在模拟生理条件下, 应用荧光光谱和表面增强拉曼光谱法对对-香豆酸(p-CA)与人血清白蛋白 (HSA) 的结合机理进行研究。结果表明, p-CA对HSA的荧光猝灭机制为静态猝灭, 并伴有非辐射能量转移。荧光光谱显示, 在298, 304, 310 K下, p-CA与HSA的结合常数(KA)分别为3.41×104, 2.09×104, 1.38×104 L/mol, 结合位点数(n)近似为1。表面增强拉曼光谱研究揭示, p-CA的酚基与HSA有效结合。标记竞争实验指出, p-CA在HSA上的结合位点主要在SiteⅠ。反应过程热力学参数表明, 二者间的作用主要为静电引力, 且根据Frster能量转移理论求得p-CA与HSA间的距离为 5.11 nm。同步荧光光谱显示, p-CA的结合没有导致HSA构象发生明显变化。

Under simulated physiological conditions, the binding mechanism between p-Coumaric acid (p-CA) and human serum albumin (HSA) was investigated by fluorescence spectrum and surface enhanced Raman scattering (SERS). The results show that the effect between p-CA and HSA is a static fluorescence quenching with Frsters non-radioactive energy transformation. At 298, 304, 310 K, the binding constants (KA) between p-CA and HSA are 3.41×104, 2.09×104, 1.38×104 L/mol, the binding site (n) value is approximate to 1. SERS reveals that the phenolic group of p-CA combines with HSA. Thermodynamic data indicate that the interaction between p-CA and HSA is mainly electrostatic attraction. Marker competition experiments point out that the primary binding site for p-CA is located at site Ⅰ in HSA. According to Frster energy transfer theory, the binding distance between p-CA and HSA is 5.11 nm. Synchronous fluorescence spectra show that the conformation of HSA does not changed apparently with the addition of p-CA.