Thermodynamics Studies on the Binding of Rutin and Serum Albumin
LUAN Ni-na1,WU Jin-xiu1,2,SONG Yu-min1*,WU Qiong1
1. College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, China 2. College of Rare Earth, Inner Mongolia University of Science and Technology, Baotou 014010, China
摘要： 在生理pH值条件下，研究了芦丁与牛血清白蛋白和人血清白蛋白之间的结合作用。通过荧光法确定了芦丁与血清白蛋白的荧光猝灭机制，根据热力学方程讨论了两者间的主要作用力类型。芦丁对血清白蛋白的荧光猝灭机制为静态猝灭。确定了不同温度下该结合反应的结合常数和结合位点数, 并根据热力学方程求得了结合反应的热力学参数。两者结合的主要作用力类型是氢键和Van der Waals力。芦丁在体内能够被血清白蛋白存储和转运, 且结合时对蛋白质构象无影响。
关键词：芦丁;牛血清白蛋白;人血清白蛋白;荧光光谱;热力学参数
Abstract：To study the binding of rutin and serum albumin (SA) in physiological condition and the quenching mechanism of the fluorescence of SA by rutin, the fluorescence method was used. The results shows that the emission spectra of BSA(HSA)in the presence and absence of rutin are different. The emission spectra of BSA(HSA)in the presence of rutin can be quenched. The quenching mechanism of rutin to SA was static quenching with non-radiation energy transfer with single molecule. The binding constants KA, the number of binding sites n and the thermodynamic parameters of the reaction of rutin with SA were determined at different temperatures. At 295 and 310 K, for BSA, KA(L·moL-1)=4.215×104 and 6.996×103 and n=0.75 and 0.64, respectively; for HSA，KA(L·moL-1)=2.660×104 and 4.110×103 and n=0.70 and 0.60, respectively. The binding constants KA decreased with the increase in temperature, which means that rutin and SA have a quite strong ability to form a new complex-system. The main binding force was discussed by thermodynamic equation, and the result is that ΔH＜0 and ΔS＜0 for the reaction of rutin with SA. So the binding forces was mainly H-bond and Van der Waals. The effect of the drug on the conformation of serum albumin was also studied by using synchronous fluorescence spectroscopy. Rutin could be deposited and transported by serum protein in vivo. Rutin had nearly no effect on the serum protein conformation.
