过渡金属离子与牛血红蛋白的相互作用

The interaction between transition metal ions and bovine hemoglobin

过渡金属离子在生理条件下会影响血红蛋白的功能,可利用光谱法对其作用机理进行研究.通过紫外可见光谱法研究了过渡金属离子对牛血红蛋白中亚铁离子的影响;通过荧光光谱法研究了过渡金属离子与牛血红蛋白之间的荧光猝灭类型和相互作用力.结果表明:过渡金属离子可部分置换血红蛋白中的亚铁离子,形成血红蛋白衍生物,衍生物的稳定性与过渡金属离子中d轨道上的电子数目(d电子数)有关;过渡金属离子通过静态猝灭显著降低牛血红蛋白的荧光强度,二者通过静电作用力形成稳定不发荧光的基态复合物;过渡金属离子通过增强牛血红蛋白中色氨酸残基的疏水性改变蛋白质构象.因此,过渡金属离子可在一定程度上影响血红蛋白的结构.

Transition metal ions could affect the function of hemoglobin in physiological conditions, which mechanism could be studied by spectroscopy. The interaction between transition metal ions and ferrous ions (Fe ^2+) of bovine hemoglobin (BHb) was studied by UV-Vis spectra. The fluorescence quenching type and interaction effect between transition metal ions and BHb was studied by fluorescence spectra. The results indicated that transition metal ions could enter into the hydrophobic cavities of hemoglobin, then replaced Fe^ 2+ partly to form hemoglobin derivatives. The stability of derivatives was associated with the electron number of d orbital (d electron number). It was showed that the BHb fluorescence intensity could be apparently quenched by transition metal ions based on static quenching model. A stable non-fluorescence ground state complex could be formed by means of electrostatic force between them. Transitional metal ions changed BHb conformation by increasing the hydrophobicity of tryptophan residues. As a result, transitional metal ions could affect the structure of BHb to some extent.