中药活性成分根皮素与人血清白蛋白相互作用机制研究

目的:研究根皮素(phloretin)与人血清白蛋白(HSA)的作用机制.方法:在模拟生理条件下,采用荧光光谱研究phloretin与HSA之间的猝灭类型,计算二者之间的结合常数、结合位点数及结合距离等.结果:Phloretin能使HSA发生内源荧光猝灭,属静态猝灭机制.在298,303,313 K下,phloretin与HSA结合常数分别为1.518 1×105,9.441 2×104,5.417 8×104 L·mol-1,结合位点数n近似为1；热力学分析表明phloretin与HSA间结合力为疏水作用；根据F(o)rster非辐射能量转移理论求得二者结合距离为4.27 nm；同步荧光光谱表明phloretin对HSA构象影响较小；金属离子的介入会影响phloretin与HSA的结合能力.结论:荧光光谱法适合于研究根皮素与人血清白蛋白的结合反应,具有简便快速,灵敏度高等优点.

Binding Machanism of Phloretin and Human Serum Albumin

Objective: To study the mechanism of interaction between phloretin and human serum albumin (HSA). Method: The binding constant, binding site and binding distance was investigated by fluorescence spectrometry. Result: Phloretin could induce an endogenous fluorescence quenching of HSA under a mechanism of static quenching. The binding constants were determined to be 1.518 1×10⁵(298 K), 9.441 2×10⁴(303 K) and 5.417 8×10⁴(313 K)L·mol^-1, respectively. The binding site (n) was about 1.The thermodynamic parameters suggested that the interaction forces between phloretin and HSA were mainly hydrophobic force. According to förster nonradiation energy transfer mechanism, the binding distance was estimated to be 4.27 nm. The results obtained from synchronous fluorescence spectra showed that phloretin had only a slight influence on the HSA conformation. The common ions could affect the binding constant of phloretin-HSA complex. Conclusion: Fluorometric analysis is a good method for the study on phloretin-HSA binding reaction. It has the advantages of high speed and high sensitivity.