Embryonal lactosaminoglycan. The structure of branched lactosaminoglycans with novel disialosyl (sialyl alpha 2----9 sialyl) terminals isolated from PA1 human embryonal carcinoma cells.
Embryonal lactosaminoglycan. The structure of branched lactosaminoglycans with novel disialosyl (sialyl alpha 2----9 sialyl) terminals isolated from PA1 human embryonal carcinoma cells.
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DOI：
10.1016/s0021-9258(18)88827-5
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发表时间：
1985-06
期刊：
影响因子：
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通讯作者：
M. Fukuda;A. Dell;J. Oates;M. Fukuda
中科院分区：
文献类型：
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作者：
M. Fukuda;A. Dell;J. Oates;M. Fukuda
从人PA 1胚胎癌细胞中分离得到乳糖胺聚糖糖肽，并对其结构进行了鉴定。在用外切糖苷酶修饰之前和之后，用弗氏大肠杆菌内切-β-半乳糖苷酶消化糖肽。通过甲基化、快原子轰击-质谱和高效液相色谱分析由此获得的核心糖肽和寡糖以及完整的糖肽。基于这些实验，发现PA 1乳糖胺聚糖的结构具有以下独特特征。1)通过Sephadex G-50凝胶过滤分离得到三种不同分子量的乳糖胺聚糖组分。最高分子量的乳糖胺聚糖（GpI）具有四触角核心，中等分子量的乳糖胺聚糖（GpII）具有三触角核心，低分子量的乳糖胺聚糖（GpIII）具有三触角和四触角核心。2)GpI由22-26个乳糖胺基单元和7-9个支链半乳糖残基组成，GpII由16-22个乳糖胺基单元和5-7个支链半乳糖残基组成，GpIII由12-16个乳糖胺基单元和3-4个支链半乳糖残基组成。3)每个分支较短，由Gal β 1- 4GlcNAc β 1- 6结构组成。4)唾液酸优先与非还原性末端区域连接，并且在较长的聚乳糖胺基侧链的末端存在大量的新型二唾液酸结构NeuNAc α 2- 9 NeuNAc α 2- 3/6 Gal。5)这些乳糖胺聚糖由Mr = 80，000约120，000的细胞表面糖蛋白携带，如凝集素-琼脂糖色谱法所证明。
Lactosaminoglycan glycopeptides were isolated from human PA1 embryonal carcinoma cells and their structures were elucidated. The glycopeptides were digested by Escherichia freundii endo-beta-galactosidase before and after the modifications by exoglycosidases. The core glycopeptides and oligosaccharides thus obtained and the intact glycopeptides were analyzed by methylation, fast atom bombardment-mass spectrometry, and high-performance liquid chromatography. Based on these experiments, the structures of PA1 lactosaminoglycans were found to have the following unique features. 1) Three lactosaminoglycan fractions of different molecular weights were isolated by Sephadex G-50 gel filtration. Lactosaminoglycans of the highest molecular weight (GpI) have tetra-antennary cores, those of intermediate molecular weight (GpII) have triantennary cores and those of low molecular weight (GpIII) have triantennary and tetra-antennary cores. 2) GpI is composed of 22-26 lactosaminyl units and 7-9 branched galactose residues, GpII is composed of 16-22 lactosaminyl units and 5-7 branched galactose residues, and GpIII is composed of 12-16 lactosaminyl units and 3-4 branched galactose residues. 3) Each branch is short and is composed of the Gal beta 1—-4GlcNAc beta 1—-6 structure. 4) Sialic acid is preferentially linked to nonreducing terminal regions and a significant amount of the novel disialosyl structure, NeuNAc alpha 2—-9NeuNAc alpha 2—-3/6Gal, is present at the terminals of the longer polylactosaminyl side chains. 5) These lactosaminoglycans are carried by cell surface glycoproteins of Mr = 80,000 approximately 120,000, as evidenced by lectin-agarose chromatography.