荧光光谱法研究Fe^(2+)和Fe^(3+)与牛血清白蛋白的竞争结合作用

Fluorescence characterization of the competitive binding of Fe^(2+) and Fe^(3+) to bovine serum albumin

利用荧光光谱法、紫外吸收光谱法、同步荧光法和三维荧光法研究了金属离子Fe2+、Fe3+与牛血清白蛋白(BSA)在模拟生理条件下的竞争结合作用.结果表明,Fe2+、Fe3+对BSA的内源荧光都有明显的猝灭作用,猝灭机理均为静态猝灭和动态猝灭的联合作用,主导作用分别为静态猝灭和动态猝灭,并分别计算了结合常数、结合位点数和热力学参数,Fe3+与BSA的结合能力强于Fe2+.弱的结合力使BSA与Fe2+、Fe3+相互作用后构型没有明显改变.当Fe2+、Fe3+同时与BSA相互作用时,二者表现出弱的竞争取代现象.

The interactions between Fe2＋ and Fe3＋ with and bovine serum albumin（BSA） were investigated by fluorescence spectroscopy,UV absorption spectroscopy,synchronous fluorescence spectroscopy,and three-dimensional fluorescence spectroscopy） under physiological condition.The intrinsic fluorescence of BSA was significantly quenched by Fe2＋ or Fe3＋ via a combination of static and dynamic quenching.Static and dynamic quenching played a major role,respectively.The binding constants,binding sites number and thermodynamic parameters were obtained.The binding ability of Fe3＋ to BSA was higher than that of Fe2＋.The conformation of BSA in the presence of Fe2＋ or Fe3＋ did not shift due to the weak binding between the two metal ions and BSA.The competitive binding behavior was exhibited when Fe2＋ and Fe3＋ bound to BSA simultaneously.