摘要
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。
Under the optimal conditions,the interaction of Isosorbide Mononitrate（IM） with bovine serum albumin（BSA） was studied by fluorescence spectrofmetry and U-V absorption spectrometry.It showed that the IM quenched the intrinsic fluorescence of BSA by forming IM-BSA complex.The mechanism of the fluorescence quench was static quenching.The binding constants Kband the numbers of binding site n at 291 K,301 K,311 K were calculated.The main binding forces were concluded as electrostatic force from values of the thermodynamic parameters.The process of binding was spontaneous because that Gibbs free energy change was negative.Studies utilizing synchronous spectra showed that the conjugation reaction between IM and BSA would affect the conformation of BSA very weakly,leading to the polarity around BSA weakened.Synchronous fluorescence indicated that the binding site of IM and BSA was near by tyrosine residue.The primary binding site for IM was located at sub-domainⅢA of BSA.The values of Hill＇s coefficients were more than 1,which indicated that there was some strong positive cooperative effect.The theoretical basis was provided for further research on Mmononitrate drugs and the further study of the inner mechanism and biological effect in organism of IM and the proteins.
出处
《基因组学与应用生物学》
CAS
CSCD
北大核心
2015年第1期66-72,共7页
Genomics and Applied Biology
基金
云南省教育厅科研项目(2012Y414)
国家自然科学基金资助项目(21261019)共同资助
关键词
光谱法
单硝酸异山梨酯
牛血清白蛋白
荧光猝灭
相互作用
Spectrometry
Isosorbide mononitrate
Bovine serum albumin
Fluorescence quenching
Interaction
