title: Isolation and partial characterization of rat gastric mucous glycoprotein.
abstract: Mucus glycoproteins from the rat stomach were characterized after their isolation from homogenates of the superficial gastric mucosa by equilibrium centrifugation in CsCl density gradients. Water-soluble as well as water-insoluble glycoproteins were studied. The latter were solubilized by 2-mercaptoethanol reduction of the homogenate. From both homogenate fractions the sames two glycoproteins 1 and 2 were purified, glycoprotein 1 being present in considerably higher amount than glycoprotein 2. Their respective buoyant densities in a CsCl gradient were 1.47--1.50 g/ml and 1.56--1.58 g/ml. The two glycoproteins expressed slight differences in gel electrophoresis and gel filtration. The results from column chromatographic comparisons between reduced and unreduced glycoproteins indicated strongly that both glycoproteins 1 and 2 were built from subunits kept together by S-S bonds. The s20,w values of the reduced glycoproteins 1 and 2 were 15.7 S and 11.6 S. Glycoprotein 1 contained 5% protein, 70% carbohydrate and 1--2% sulphate, whereas these percentages for glycoprotein 2 were 10% protein, 65% carbohydrate and 10% sulphate. The molar proportions of the main sugar components galactose, fucose, glucosamine and galactosamine were 4 :2 : 4 : 1 (glycoprotein 1) and 3 : 2 : 3 : 1 (glycoprotein 2). Blood-group activity A was expressed by glycoprotein 1, whereas glycoprotein 2 showed mainly blood-group activity Leb, some B activity and also some A activity, but to a lesser extent than glycoprotein 1.
mesh_terms: D000017:ABO Blood-Group System; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002499:Centrifugation, Density Gradient; D005753:Gastric Mucosa / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis*; D006385:Hemagglutination Inhibition Tests; D007983:Lewis Blood Group Antigens; D008623:Mercaptoethanol / Q000494:pharmacology; D051381:Rats; D012995:Solubility; D014461:Ultracentrifugation; D014867:Water
chemical_list: D000017:ABO Blood-Group System; D000596:Amino Acids; D002241:Carbohydrates; D006023:Glycoproteins; D007983:Lewis Blood Group Antigens; D014867:Water; D008623:Mercaptoethanol