摘要
利用紫外可见吸收光谱和荧光光谱研究了在生理pH条件下桑色素与牛血红蛋白(BHb)的相互作用。实验结果表明:桑色素分子与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,桑色素与BHb之间以疏水和静电作用力为主;根据F rster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桑色素对BHb构象的影响。
Morin is a bioactive plant flavonoid of immense importance as a potentially useful therapeutic drug. The interaction between morin and bovine hemoglobin （BHb） was investigated by UV/Vis absorption spectrum and fluorescence quenching spectroscopic methods. The experimental results showed that the fluorescence quenching of BHb by morin is a result of the formation of morin-BHb complex;static quenching was confirmed to result in the fluorescence quenching. The binding site number n（293 K： 1.11;308 K： 1.08）,apparent binding constant KA （293 K：4.96 L·mol^-1308 K： 4.64 L·mol^-1 and corresponding thermodynamic parameters （ΔH^Θ3.34 kJ·mol^-1ΔG^Θ26.34 kJ·mol^-1-27.51 kJ·mol^-1ΔS^Θ8.50 J·mol^-1K^-1） were measured at two temperatures. The process of binding morin molecule on BHb was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. The binding distance r（r= 4.13 nm） and energy-transfer efficiency E（E=0.10） between morin and BHb were obtained according to fluorescence resonance energy transfer. The hydrophobic and electrostatic interactions play a major role in stabilizing the complex. The interaction of morin with BHb does not obviously affect the conformation of tryptophan and tyrosine micro-region of BHb. Thus,the results provided a quantitative understanding of the binding of morin to BHb,which is important in understanding its effect as therapeutic agent in therapy.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第4期566-572,共7页
Chinese Journal of Luminescence
基金
江苏省滩涂生物资源与环境保护重点建设实验室资助项目(JLCBE06032)~~
