵变(ΔS)>0,可推断两者的相互作用力主要为静电作用力。结果表明:间硝基苯胺对牛血清白蛋白的荧光猝灭方式为静态猝灭,最后用紫外吸收光谱法对其作用机理进行了确认。

Fluorospectrophotometry was applied to the study the interaction between m-nitroaniline and bovine serum albumin.The maximum quenching effect between m-nitroaniline and bovine serum albumin occurred in Tris-HCl buffer solutions of pH 7.50 after reacting for 30 min.The optimum excitation and emission wavelength were 280 nm and 342 nm respectively.The binding constants at 289,304,318 K were found to be 1.667×104,1.428×104,1.250×104 L· mol-1 respectively.Base on the force of interaction between the molecules and correlation among the thermodynamic parameters,as well as the values ofΔH(<0)and ΔS(>0)of the interaction between m-nitroaniline and bovine serum albumin,it was deduced that the force of the reaction was mainly due to electrostatic force.It was found that the fluorescence quenching mechanism was static quenching,which was further confirmed by ultraviolet absorption spectrometry.