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Full-Text Articles in Marine Biology
Ca2+ And Zn2+ Are Transported By The Electrogenic 2na+/1h+ Antiporter In Echinoderm Gastrointestinal Epithelium, Zhenpeng Zhuang, Jeff Duerr, Gregory A. Ahearn
Ca2+ And Zn2+ Are Transported By The Electrogenic 2na+/1h+ Antiporter In Echinoderm Gastrointestinal Epithelium, Zhenpeng Zhuang, Jeff Duerr, Gregory A. Ahearn
Faculty Publications - Department of Biological & Molecular Science
45Ca2+ uptake by purified brush-border membrane vesicles of starfish (Pycnopodia helianthoides) pyloric ceca was stimulated by an outwardly directed H+ gradient and this stimulation was enhanced by the simultaneous presence of an induced membrane potential (inside negative; K+/valinomycin). External amiloride (competitive inhibitor; Ki=660mmol l21) and a monoclonal antibody raised against proteins associated with the lobster (Homarus americanus) electrogenic 2Na+/1H+ antiporter both inhibited approximately half of the proton-gradient stimulated 45Ca2+ uptake. These results suggested that Ca2+ might be transported by the electrogenic antiporter and that the crustacean antibody was inhibitory to the exchange function in echinoderms, as was recently shown in …
Role Of The Invertebrate Electrogenic 2na+/H+ Antiporter In Monovalent And Divalent Cation Transport, Gregory A. Ahearn, Jeff Duerr, V. Pennington
Role Of The Invertebrate Electrogenic 2na+/H+ Antiporter In Monovalent And Divalent Cation Transport, Gregory A. Ahearn, Jeff Duerr, V. Pennington
Faculty Publications - Department of Biological & Molecular Science
In recent years, an electrogenic 2Na+/1H+ antiporter has been identified in a variety of invertebrate epithelial brush-border membranes of gut, kidney and gill tissues. The antiporter differs significantly in its physiological properties from the electroneutral 1Na+/1H+ antiporter proposed for vertebrate cells. In all invertebrate cells examined, the antiporter displayed a 2:1 transport stoichiometry, responded to an induced transmembrane potential and exhibited a high binding affinity for the divalent cation Ca2+, which acted as a competitive inhibitor of Na+ transport. A monoclonal antibody specific for the crustacean electrogenic antiporter inhibited 2Na+/1H+ exchange, but was without effect on Na+-dependent D-glucose transport. Immunoreactivity …