光谱技术分析尿素对BSA糖基化反应的影响

Effect of Urea on Glycosylation of BSA Based on Spectral Techniques

以牛血清白蛋白(BSA)和葡萄糖为原料,采用光谱技术从分子水平上研究不同浓度尿素(0~7 mol·L^-1)对BSA糖基化反应的影响。结果表明:BSA经过尿素处理后,其糖基化产物的自由氨基含量和内源荧光强度均显著下降;同步荧光光谱表明BSA与尿素的结合点更接近于色氨酸(Trp)残基;紫外光谱分析表明经尿素处理后BSA的糖基化产物的紫外吸收值均有不同程度的增加;三维荧光光谱表明随着尿素浓度的增加,BSA的最大发射波长产生先红移再蓝移的变化趋势,说明其结构展开,促进了BSA的糖基化反应。结果表明,尿素处理会使BSA的空间结构发生不同程度的伸展,且当尿素浓度为3 mol·L^-1时BSA的糖基化反应程度最大。

In this experiment,the effect of urea with different concentrations(0~7 mol·L^-1)on the glycosylation of BSA with D-Glucose was investigated at the molecular level by spectral techniques.After urea treatment,the intrinsic fluorescence intensity and the free amino group content of BSA-Glucose glycosylation product were all significantly decreased.Synchronous fluorescence spectra showed that the binding point of BSA and urea was near tryptophan residue.Ultraviolet spectrum analysis showed that the ultraviolet absorption value of glycosylation product was all increased with different the increase of urea concentration.The three-dimensional fluorescence spectra showed that the maximum emission wavelength of BSA firstly shifted red and then blue with the increase of urea concentration,indicating that its structure extended,which promoting the glycosylation reaction of BSA.These results indicated that urea treatment could make the spatial structure of BSA extend to different degrees,and the degree of glycosylation is maximum when urea concentration is 3 mol·L^-1.