吲哚美辛与牛血清白蛋白相互作用的光谱研究

摘要

在模拟生理条件下,用荧光光谱法结合圆二色谱法研究了吲哚美辛(IM)与牛血清白蛋白(BSA)的相互作用.实验结果表明,IM对BSA的猝灭机制属于形成复合物的静态猝灭过程,由修正的Stem-Volmer方程求出不同温度下相应的结合常数分别为11.87×104、8.351 ×104、6.110×104L·mol-1.利用范特霍夫方程及结合常数的数据分别计算体系的焓变、熵变和吉布斯自由能变.焓变值(-42.54 kJ·mol-1)和熵变值(-45.65J·mol-1·K-1)表明,氢键和van der Waals是IM与BSA之间缔合作用的主要作用力.圆二色谱、三维荧光光谱的研究结果显示,在与IM结合后,BSA中a-螺旋的含量减少,说明在与IM结合反应过程中,BSA的微环境和构型发生了改变.%The interaction between indomethacin(IM)and bovine serum albumin(BSA)was investigated by fluorescence spectrosco-py combined with circular dichroism spectroscopy under simulative physiological conditions. The experiment results snowed that the fluorescence intensity of BSA was dramatically decreased owing to the formation of IM-BSA complex. The corresponding effective quenching constants ( Ka)between IM and BSA at three different temperatures(298,304 and 310 K)were 11.87×104 ,8.351×l04 and 6.110×104 L· mol-1 ,respectively. The thermodynamics parameters: enthalpy change (ΔH) and entropy change (ΔS) were calculated to be-42. 54 Kj·mol-1 and-45. 65 J·mol-1·K-1 .which suggested that hydrogen bond, van der Waals force interaction was the predominant intermolecular force in stabilizing the complex The conformational investigation showed that the presence of IM decreased the α-helical content of BSA and induced the slight unfolding of the polypeptides of protein, which confirmed some micro-environmental and conformational changes of BSA molecules.