a membrane-bound enzyme occurring on the secretory surfaces of parietal cells that uses the energy derived from the hydrolysis of ATP to drive the exchange of ions across the cell membrane, secreting acid into the gastric lumen. Protons and chloride ions are pumped against gradients across the apical membranes of activated parietal cells into the gastric lumen in exchange for potassium ions. See also adenosine triphosphatase.


widely distributed enzyme consisting of two large α-subunits and two smaller β-subunits, whose function is to transport Na+ and K+ against their concentration gradients using hydrolysis of ATP as the thermodynamic couple. The stoichiometry of exchange is two K+ for every three Na+ pumped. Often called the sodium pump.
References in periodicals archive ?
Methods: Enzymatic assays, measuring the amount of inorganic phosphate produced, were used to estimate the activity of Na+, K+-ATPase.
Results: The results show that Porphyrin compounds exert an insulin-like effect on Na+, K+-ATPase.
Conclusion: All the three Porphyrin compounds increased the activity of erythrocyte Na+, K+-ATPase.
KEY WORDS: Na+, K+-ATPase, Porphyrin derivatives, Diabetes Mellitus, Acetylcholinesterase, Dysnatremias.
Na+, K+-ATPase pumps Na+ and K+ ions across the cell membranes to maintain the transmembrane gradients of these ions.
9 A decreased activity of erythrocyte membrane Na+, K+-ATPase has been reported in Diabetics.
15,16 This study was conducted to investigate the three Porphyrin derivatives: Tetraphenylporphinesulfonate (TPPS), 5,10,15,20-Tetrakis (4sulfonatophenyl) porphyrinato Iron(III) Chloride (FeTPPS) and 5,10,15,20-Tetrakis (4sulfonatophenyl) porphyrinato Iron(III) nitrosyl Chloride (FeNOTPPS), as candidate compounds for increasing the Na+, K+-ATPase activity in erythrocytes.
Determination of Na+, K+-ATPase activity: The enzymatic activity of Na+, K+-ATPase was measured using published protocols.
In vitro experiments of Porphyrin compounds with Na+, K+-ATPase: The effect of Porphyrin compounds on Na+, K+-ATPase activity was investigated using published protocols.
Treatment of erythrocyte Na+, K+-ATPase with the three Porphyrin compounds resulted in an increase in activity of the enzyme significantly (Table-I).
Change in the activity of Na+, K+-ATPase in embryos of the sea urchin, Hemicentrotus pulcherrimus, during early development.
Expression of Na+, K+-ATPase [alpha]s-subunit in animalized and vegetalized embryos of the sea urchin, Hemicentrotus pulcherrimus.