Opening the gate of glycobiology in the field of N-linked sugar chains

Abstract

Based on the successful use of human milk oligosaccharide patterns for elucidation of the biochemical basis of ABO and Lewis blood types in humans, a strategy to establish reliable techniques to analyze the structures and functions of the N-linked sugar chains of glycoproteins was devised. N-Linked sugar chains were first released quantitatively as oligosaccharides by enzymatic or chemical means, and labeled by reduction with NaB3H4. After fractionation by gel-permeation chromatography and lectin-affinity chromatography, structure of each radioactive oligosaccharide was determined by a series of sensitive methods, which were developed for the structural study of oligosaccharides. By using these techniques, structural rules of the N-linked sugar chains were found. Furthermore, occurrence of site-specific, organ-specific and species-specific N-glycosylation of proteins, which served as important bases for the development of Glycobiology, was revealed.