Cation activation of the basolateral sodium-potassium pump in turtle colon

D. R. Halm, D. C. Dawson

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

The current generated by electrogenic sodium-potassium exchange at the basolateral membrane of the turtle colon can be measured directly in tissues that have been treated with serosal barium (to block the basolateral potassium conductance) and mucosal amphotericin B (to reduce the cation selectivity of the apical membrane). We studied the activation of this pump current by mucosal sodium and serosal potassium, rubidium, cesium and ammonium. The kinetics of sodium activation were consistent with binding to three independent sites on the cytoplasmic sides of the pump. The pump was not activated by cellular lithium ions. The kinetics of serosal cation activation were consistent with binding to two independent sites with the selectivity Rb > K > Cs > NH4. The properties and kinetics of the basolateral Na/K pump in the turtle colon are at least qualitatively similar to those of the well-characterized Na/K-ATPase of the human red blood cell.

Original languageEnglish (US)
Pages (from-to)315-329
Number of pages15
JournalJournal of General Physiology
Volume82
Issue number3
DOIs
StatePublished - Jan 1 1983

ASJC Scopus subject areas

  • Physiology

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