NaKATPazy

Na+/K+-ATPase, sometimes referred to as the sodium-potassium pump, is a membrane-bound enzyme that uses energy from ATP hydrolysis to transport sodium and potassium ions across the plasma membrane. In animal cells it exports three Na+ ions in exchange for two K+ ions, generating a net outward current and maintaining essential electrochemical gradients.

The enzyme is a P-type ATPase composed mainly of a catalytic α subunit and a regulatory β subunit. In vertebrates additional regulatory or tissue-specific subunits (such as the γ subunit of the FXYD family) can modulate activity. Multiple α isoforms (for example, α1, α2, α3, α4) and β isoforms (β1–β3) are expressed in different tissues, contributing to functional diversity and localization.

Mechanistically, Na+/K+-ATPase cycles between E1 and E2 conformations as it binds Na+, becomes phosphorylated by ATP, releases Na+ outside the cell, binds K+ from outside, is dephosphorylated, and returns to its initial state to begin a new cycle. The pump’s activity is electrogenic and couples ATP hydrolysis to ion transport, establishing the resting membrane potential and driving secondary active transport processes.

Physiological roles are broad: it sustains membrane excitability in neurons and muscle, regulates cell volume, and supports transporters and exchangers that depend on Na+ and K+ gradients. Regulation occurs through intracellular Na+ levels, hormonal signals, phosphorylation, and interactions with signaling pathways. Clinically, cardiac glycosides such as digoxin inhibit the pump, increasing intracellular Na+ and enhancing cardiac contractility; the pump also participates in signaling functions beyond ion transport, involving kinases and second messengers.

Notes: the term NaKATPazy appears to be a misspelling of Na+/K+-ATPase.