Chemical characterization of urinary glycopeptides

We prepared human urinary glycopeptides from the supernatant liquid remaining after precipitation of the nondialyzable fraction with cetylpyridinium chloride. Using cation exchange and affinity chromatographies and gel filtration, we obtained 28 glycopeptide subfractions. By compositional analyses of sugar and amino acid, and by reducing-terminal analyses after reduction with NaBH4, we determined the size of the carbohydrate moiety and the types of carbohydrate-peptide linkage involved. We isolated several glycopeptides not previously described: six with sialic acid, two with fucose, two with glucose, and one with N-acetylgalactosamine. The sialic acid glycopeptides had a short carbohydrate chain of the O-glycoside type. The fucose-containing glycopeptides were fucosyllactosaminoglycans. The glucose glycopeptides were polymers linked to a small peptide moiety. The N-acetylgalactosamine-rich glycopeptide was found in an N-glycoside-type fraction, with N-acetylgalactosamine at the nonreducing terminal.