Localization of ATPases in retinal receptor cells.
Ouabain-sensitive, K-dependent p-nitrophenylphosphatase (K- NPPase ) activity of the Na-K-ATPase complex and the Ca-ATPase activity were studied ultracytochemically in the inner and outer segments of guinea pig photoreceptor cells by means of newly developed methods. The K- NPPase activity was demonstrated on the plasmalemma of the inner segments, whereas the Ca-ATPase activity was restricted to the matrix side of the inner membrane of the mitochondria which were accumulated in the inner segments. In contrast to the enzyme activities in the inner segments no such activity could be detected on the plasma and disk membranes of the outer segments. The functional meaning of the enzyme activities is discussed.
D009597:4-Nitrophenylphosphatase / Q000032:analysis*; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000032:analysis*; D002462:Cell Membrane / Q000201:enzymology; D006168:Guinea Pigs; D008928:Mitochondria / Q000201:enzymology; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis*; D010786:Photoreceptor Cells / Q000201:enzymology* / Q000378:metabolism / Q000648:ultrastructure; D012374:Rod Cell Outer Segment / Q000201:enzymology* / Q000648:ultrastructure; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis*
D010744:Phosphoric Monoester Hydrolases; D009597:4-Nitrophenylphosphatase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase