Sulfide-quinone and sulfide-cytochrome reduction in Rhodobacter capsulatus

Yosepha Shahak*, Christof Klughammer, Ulrich Schreiber, Etana Padan, Inge Herrman, Günter Hauska

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

The reduction by sulfide of exogenous ubiquinone is compared to the reduction of cytochromes in chromatophores of Rhodobacter capsulatus. From titrations with sulfide values for Vmax of 300 and 10 μmoles reduced/mg bacteriochlorophyll a·h, and for Km of 5 and 3 μM were estimated, for decyl-ubiquinone-and cytochrome c-reduction, respectively. Both reactions are sensitive to KCN, as has been found for sulfide-quinone reductase (SQR) in Oscillatoria limnetica, which is a flavoprotein. Effects of inhibitors interfering with quinone binding sites suggest that at least part of the electron transport from sulfide in R. capsulatus employs the cytochrome bc1-complex via the ubiquinone pool.

Original languageEnglish
Pages (from-to)175-181
Number of pages7
JournalPhotosynthesis Research
Volume39
Issue number2
DOIs
StatePublished - Feb 1994

Keywords

  • anoxygenic photosynthesis
  • Chlorobium limicola
  • electron transport
  • LED array spectrophotometer
  • Oselllatoria limnetiea
  • sulfide-quinone reductase (SQR)

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