Inhibition of the plasma-membrane H+-ATPase from Dunaliella adidophila by omeprazole

I. Sekler, D. Remis, H. Gimmler, U. Pick

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The acid-activated sulfhydryl reagent omeprazole inhibits light-induced H+ secretion at pH 1 in cells of the halotolerant alga Dunaliella acidophila. Plasma-membrane vesicles, prepared from omeprazole-treated cells, have impaired vanadate-sensitive ATPase and ATP-induced H+ uptake activities. Omeprazole inhibits ATPase activity also in isolated plasma-membrane vesicles. The inhibition is enhanced at acidic pH and can be prevented by protonophores indicating that it is promoted by internal acidification of the vesicles. Mercaptoethanol partially reverses omeprazole inhibition. ADP does not afford protection against omeprazole but it does protect against inhibition by N-ethylmaleimide, indicating that these reagents modify different sulfhydryl groups. It is suggested that omeprazole blocks SH groups of the D. acidophila plasma-membrane H+-ATPase, which face the outer side of the cell.

Original languageEnglish
Pages (from-to)88-92
Number of pages5
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number1-2
StatePublished - 5 Apr 1993
Externally publishedYes


  • (D. adidophila)
  • ATPase, H-
  • Omeprazole


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