Na+/K+-ATPase

Na+/K+-ATPase is an essential enzyme found in the plasma membrane of all animal cells. The Na+/K+-ATPase enzyme is a solute pump that pumps sodium out of cells while pumping potassium into cells, both against their concentration gradients. This pumping is active and is important for cell physiology.

Structure

The Na+/K+-ATPase enzyme is composed of three subunits – alpha, beta, and gamma. The alpha subunit is the largest and spans the membrane multiple times. It is the site of ATP hydrolysis. The beta subunit is necessary for the correct insertion and functioning of the alpha subunit. The gamma subunit is a smaller, regulatory subunit.

Function

The primary role of Na+/K+-ATPase is to maintain the electrochemical gradient across the cell membrane. It does this by pumping three sodium ions out of the cell for every two potassium ions it pumps in. This creates a net charge, which is essential for many cellular processes, including nerve impulse transmission and muscle contraction.

Clinical significance

Mutations in the genes encoding the subunits of Na+/K+-ATPase can lead to several diseases, such as Familial hemiplegic migraine and Rapid-onset dystonia parkinsonism. In addition, inhibition of Na+/K+-ATPase by drugs such as digoxin and ouabain is used in the treatment of heart failure and arrhythmia.

See also

• Active transport
• Cell membrane
• Electrochemical gradient