光谱法研究羧甲基壳聚糖与牛血清白蛋白的相互作用

摘要

The interaction process and mechanism between carboxymethyl chitosan (CMCS) and bovine serum albumin (BSA ) are investigated by means of fluorescent spectrometry ,ultraviolet spectrosco‐py ,infrared spectroscopy ,and circular dichroism (CD) .And it is found that the fluorescence quench‐ing of BSA accorded with the CMCS concentration -dependent .And the Stern-Volmer curve of the fluorescence quenching of BSA by CMCS shows that the mechanism is mainly static quenching .The UV indicates that the BSA molecules are combined with the CMCS ,forming a complicated ground -state .The analytical results with the CD and infrared spectroscopy indicate that the peptide bonds within the CMCS and the BAS are affected each other and theα-helix content of BSA is changed with CMCS by CD ,leading to the changes of secondary structure in the BSA .The experimental result with three-dimension fluorescence shows that the strength of overall intrinsic fluorescence is significantly reduced when the CMCS is added into the BAS .The results with the synchronous fluorescence and the site competition suggest that the binding sites between the CMCS and the BSA are more close to tryptophan residues ,w here the binding sites are located at Site I .%采用荧光光谱法、紫外光谱法、红外光谱法和圆二色谱法研究了羧甲基壳聚糖（CMCS）与牛血清白蛋白（BSA）的相互作用过程及机理。研究结果表明，CMCS对BSA的内源荧光有猝灭作用，且为静态猝灭；紫外光谱分析表明，CMCS与BSA分子发生了相互作用，形成了基态复合物；圆二色谱和红外光谱分析结果表明，CMCS与BSA中肽键发生作用，α－helix结构含量发生改变，使BSA二级结构发生变化；三维荧光的实验结果表明，当在BSA中加入CMCS后，分子全局的内源荧光强度明显降低；同步荧光和位点竞争实验结果表明，CMCS与BSA 的结合位点更接近于色氨酸残基，结合部位为Site I。