单宁酸与牛血红蛋白相互作用的光谱研究

利用荧光光谱技术研究了单宁酸与牛血红蛋白分子的相互作用。实验结果表明:单宁酸分子与BHb发生反应生成基态复合物,导致BHb内源荧光的猝灭,该猝灭属于静态猝灭。测定了不同温度下该反应的表观结合常数、结合位点数及结合热力学参数,热力学参数的变化表明上述作用过程是一个熵增加、自由能降低的自发分子间作用过程,单宁酸与BHb之间以疏水和氢键作用力为主;根据Frster能量转移理论,测得供体与受体间结合距离r和能量转移效率E;并用同步荧光光谱法探讨了单宁酸对BHb构象的影响。

Spectroscopic studies of interaction between tannic acid and bovine hemoglobin

The interaction between tannic acid and bovine hemoglobin(BHb) was investigated using UV/Vis and fluorescence.The experimental results showed that the fluorescence quenching of BHb by tannic acid is a result of the formation of tannic acid-BHb complex;static quenching was confirmed to result in the fluorescence quenching.The binding site number n,apparent binding constant KA and corresponding thermodynamic parameters were measured at different temperatures.The process of binding tannic acid molecule on BHb was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased.The hydrophobic and hydrogen bonds interactions play a major role in stabilizing the complex.The binding distance r and energy-transfer efficiency E between tannic acid and BHb were obtained according to fluorescence resonance energy transfer;the effect of tannic acid on the conformation of BHb was analyzed using synchronous fluorescence spectroscopy.