金属离子对齐多夫定与牛血清白蛋白结合作用的影响

用荧光光谱法和紫外分光光度法研究了水溶液(Tris-HCl缓冲溶液, pH 7.1)中齐多夫定(ZDV)与牛血清白蛋白(BSA)的结合作用及三种金属离子(Cu2+, Mg2+, Zn2+)对其的影响. 结果表明: 齐多夫定及金属离子均导致BSA的内源荧光猝灭, 猝灭机制均为静态猝灭; 齐多夫定与BSA间存在较强结合作用, 热力学参数△H和△S分别为-10.2 kJ·mol-1和77.5 J·mol-1·K-1 (298 K), 表明其结合力以静电作用力为主; 298 K下结合常数、结合位点数和结合距离分别为6.92×105 L·mol-1、1.18和2.28 nm; 温度升高结合常数和结合位点数减小. 三种金属离子均导致ZDV与BSA的结合常数减小, 结合距离增大.

Effecting of Metal Ions on the Interaction between Zidovudine and Bovine Serum Albumin

The interaction between zidovudine (ZDV) and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy and ultraviolet-visible spectroscopy in aqueous solution (Tris-HCl buffer, pH 7.1). The effect of metal ions (Cu2+, Mg2+, Zn2+) on the interaction was also investigated. Results showed that the fluorescence intensity of BSA at 346 nm was quenched when zidovudine or metal ions were added. The quenching mechanism was a static quenching mechanism. A strong interaction exists between zidovudine and BSA. The thermodynamic parameters △H and △S were -10.2 kJ·mol-1 and 77.5 J·mol-1·K-1 at 298 K, respectively, indicating that electro-static forces played a major role. The binding constant, the number of binding site and the binding distance were 6.92×105 L·mol-1, 1.18, and 2.28 nm at 298 K, respectively. The binding constant and the number of binding sites decreased with the increase in temperature. The metal ions, Cu2+, Mg2+ and Zn2+, all decreased the binding constant and increased the binding distance for binding between ZDV and BSA.