Synthesis and Function of Modified Oligosaccharides

为了阐明葡萄糖苷酶和糖基转移酶的反应机理，合成了各种寡糖模拟物，并研究了它们的生化行为。合成了在非还原端具有5-硫代-L-岩藻糖残基的二糖和三糖，并且前者类似物被证明是针对α-L-岩藻糖苷酶的连接特异性抑制剂，而后者类似物中的一种（H 2型）表现出不同的行为与天然三糖对凝集素和抗体的反应。此外，还开发了通过脒键在非还原端具有氮杂糖的二糖的合成路线。合成了糖基转移酶的各种糖基供体类似物。其中，发现UDP-5-硫代-GalNAc、GDP-5-硫代-L-Fuc和CMP-NeuNAc的唾液酸膦酸酯类似物分别作为β-1，4-半乳糖基转移酶、α-L-岩藻糖基转移酶和α-唾液酸转移酶的糖基供体具有活性。

In order to elucidate the reaction machanisms of glucosidases and glycosyltransferases, various oligosaccharide mimics were synthesized and their biochemical behaviors were examined. Di-and trisaccharides having 5-thio-L-fucose residue at the non-reducing end were synthesized and the former analogs were proved to be effective as a linkage-specific inhibitor against alpha-L-fucosidase, while one (H type 2) of the latter analogs showed different behaviors from the natural trisaccharide toward the lectin and antibody. Further, synthetic routes of disaccharides having azasugar at the non-reducing end through amidine linkage were developed. Various glycosyl donor analogs of glycosyltransferases were synthesized. Among them, UDP-5-thio-GalNAc, GDP-5-thio-L-Fuc, and sialyl phosphonate analog of CMP-NeuNAc were found to be active as glycosyl donors, for beta-1,4-galactosyltransferase, alpha-L-fucosyltransferase, and alpha-sialytransferase, respectively.