采用荧光猝灭光谱、 同步荧光光谱和紫外-可见吸收光谱， 研究了大豆苷元与人血清白蛋白（HSA）之间的结合反应。 大豆苷元对人血清白蛋白有较强的荧光猝灭作用， 猝灭机制属于静态猝灭， 并发生了分子内非辐射能量转移。 利用Stern-Volmer方程处理实验数据， 得到大豆苷元与HSA之间的结合常数KA为0.34×104(23 ℃)， 1.10×104(30 ℃)和4.36×104 L·mol-1(40 ℃)。 根据Frster非辐射能量转移理论， 求出了大豆苷元与HSA之间的结合距离为1.50 nm(23 ℃)， 1.46 nm(30 ℃)和1.42 nm(40 ℃)。 通过计算相应的热力学参数， 可知大豆苷元与人血清白蛋白的相互作用是一个吉布斯自由能降低的自发过程， 且二者之间的主要作用力类型为疏水作用力， 同时用同步荧光光谱考察了大豆苷元对HSA构象的影响。

The binding reaction between daidzein and human serum albumin (HAS) was studied by fluorescence quenching spectra, synchronous fluorescence spectra and ultraviolet spectra. The results indicated that daidzein led to the quenching of the intrinsic fluorescence of HSA. The fluorescence quenching mechanism between daidzein and HSA was mainly static quenching, with non-radiation energy transfer occurring within single molecule. The binding constants (KA) between daidzein and HSA were 0.34×104 (23 ℃), 1.10×104 (30 ℃) and 4.36×104 (40 ℃), respectively. According to the Frster theory of non-radiation energy transfer, the binding distances (r) were 1.50 nm (23 ℃), 1.46 nm (30 ℃) and 1.42 nm (40 ℃), respectively. The thermodynamic parameters were calculated, which indicated that the hydrophobic force played major roles between daidzein and human serum albumin. The effect of daidzein on the conformation of HAS was investigated using synchronous spectrum.