Effects of Calcium Ions on the Adenosine-Triphosphatase Activities of Erythrocyte Membrane

概要

論文の詳細を見る
Calcium ions were found to stimulate the Na^+-K^+-sensitive ATPase as well as Mg^<2+>-ATPase (Na^+-K^+-insensitive ATPase) activities of human erythrocyte membrane in a concentration between approximately 0.04-0.4mM, and to inhibit them in a concentration higher than 4 mM. In the presence of Ca ions, the Na^+-K^+-ATPase activity dose not correspond to the ouabain-sensitive ATPase activity anymore which is apparently inhibited with increasing concentration of Ca ions. The effects of Ca^<2+> on the Mg^<2+>-ATPase seems to be dependent on the ratio of Ca^<2+>/Mg^<2+> concentrations. Erythrocyte stroma previously in contact with CaCl_2 and then washed, showed increased Mg^<2+>-ATPase activity when assayed in the absence of added Ca^<2+> in the incubation mixture, with the maximal level of the activity almost equivalent to the maximal Ca^<2+>-Mg^<2+>-ATPase activity. This would mean that the Ca ions absorbed on the outer surface of the erythrocyte membrane is well capable of stimulating the ATPase activity. Normal values of these ATPase activities of human erythrocyte stroma were established. The ATPase of porcine erythrocyte membrane were similarly stimulated by Caions, whereas those of bovine erythrocyte were only slightly stimulated by this divalent cation.
公益社団法人日本薬学会の論文
1971-09-25