title: Relation between phosphorylation and adenosine triphosphate-dependent Ca2+ binding of swine and bovine erythrocyte membranes.
abstract: The correlation between the ATP-dependent Ca2+ binding and the phosphorylation of the membranes from swine and bovine erythrocytes was studied. The Ca2+ binding was measured by using 45CaCl2, and the phosphorylation by [gamma-32P]ATP was studied with the technique of SDS polyacrylamide gel electrophoresis. 200 mM NaCl and KCl markedly repressed the Ca2+ binding of swine erythrocyte membranes. The radioactivity of 32P-labelled membranes was revealed mainly in 250,000 dalton protein and a lipid fraction. NaCl and KCl also repressed the phosphorylation of the lipid which was identified as triphosphoinositide by paper chromatography. The membranes prepared from trypsin-digested erythrocytes completely retained the Ca2+-binding activity, and lost 30% of (Ca2+ + Mg2+)-ATPase activity. The Ca2+-binding and ATPase activity of isolated membranes decreased to 55% and to 0%, respectively, by tryptic digestion. Neither the Ca2+ binding nor the phosphorylation of polyphosphoinositides were detected in bovine erythrocyte membranes. These results suggest that the formation of triphosphoinositide rather than the (C2+ + Mg2+)-ATPase of membranes is linked to the ATP-dependent Ca2+ binding of erythrocyte membranes.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D000252:Calcium-Transporting ATPases / Q000097:blood*; D002417:Cattle; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D066298:In Vitro Techniques; D008563:Membrane Lipids / Q000097:blood; D008565:Membrane Proteins / Q000097:blood; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000097:blood; D010766:Phosphorylation; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013552:Swine; D014357:Trypsin / Q000494:pharmacology
chemical_list: D008563:Membrane Lipids; D008565:Membrane Proteins; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C018803:triphosphoinositide; D000255:Adenosine Triphosphate; D012964:Sodium; D014357:Trypsin; D000252:Calcium-Transporting ATPases; D011188:Potassium