Studies on Glycobilogy

1)聚糖分析新技术的研究：对植物凝集素的特异性研究表明，凝集素的结合特异性非常严格，使用具有不同特异性的各种凝集素柱组合可以从混合物中分离出聚糖链并阐明其部分结构。引入了一种新的核磁共振技术（简称HOHAHA），有效地分析了人乳中酸性低聚糖的结构。在糖-蛋白连接区发现了两种新的酶活性：一种（内切- α -氨基-乙酰半乳糖苷酶）作用于黏蛋白型糖蛋白，具有广泛的特异性；另一种（内切- β -半乳糖苷酶）作用于蛋白聚糖。这些酶被部分纯化。2)多糖的生物学功能研究：淋巴细胞上细胞粘附分子的多糖具有三、四天线复合物型聚糖，并通过n -乙酰乳胺、Lewis X和唾液酰Lewis X的附着进行修饰。在成纤维细胞上发现了硫酸软骨素特异性受体。巨噬细胞凝集素基因。克隆了asialal糖蛋白结合蛋白（ASGP-BP）并确定了其碱基序列。巨噬细胞凝集素的氨基酸序列与肝脏ASGP-BP非常相似，但与后者有明显区别。利用基因重组技术鉴定了植物凝集素的糖结合位点。制备了识别肿瘤相关黏蛋白型寡糖的单克隆抗体。

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.