光谱法研究羟喜树碱与牛血清白蛋白的相互作用

Studies on the Interaction between 10-Hydroxycamptothecin and Bovine Serum Albumin by Spectrometry

在模拟人体生理条件下,采用光谱法研究了羟喜树碱(HCPT)与牛血清白蛋白(BSA)的相互作用,计算了不同温度下的结合常数及ΔHθ、ΔGθ、ΔSθ等热力学参数。结果表明,HCPT对BSA的猝灭是由于形成HCPT-BSA复合物而引起的静态猝灭;ΔHθ(-35.91kJ.mol-1)和ΔSθ(-24.30J.mol-1.K-1)的值表明氢键和范德华力在HCPT-BSA的结合中起主要作用;圆二色谱和三维荧光光谱表明,在与HCPT结合后,BSA中的α-螺旋含量减少、微环境和二级结构均发生改变。

The interaction between 10-hydroxycamptothecin（HCPT） and bovine serum albumin（BSA） was investigated by spectrometry under simulated physiological conditions.The association constant and the thermodynamic parameters ΔHθ,ΔGθ,ΔSθ at different temperatures were calculated.It was proved that the fluorescence quenching of BSA by HCPT was a result of the formation of HCPT-BSA complex.The mechanism was a static quenching procedure.The value of ΔHθ（-35.91 kJ·mol-1） and ΔSθ（-24.30 J·mol-1·K-1） indicated that hydrogen bonds and van der Waals interactions were the predominant intermolecular forces in stabilizing the complex.Circular dichroism and three-dimensional fluorescence spectra showed that the α-helical content of BSA decreased,some microenvironment and secondary structure of BSA molecules changed in the presence of HCPT.