title: UDP-GalNAc:GalNAc-mucin alpha-N-acetylgalactosamine transferase activity in human intestinal cancerous tissues.
abstract: GalNAc transferase activities of 6 human intestinal cancerous tissues were examined using bovine submaxillary gland mucin and its desialylated derivative, asialomucin, as acceptors. A Triton X-100 extract of these tissues was used an an enzyme source. All the tissues examined had GalNAc transferase that catalyzes the transfer of GalNAc from UDP-GalNAc to serine or threonine residues of the polypeptide chain. One of 6 specimens showed in addition UDP-GalNAc:GalNAc-mucin alpha-GalNAc transferase activity, synthesizing a disaccharide unit, GalNAc alpha----GalNAc, when asialomucin was used as an acceptor. This carbohydrate structure was deduced on the basis of results of gel filtration, exoglycosidase digestion, and high-voltage paper electrophoresis.
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology*; D000818:Animals; D002384:Catalysis; D002417:Cattle; D002850:Chromatography, Gel; D004590:Electrophoresis, Paper; D005700:Galactosyltransferases / Q000378:metabolism*; D006801:Humans; D009077:Mucins / Q000378:metabolism; D017350:N-Acetylgalactosaminyltransferases; D012004:Rectal Neoplasms / Q000201:enzymology*; D013363:Submandibular Gland / Q000378:metabolism
chemical_list: D009077:Mucins; D005700:Galactosyltransferases; D017350:N-Acetylgalactosaminyltransferases; C046901:N-acetylgalactosamine-mucin alpha-N-1,3-N-acetylgalactosaminyltransferase