药物小分子白杨素与人血清白蛋白结合作用的光谱法研究

Studies on Interaction between Chrysin and Human Serum Albumin by Spectroscopic Method

应用荧光光谱法、共振瑞利散射光谱法和同步荧光法,研究了生理条件下白杨素与人血清白蛋白(HSA)相互作用。研究表明,白杨素与HSA发生作用并形成了新的基态化合物,静态猝灭是导致HSA内源荧光猝灭的主要原因;求得不同温度(17℃、26℃和35℃)下白杨素与HSA作用的结合常数分别为2.373×106、1.680×106和1.346×106L.mol-1;由求得的热力学参数,确定了白杨素与HSA间的结合反应主要由静电引力驱动。根据F rster非辐射能量转移理论,计算出白杨素在蛋白质中的结合位置与214位色氨酸残基间的距离为3.52 nm;同步荧光光谱表明,白杨素使得HSA的二级结构发生了变化。

The interaction of chrysin with human serum albumin（HSA） under physiological condition was studied using fluorescence, resonance rayleigh scattering and synchronous fluorescence spectroscopy. The experimental results showed that there was a strong fluorescence quenching reaction of chrysin to HSA. The probable quenching mechanism of fluorescence of HSA by chrysin was a static quenching by forming the ground-state chrysin-HSA complex. The binding constants obtained at different temperatures were found to be 2. 373 × 106 （17℃）, 1. 680× 106 （26℃） and 1. 346 × 106 L·mol^-1 （35℃）, respectively. According to the thermodynamic parameters, it could be concluded that the interaction between chrysin and HSA was driven mainly by the electrostatic force. The binding locality was an area 3.52 nm away from tryptophan residue-214 in HSA based on Forster nonradiation energy transfer mechanism. The results of synchronous fluorescence spectra indicated that the binding of chrysin to HSA induced conformational changes in HSA.