CARBOHYDRATE MOIETIES OF PORCINE 32 KDA ENAMELIN

The structures of asparagine-linked oligosaccharides of porcine 32 kDa enamelin are reported. The oligosaccharides were released by N-oligos accharide glycopeptidase digestion, and the reducing ends of the oligo saccharides were derivatized with a fluorescent reagent, 2-aminopyridi ne. The pyridylamino oligosaccharides were separated into eight kinds of oligosaccharides. The structures of these oligosaccharides were det ermined by a combination of a sequential exoglycosidase digestion and a two-dimensional sugar mapping technique. The oligosaccharides consis ted of fucose, galactose, mannose, N-acetylglucosamine, and N-acetylne uraminic acid, and were classified into two groups according to their core-sugar chain structures; one was a biantennary-type and the other was a triantennary-type oligosaccharide. The variation of the oligosac charides in each of these groups was caused by the differences in the number, the site, and the mode of linkage of N-acetylneuraminic acid t o the core-sugar chains.