头孢唑啉钠与牛血清白蛋白的相互作用研究及共存金属离子的影响

Study on the interaction between cefazolin sodium and bovine serum albumin and the effect of coexistent metal ion on the reaction

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唑啉钠(CS)与牛血清白蛋白(BSA)之间的相互作用,考察了Pb2+,Fe3+,Cr3+,Ni 2+和Cu2+对CS与BSA相互作用的影响,计算了不同温度下的热力学参数、静态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ⅡA.Hill系数值略小于1,表明药物之间有弱的负协同作用.同步荧光光谱表明,CS对BSA构象产生一定影响,使BSA腔内疏水环境的极性增强,结合位点更接近于酪氨酸.金属离子对CS与BSA的结合常数和结合位点数均有影响,除Pb2+以外,其他金属离子都降低了其结合能力.

Under the optimal conditions,fluorescence spectrometry and U-V absorption spectrometry are used to investigate the interaction of cefazolin sodium（CS）with bovine serum albumin（BSA）.The effects of metal ions on the interaction CS with BSA are also discussed.The quenching of fluorescence of BSA by CS is a static quenching procedure involving complex formation. Under different temperature,thermodynamic parameters,static binding constants and number of binding sites are calculated.The interaction between BSA and CS is dominated by van der Waals forces or hydrogen bond.The primary binding site for CS is located at sub-domainⅡ A of BSA.The values of Hill＇s coefficients are less than 1,which indicated that there is some very weak negative cooperative effect.Synchronous spectra shows that the conjugation reaction between CS and BSA can affect the conformation of BSA,leading to the polarity around BSA weakened.Synchronous fluorescence indicates that the binding site of CS and BSA is near by tyrosine residue.The effects of metal ions Pb^2＋,Fe^3＋,Cr^3＋,Ni^2＋and Cu^2＋on the interactions between BSA and CS are investigated,and the results show that Fe3＋,Cr3＋,Ni^2＋and Cu2＋have negative influence and Pb2＋has positive influence on the combination of CS and BSA.