槲皮素与牛血清白蛋白相互作用的研究

利用荧光光谱(FS)和紫外光谱(UV)法研究了槲皮素与牛血清白蛋白之间的相互作用。结果表明，静态猝灭和非辐射能量转移是导致槲皮素对BSA荧光猝灭的两大原因，槲皮素与BSA的结合常数K_A为2.8×108(26 ℃)和3.1×108(36 ℃)，结合位点数为1.76±0.01，根据Frster非辐射能量转移理论得到槲皮素与BSA之间的结合距离为3.25 nm (26 ℃)和3.30 nm(36 ℃)，表明槲皮素的部分片段可以插入BSA分子内部。通过计算热力学参数，可知该药物与蛋白的相互作用是一个熵增加和吉布斯自由能降低的自发过程，并由此推断槲皮素与BSA之间的作用力是以疏水相互作用为主。

Interaction of Quercetin and Bovine Serum Albumin

The interaction of quercetin and bovine serum albumin (BSA) was investigated using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The apparent binding constants (K_A) between quercetin and BSA were 2.8×108(26 ℃) and 3.1×108(36 ℃), and the binding sites (n) were 1.7±0.02. According to the Frster theory of non-radiation energy transfer, the binding distances (r) were also obtained. The experimental results showed that the quercetin could be inserted into the BSA, quenching the inner fluorescence by forming the quercetin-BSA complex. It was found that both static quenching and non-radiation energy transfer were the main reasons for the fluorescence quenching. The process of binding was a spontaneous molecular interactio1n in which entropy increased while Gibbs free energy decreased, indicating that the interaction of quercetin and BSA was driven mainly by hydrophobic force.