title: Two enzymes involved in the synthesis of O-linked oligosaccharides are localized on membranes of different densities in mouse lymphoma BW5147 cells.
abstract: Microsomal membranes from mouse lymphoma BW5147 cells were fractionated on a continuous sucrose gradient and assayed for two enzymes involved in the synthesis of O-linked oligosaccharides. Both enzymes were recovered in membranes that were less dense than the membranes containing the endoplasmic reticulum marker enzymes, glucosidase I and II. UDP-Gal:N-acetylgalactosamine-beta 1, 3-galactosyltransferase had a distribution that coincided with that of the galactosyltransferase that acts on asparagine-linked oligosaccharides. This latter enzyme has been immunolocalized to the trans Golgi elements. The UDP-GalNAc:polypeptide N-acetylgalactosaminyl-transferase was recovered in a membrane fraction of intermediate density, between the endoplasmic reticulum and trans Golgi markers. These findings are consistent with the assembly of O-linked oligosaccharides occurring in at least two different Golgi compartments.
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D002854:Chromatography, Paper; D005700:Galactosyltransferases / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D007425:Intracellular Membranes / Q000201:enzymology*; D008223:Lymphoma / Q000648:ultrastructure*; D051379:Mice; D008861:Microsomes / Q000201:enzymology; D017350:N-Acetylgalactosaminyltransferases; D009844:Oligosaccharides / Q000096:biosynthesis*; D013379:Substrate Specificity
chemical_list: D009844:Oligosaccharides; D005700:Galactosyltransferases; D017350:N-Acetylgalactosaminyltransferases; C003742:UDPgalactosamine-galactose acetylgalactosaminyltransferase