Development of Glyco-medicines Using Mutant Enzyme of Microbial Endoglycosidase and Establishment of Its Preparation Method

从土壤样品中分离的冬夜毛霉（Mucor hiemalis）的内切-β-N-乙酰氨基葡萄糖苷酶（endo-β-N-acetylglucosaminidase）是一种独特的酶，它能将糖蛋白中的寡糖整体转移到不同的受体上，从而酶促生成不同的糖缀合物。我们进行了突变研究，以获得酶的突变体，其水解活性显著降低，但具有高的转糖基化活性。我们发现一些突变体可以有效地利用合成糖恶唑啉表现出转糖基活性。因此，我们利用该突变酶合成了一种有效的流感病毒结合抑制剂，它是由唾液酸寡糖在壳聚糖上组成的。该化合物对流感病毒感染显示出足够的抑制活性。

The endo-β-N-acetylglucosaminidase from Mucor hiemalis isolated from soil sample is unique in that it can transfer en bloc the oligosaccharide of glycoproteins onto different acceptors, and thereby it enzymatically generates diverse glycoconjugates. We performed mutational studies to obtain the mutant of the enzyme which had significantly diminished hydrolysis activity but had a high transglycosylation activity. We have found that some mutant could efficiently exhibit transglycosylation activity using synthetic sugar oxazoline. Therefore, we used the mutant enzyme to synthesize an efficient binding inhibitor for influenza virus, which is composed of sialyloligosaccharides on chitosan. This compound showed sufficient inhibitory activity against influenza virus infection.