title: Re-evaluation of the structural integrity of red-cell glycoproteins during aging in vivo and nutrient deprivation.
abstract: Results presented in this paper show that removal of white-cell contaminations from human red blood cells by filtration through cellulose [Beutler, West & Blume (1976) J. Lab. Clin. Med. 88, 328-333] is a necessity whenever red cells are incubated at elevated temperatures or haemolysed after density separation. Omission of this precaution results in proteolysis of sialoglycoproteins in membranes from less-dense (young), but not dense (old), subpopulations. This proteolytic damage occurs during haemolysis of the cytoplasmic domain of glycophorin. A different type of proteolysis occurs if white-cell-contaminated red cells are incubated in the absence of glucose at elevated temperatures. Red cells release sialoglycopeptides. This process is stimulated by Ca2+ ions and is accompanied by the release of vesicles that differ from spectrin-free vesicles [Lutz, Liu & Palek (1977) J. Cell Biol. 73, 548-560]. This sialoglycopeptide release is dependent on white-cell contamination and is not required for the release of spectrin-free vesicles.
mesh_terms: D002469:Cell Separation; D004591:Electrophoresis, Polyacrylamide Gel; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000378:metabolism*; D005374:Filtration; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D012795:Sialoglycoproteins / Q000097:blood
chemical_list: D006023:Glycoproteins; D012795:Sialoglycoproteins