稀土La(Ⅲ)、Nd(Ⅲ)与牛血清白蛋白的相互作用

Interaction of Rare Earth with Bovine Serum Albumin

采用紫外吸收、荧光光谱和红外光谱,研究了稀土离子La(Ⅲ)和Nd(Ⅲ)与牛血清白蛋白(BSA)的相互作用。结果表明:La(Ⅲ)和Nd(Ⅲ)离子能配位诱导BSA,使其分子中色氨酸和酪氨酸芳杂环疏水基团外露,在280 nm处的吸收增强而表现出增色效应和较小的蓝移。La(Ⅲ)和Nd(Ⅲ)可以有规律地猝灭BSA的内源荧光,其猝灭机理是稀土离子与BSA形成复合物的静态猝灭。在20℃下,La(Ⅲ)和Nd(Ⅲ)与BSA的结合常数KA分别为8.12×106和3.85×106。

The interaction of rare earth La （Ⅲ ） and Nd （ Ⅲ ） with BSA were studied by ultraviolet spectrum, fluorescence spectrum and IR spectrum. The results showed that the ultraviolet absorption intensity of BSA increases with the concentration of rare earth. Rare earth can strongly quench the fluorescence of BSA which is the static quenching. The binding constant （KA） of La （Ⅲ） or Nd （Ⅲ） with BSA at room temperature are 8.12 × 106 and 3.85 × 106, respectively.