目的 研究槲皮苷与人血清白蛋白(HSA)的相互作用,并探讨葡萄糖对二者结合的影响。方法 应用光谱法研究槲皮苷与HSA的作用机制,以双对数方程和能量转移原理计算槲皮苷与HSA的结合常数、结合位点数和结合距离;根据热力学参数判断二者的作用力类型;用同步荧光光谱考察槲皮苷对HSA构象的影响;观察葡萄糖浓度对反应结合常数和结合位点数的影响。结果 槲皮苷对HSA的荧光猝灭过程为生成复合物的静态猝灭;结合常数和结合位点数随温度的升高而降低;结合距离小于7 nm;二者主要以疏水作用力相结合;槲皮苷与HSA的相互作用改变了色氨酸残基所处的微环境;葡萄糖的加入使结合常数和结合位点数均增加。结论 槲皮苷能与HSA结合并改变HSA的构象,生理浓度的葡萄糖可增加槲皮苷与HSA的结合常数和结合位点数。

Objective To study the interaction of quercitrin with human serum albumin (HSA) and the influence of glucose. Methods To investigate the interaction mechanism between quercitrin and HSA by spectroscopic method; to calculate the binding constants,binding sites, and binding distance according to double logarithmic plot and Fosters energy transfer theory, respectively; to explain the type of interaction force between quercitrin with HSA by thermodynamic parameters; to discuss the conformation change of HSA via synchronous fluorescence spectra. Results The fluorescence quenching mechanism of quercitrin to HSA was static quenching; The binding constants and the number of binding sites decreased with the increasing of temperature and glucose; The distance between the donor and acceptor was less than 7 nm; The hydrophobic forces played a major role in stabilizing quercetrin and HSA complex; The binding reaction had changed the micro-environmention of tryptophan residues. Conclusion Quercetrin could bind with HSA and change the conformation of HSA; The physiological concentration of glucose increases the binding constants and the number of binding sites of quercetrin with HSA.

中国博±后科学基金面上项目(20070410868);河北省自然科学基金项目(08B033)