title: The structure of sialyl-glycopeptides of the O-glycosidic type, isolated from sialidosis (mucolipidosis I) urine.
abstract: Sialyl-glycopeptides containing an O-glycosidically linked tetrasaccharide chain were obtained from the urine of a patient suffering from mucolipidosis I. Isolation of these compounds was achieved by gel filtration, ion-exchange chromatography and preparative paper chromatography. Their structures were determined by a combination of carbohydrate and amino acid analysis, dansylation, periodate oxidation, methylation studies, enzymatic hydrolysis and 1H-NMR spectroscopy, to be as follows: (formula; see text) wherein R = peptide linked through -Thr-, -Ser-Thr- or -Thr-Ser-. The finding of these glycopeptides in urine shows that mucolipidosis I is characterized by a general "glycoprotein-specific" sialidase deficiency. The possibility of the existence of a human endo-alpha-N-acetylgalactosaminidase is discussed.
mesh_terms: D000596:Amino Acids / Q000302:isolation & purification; D055598:Chemical Phenomena; D002621:Chemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D009081:Mucolipidoses / Q000652:urine*; D012795:Sialoglycoproteins / Q000652:urine*
chemical_list: D000596:Amino Acids; D012795:Sialoglycoproteins