中文摘要：

采用荧光光谱技术研究了大豆甙元与牛血清白蛋白（BSA）的相互作用。研究结果表明：290K、303K、310K、315K温度下大豆甙元对BSA的猝灭速率常数KSV随着温度升高逐渐降低,且均大于最大动态猝灭速率常数2×1010 L.mol-1.s-1,表明大豆甙元对BSA的荧光猝灭属静态猝灭过程。根据Frster非辐射能量转移理论计算出大豆甙元与BSA间的结合距离r为4.02nm;结合过程的热力学参数△r Hm=-238.213kJ.mol-1,△rSm=-711.855J.mol-1,△r Gm=-17.538kJ.mol-1（310K）,△r Gm=-13.978kJ.mol-1（315K）,表明大豆甙元与BSA之间主要是以氢键和范德华力相结合的自发反应过程;应用同步荧光光谱技术考察了大豆甙元对BSA构象的影响。

英文摘要：

The interaction between Daidzein and bovine serum albumin（BSA） in physiological buffer（pH=7.4） was studied by fluorescence spectroscopy.The quenching constants were obtained at 290 K,303 K,310 K and 315 K,which decreased with increase of the temperature and all the quenching constants were larger than 2×1010L·mol-1·s-1（the maximum collision quenching constant of various quenchers）.The results indicated that the fluorescence quenching mechanism for BSA through Daidzein binding was likely a static quenching process.According to the Frster theory of non-radiation energy transfer,the binding distance（r） was calculated as 4.02 nm.The thermodynamic parameters,enthalpy change（△H） and entropy change（△S）,were calculated to be-238.213 kJ·mol-10,and-711.855 J·mol-1·K-10,respectively,which indicated that the interaction of Daidzein with BSA was driven mainly by the hydrogen bond and Van der Waals force.The process of binding was a spontaneous process in which Gibbs free energy changes were negative（△rGm=-17.538 kJ·mol-1（310 K）,△rGm=-13.978 kJ·mol-1（315 K））.The effect of Daidzein on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.