A second site for herbicide action in Photosystem II

Robert Carpentier, E. Patrick Fuerst, Herbert Y. Nakatani, Charles J. Arntzen

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The results in this report confirm the existence of a second site of herbicide inhibition on the oxidizing side of Photosystem II (PS II). The inhibitors which were examined in this study were initially found to inhibit the photoreduction of silicomolybdate with chloroplast thylakoids utilizing water as the electron donor. This indicated a site other than the well-characterized inhibition site on the reducing side of PS II at the 32 kDa polypeptide, Qb apoprotein. Further studies were conducted utilizing Triton X-100 extracted PS II oxygen-evolving particles from spinach and atrazine-resistant and susceptible Amaranthus hybridis. Fluorescence data and the ability to overcome the inhibition of DCIP reduction by diphenylcarbazide both indicated that the oxidizing side of PS II was affected. 14C-atrazine binding studies are also presented.

Original languageEnglish (US)
Pages (from-to)293-299
Number of pages7
JournalBBA - Bioenergetics
Issue number2
StatePublished - Jul 17 1985


  • (Pea, Spinach, Amaranthus chloroplasts)
  • Electron transport
  • Herbicide
  • Oxygen evolution
  • Photosystem II

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology


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