Precise hybrid synthesis of glycoprotein through amino acid sequence-specific introduction of oligosaccharide followed by enzymatic transglycosylation reaction

虽然人们对糖蛋白的生理功能的了解不断增加，但要获得均一的糖蛋白是很困难的。现在，通过使用大肠杆菌等原核细胞，可以非常容易地获得适当折叠的裸蛋白，并且可以通过与寡糖和蛋白质精确地结合来获得所需的糖蛋白。近年来，有报道寡糖和蛋白质之间发生了序列特异性的Amadori重排。在此基础上，研究了添加剂对Amadori重排反应的影响及其对反应速率的加速作用。最显著的结果是硼酸根离子的作用依赖于糖的化学结构。例如，在磷酸盐缓冲液中观察到使用D-果糖的非常大的反应速率，尽管在硼酸盐缓冲液中几乎没有观察到反应。Amadori重排的序列特异性研究正在进行中。

It is difficult to obtain homogeneous glycoproteins, although it is increasing our knowledge concerning physiological functions of glycoproteins. Nowadays, it is very easy to obtain bare proteins that fold appropriately by using prokaryote cells like Escherichia coli, and it is possible to obtain desired glycoproteins by conjugating with oligosaccharide and proteins precisely. Recently, it was reported that the Amadori rearrangement occurred between oligosaccharides and proteins in a sequence specific manner. Based on this report, I have investigated the effect of additives on the Amadori rearrangement reaction and acceleration of its reaction rate. The most striking result was that the effects of borate ion were depended upon chemical structure of sugars. For example, very large reaction rate using D-fructose was observed in phosphate buffer, although almost no reaction was observed in borate buffer. Investigation of sequence specificity of the Amadori rearrangement is under way.