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为研究单硝酸异山梨酯(IM)与牛血清白蛋白(BSA)之间的相互作用,用紫外-可见光谱法和荧光光谱法在优化的实验条件下进行研究。结果表明:IM与BSA形成基态复合物从而猝灭BSA的内源性荧光,猝灭机理为静态猝灭。通过计算得出IM与BSA的结合常数Kb及结合为点数n。根据热力学参数确定了IM和BSA之间的作用力类型主要为静电引力。生成自由能变驻G为负值,表明IM与BSA的作用过程是一个自发过程。同步荧光光谱表明IM对BSA构象产生很微弱的影响,使BSA腔内疏水环境的极性减弱。同步荧光光谱显示两者的结合位点更接近于酪氨酸,两者的结合部位主要位于亚螺旋域ⅢA中。Hill系数nH>1,表明IM有正协同作用。为后续硝酸脂类药物的研发和进一步探讨IM在生物体内与蛋白质的作用机制和生物学效应提供了理论依据。
In order to study the interaction between isosorbide mononitrate (IM) and bovine serum albumin (BSA), UV-vis spectroscopy and fluorescence spectroscopy were used to investigate the interaction between isosorbide mononitrate (IM) and bovine serum albumin The results showed that IM and BSA formed a ground state complex, which quenched endogenous fluorescence of BSA. The quenching mechanism was static quenching. The binding constant Kb between IM and BSA and the number of points n are obtained by calculation. According to the thermodynamic parameters, the type of force between IM and BSA is mainly electrostatic attraction. Generated free energy change in G is negative, indicating that the role of IM and BSA process is a spontaneous process. Simultaneous fluorescence spectroscopy showed that IM had a very weak effect on the conformation of BSA, which reduced the hydrophobicity of BSA cavity. Synchronous fluorescence spectroscopy showed that the binding sites of both were closer to tyrosine, and the binding sites of the two were mainly located in the helix domain IIIA. Hill coefficient nH> 1, indicating that IM has a positive synergistic effect. This provided the theoretical basis for the follow-up research and development of nitric-lipid drugs and further exploration of the mechanism of action and biological effect of IM in vivo.