SODIUM – POTASSIUM PUMP

By: Mrs. Kalaivani Sathish

Na+ / K + - ATPase• A specific case of “active transport”.• This is one of the best examples of active transport in animal cells.• This pump transports Na+ ions out of the cells and K+ ions into

the cell. Thus keeping the intracellular concentration of Na low compared to outside, and the intracellular concentration of K high.

• This pump is driven by the hydrolysis of ATP.• It uses about 30 % of the energy available to any one animal cell.• The pump is a trans membrane carrier protein made up of 4

subunits.

• Structure: it has 3 binding sites for sodium ions, 2 potassium ions and a phosphorylation site to accept a phosphate from ATP.

• Hydrolysis of one ATP molecule fuels the export of 3 Na + ions and the impact of K+ ions.

• This pump can work as fast as 300 Na+ per second if required.