title: The isolation and analysis of the luminal plasma membrane of calf urinary bladder epithelium.
abstract: The luminal plasma membrane of calf urinary bladder epithelium (urothelium) has been isolated by a method designed to preserve enzymic activity as well as structural integrity. The yield was about 80 micrograms per calf bladder. Low levels of 5' nucleotidase, Mg2+-ATPase and (Na+ + K+)-ATPase activities were found in the luminal membrane fraction. Cerebroside was the major lipid present and dodecyl sulphate gel electrophoresis revealed a complex protein and glycoprotein composition in the whole membrane. A membrane fraction consisting of only the plaque areas was shown to have a simpler protein composition with major polypeptides of apparent Mr 12 000 and 22 000. These may associate to form a 30 000 apparent Mr complex which could represent the individual 'particles' of the dodecameric subunits seen by electron microscopy in the plaque regions.
mesh_terms: D000818:Animals; D002417:Cattle; D002458:Cell Fractionation / Q000379:methods; D002462:Cell Membrane / Q000648:ultrastructure*; D004848:Epithelium / Q000648:ultrastructure; D006020:Glycopeptides / Q000032:analysis; D008563:Membrane Lipids / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D008854:Microscopy, Electron; D001743:Urinary Bladder / Q000648:ultrastructure*
chemical_list: D006020:Glycopeptides; D008563:Membrane Lipids; D008565:Membrane Proteins