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: Transport of inorganic pyrophosphate across the spinach chloroplast envelope.
    Author: Lunn JE, Douce R.
    Journal: Biochem J; 1993 Mar 01; 290 ( Pt 2)(Pt 2):375-9. PubMed ID: 8383964.
    Abstract:
    Spinach-leaf chloroplasts take up PPi at a rate of 1.9 mumol/h per mg of chlorophyll (Chl) in the dark and 1.6 mumol/h per mg of Chl in the light. The Km for PPi transport is 32 microM in the dark and 6 microM in the light. Uptake is inhibited by pyridoxal phosphate, 4,4'-di-isothiocyanatostilbene-2,2'-disulphonic acid and imidodiphosphate, but not by NaF or EDTA. PPi does not appear to cross the chloroplast envelope in exchange for Pi, suggesting that it is not transported by the phosphate translocator. Exchange of PPi and adenine nucleotides across the chloroplast envelope is very slow and PPi does not competitively inhibit ATP uptake, suggesting that little, if any, PPi is transported by the adenine-nucleotide translocator. These results are consistent with the presence of a specific, high-affinity PPi translocator in the spinach chloroplast envelope. It is proposed that in vivo PPi is taken up into the chloroplast from the cytosol to replenish the Pi pool in the stroma.
    [Abstract] [Full Text] [Related] [New Search]