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Naumowicz M, Kotynska J, Petelska A, Figaszewski Z.
Impedance analysis of phosphatidylcholine membranes modified
with valinomycin.
Eur Biophys J. 2006 Feb;35(3):239-46
Institute of Chemistry, University of Bialystok, Al. J.
Pilsudskiego 11/4, 15-443, Bialystok, Poland.
The effect of the ion carrier valinomycin on the electrochemical
features of the phosphatidylcholine membrane was investigated by
electrochemical impedance spectroscopy. Phosphatidylcholine and
valinomycin were chosen for the study because they fulfil
essential functions in lively organisms. The experimental
impedance values obtained in the presence of different amounts
of carrier, studied with several potassium ion concentrations,
were used for the research ability of valinomycin to form a 1:1
potassium ion complex on the lipid bilayer/electrolyte solution
interface. Based on derived mathematical equations, the
heterogeneous equilibrium constant (K (h)), association rate
constant of the complex (k (R)) and dissociation rate constant
of the complex (k (D)) were calculated. The result of the
investigation is the proposal of a new method for the
determination of the parameters used to describe the chemical
reaction at the interface between a carrier molecule from the
membrane and a monovalent ion from the aqueous phase.
PMID: 16283290
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