FORSTNER, J. I?., JABBAL, I., and FORSTNEW, G. G. Goblet cell mucin of rat small intestine. Chemical and physical characterization. Can. J, Biochem. 51, 1154-1 165 (1933).Goblet cell mucin (GCM) s f rat small intestine has been isolated previously, and its location established by immunofluorescence techniques. In the present study, GCM was characterized more fully by chemical and physical methods. It was found to be a flexible negatively charged mcromolecule with a molecular weight of about 2.0 X 106, an intrinsic viscosity of 15.3 dl /g, and an axial ratio of about 225:l. Its composition was protein 12%, total hexose 23%, hexosamine 22.49&, sialic acid 80%, fucose 6.6%, and sulfate < 1% of the dry weight. It contained approximately 34 disulfide bonds per molecule.Like most mucin glycoproteims it was rich in serine, threonine, and proline (45.5 mol7,) and poor in hydrophobic and sulfur containing amino acids. One major and two minor components were identified by acrylamide disc gel electrophoresis and analytic ultracentrifugation. The components appeared to represent different molecular weight species of GCM. No evidence of subunit structure could be obtained using a variety of techniques, including the disruption of ionic, hydrophobic, and disulfide bonds by detergents, denaturants, or reducing agents. FORSTNEW, J. F., JABBAL, I., et F Q R~N E R , G. G. Goblet cell mucin of rat small intestine. Chemical and physical characterization. Can. J. Biochem. 51, 1154-1 166 (1933). La mucine des cel%uIes caliciformes du petit intestin de rat a ddjh Ct C isolCe et sa localisation, dCterminCe par des techniques d'immunofiuorescence. Bans le prCsent travail, nous caractkrisons plus complhtement cette mucine par des mdthdes chimiques et physiques. Nous dhontrons qu'il s'agit d'une m a c r o m o~~u l e flexible, ehargCe nkgativement et dant le poids moldculaire est d'environ 2.0 x 106, la viscositC intrinsbque de 15.3 d B /g et le rapport axial d'environ 225:l. Sa composition par rapport BU poids sec est la suivante: protkine 12%, hexose total %3%, hexosamine 22.4%, aeide sialique 10%, fucose 6.5% et sulfate <1 %. Elle contient environ 34 ponts disulfure par moHCc4.de. Cornme la plupart des glycoprot6ines muciques, elle est riche en drine, en thrbonine et en proline (45.5 msl %) et pauvre en acides aminCs hydrophobes et en acides aminis soufr6s. L'Clectrophor&se sur disque d'etcrylamide et l'ultracentrifugation analytique ont pemis I'identifieation d'un canstituant rnajeur et de deux constitumts mineurs. Les constituants reprisenteraient des espkes de mucine ii poids rno%k~laire digdrent. Nous n9aavons pu ddmontrer H a prQence dde sous-unit&, meme avec diverses techniques dont la rupture des liaisons ioniques, hydrophobes et disulfure par des detergents et des agents de dknaturation ou de rdduction.[Traduit par le journal]