Flash-induced reduction of cytochrome b-559 by QinfBsup- in chloroplasts in the presence of protonophores

Klára Barabás, Tatjana Kravcova, G. Garab

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Flash-induced, fast (t1/2 ≈ 1 ms), reversible reduction of the high potential cytochrome b-559 (cyt b-559HP) was observed in chloroplasts in the presence of 2 μM protonophore, FCCP (carbonylcyanide p-trifluoromethoxyphenylhydrazone), CCCP (carbonylcyanide 3-chlorophenylhydrazone) or SF 6847 (2,6-di-(t-butyl)-4-(2′,2′-dicyanovinyl)phenol). These protonophores promote autooxidation of cyt b-559HP in the dark (Arnon and Tang 1988, Proc Natl Acad Sci USA 85: 9524). No fast photoreduction could, however, be observed if the molecules were oxidized with ferricyanide in the absence of protonophores. This suggests that the molecules must be deprotonated to be capable for fast photoreduction. Photoreduction of cyt b-559HP was largely insensitive to DBMIB (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone), but was inhibited by DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea). With a train of flashes, no oscillation could be observed in the amplitudes of photoreduction. These data strongly suggest that cyt b-559HP is reduced by the semireduced secondary quinone acceptor (QB-) of Photosystem 2.

Original languageEnglish
Pages (from-to)59-64
Number of pages6
JournalPhotosynthesis Research
Volume36
Issue number1
DOIs
Publication statusPublished - Apr 1993

Fingerprint

Diuron
ferricyanides
benzoquinones
autoxidation
Chloroplasts
quinones
cytochrome b
phenol
oscillation
Dibromothymoquinone
chloroplasts
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
Molecules
Phenol
cytochrome b559
hexacyanoferrate III
SF 6847
benzoquinone
carbonylcyanide 4-trifluoromethoxyphenylhydrazone

Keywords

  • ADRY
  • deprotonation
  • high potential form of cytochrome b-559
  • photoreduction
  • Photosystem 2

ASJC Scopus subject areas

  • Plant Science

Cite this

Flash-induced reduction of cytochrome b-559 by QinfBsup- in chloroplasts in the presence of protonophores. / Barabás, Klára; Kravcova, Tatjana; Garab, G.

In: Photosynthesis Research, Vol. 36, No. 1, 04.1993, p. 59-64.

Research output: Contribution to journalArticle

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