1984 Volume 34 Issue 1 Pages 2-11
A proline-rich glycoprotein of human parotid saliva was purified by precipitation with 80% ammonium sulfate and gel filtration and ensued by affinity chromatography on Concanavalin A (Con A) -Sepharose. The purified sample, which showed a single band on gel-electrophoresis, contains abundant praline, glycine, and glutamine. The purified glycoprotein treated with pronase produced glycopeptide (molecular weight, ca, 2, 600) consisting of L-fucose, D-galactose, D-mannose, and N-acetyl-D-glucosamine residues in the approximate molar ratio of 2: 3: 3: 4, together with asparagine as well as glycine. Glycopeptide, through permethylation followed by acid hydrolysis yielded 2, 3, 4-tri-O-methyl-L-fucose, 2, 3, 4, 6-tetra-O-methyl-D-galactose, 3, 4, 6-tri-O-methyl-D-galactose, 3, 4, 6-tri-O-methyl-D-mannose, 2, 4-di-O-methyl-D-mannose, 3, 6-di-O-methyl-N-acetyl-D-glucosamine and 6-mono-O-methyl-N-acetyl-D-glucosamine in the approximate molar ratio of 2: 2: 1: 2: 1: 2: 2. By combination techniques which included successive digestions with various glycosidases, mild Smith degradation, and also methylation analyses, the probable structure of the carbohydrate unit chains of the glycoprotein is defined as follows;
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