RELATIONSHIP BETWEEN RABBIT ERYTHROCYTE-MEMBRANE ANION-SENSITIVE MG2+-ATPASE AND (CA2++MG2+)-ATPASE

1. 1. Anion-sensitive Mg2+-ATPase and (Ca2+ + Mg2+-ATPase of rabbit erythrocyte membrane could be stimulated by (Ca2++ Mg2+)-ATPase activator protein from pig erythrocytes and cyclic 3':5'-nucleotide phosphodiesterase activator from rat cerebrum. 2. 2. Both rabbit erythrocyte membrane enzymes could be inhibited by (Ca2+ + Mg2+)-ATPase inhibitor protein from pig erythrocytes. 3. 3. Furthermore, the activities of both enzymes were higher in low density rabbit erythrocytes than in high density erythrocytes. 4. 4. While activation of the anion-sensitive ATPase in stored membranes by the (Ca2+ + Mg2+)-ATPase activator was possible, freshly prepared membranes were required for demonstration of (Ca2+ + Mg2+-ATPase stimulation. © 1979.