光谱法研究头孢西丁钠与牛血清白蛋白的相互作用及共存金属离子的影响

Study on Interaction between Cefoxitin Sodium and Bovine Serum Albumin and the Effect of Coexistent Metal Ion on the Reaction by Spectrometry

在优化的试验条件下,运用荧光光谱和紫外-可见光谱法研究了头孢西丁钠(CS)与牛血清白蛋白(BSA)之间的相互作用和共存金属离子对CS与BSA的相互作用的影响。计算了不同温度下的热力学参数、结合常数和结合位点数。结果表明,CS对BSA的猝灭机制属于形成复合物的静态猝灭过程;两者之间的作用主要是氢键或范德华力。CS在BSA中的结合位点主要位于ⅢA。Hill系数nH>1,表明CS有强的协同作用。根据同步荧光光谱法研究了CS对BSA构象的影响。考察了Fe3+、Mn2+、Cr2+、Ni2+、Mg2+金属离子对两者相互作用的影响,结果表明金属离子对CS与BSA的结合常数和结合位点数均有影响,降低了其结合能力。

Under the optimized conditions, the interaction of cefoxitin sodium（CS） with bovine serum albumin（BSA） and the effects of the coexisted metal ion on the reaction were investigated by fluorescence spectrometry and ultraviolet-visible light absorption spectrometry. The evaluation index was the binding constants, number of binding sites and thermodynamic parameters under different temperatures. The results showed that the quenching of BSA by CS was a static quenching procedure involving complex formation. The interaction between BSA and CS was dominated by Van Der Waals forces or hydrogen bond.The primary binding site for TI was located at sub-domain ⅢA of BSA. The values of Hill＇s coefficients were more than 1,which suggested that there was some strong positive cooperative effect. The effect of CS on the conformation of BSA was analyzed by synchronous fluorescence spectrometry. The metal ion such as Fe3 ＋、Mn2 ＋、Cr2 ＋、Ni2 ＋and Mg2 ＋, had effects on the binding constants and binding sites numbers of CS and BSA and declined its abilities of combination.