Effects of taurine on the ATPase activity in the human erythrocyte membrane

Effects of taurine on the total ATPase activity inhibited by ouabain were investigated in the human erythrocyte membrane. The enzyme activity was not activated by taurine in the absence of calcium, but was significantly activated by taurine (15-60 mM) in the presence of calcium (5 mM) by which the enzyme is inhibited. Since taurine does not form a chelate complex with calcium ion, this activation may be due to an action of taurine in the presence of calcium through competition with these ions on the membrane.