【摘要】 本文通过荧光淬灭的方法对犁头尖凝集素(TDL)的内源荧光进行了淬灭研究。研究结果表明:丙烯酰胺与TDL分子中Trp残基的可接近程度达到100%,而KI和CsCl与Trp残基的可接近程度分别为83.3%和50%,说明TDL中大部分Trp残基位于分子表面或近表面区域,且位于表面的Trp残基所处微环境中带正电荷基团约为带负电荷基团的一倍。荧光淬灭数据分析表明这三种淬灭剂对TDL的荧光淬灭作用均属动态淬灭机制。此外,本文还研究了变性剂对TDL凝血活性与荧光光谱的影响,研究表明同浓度的盐酸胍对TDL变性作用明显强于脲,TDL活性的丧失主要是由于其活性中心被变性剂破坏而造成。更多还原

【Abstract】 In the present study,three different quenchers were chosen to research the micro-environment of tryptophan residues in Typhonium divaricatum (L.) Decne lectin (TDL).Fluorescence quenching results showed that the accessibility to tryptophan residues of TDL for acrylamide,KI and CsCl were 100%,83.3% and 50%,respectively.These results suggested that most of the tryptophan residues in TDL were located on the surface or near the surface of the molecule.In addition,the ratio between the positive charged residues and negative charged residues around surface-located tryptophan residues was about 2.Stern-Volmer analysis of the quenching data indicated that all the three fluorescence quenching mechanisms were dynamic quenching processes.Hemagglutinating activity and fluorescence spectra of TDL after denaturing with GuHCl and urea suggested that the denaturing effect by GuHCl was much more powerful than urea.The loss of the hemagglutinating activity after denaturation was resulted from the destroy of the active centre of TDL.更多还原