Structure of the carbohydrate units of IgE immunoglobulin. I. Over-all composition, glycopeptide isolation, and structure of the high mannose oligosaccharide unit.
Structure of the carbohydrate units of IgE immunoglobulin. I. Over-all composition, glycopeptide isolation, and structure of the high mannose oligosaccharide unit.
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IgE 免疫球蛋白碳水化合物单位的结构。
DOI：
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发表时间：
1974
影响因子：
4.8
通讯作者：
Shaul Kochwa
中科院分区：
文献类型：
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作者：
J. Baenziger;Stuart Kornfeld;Shaul Kochwa
已经确定了一种IgE骨髓瘤蛋白的总碳水化合物组成。甘露糖、n -乙酰氨基葡萄糖、半乳糖、唾液酸和焦糖分别以每摩尔重链16、12、7、5和4摩尔的量存在。以前已经确定所有的碳水化合物部分位于IgE蛋白的重链上（Kochwa， S., Terry， W. D., Capra， J. D., and Yang， N. L.(1971)）。中华科学杂志，1999,49)。蛋白经酶降解后分离出5个主要的含糖肽部分。B型含有唾液酸、焦糖、甘露糖、半乳糖和n -乙酰氨基葡萄糖，摩尔比为1至2:1:3:2:4。在每条重链上发现了3个b型寡糖单位。这些糖肽的完整结构在以下论文中介绍(Baenziger， J., Kochwa， S., and Kornfeld， S. (1974) J. Biol。化学。249,1897)。此外，还分离出一种高甘露糖糖肽，命名为C-1，它只含有甘露糖和n -乙酰氨基葡萄糖，比例为6:2。每条重链只有一条这种类型的链。这个糖肽的完整序列是用顺序酶降解、高碘酸盐氧化和甲基化的组合来确定的。α-甘露糖苷酶去除6个甘露糖残基中的4个后，剩下一个序列如下的核心。Man (β1,4)/→GlcNAc(α1,3)/→Man (β1,4)/→GlcNAc(β)/→Asn这是在循环糖蛋白中描述的α-连接n -乙酰氨基葡萄糖的第一个例子。这种糖肽也不寻常，因为它不具有更常见的壳聚糖核心单元(GlcNAc (β1,4)/→GlcNAc (β)/→Asn)，并且没有微观异质性的证据。
Abstract The total carbohydrate composition of an IgE myeloma protein has been determined. Mannose, N-acetylglucosamine, galactose, sialic acid, and fucose were found to be present in the amount of 16, 12, 7, 5, and 4 moles, respectively, per mole of heavy chain. Previously it had been determined that all of the carbohydrate moieties were located on the heavy chain of the IgE protein (Kochwa, S., Terry, W. D., Capra, J. D., and Yang, N. L. (1971) Ann. N. Y. Acad. Sci. 190, 49). Five major glycopeptide-containing fractions were isolated after pronase degradation of the protein. The type designated B contained sialic acid, fucose, mannose, galactose, and N-acetylglucosamine in the molar ratios of 1 to 2:1:3:2:4. Three of the B-type oligosaccharide units were found to be present per heavy chain. The complete structure of these glycopeptides is presented in the following paper (Baenziger, J., Kochwa, S., and Kornfeld, S. (1974) J. Biol. Chem. 249, 1897). In addition, a high mannose glycopeptide, termed C-1, was isolated which contained only mannose and N-acetylglucosamine in the ratio of 6:2. Only one chain of this type was present per heavy chain. The complete sequence of this glycopeptide was determined using a combination of sequential enzymatic degradation, periodate oxidation, and methylation. After removal of 4 of the 6 mannose residues with α-mannosidase, a core with the following sequence remained. Man (β1,4)/→ GlcNAc(α1,3)/→ Man (β1,4)/→ GlcNAc (β)/→ Asn This is the first example of an α-linked N-acetylglucosamine to be described in a circulating glycoprotein. This glycopeptide is also unusual in that it does not have the more commonly found chitobiose core unit (GlcNAc (β1,4)/→ GlcNAc (β)/→ Asn) and gives no evidence of microheterogeneity.