Pumping Na+?

Pumping Na+ against its conc gradient requires energy, provided by cleaving ATP, the ATP transfers a phosphate group to the pump in a high energy linkage. Phosphorylation causes a dramatic change in the pumps conformation, sodium ions become exposed and released outside of the cell. This also exposes binding sites for potassium ions in the pump. There are two potassium-binding sites, binding of the potassium ions triggers release of the phosphate group and return the pump to its normal conformation