Fanger M W, Smyth D G
Biochem J. 1972 May;127(5):757-65. doi: 10.1042/bj1270757.
The carbohydrate structure of rabbit immunoglobulin G isolated from pooled sera was investigated. Amino sugar analysis of fragments of the molecule allowed three oligosaccharides to be located at separate sites on the H-chain. The corresponding glycopeptides were isolated. The average composition of the C1-oligosaccharide was 2 glucosamine, 1 mannose and 2 galactose residues. It appeared to be present in approx. 15% of the H-chains; the carbohydrate was coupled through the amide group of asparagine in a peptide containing asparagine, glycine and threonine within the Fd fragment of the molecule. The average composition of the C2-oligosaccharide was 1 galactosamine, 1 galactose and either 1 or 2 sialic acid residues. It was present on approx. 40% of the H-chains and was attached glycosidically to the OH group of threonine in a peptide Ser-Lys-Pro-Thr-Cys-Pro-Pro-Glu-Leu in the hinge region of the molecule. The average composition of the C3-oligosaccharide was 5 glucosamine, 2 galactose, 5 mannose, 1 fucose and 1 sialic acid residue. It appeared to be present in all the H-chains and was linked through the amide group of asparagine in a peptide Gln-Gln-Phe-Asn-Ser-Thr-Ile-Arg within the Fc fragment of the molecule.
对从混合血清中分离出的兔免疫球蛋白G的碳水化合物结构进行了研究。对该分子片段的氨基糖分析表明,有三种寡糖位于重链上的不同位点。相应的糖肽被分离出来。C1-寡糖的平均组成为2个氨基葡萄糖、1个甘露糖和2个半乳糖残基。它似乎存在于约15%的重链中;碳水化合物通过分子Fd片段内一个含有天冬酰胺、甘氨酸和苏氨酸的肽中天冬酰胺的酰胺基团相连。C2-寡糖的平均组成为1个半乳糖胺、1个半乳糖和1或2个唾液酸残基。它存在于约40%的重链上,通过糖苷键连接到分子铰链区一个肽Ser-Lys-Pro-Thr-Cys-Pro-Pro-Glu-Leu中苏氨酸的OH基团上。C3-寡糖的平均组成为5个氨基葡萄糖、2个半乳糖、5个甘露糖、1个岩藻糖和1个唾液酸残基。它似乎存在于所有重链中,并通过分子Fc片段内一个肽Gln-Gln-Phe-Asn-Ser-Thr-Ile-Arg中天冬酰胺的酰胺基团相连。