槐定碱与牛血清白蛋白的相互作用研究

在模拟动物体生理条件下,用荧光猝灭、荧光偏振和紫外-可见吸收光谱法研究了槐定碱与牛血清白蛋白(BSA)结合作用。荧光猝灭数据显示,槐定碱与BSA发生反应生成了新的复合物,属于静态荧光猝灭。求出了不同温度(19、25、31、37℃)下槐定碱与BSA作用的结合常数分别为1.219×106,1.164×106,1.110×106和1.057×106L/mol,由van’tHoff方程式计算槐定碱与BSA反应的热力学参数:焓变ΔH和熵变ΔS值分别为-5.97kJ/mol和96.11J/(mol.K),表明槐定碱与BSA间的作用力以静电引力为主。以华法林和布洛芬(分别为siteI和siteII探针)为标记药物研究槐定碱在BSA上的结合位点,结果表明,槐定碱结合在BSA疏水空腔的siteI位点。

Studies on the Interaction of Sophordine with Bovine Serum Albumin

The interaction of scphordine with bovine serum albumin (BSA) was investigated by fluorescence quenching, fluorescence anisotropy, and UV-vis absorhance under the simulative physiological condition.Fluorescence quenching da-ta showed that the interaction of sophordine with BSA formed a new complex ,the quenching mechanism belonged to stat-ic fluorescence quenching.The binding constants were obtained at 292,298,304 and 310 K to be 1.219 × 10~6 ,1.164 ×10~6 ,1.110 × 10~6 and 1.057 × 10~6 L/mol,respectively.The thermodynamic parameters,enthalpy change (△H) and entropy change (△S) were calculated to be-5.97kJ/mol and 96.11 J/(mol·K) via van't Hoff equation,which indiccated that the interaction between sophordine and BSA was driven mainly by electrostatic force.The competitive probes, such as warfarin and ibuprofen (site Ⅰ and site Ⅱ probes,respectively) ,revealed that the binding location of sophordine to BSA in the site Ⅰ of the hydrophobic pocket.