光谱法研究文多灵碱与牛血清白蛋白的键合

Study on the Interaction between Vindoline and Bovine Serum Albumin by Spectroscopy

利用荧光增敏光谱法结合紫外光谱法研究了文多灵碱与牛血清白蛋白的相互作用。实验所得到的热力学参数表明维持药物与蛋白质的相互作用力主要是疏水作用和氢键(依据范德霍夫公式计算得ΔH0与ΔS0的值分别为-9.03kJ·mol-1和76.83J·mol-1·K-1)。根据荧光增敏的有关方程分别求得不同温度下(298K,308K和318K)药物与蛋白相互作用的结合常数及结合位点数;从紫外光谱获得的信息定性地讨论了药物与蛋白的相互作用时药物对蛋白微环境的影响。且利用Foerster能量转移理论,求得药物与蛋白间的键合距离为6.62nm。此外,基于文多灵碱的荧光敏化效应,首次探讨了药物-蛋白质体系的几种物理化参数,包括电荷密度、离解常数(pKa)及量子产率的变化效应;及共存离子对药物-蛋白质体系结合常数的影响。

The interaction of vindoline and bovine serum albumin （BSA） was investigated by fluorescence and absorption spectra under the simulated physiological conditions for the first time. The evidences from fluorescence and absorption spectra indicated the effects of indulines on the microenvironment around BSA in aqueous solution. The binding parameters between vindoline and BSA at different temperatures （298K, 308K, 318K） were calculated according to the data obtained from fluorescence titration. The -9.03kJ ·mol^-1,76.83J·mol^-1·K^-1 were obtained. Hydrophobic and electrostatic interactions are the predominant intermolecular forces stabilizing the complex. Under the conditions studied, the values of the negative charge densitys （δ） of vindoline, the dissociation constants （pKα） and Quantum yield（Ф） were calculated. In addition,the effects of common ions on the constants of vindoline-BSA complex were also discussed.