These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Flash-induced photophosphorylation in Rhodospirillum rubrum chromatophores. I. The relationship between cytochrome c-420 content and photophosphorylation.
    Author: del Valle-Tascon S, van Grondelle R, Duysens LN.
    Journal: Biochim Biophys Acta; 1978 Oct 11; 504(1):26-39. PubMed ID: 213110.
    Abstract:
    The content of cytochrome c-420 in Rhodospirillum rubrum chromatophores prepared by grinding with alumina is 5--10% of that in whole cells, and 20--40% in chromatophores by 'French' pressing. Flash-induced phosphorylation of various chromatophores which varied in cytochrome content from 7 to 40% is proportional to the cytochrome content. Extrapolating the cytochrome c-420 content to that observed in whole cells, a ratio ATP/P+X- near 1 is calculated. At low flash intensity the phosphorylation per flash is proportional to flash energy. Photophosphorylation in flashes given after a time of several minutes is only slightly dependent on the number of flashes. If the flashes are spaced from 0.1 to 10 s, relative phosphorylation in the first flash is about 70% and in the second 90+ of that observed in the following flashes. Proton binding is not affected by the cytochrome c-420 content and a ratio of H+/P+x- of 2.3 was found. These results can be explained by a working hypothesis in which charge separation occurring at one reaction centre and the resulting electron transport mediated amongst others by c-420, results in the injection of two protons into an ATPase, this in contrast to a chemiosmotic mechanism, where the protons are released in the chromatophore inner space.
    [Abstract] [Full Text] [Related] [New Search]