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: Demonstration of two exchangeable non-catalytic and two cooperative catalytic sites in isolated bovine heart mitochondrial F1, using the photoaffinity labels [2-3H]8-azido-ATP and [2-3H]8-azido-ADP.
    Author: van Dongen MB, Berden JA.
    Journal: Biochim Biophys Acta; 1986 Jun 10; 850(1):121-30. PubMed ID: 2871864.
    Abstract:
    The photoreactive nucleotides [2-3H]8-azido-ATP and [2-3H]8-azido-ADP could be used to label the nucleotide binding sites on isolated mitochondrial F1-ATPase to a maximum of 4 mol of nucleotide per mol F1, also when the F1 was depleted of tightly bound nucleotides. At a photolabel concentration of 300-1000 microM, label was found on both alpha and beta subunits in a typically 1:3 ratio, independent of the total amount bound. Under these conditions the covalent binding of two nucleotides is needed for full inactivation (Wagenvoord, R.J., Van der Kraan, I. and Kemp, A. (1977) Biochim. Biophys. Acta 460, 17-24). At lower concentrations of [2-3H]8-azido-ATP (20 microM), it was found that covalent binding of only 1 mol of nucleotide per mole F1 was required for complete inactivation to take place indicating catalytic site cooperativity in the mechanism of ATP hydrolysis. Under those conditions, radioactivity was only found on the beta subunits, which would indicate that the catalytic site is located on a beta subunit and that a second site is located on the alpha/beta interface. It is found that four out of the six nucleotide binding sites are exchangeable and can be labelled with 8-azido-AT(D)P, i.e., two catalytic sites and two non-catalytic sites.
    [Abstract] [Full Text] [Related] [New Search]