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. 1979 Jun;76(6):2765–2769. doi: 10.1073/pnas.76.6.2765

Electron flow through plastoquinone and cytochromes b6 and f in chloroplasts.

B R Velthuys
PMCID: PMC383689  PMID: 288064

Abstract

With dark-adapted chloroplasts in which the plastoquinone was oxidized, a partial reduction of cytochrome b6 was obtained upon illumination with a pair of short saturating flashes. The second flash of the pair was much more effective than the first, and the reduction was inhibited by the system II inhibitor diuron. When the plastoquinone pool was reduced, both the reduction and the oxidation of cytochrome b6 were accelerated. The cytochrome b6 oxidation appeared to proceed in association with the reduction of cytochrome f, although these cytochromes are not simply connected in series. From these observations it is inferred that electron flow to the secondary donors of system I alternately caused the reduction and the oxidation of cytochrome b6. An interpretation is offered that also accounts for the transmembrane proton translocation that is associated with the oxidation of plastohydroquinone.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bouges-Bocquet B. Cytochrome f and plastocyanin kinetics in Chlorella pyrenoidosa. I. Oxidation kinetics after a flash. Biochim Biophys Acta. 1977 Nov 17;462(2):362–370. doi: 10.1016/0005-2728(77)90134-7. [DOI] [PubMed] [Google Scholar]
  2. Bouges-Bocquet B. Electron transfer between the two photosystems in spinach chloroplasts. Biochim Biophys Acta. 1973 Aug 31;314(2):250–256. doi: 10.1016/0005-2728(73)90140-0. [DOI] [PubMed] [Google Scholar]
  3. Bouges-Bocquet B. Electron transport in photosystem I in spinach chloroplasts. Biochim Biophys Acta. 1975 Sep 8;396(3):382–391. doi: 10.1016/0005-2728(75)90144-9. [DOI] [PubMed] [Google Scholar]
  4. Böhme H. On the role of ferredoxin and ferredoxin-NADP+ reductase in cyclic electron transport of spinach chloroplasts. Eur J Biochem. 1977 Jan;72(2):283–289. doi: 10.1111/j.1432-1033.1977.tb11251.x. [DOI] [PubMed] [Google Scholar]
  5. Dolan E., Hind G. Kinetics of the reduction and oxidation of cytochromes b6 and f in isolated chloroplasts. Biochim Biophys Acta. 1974 Sep 20;357(3):380–385. doi: 10.1016/0005-2728(74)90028-0. [DOI] [PubMed] [Google Scholar]
  6. Dutton P. L., Prince R. C. Equilibrium and disequilibrium in the ubiquinone-cytochrome b-c2 oxidoreductase or Rhodopseudomonas sphaeroides. FEBS Lett. 1978 Jul 1;91(1):15–20. doi: 10.1016/0014-5793(78)80007-6. [DOI] [PubMed] [Google Scholar]
  7. Fowler C. F., Kok B. Determination of H+/e- ratios in chloroplasts with flashing light. Biochim Biophys Acta. 1976 Mar 12;423(3):510–523. doi: 10.1016/0005-2728(76)90204-8. [DOI] [PubMed] [Google Scholar]
  8. Haehnel W. Electron transport between plastoquinone and chlorophyll Ai in chloroplasts. II. Reaction kinetics and the function of plastocyanin in situ. Biochim Biophys Acta. 1977 Mar 11;459(3):418–441. doi: 10.1016/0005-2728(77)90043-3. [DOI] [PubMed] [Google Scholar]
  9. Heber U., Boardman N. K., Anderson J. M. Cytochrome b-563 redox changes in intact CO-fixing spinach chloroplasts and in developing pea chloroplasts. Biochim Biophys Acta. 1976 Feb 16;423(2):275–292. doi: 10.1016/0005-2728(76)90185-7. [DOI] [PubMed] [Google Scholar]
  10. Knaff D. B., Arnon D. I. Spectral evidence for a new photoreactive component of the oxygen-evolving system in photosynthesis. Proc Natl Acad Sci U S A. 1969 Jul;63(3):963–969. doi: 10.1073/pnas.63.3.963. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Marsho T. V., Kok B. Interaction between electron transport components in chloroplasts. Biochim Biophys Acta. 1970 Dec 8;223(2):240–250. doi: 10.1016/0005-2728(70)90181-7. [DOI] [PubMed] [Google Scholar]
  12. Mitchell P. The protonmotive Q cycle: a general formulation. FEBS Lett. 1975 Nov 15;59(2):137–139. doi: 10.1016/0014-5793(75)80359-0. [DOI] [PubMed] [Google Scholar]
  13. Prince R. C., Dutton P. L. A kinetic completion of the cyclic photosynthetic electron pathway of Rhodopseudomonas sphaeroides: cytochrome b-cytochrome c2 oxidation-reduction. Biochim Biophys Acta. 1975 Jun 17;387(3):609–613. doi: 10.1016/0005-2728(75)90101-2. [DOI] [PubMed] [Google Scholar]
  14. Rieske J. S. Composition, structure, and function of complex III of the respiratory chain. Biochim Biophys Acta. 1976 Sep 27;456(2):195–247. doi: 10.1016/0304-4173(76)90012-4. [DOI] [PubMed] [Google Scholar]
  15. Schwartz M. N-tetramethyl-rho-phenylenediamine as a catalyst of photophosphorylation. Biochim Biophys Acta. 1966 Feb 7;112(2):204–212. doi: 10.1016/0926-6585(66)90321-9. [DOI] [PubMed] [Google Scholar]
  16. Siggel U., Renger G., Stiehl H. H., Rumberg B. Evidence for electronic and ionic interaction between electron transport chains in chloroplasts. Biochim Biophys Acta. 1972 Feb 28;256(2):328–335. doi: 10.1016/0005-2728(72)90063-1. [DOI] [PubMed] [Google Scholar]
  17. Slovacek R. E., Hind G. Flash spectroscopic studies of cyclic electron flow in intact chloroplasts. Biochem Biophys Res Commun. 1978 Oct 30;84(4):901–906. doi: 10.1016/0006-291x(78)91668-6. [DOI] [PubMed] [Google Scholar]
  18. Stiehl H. H., Witt H. T. Quantitative treatment of the function of plastoquinone in phostosynthesis. Z Naturforsch B. 1969 Dec;24(12):1588–1598. doi: 10.1515/znb-1969-1219. [DOI] [PubMed] [Google Scholar]
  19. Stuart A. L., Wasserman A. R. Purification of cytochrome b6. A tightly bound protein in chloroplast membranes. Biochim Biophys Acta. 1973 Sep 26;314(3):284–297. doi: 10.1016/0005-2728(73)90113-8. [DOI] [PubMed] [Google Scholar]
  20. Velthuys B. R. A third site of porton translocation in green plant photosynthetic electron transport. Proc Natl Acad Sci U S A. 1978 Dec;75(12):6031–6034. doi: 10.1073/pnas.75.12.6031. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. White C. C., Chain R. K., Malkin R. Duroquinol as an electron donor for chloroplast electron transfer reactions. Biochim Biophys Acta. 1978 Apr 11;502(1):127–137. doi: 10.1016/0005-2728(78)90137-8. [DOI] [PubMed] [Google Scholar]
  22. Wood P. M., Bendall D. S. The reduction of plastocyanin by plastoquinol-1 in the presence of chloroplasts. A dark electron transfer reaction involving components between the two photosystems. Eur J Biochem. 1976 Jan 15;61(2):337–344. doi: 10.1111/j.1432-1033.1976.tb10027.x. [DOI] [PubMed] [Google Scholar]

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