Studies on Glycobilogy

1)糖链分析新技术的研究：对植物凝集素的专一性研究表明，凝集素的结合专一性是非常严格的，结合使用不同专一性的凝集素柱可以从多个糖链混合物中分离出一条糖链，并阐明其部分结构。介绍了一种新的~1H-核磁共振分析技术(中继式HOHAHA)，该技术非常有效地用于从母乳中提取的酸性寡糖的结构分析。在糖蛋白连接区发现了两种新的裂解键的酶活性：一种是具有广泛特异性的内切-α-Nu-乙酰半乳糖胺酶，另一种是作用于蛋白多糖的内切-β-半乳糖苷酶。这些酶得到了部分纯化。2)多聚糖的生物学功能研究：细胞黏附分子在淋巴细胞上形成的多聚糖具有N-乙酰乳糖胺、Lewis X和唾液酸化Lewis X结构修饰的三烯和四烯复合型多糖。成纤维细胞上存在4-硫酸软骨素特异性受体。编码巨噬细胞凝集素的基因。克隆了去唾液酸糖蛋白结合蛋白(ASGP-BP)，并测定了其碱基序列。已阐明的巨噬细胞凝集素的氨基酸序列与肝脏的ASGP-BP非常相似，但明显不同于后者。利用基因重组技术对植物凝集素的糖结合部位进行了研究。制备了识别肿瘤相关粘蛋白类低聚糖的单抗。

1) Studies on new technologies for glycan analysis :Specificity studies on plant lectins demonstrated that the binding specificity of a lectin is so strict that use of various lectin columns with distinct specificity in combination allow us to isolate a glycan chain from a mixture of glycans and elucidate its partial structure. A new technology in ^1H-NMR analysis (relayed HOHAHA) was introduced very effectively for the structural analysis of acidic oligosaccharides isolated from human milk. Two new types of enzymatic activities which cleave bonds in the carbohydrate-protein linkage regions were found : one (endo-alpha-NU-acetylgalactosaminidase) acted on mucin-type glycoproteins with a broad specificity and the other (endo-beta-galactosidase) acted on proteoglycans. These enzymes were partially purified.2) Studies on biological functions of glycans :Glycans from a cell adhesion molecule on lymphocytes were found to have tri-and tetra-anntenary complex-type glycans modified with the attachment of N-acetyllactosamine, Lewis X and sialyl Lewis X structure. The presence of a receptor specific for chondroitin 4-sulphate on fibroblasts was established. A gene encoding a macrophage lectin. asialoglycoprotein binding protein (ASGP-BP) was cloned and its base sequence was determined. The elucidated amino acid sequence of the macrophage lectin was very similar to that of the hepatic ASGP-BP but was clearly distinct from the latter. Sugar binding sites of plant lectins were elucidated by utilizing gene recombinant technology. Monoclonal antibodies recognizing cancer associated mucin-type oligosaccharides were prepared.