Somawardhana C W, Brunngraber E G
J Neurochem. 1983 Aug;41(2):321-30. doi: 10.1111/j.1471-4159.1983.tb04746.x.
A neutral, mannose-rich, concanavalin A (Con A)-binding glycopeptide fraction was obtained by proteolytic digestion of defatted beef brain tissue. Hydrazinolysis followed by gel filtration of the reaction products provided three oligosaccharides. A portion of each oligosaccharide was treated by exhaustive digestion with alpha-mannosidase. Another portion was subjected to selective acetolysis of Man alpha 1 leads to 6Man linkages, providing two fragments that were recovered by gel filtration. The structure of the intact oligosaccharides, as well as the fragments obtained by selective acetolysis and enzymatic treatment, were resolved by gas-liquid chromatographic-mass spectrometric analysis. The structures of the three oligosaccharides were: (a) Man alpha 1 leads to 2Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man alpha 1 leads to 6(Man alpha 1 leads to 2Man alpha 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4-N-acetylglucosamine (GlcNAc)beta 1 leads to 4N-acetylglucosaminitol (GlcOLNAc); (b) Man alpha 1 leads to 2Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man alpha 1 leads to 6(Man alpha 1 leads to 2Man alpha 1 leads to 3)-Man beta 1 leads to 4GlcNAc beta 1 leads to 4GlcOLNAc; and (c) Man alpha 1 leads to 6(Man alpha 1 leads to 3) Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc-beta 1 leads to 4GlcOLNAc. These structures account for 15-20% of the glycoprotein-carbohydrate of whole beef brain and most of the oligosaccharides that demonstrate a high affinity for Con A. In view of the large number of Con A-binding glycoproteins in brain tissue, it appears that many of these different glycoproteins must contain structurally identical oligosaccharides.
通过对脱脂牛脑组织进行蛋白酶消化，获得了一种中性、富含甘露糖、能与伴刀豆球蛋白A（Con A）结合的糖肽组分。肼解后对反应产物进行凝胶过滤，得到了三种寡糖。每种寡糖的一部分用α-甘露糖苷酶进行彻底消化处理。另一部分对Manα1→6Man键进行选择性乙酰解，得到两个片段，通过凝胶过滤回收。完整寡糖以及通过选择性乙酰解和酶处理得到的片段的结构，通过气-液色谱-质谱分析得以解析。这三种寡糖的结构分别为：（a）Manα1→2Manα1→6（Manα1→3）Manα1→6（Manα1→2Manα1→2Manα1→3）Manβ1→4-N-乙酰葡糖胺（GlcNAc）β1→4N-乙酰葡糖胺醇（GlcOLNAc）；（b）Manα1→2Manα1→6（Manα1→3）Manα1→6（Manα1→2Manα1→3）-Manβ1→4GlcNAcβ1→4GlcOLNAc；（c）Manα1→6（Manα1→3）Manα1→6（Manα1→3）Manβ1→4GlcNAc-β1→4GlcOLNAc。这些结构占全牛脑糖蛋白碳水化合物的15 - 20%，并且是大多数对Con A具有高亲和力的寡糖。鉴于脑组织中存在大量与Con A结合的糖蛋白，似乎这些不同的糖蛋白中有许多必定含有结构相同的寡糖。
