The Sodium Pump and the Pump-ATPase of Erythrocyte Membranes Prepared from Cold-Stored Blood 1

Summary

Blood was stored in ACD solution at 4°. The Na⁺, K⁺-ATPase activity of the red cell membranes remained constant during prolonged storage (60 days). Within this period the membranes also retained the capacity to transport Na⁺ actively when inosine was used as the source of energy for the pump. However, after 3–4 weeks of storage, active transport of Na⁺ by the membranes could not be detected when ATP was incorporated into the ghosts. These observations suggest that the ATP generated by the metabolism of inosine may be in a pool that is more suitable for utilization by the pump.