Kornfeld R, Ferris C
J Biol Chem. 1975 Apr 10;250(7):2614-9.
A number of intact and partially degraded immunoglobulin glycopeptides have been tested for their ability to interact with concanavalin A. The degraded glycopeptides were prepared by using purified glycosidases to remove sugar residues from the nonreducing ends of the oligosaccharide chains of intact glycopeptides. A quantitative and sensitive assay was devised to measure the potency of the glycopeptides as haptene inhibitors of 125I-concanavalin A binding to guinea pig erythrocytes. The most potent haptene, derived from an immunoglobulin G glycopeptide, had a branched chain oligosaccharide with two GlcNAc (see article) Man (see article) nonreducing termini linked to a mannose residue in the core. The other very potent glycopeptide was an immunoglobulin E high mannose glycopeptide which contained 3 terminal alpha-mannose residues and 1 internal 2-O-mannose residue. Removal of terminal beta-N-acetylglucosamine residues or alpha-mannose residues reduced the activity of these and other glycopeptides as inhibitors of 125I-concanavalin A binding. It was concluded that the ability of these glycopeptides to interact with concanavalin A is dependent on their content of terminal beta-N-acetylglucosamine residues, terminal alpha-mannose residues, and also internal mannose residues substituted on the C-2 hydroxyl group, and that the saccharide combining site of concanavalin A must be able to bind several sugar residues.
已对多种完整的和部分降解的免疫球蛋白糖肽与伴刀豆球蛋白A相互作用的能力进行了测试。通过使用纯化的糖苷酶从完整糖肽寡糖链的非还原端去除糖残基来制备降解的糖肽。设计了一种定量且灵敏的测定方法，以测量糖肽作为125I-伴刀豆球蛋白A与豚鼠红细胞结合的半抗原抑制剂的效力。最有效的半抗原源自免疫球蛋白G糖肽，其具有一条支链寡糖，带有两个与核心中的一个甘露糖残基相连的GlcNAc（见文章）Man（见文章）非还原末端。另一种非常有效的糖肽是免疫球蛋白E高甘露糖糖肽，其含有3个末端α-甘露糖残基和1个内部2-O-甘露糖残基。去除末端β-N-乙酰葡糖胺残基或α-甘露糖残基会降低这些糖肽和其他糖肽作为125I-伴刀豆球蛋白A结合抑制剂的活性。得出的结论是，这些糖肽与伴刀豆球蛋白A相互作用的能力取决于它们末端β-N-乙酰葡糖胺残基、末端α-甘露糖残基以及C-2羟基上取代的内部甘露糖残基的含量，并且伴刀豆球蛋白A的糖结合位点必须能够结合多个糖残基。
