title: Properties of the Na+/H+ antiporter in Vibrio parahaemolyticus.
abstract: The properties of the Na+/H+ antiporter in Vibrio parahaemolyticus, a slightly halophilic bacterium, were investigated using everted membrane vesicles. It appears that at least two Na+/H+ antiporters are present, one that is pH-dependent and one that is pH-independent. These two antiporters appear to correspond to the NhaA and NhaB antiporters of Escherichia coli, respectively. It seems that amiloride strongly inhibits the pH-dependent antiporter. Na+ is the best substrate for both of the two V. parahaemolyticus antiporters. Li+ is a poorer substrate and K+ is not a substrate. No K+/H+ antiport activity was detected in membrane vesicles of this organism. The Na+(Li+)/H+ antiport activity greatly increased with an increase in pH of the assay medium. pH did not affect the Km value of the Na+/H+ antiport, but it did increase the Vmax.
authors.affiliation: Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University.
authors.forename: T
authors.initials: T
authors.lastname: Kuroda
authors.forename: T
authors.initials: T
authors.lastname: Shimamoto
authors.forename: K
authors.initials: K
authors.lastname: Inaba
authors.forename: T
authors.initials: T
authors.lastname: Kayahara
authors.forename: M
authors.initials: M
authors.lastname: Tsuda
authors.forename: T
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D006863:Hydrogen-Ion Concentration; D017923:Sodium-Hydrogen Exchangers / Q000032:analysis*; D014736:Vibrio parahaemolyticus / Q000737:chemistry*
chemical_list: D017923:Sodium-Hydrogen Exchangers