Wang Yan-Qing, Zhang Hong-Mei, Zhang Gen-Cheng, Liu Shuang-Xia, Zhou Qiu-Hua, Fei Zheng-Hao, Liu Zong-Tang
Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, People's Republic of China.
Int J Biol Macromol. 2007 Aug 1;41(3):243-50. doi: 10.1016/j.ijbiomac.2007.02.011. Epub 2007 Mar 3.
The interaction between paraquat (PQ) and bovine hemoglobin (BHb) was investigated using fluorescence and UV/vis absorption spectroscopy. The reactivity of the heme centers with superoxide anions formed by PQ was judged on the basis of the decrease of the Soret band. The experimental results showed that the fluorescence quenching of BHb by PQ was a result of the formation of PQ-BHb complex; static quenching was confirmed to result in the fluorescence quenching. The binding site number n, apparent binding constant K(A) and corresponding thermodynamic parameters were measured at different temperatures. The process of binding PQ molecule on BHb was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Hydrophobic and electrostatic interactions played a major role in stabilizing the complex. The effect of PQ on the conformation of BHb was analyzed using synchronous fluorescence spectroscopy.
利用荧光光谱和紫外/可见吸收光谱研究了百草枯（PQ）与牛血红蛋白（BHb）之间的相互作用。基于Soret带的降低来判断血红素中心与PQ形成的超氧阴离子的反应活性。实验结果表明，PQ对BHb的荧光猝灭是PQ-BHb复合物形成的结果；证实静态猝灭导致了荧光猝灭。在不同温度下测量了结合位点数n、表观结合常数K(A)及相应的热力学参数。PQ分子与BHb结合的过程是一个自发的分子相互作用过程，其中熵增加，吉布斯自由能降低。疏水作用和静电作用在稳定复合物中起主要作用。利用同步荧光光谱分析了PQ对BHb构象的影响。
