Regulation of the Ca2+-pump by calmodulin in intact cells.
ATP-enriched human red cells display high rates of Ca2+-dependent ATP hydrolysis (16 mmol . litre cells-1 . h-1) with a high Ca2+ affinity (K0.5 approximately 0.2 microM). The finding suggests a mechanism for regulation of cell Ca2+ levels, involving highly-cooperative stimulation of active Ca2+ extrusion following binding of calmodulin to the (Ca2+ +Mg2+)-ATPase.
D000255:Adenosine Triphosphate / Q000097:blood*; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium / Q000097:blood*; D002135:Calcium-Binding Proteins / Q000097:blood*; D000252:Calcium-Transporting ATPases / Q000097:blood*; D002147:Calmodulin / Q000097:blood*; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D010710:Phosphates / Q000097:blood
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D010710:Phosphates; D000255:Adenosine Triphosphate; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium