title: Mass isolation of cell surface membrane fragments from pigeon heart.
abstract: Cell surface membrane fragments were isolated and purified by successive rate zonal and isopycnic centrifugation of calcium oxalate-loaded pigeon heart microsomes in sucrose density gradients. The most highly purified cell membrane fraction sediments at a buoyant density of 1.105 g/ml. Some of the membrane pieces are present as open fragments and leaky vesicles, while others form tightly sealed vesicles of both inside-in and inside-out membrane orientation. The pigeon heart cell membrane preparation exhibits high (Na+ + K+ + Mg2+)-ATPase and adenylate cyclase activities. Additional activity of these enzymes is uncovered by sodium dodecyl sulfate and alamethicin, respectively. Electron microscopic inspection of the cell surface membrane preparation revealed (a) a predominance of thick-walled vesicles with smooth surfaces on negative staining and (b) binding of concanavalin A to the bulk of isolated membrane pieces following their incubation with the lectin.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002458:Cell Fractionation / Q000379:methods; D002462:Cell Membrane / Q000032:analysis*; D008274:Magnesium; D009206:Myocardium / Q000201:enzymology / Q000648:ultrastructure*; D011952:Receptors, Concanavalin A / Q000378:metabolism; D012508:Sarcolemma / Q000032:analysis*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase
chemical_list: D011952:Receptors, Concanavalin A; D000262:Adenylyl Cyclases; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D008274:Magnesium; D002118:Calcium