Interaction of External K, Na, and Cardioactive Steroids with the Na-K Pump of the Human Red Blood Cell

摘要: The interaction of extracellular Na (Nao), K (Ko), and strophanthidin with the Na-K pump human red blood cell has been investigated. Inhibition by submaximal concentrations rapidly reaches a level which does not increase further over relatively long period time. Under these circumstances, it is possible to apply steady-state kinetic analysis Nao, Ko, pump. In Na-free solutions, increases apparent K1/2 for but change form relation between reciprocal active influx (iMKP–1) [Ko] ([Ko]–1); both in presence absence adequately described straight line. solutions containing Na, changes curve describing iMKP–1 vs. [Ko]–1; becomes more parabolic strophanthidin. rate ouabain binding K-free cells also measured; K, unaffected Nao. data are considered terms simple model. findings can be explained if supposed that at low external combined one Nao likely combine than uncombined even very Ko