キャピラリーアフィニティー電気泳動による糖タンパク質糖鎖解析

抄録

We proposed an approach to categorize carbohydrate chains in glycoconjugates using capillary affinity electrophoresis (CAE). CAE allows the determination of the interaction between carbohydrate chains and proteins (Nakajima et al. J. Proteome Res. 2003), and specific affinity of an oligosaccharide toward a lectin results resolution of complex mixture of oligosaccharides. In the present lecture, the principle of capillary affinity electrophoresis is briefly shown for categorizing carbohydrate chains or detection of carbohydrate-binding proteins in biological samples. And some applications are also shown for detection of novel carbohydrates in serum samples of cancer patients. An example to detect a carbohydrate-binding protein is also shown. 1. We can simultaneously determine the carbohydrate chains of high-mannose, complex and hybrid type oligosaccharides in biological samples using some defined sets of lectins (ConA, TGA, DSA, LTA, UEA and RSL) with extremely high sensitivity. Total time required for the analysis of an oligosaccharide mixture derived from one glycoprotein sample was within 2 h. Total amount required for the analysis was 200 ng (5 pmol) as glycoprotein. It should be noticed that the present method does not need purification of each oligosaccharide prior to CAE.2. We found marked changes in carbohydrate chains of alpha1-acid glycoprotein (AGP) in sera under malignancy. Alternations in branching patterns of carbohydrate chains and appearance of hyperfucosylated carbohydrate chains were especially interesting. These changes of carbohydrate chains in AGP may reflect the physiological environment in malignancy.