Regulation and reversibility of vacuolar H+-ATPase

Tomoyuki Hirata, Norihiro Nakamura, Hiroshi Omote, Yoh Wada, Masamitsu Futai

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57 Citations (Scopus)


Arabidopsis thaliana vacuolar H+-translocating pyrophosphatase (V- PPase) was expressed funtionally in yeast vacuoles with endogenous vacuolar H+-ATPase (V-ATPase), and the regulation and reversibility of V-ATPase were studied using these vacuoles. Analysis of electrochemical proton gradient (ΔμH) formation with ATP and pyrophosphate indicated that the proton transport by V-ATPase or V-PPase is not regulated strictly by the proton chemical gradient (ΔpH. On the other hand, vacuolar membranes may have a regulatory mechanism for maintaining a constant membrane potential (ΔΨ). Chimeric vacuolar membranes showed ATP synthesis coupled with Δμh established by V-PPase. The ATP synthesis was sensitive to bafilomycin A1 and exhibited two apparent K(m) values for ADP. These results indicate that V-ATPase is a reversible enzyme. The ATP synthesis was not observed in the presence of nigericin, which dissipates ΔpH but not ΔΨ, suggesting that ΔpH is essential for ATP synthesis.

Original languageEnglish
Pages (from-to)386-389
Number of pages4
JournalJournal of Biological Chemistry
Issue number1
Publication statusPublished - Jan 7 2000
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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