Title : Comparative structural study of
the N-linked oligosaccharides of
human normal and pathological immunoglobulin G
Abstract :
- The structures of oligosaccharides of normal and pathological immunoglobulin G ( IgG ) are reported
- Asparagine Asparagine-linked neutral oligosaccharides were released by N-oligosaccharide glycopeptidase (almond) digestion
- The reducing ends of the oligosaccharide chains thus obtained were aminated with a fluorescent reagent, 2-aminopyridine, and the mixture of pyridylamino derivatives of the oligosaccharides was separated by reverse-phase high-performance liquid chromatography
- It was possible to separate 15 out of the 16 kinds of oligosaccharides that have been suggested to exist in normal human IgG
- High-resolution proton nuclear magnetic resonance spectroscopy was used along with chemical methods to determine the structures of the separated oligosaccharides
- It has been shown that in normal IgG a biantennary complex-type oligosaccharide with a fucose residue (formula; see text) is predominant and four kinds of oligosaccharides , which are biantennary with bisecting N-acetylglucosamine and without fucose residues, exist only in a very small quantity
- The results obtained for normal IgG were compared with those obtained for three myeloma IgG proteins
- It has been found that the most abundant species that exist in the pathological proteins analyzed in the present work lack one or two galactose residues residues at the nonreducing terminal
- We show that the fractions of fucose-containing oligosaccharides are markedly decreased in the heavy-chain disease protein Per
- It is of particular interest that in this paraprotein the major component is a biantennary complex-type oligosaccharide that lacks a fucose residue and an oligosaccharide with the structure (Formula: see text) exists as one of the most abundant components