Uni-site ATP synthesis in thylakoids

Andreas Labahn, Petra Fromme, Peter Gräber

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Uni-site ATP synthesis was measured with thylakoids. The membrane-bound ATP-synthase, CF0F1 was brought into the active, reduced state by illumination in the presence of thioredoxin, dithiothreitol and phosphate. This enzyme contains two tightly bound ATP per CFoF1. ATP was released from the enzyme when ADP was added in substoichiometric amounts during illumination. Experiments with [14C]ADP indicated that after binding the same nucleotide was phosphorylated and released as [14C]ATP, i.e. only one site is involved in ATP-synthesis (uni-site ATP-synthesis'). The two tightly bound ATP are not involved in the catalytic turnover. The rate constant for ADP binding was (4 ± 2) × 106 M-1s-1. Compared to deenergized conditions the rate constant for ADP binding and that for ATP-release were drastically increased, i.e. membrane energization increased the rate constants for the ATP-synthesis direction.

Original languageEnglish
Pages (from-to)116-118
Number of pages3
JournalFEBS Letters
Volume271
Issue number1-2
DOIs
Publication statusPublished - Oct 1 1990

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Keywords

  • ATP synthesis
  • ATPase H
  • CFF
  • Chloroplast
  • Uni-site catalysis

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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