在模拟动物体生理条件和不同温度下,采用荧光、紫外光谱法来研究苋菜红(AMR)与牛血清白蛋白(BSA)结合反应.用Stem-Volmer和Lineweaver-Burk方程分别处理试验数据,发现BSA与AMR发生反应,生成新的复合物,属于静态荧光猝灭.实验求出反应时复合物的形成常数KLB、热力学参数与结合位点数,证明苋菜红与牛血清白蛋白的结合主要为静电作用力.位点竞争实验结果显示AMR与BSA的作用位置主要在BSA的Site I(sub-domain IIA).位.通过同步荧光光谱和三维荧光光谱法,探讨AMR对BSA构象的影响,实验结果表明,AMR使BSA酪氨酸残基和色氨酸残基所处微环境的极性减弱,疏水性增强.本文为探讨AMR的染色机理、毒理效应和生物学效应提供了重要信息.
Under simulated physiological conditions of animals and at various temperatures, the binding reaction of Amaranth (AMR) to bovine serum albumin (BSA) was studied by fluorescence spectrum and ultra-violet spectrum spectroscopy. The fluorescence quenching data were analyzed according to Stem-Volmer equation and Lineweaver- Burk double-reciprocal equation. The study showed that BSA reacted with AMR and formed a certain new compound, which belonged to static fluorescence quenching. The formation constants of the compound KLB, the thermodynamic parameters and the number of binding sites were obtained from experimental data. It showed that the binding power was mainly the electrostatic acting force. Site marker competitive experiments showed that the binding of AMR to BSA primarily took place in site I (sub-domain IIA) of BSA. The effect of AMR on the conformation of BSA was analyzed by synchronous fluorescence spectra and three-dimensional fluorescence spectra. It indicates that the polarity microenvironment around Trp residues decreased, and hydrophobic forces increased. The study provided important information for the dying mechanisms, the toxicity effects and biological effects of AMR.