胆红素与血红蛋白分子作用的发光光谱分析

利用荧光光谱技术研究了胆红素对血红蛋白分子中发光基团结构变化的影响及其与血红蛋白结合方式。结果表明,不同浓度的胆红素可以不同程度地猝灭血红蛋白荧光,导致330nm处色氨酸残基荧光峰下降,410nm处荧光峰消失;pH值94时血红蛋白与胆红素以非静电引力如疏水作用、范德华力的协同作用结合,且随着作用时间的延长,荧光强度下降。血红蛋白中氨基酸残基上的-NH₂与胆红素分子中两个-COOH结合,形成复杂的卷曲结构。血红蛋白的紫外光谱受胆红素分子中二吡咯发色团的影响,导致光吸收劈裂,在350,406nm处形成肩峰。另外,体系受温度影响也较大。

Spectral Analyses for the Molecular Interaction between Bilirubin and Hemoglobin

Protein and Bilirubin(BR) are the main components in animal bile. When the metabolization is disordered, the unnecessary and free bilirubin can combine with some proteins to form compositions and produce toxin. To learn the mechanism of toxicity, the effects of bilirubin on the molecular structure of Hemoglobin(Hb) and the means of their combination were studied by fluorescence and UV absorption spectra. It was shown that BR can quench the fluorescence of Hb extently,which decreased the fluorescent intensity of tryptophan(Try) at 330 nm and the peak at 410 nm disappeared; at pH 9.4 BR can bind with Hb in cooperative actions of nonelectrostatic attraction, e g. Hydrophobic action, Van der Waals force. The intensity declinded with the delay of time. The group of -NH₂ on the Try residue of Hb molecule reacted with two -COOH groups, and formed a complex with curly structures. The spectra can vary with temperature, the conformation of BR changed from Z-Z to Z-E or E-Z, which caused complex structures. It showed two peaks at 350 nm and 406 nm induced by dipyrrole chromphoses of BR,the absorption fissions occurred in Hb UV spectra. Therefore, the present of free bilirubin molecules damaged the structure of Hb molecule and the spectra appeared different. It is less reported about the interaction of Hb and BR at present, the discussions in this paper provide experimental information for the study on medicine and biochemistry, and also offer some theoretical bases for the relation between biological macromolecules and organic micromolecules.