title: Impedance analysis of phosphatidylcholine membranes modified with valinomycin.
abstract: 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.
authors.affiliation: Institute of Chemistry, University of Bialystok, Al. J. Pilsudskiego 11/4, 15-443 Bialystok, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Naumowicz
authors.forename: Joanna
authors.initials: J
authors.lastname: Kotynska
authors.forename: Aneta
authors.initials: A
authors.lastname: Petelska
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Figaszewski
mesh_terms: D025802:Electric Capacitance; D017097:Electric Impedance; D004563:Electrochemistry / Q000379:methods; D017136:Ion Transport; D007476:Ionophores / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008956:Models, Chemical; D010713:Phosphatidylcholines / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D012996:Solutions; D013057:Spectrum Analysis; D014634:Valinomycin / Q000737:chemistry*
chemical_list: D007476:Ionophores; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D012996:Solutions; D014634:Valinomycin; D011188:Potassium