锌酞菁与牛血红蛋白相互作用的光谱研究

Spectroscopic study on interaction between zinc phthalocyanine and bovine hemoglobin (BHb)

运用荧光光谱和紫外-可见吸收光谱法研究了锌酞菁与牛血红蛋白的相互作用。结果表明,锌酞菁与牛血红蛋白之间主要存在疏水作用,而且锌酞菁对牛血红蛋白还表现出较强的荧光猝灭作用。测定了不同温度下锌酞菁与牛血红蛋白相互作用的表观结合常数KA和热力学参数ΔG、ΔH、ΔS,基于能量转移机制计算了锌酞菁和牛血红蛋白结合时的作用距离r,并用同步荧光技术研究了锌酞菁对牛血红蛋白构象的影响。

The interaction between zinc phthalocyanine （ZnPc） and bovine hemoglobin （BHb） was investigated using UV/Vis and fluorescence spectroscopy. The experimental results showed that the fluorescence quenching of BHb by ZnPc was attributed to the formation of ZnPc-BHb complex; and static quenching was confirmed to result in the fluorescence quenching. The binding site numbern, the apparent binding constant KA and correspond-ing thermodynamic parameters were measured at different temperatures. The process of binding ZnPc molecule on BHb was a spontaneous molecular interaction procedure, in which the entropy increased and the Gibbs free energy decreased. The hydrophobic interactions played a major role in stabilizing the complex. The binding distancer and the energy-transfer efficiency E between ZnPc and BHb were obtained according to fluorescence resonance energy transfer; and the effect of ZnPc on the conformation of BHb was analyzed using the synchronous fluorescence spectroscopy.