光谱法研究儿茶素与牛血清白蛋白的相互作用  

Investigation of Interaction between Catechin and Bovine Serum Albumin by Spectroscopic Methods

作　　者：张海蓉[1] 边贺东[1] 潘英明[1] 田建嬝 于青[1] 梁宏[1] 陈振锋[1] 

机构地区：[1]广西师范大学药用资源化学与药物分子工程教育部重点实验室,广西桂林541004

出　　处：《光谱学与光谱分析》2009年第11期3052-3056,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(20671023;30460153);广西自然科学基金项目;广西高校自然科学基金;教育部重点基金项目(03101;204111);药用资源化学与药物分子工程教育部重点实验室项目资助

摘　　要：运用荧光猝灭光谱、傅里叶红外光谱(FTIR)等光谱手段研究了模拟人体生理条件下儿茶素与牛血清白蛋白(bovine serumal bumin,BSA)的相互作用,求出了儿茶素与BSA结合的结合常数、结合位置、结合类型等参数,并研究了共存离子对儿茶素与BSA的结合常数的影响。实验结果表明:儿茶素与BSA形成复合物从而猝灭BSA的内源荧光,且其荧光猝灭机理符合静态机制。296,303,310K下儿茶素与BSA结合的结合常数分别为:2.368,2.249,2.152×106L·mol-1。热力学数据表明儿茶素与BSA主要靠疏水作用力和静电作用力结合,探针实验表明儿茶素与BSA在结合位点SiteI发生结合。Fster偶极一偶极非辐射能量转移机理确定了儿茶素在BSA中与第214位色氨酸残基之间的距离r=1.93nm。FTIR光谱显示,儿茶素诱导BSA的二级结构发生了变化。In the present work,the interaction of catechin with bovine serum albumin （BSA） under physiological condition was studied by fluorescence quenching spectra in combination with Fourier transform infrared （FTIR） spectroscopy. The binding constants,the drug-binding mode,the binding site between catechin and BSA in aqueous solution at pH 7.40,and the effect of common ions were studied. The results show that catechin has the ability to quench the intrinsic fluorescence of BSA because of a complex formed,and the quenching mechanism is static quenching. The binding constants K under 296,303 and 310 K were 2.368,2.249 and 2.152×10^6 L·mol^-1 respectively. The thermodynamic parameters showed that the interaction between catechin and BSA was driven mainly by hydrophobic force and electrostatic interaction. The displacement experiment shows that catechin can bind to the site Ⅰ of BSA. The distance between the 214 tryptophan residues in BSA and catechin was estimated to be 1.46 nm using Fster＇s equation on the basis of fluorescence energy transfer. According to FTIR,the secondary structure of BSA changed when catechin was added.

关 键 词：儿茶素 牛血清白蛋白 荧光光谱 傅里叶红外光谱 

分 类 号：O657.3[理学—分析化学]