N-(2-亚甲基吡啶)脱氢枞胺希夫碱及其铜配合物与牛血清白蛋白的作用研究

运用紫外光谱、荧光光谱和圆二色谱研究了具有抗癌活性的N-(2-亚甲基吡啶)脱氢枞胺希夫碱(L)及其铜配合物Cu(L)2Br]Br(1)在模拟生理条件(p H值7.2)下与牛血清白蛋白(BSA)的相互作用,分析了它们之间相互作用的机制。结果表明,1对BSA的荧光猝灭方式为静态猝灭,L为动态猝灭;通过计算得到了不同温度下的结合常数(Ka)、结合位点数(n)及相关的热力学参数(ΔG0、ΔH0和ΔS0),表明L和1与BSA的相互作用力以疏水作用为主,且结合反应是由焓和熵驱动的自发过程。同步荧光光谱分析表明,化合物与BSA的作用使蛋白质的构象发生改变,圆二色谱也证明了化合物能够显著改变BSA的构象,由典型的α-螺旋结构变为扭曲链。

Binding Ability of N-(2-Methylene Pyridine) Dehydroabietylamine Schiff Base and Its Copper Complex with Bovine Serum Albumin

The binding abilities of anticancer compounds N-(2-methylene pyridine) dehydroabietylamine Schiff bases (L) and its copper complexCu(L)2Br]Br(1) with bovine serum albumin (BSA) under simulated physiological conditions were investigated by UV absorption spectroscopy, fluorescence spectroscopy and circular dichroism ( CD ) . The results indicated that the fluorescence quenching of BSA was a static process by 1, and a dynamic quenching by L. Binding constants(Ka), binding sites (n) and corresponding thermodynamic parameters (ΔG <0,ΔH >0 and ΔS >0) at different temperatures were calculated, respectively. The main binding force between BSA and the compounds was proved to be hydrophobic interaction. The binding reactions were spontaneous processes controlled by enthalpy and free energy. And the analysis of synchronous fluorescence spectroscopy indicated that the binding of compounds changed BSA conformation, and circular dichroism confirmed that the binding interaction obviously modified the secondary structure of BSA from the typical α-helix structure into twisted chain.