荧光分析法研究水杨酸磺胺类似物与牛血清白蛋白的作用机制

Fluorescence Analyses on Interaction Mechanism of Analogues of Salicylic Acid-Sulfonamides with Bovine Serum Albumin

采用荧光分析法研究了4个水杨酸磺胺类似物Ⅰ、Ⅱ、Ⅲ、Ⅳ在不同温度(25℃、30℃、35℃)时与牛血清白蛋白(BSA)的相互作用。结果表明:4个水杨酸磺胺类似物与BSA发生荧光猝灭的作用机理为静态猝灭。在25℃时,4个水杨酸磺胺类似物与BSA的结合常数分别为3.87×105 L·mol-1、9.24×104 L·mol-1、2.04×105 L·mol-1、2.06×105 L·mol-1,4个结合体系的结合位点都近似为1。类似物Ⅰ、Ⅱ、Ⅲ与BSA的结合作用力主要为疏水作用力,而类似物Ⅳ与BSA的结合作用力主要为氢键和范德华力。同步荧光光谱显示,4个类似物均没有发生蓝移或者红移,表明这4个类似物对BSA的色氨酸残基(Trp residues)及酪氨酸残基(Tyr residues)微环境几乎没有影响。

The interaction of four analogues of salicylic acid-sulfonamides with bovine serum albumin（BSA）were studied by fluorescence spectrometry under different temperatures,such as 25 ℃,30 ℃,35 ℃.Results showed that,the fluorescence quenching mechanism for the interaction of analoguesⅠ,Ⅱ,Ⅲ andⅣ with BSA were static quenching.Binding constant of four analogues of salicylic acid-sulfonamides with BSA at 25 ℃ was3.87×10^5 L·mol^-1,9.24×10^4 L·mol^-1,2.04×10^5 L·mol^-1,2.06×10^5 L·mol^-1,respectively.The binding number for each of the four interaction systems was equal to 1.The major binding force for the interaction of analoguesⅠ,Ⅱ,Ⅲ with BSA was hydrophobic interactions,while that for the interaction of analoguesⅣ with BSA consists of hydrogen bonds and Van der Waals interactions.According to the synchronous fluorescence spectra,neither a blue shift nor a red shift in the fluorescence peak were observed,which indicated that none of the four analogues exerted an effect on the microenvironment of the tryptophan（Trp）residues and tyrosine（Tyr）residues.