Some properties of the purified (Ca2+ + Mg2+)-ATPase from human red cell membranes.
The (Ca2+ + Mg2+)-ATPase from red cell membranes, purified by means of a calmodulin-containing affinity column according to the method of Gietzen et al. (Gietzen, K., Tejcka, M. and Wolf, H.U. (1980) Biochem. J. 189, 81-88) with either phosphatidylcholine or phosphatidylserine as phospholipid is characterized. The phosphatidylcholine preparation can be activated by calmodulin, while the phosphatidylserine preparation is fully activated without calmodulin. The enzyme shows a biphasic ATP dependence with two Km values of 3.5 and 120 microM. The enzyme is phosphorylated by ATP in the presence of Ca2+ only.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000097:blood* / Q000302:isolation & purification; D002147:Calmodulin / Q000494:pharmacology; D002846:Chromatography, Affinity; D004910:Erythrocyte Membrane / Q000201:enzymology*; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D010766:Phosphorylation
D002147:Calmodulin; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D000255:Adenosine Triphosphate; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium