The absence of bicarbonate-stimulated ATPase activity in the plasma membranes of the bicarbonate secreting ox corneal endothelial cells.
Membranes of ox corneal endothelial cells were studied for their surface area by electron microscopical stereology and then separated from homogenates on self forming Percoll gradients. Enzymic analysis of the plasma membrane-enriched fraction failed to demonstrate an ATPase activity which was stimulated by the presence of bicarbonate ions. It is proposed that the well-established bicarbonate secretion of these cells may be coupled to the plasma membrane (Na+ + K+)-ATPase activity by the stoichiometry of Na+/HCO3- close to 1:1.
Hodson
S
S
Laboratory of Experimental Optometry, University of Wales Institute of Science and Technology, Cardiff, U.K.
Hodson
G
G
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism / Q000494:pharmacology*; D002417:Cattle; D002452:Cell Count; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D003315:Cornea / Q000378:metabolism* / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D004727:Endothelium / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D011506:Proteins / Q000032:analysis; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013053:Spectrophotometry
D001639:Bicarbonates; D011506:Proteins; D000251:Adenosine Triphosphatases; D000254:Sodium-Potassium-Exchanging ATPase