光谱法研究头孢替唑钠与牛血清白蛋白相互作用

The Study on Interaction between Ceftezole Sodium and Bovine Serum Albumin by Spectrometry

在优化的实验条件下,运用荧光光谱和紫外-可见光谱法研究了头孢替唑钠(CS)与牛血清白蛋白(BSA)之间的相互作用.实验结果表明:CS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.通过计算获得了二者在不同温度下的结合常数及结合位点数.通过计算反应热力学参数值,可推断CS与BSA作用力主要为静电引力,生成自由能变ΔG为负值,表明CS与BSA的作用过程是一个自发过程.两者的结合部位主要位于亚螺旋域ⅡA中.Hill系数nH大于1,表明CE有正协同作用.同步荧光光谱表明CS对BSA构象不产生影响,结合位点更接近于酪氨酸.

Under the optimal conditions,the interaction of ceftezole sodium（ CS）with bovine serum albumin（ BSA） was investigated by fluorescence spectrometry and ultraviolet-visible light absorption spectrometry. The experiments demonstrated that the CS quenched the intrinsic fluorescence of BSA by forming CS-BSA complex. The mechanism of the fluorescence quench was static quenching. The binding constants and the numbers of binding site at different temperatures were calculated. The main binding forces were concluded as electrostatic forces from the calculated values of the thermodynamic parameter. The process of binding was spontaneous because that Gibbs free energy change was negative. The primary binding site for CS was located at sub-domain ⅡA of BSA. The values of Hillˊs coefficients were more than 1,which indicated that there was some positive cooperative effect. The effect of CS on the conformation of BSA was also studied by using synchronous fluorescence spectroscopy. Studies utilizing synchro-nous spectra showed that the conjugation reaction between CS and BSA would not affect the conformation of BSA. Synchronous fluorescence indicated that the binding site of CS and BSA was near by tyrosine residue.