Isolation and characterization of oligosaccharides from rat colonic mucus glycoprotein.

The structure of carbohydrate units of rat colonic mucus glycoproteins was investigated. Alkaline borohydride reductive cleavage of the glycoprotein resulted in the release of a series of reduced oligosaccharides. Eight of the oligosaccharides (1 to 8), ranging in length from 2 to 12 sugar units, have been purified to homogeneity and their structures determined. Based on the results of immunological assays, analysis of sugar composition, sequential degradation with specific glycosidases, and methylation analyses of the intact and desialyzed oligosaccharides, we propose the following structures for these compounds: (Formula: See text).