title: A water-soluble Mg2+-ATPase from erythrocyte membranes.
abstract: A ouabain-insensitive ATPase activity associated with the water-soluble proteins of the human and bovine erythrocyte membrane is demonstrated by means of activity-staining in polyacrylamide gels. The ATPase activity from both sources had an absolute requirement  for Mg2+, activity becoming easily detectable at 0.2 mM Mg2+. At low Mg2+ concentrations added Ca2+ appeared to decrease the intensity of the ATPase stain. The activity is unaffected by monovalent cations, does not hydrolyse p-nitrophenyl phosphate and is not inhibited by 2 : 4 dinitrophenol. The ATPase has an apparent molecular weight of approximately 100 000 as determined by electrophoresis in acrylamide gels containing dodecyl sulphate.
mesh_terms: D000251:Adenosine Triphosphatases / Q000097:blood* / Q000302:isolation & purification; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D008274:Magnesium / Q000494:pharmacology*; D008970:Molecular Weight; D010042:Ouabain / Q000494:pharmacology; D012995:Solubility; D013045:Species Specificity
chemical_list: D010042:Ouabain; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium