Sodium (Na+) / Potassium (K+) Pump (ATPase)

Author: Scott A. Sheffield MS

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Sodium-potassium pumps (or Na+/K+ -ATPase) are transmembrane proteins that actively transport Na+ ions to the extracellular fluid (ECF) and K+ ions to the intracellular fluid (ICF). The process basically consists of the following steps.

  1. image description3 Na+ ions from the ICF bind to the pump (with ATP or adenosine triphosphate attached).
  1. The image descriptionpump is phosphorylated after the third phosphate on the ATP is hydrolyzed by ATPase.
  1. The image descriptionNa+ are released to the ECF as the pump changes conformation (shape).

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  1. image descriptionTwo K+ ions from the ECF bind to the pump.
  1. The attached K+ ions trigger image descriptiondephosphorylation of the pump.
  1. The image descriptionK+ are released to the ICF as the pump changes conformation due to dephosphorylation.
  • As a result, both chemical (diffusion) and electrical gradients are created.