Structural characterization of neutral oligosaccharides of human H+Leb+ gastric mucin.

The structure of carbohydrate chains of human gastric mucin was investigated. The mucin, purified from pronase-degraded gastric aspirates of the secretors with blood group H+Leb, was subjected to alkaline borohydride treatment and a heterogeneous population of neutral (72.1%) and acidic (27.9%) oligosaccharide alditols was obtained. Ten oligosaccharides (I-X), representing 80.3% of the neutral oligosaccharide fraction, have been purified to homogeneity and their structures determined. These oligosaccharides ranged in length from 4 to 12 sugar units and contained mono-, bi-, and triantennary structures. Based on hemagglutination inhibition data in H-anti-H, Leb-anti-Leb, and I-anti-I systems, and the results of structural analyses, we proposed the following structures for these oligosaccharides: (formula, see text)