Cl- -HCO3- dependent ATPase in gills of freshwater and seawater adapted eels (Anguilla anguilla L.) |
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Authors: | R Naon M Bornancin G De Renzis |
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Institution: | 1. Groupe de Biologie marine du Commissariat à l''Energie Atomique, Station Zoologique, 06230 Villefranche-sur-Mer, France |
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Abstract: | The gills of both seawater and freshwater adapted eels have an ATPase activity which is stimulated by anions in the presence of Mg2+. Plasma membranes were distinguished from mitochondrial membranes with specific enzyme markers, the membrane fractions separated on a discontinuous sucrose gradient, and the ATPase activity of the plasma membranes studied. Activation by the anions of Cl- or HCO3- followed Michaelis-Menten kinetics and was competitively inhibited by SCN-. The Cl- and HCO3- activation characteristics were determined: no differences between the plasma membrane ATPase activities of freshwater and seawater-adapted fishes were observed. Maximal activity measurements after solubilization of the enzymes by Triton X 100 confirmed these findings. The function of a membrane anion-dependent ATPase in the brachial epithelium of euryhaline fish is discussed. |
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Keywords: | ATPase anionique équilibre acide-base anion ATPase acid-base |
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