三种抗氧化物质与牛血清白蛋白的相互作用

运用荧光光谱(FS)、紫外光谱(UV)和超滤(UF)法, 研究了阿魏酸、毛蕊异黄酮及芒柄花素三种抗氧化小分子物质与牛血清白蛋白(BSA)的结合反应. 以Lineweaver-Burk双倒数方程和能量传递原理分别计算了三者与BSA反应的结合常数(K_LB)和结合距离(r)以及由热力学参数的计算判断了三种小分子物质与BSA结合的作用力类型; 以Scatchard方程计算了三种小分子与BSA的结合常数(K_a)和结合位点数(n); 并对阿魏酸与毛蕊异黄酮及芒柄花素的竞争结合反应进行了研究. 实验结果表明: 这三种物质能与BSA结合形成非共价复合物, 导致BSA内源性荧光的静态猝灭; 它们与BSA的结合能力随着极性基团的增多、分子体积的增大而减弱; 静电作用和疏水作用可能是它们与BSA结合的主要作用力; 阿魏酸与芒柄花素或毛蕊异黄酮会产生与BSA的竞争结合效应.

Interaction between Three Antioxygenic Micromolecules and Bovine Serum Albumin

The conjugation between bovine serum albumin (BSA) and three antioxygenic micromolecules of ferulic acid, calycosin and formononetin was investigated here, using fluorescence spectroscopy (FS), ultraviolet spectroscopy (UV) and ultrafiltration (UF). The binding constants KLB and distances r of these compounds and BSA were calculated respectively, according to Lineweaver-Burk equation and energy transfer theory. And every type of conjugation effort was estimated by the calculation of thermodynamic parameters. Besides, the binding constants Ka and binding site numbers n in terms of Scatchard equation were also obtained. The results were showed as follows: the ferulic acid, calycosin and formononetin could form non-covalent compounds with BSA, which led to the static quenching of endogenous fluorescence of BSA; but the enlargement of polarity and volume of the molecules caused the decrement of the affinity, which was mainly on the electrostatic interaction of these compounds with BSA. In the concentration of our experiment, the results indicated the competitive binding reaction of ferulic acid, formononetin and calyco- sin with BSA.