Anderson D R, Grimes W J
J Biol Chem. 1982 Dec 25;257(24):14858-64.
Mouse myeloma immunoglobulin IgM heavy chains were cleaved with cyanogen bromide into nine peptide fragments, four of which contain asparagine-linked sites of glycosylation. Three of these glycopeptides contain a single site located at asparagines 171, 403, and 563 in the sequence of the intact heavy chain. Another glycopeptide contains two sites of glycosylation at asparagines 332 and 364. All sites contain multiple oligosaccharide structures with a trend towards increased processing from the COOH to the NH2 terminus. Structures present at asparagine 563, located only exclusively high mannose oligosaccharides. Asparagine 403, located penultimate to the COOH terminus, has a major component that is of a complex nature but is incompletely processed. Other sites contain predominantly complex structures consisting of biantennary or triantennary branches. The unusual structure found at asparagine 403 contains fucose even though only one branch has been processed to a terminal galactose. These studies suggest that each site has a unique set of heterogeneous oligosaccharides derived from a complex processing system which utilizes a combination of "position completeness" and polypeptide structure to determine final carbohydrate structure.
小鼠骨髓瘤免疫球蛋白IgM重链用溴化氰裂解成九个肽片段，其中四个含有天冬酰胺连接的糖基化位点。这些糖肽中的三个含有位于完整重链序列中天冬酰胺171、403和563处的单个位点。另一个糖肽在天冬酰胺332和364处含有两个糖基化位点。所有位点都含有多个寡糖结构，且有从COOH端到NH2端加工增加的趋势。天冬酰胺563处存在的结构仅为高甘露糖寡糖。位于COOH端倒数第二个位置的天冬酰胺403，其主要成分具有复杂的性质，但加工不完全。其他位点主要含有由双天线或三天线分支组成的复杂结构。在天冬酰胺403处发现的异常结构含有岩藻糖，尽管只有一个分支已加工成末端半乳糖。这些研究表明，每个位点都有一组独特的异质寡糖，它们来自一个复杂的加工系统，该系统利用“位置完整性”和多肽结构的组合来确定最终的碳水化合物结构。
