Gastric proton pump localization. Application of triphosphatase and monophosphatase techniques.
Potassium-dependent phosphatase activity can be demonstrated in unfixed frozen sections of mouse stomach using either adenosine triphosphate (ATP) or p-nitrophenyl phosphate (NPP) as substrate. In both cases the potassium-dependent reaction is confined to oxyntic cells, but with ATP, a strong, potassium-independent reaction occurs in the connective tissue of the lamina propria and elsewhere. In the NPP system potassium-independent reaction is very slight, and the oxyntic cell reaction shows responses to inhibitors that differentiate it from Na+, K+-ATPase and that are consistent with its identification with the dephosphorylation step of the proton pump enzyme H+, K+-ATPase, recognized as the active transport component in gastric acid secretion.
D009597:4-Nitrophenylphosphatase / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D005260:Female; D006651:Histocytochemistry; D006863:Hydrogen-Ion Concentration; D051379:Mice; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013270:Stomach / Q000166:cytology / Q000201:enzymology*
D010744:Phosphoric Monoester Hydrolases; D009597:4-Nitrophenylphosphatase; D000251:Adenosine Triphosphatases; D000254:Sodium-Potassium-Exchanging ATPase