本文利用荧光光谱法和紫外吸收光谱法研究了硫酸长春碱(Vinblastine Sulfate,VS)与牛血清白蛋白(Bovine Serum Albumin,BSA)的相互作用,讨论了药物与蛋白相互作用时药物对蛋白微环境的影响。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。利用F6rster能量转移理论得药物与蛋白间的键合距离为3.34nm。热力学参数(△H=14.34kJ/mol,△S=36.92J/(mol·K))表明维持药物与蛋白质的相互作用力主要是疏水作用和静电作用。此外,基于硫酸长春碱的荧光猝灭效应,探讨了药物-蛋白质体系的几种物理化学参数包括电荷密度、离解常数及量子产率的变化效应;以及共存离子对药物-蛋白质体系结合常数的影响。
In this paper, the interaction of vinblastine sulfate (VS) and bovine serum albumin (BSA) was investigated by fluorescence and absorption spectra under the simulated physiological conditions. The effect of VS on the microenvironment around BSA in aqueous solution was discussed by the evidences from fluorescence and absorption spectroscopes. The binding constants and the number of binding sites between VS and BSA at different temperatures were calculated according to the data obtained from fluorescence titration. Fǒrster' theory of dipole-dipole energy transfer was used to determine the distances between BSA and VS(r=3.34 nm). The thermodynamic parameters obtained (△H°:-14.34 kJ·mol^-1,AS°:36.92 J·mol^-1·K^-1) suggested that hydrophobic and electrostatic interaction should be the predominant intermolecular forces stabilizing the complex. Under the conditions studied, the values of the negative charge densitys (δ) of VS, the dissociation constants (Ka) and quantum yield(φ) were calculated. In addition, the effects of common ions on the constants of VS-BSA complex were also discussed.