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Stoichiometry of K + /H + antiport helps to explain extracellular pH 11 in a model epithelium
Author(s) -
Azuma Masaaki,
Harvey William R.,
Wieczorek Helmut
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00146-z
Subject(s) - antiporter , extracellular , stoichiometry , chemistry , intracellular , midgut , intracellular ph , membrane , proton , biophysics , biochemistry , biology , physics , botany , quantum mechanics , larva
The stoichiometry of K + /H + antiport was measured fluorometrically by the static head method in highly purified vesicles from goblet cell apical membranes of larval lepidopteran midgut. The measured stoichiometry of 1 K + /2 H + explains how the antiport results in electrophoretic exchange of extracellular H + for intracellular K + , driven by the voltage component of the proton‐motive force of an H + translocating V‐ATPase that is located in the same membrane. In turn, the exchange of K + for H + helps to explain how the midgut contents are alkalinized to a pH of 11.