| Abstract: | The carbohydrate moieties of hen ovomucoid were released as oligosaccharides by hydrazinolysis. The neutral oligosaccharide fraction which comprised about 85% of the total sugar was fractionated into eight oligosaccharide fractions by Bio-Gel P-4 column chromatography. Occurrence of novel penta-antennary oligosaccharides in the larger three fractions was reported in the preceding paper (Yamashita, K., Kamerling, J.P., and Kobata, A. (1982) J. Biol. Chem. 257, 12809-12814). Structural studies of the remaining smaller oligosaccharides indicated that they all have Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc as their common core. The alpha-mannosyl residues occur either free or as one of the following five groups: GlcNAc beta 1 leads to 2Man, GlcNAc beta 1 leads to 4Man, GlcNAc beta 1 leads to 4(GlcNAc beta 1 leads to 2)Man, GlcNAc beta 1 leads to 6(GlcNAc beta 1 leads to 2)Man, and GlcNAc beta 1 leads to 6(GlcNAc beta 1 leads to 4)(GlcNAc beta 1 leads to 2) Man. In most oligosaccharides, a beta-N-acetylglucosamine residue is linked at the C-4 position of the beta-mannosyl residue of the core. The structural characteristic of the sugar chains of hen ovomucoid indicated that they are not formed by the ordinary processing pathway of the asparagine-linked sugar chains. |
