Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Life Sciences
Characterization Of A Basolateral Electroneutral Na+/H+ Antiporter In Atlantic Lobster (Homarus Americanus) Hepatopancreatic Epithelial Vesicles, Jeff Duerr, Gregory A. Ahearn
Characterization Of A Basolateral Electroneutral Na+/H+ Antiporter In Atlantic Lobster (Homarus Americanus) Hepatopancreatic Epithelial Vesicles, Jeff Duerr, Gregory A. Ahearn
Faculty Publications - Department of Biological & Molecular Science
Purified basolateral membrane vesicles (BLMVs) were prepared from Atlantic lobster (Homarus americanus) hepatopancreas using a Percoll density gradient technique. Enrichments of the Na+/K+-ATPase and alkaline phosphatase activities of these vesicles were 15.4- and 1.2- fold, respectively. The presence of amiloride-sensitive Na+/H+ exchange was demonstrated. Contrary to electrogenic 2Na+/1H+ exchange on apical membranes from the same tissue, kinetic studies of Na+ transport by these basolateral membranes indicate an electroneutral antiport with a Km of 28±1.7 mmol l21 and a Jmax of 1.74±0.13 mmol mg21 min21. Amiloride interacted at a single binding site (Ki=39mmol l21) and external Li+ was shown to be …
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 …