利复星药物与牛血清白蛋白作用的荧光光谱研究

Fluorescence spectroscopy study of bovine serum albumin quenched by Levofloxacin

以荧光光谱为手段,研究了药物利复星(Levofloxacin)与牛血清白蛋白(BSA)的作用和影响,研究了它的荧光淬灭现象。在向该溶液滴加利复星时,观察不到激发峰的明显移动,而发射峰出现了新颖的现象, 原有的353．1 nm的发射峰强度明显的减弱;新出现了峰位位于450．4 nm的新的荧光发射峰。利复星-BSA 体系的猝灭过程不是因为分子扩散和碰撞所引起的动态猝灭,而是分子之间结合形成了化合物所引起的静态猝灭。利复星的离解常数为Kd=3．39×10-5mol／L。利复星的能量转移效率为50％时给体和受体之间距离的 R0=1．81×10-7cm,利复星和牛血清白蛋白的能量转移效率为E=0．351,根据这些计算结果可以知道利复星和牛血清白蛋白的色氨酸残基的结合位置为r=2．01×10-7cm。

The fluorescence spectroscopy of bovine serum albumin（BSA） influenced by Levofloxacin is studied. When the Levofloxacin is added into BSA solution gradually, the excitation peak has not obvious remove. However, the new phenomenon is emerged in emission spectrum. The intensity of 353.1 nm emission peak is decrease obviously, which is a typical quenching phenomenon. A new peak is emerged at 450.4 nm. The quenching progress of Levofloxacin-BSA is not dynamic quenching resulted from the molecular diffusion and collision. It resulted from the static quenching progress due to the chemical component between molecules. The dissociation constant of Levofloxacin from BSA is about Kd=3.39 × 10^-5 mol/L. The critical distance R0 between provider and acceptor, when energy transfer efficiency is 50%, is about R0=1.81 × 10^-7 cm. The energy transfer efficiency between Levofloxacin and BSA is E = 0.351. According to these calculation results, it could be known the combined position between the binding site of Levofloxacin and the tryptophane of BSA is about r=2.01 × 10^-7 cm.