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: Mechanism of Na+/H+ exchange by Escherichia coli NhaA in reconstituted proteoliposomes.
    Author: Dibrov PA, Taglicht D.
    Journal: FEBS Lett; 1993 Dec 28; 336(3):525-9. PubMed ID: 8282121.
    Abstract:
    Purified NhaA, a Na+/H+ antiporter from Escherichia coli, reconstituted into proteoliposomes was used to study partial reactions catalyzed by this protein. Homologous Na+/Na+ exchange as well as Na+/Li+ exchange via NhaA were detected by monitoring the effects of external Li+ and Na+ ions on the delta pH-driven sodium uptake into NH4 Cl-loaded vesicles. Furthermore, a sodium counterflow reaction was demonstrated in proteoliposomes preloaded with non-radioactive Na+ and placed into the experimental buffer containing low amounts of 22Na+ under experimental conditions when both components of protonmotive force generated by the antiporter. delta psi and delta pH, were dissipated by corresponding ionophores. The apparent Km for sodium counterflow is 1.1 mM, and Vmax is 80 mumol/min/mg of protein. External Na+ accelerates the downhill efflux of 22Na+ suggesting that the translocation of the Na(+)-loaded form of the carrier is faster than the rest of the catalytic cycle.
    [Abstract] [Full Text] [Related] [New Search]