Only solid red blood cell ghosts transport K+, and Na+ against concentration gradients: hollow intact ghosts with K+-Na+ activated ATPase do not.

Human red blood cell ghosts, prepared by simple hypotonic lysis are filled with cytoplasmic proteins. These solid ghosts can transport K+ and Na+ against concentration gradients in the presence of ATP. In hollow red cell ghosts prepared by repeated hypotonic lysis followed by high salt wash, this ability to transport K+ and Na+ in the presence of ATP is lost even though these hollow ghost membranes remain intact and are equipped with Na+-K+ activated ATPase.