What is a Sodium Potassium Pump? How does it work?

The sodium potassium pump (sodium potassium ATPase) is an enzyme found in the membrane of all animal cells. Its job is to move NA+ out of the cell and K+ in the cell against their concentration gradient. This allows the cell to keep a concentration gradient and generates a resting membrane potential. In order to do so, the pump needs energy and therefore it is ATP dependent. When the pump binds ATP, it can then bind 3 Na+ ions intracellularly. Hydrolysis of ATP causes the phosphorylation of the pump which now undergoes a conformational change and opens towards the exterior of the cell and releases the 3 Na+ ions. On the exterior, it binds 2 K+ ions. This causes a dephosphorylation and an opening of the enzyme towards the inside of the cell. The dephosphorylated form has now a greater affinity for Na+ so K+ is released. The pump binds ATP and the whole process starts again