title: Impedance analysis of phosphatidylcholine membranes modified with gramicidin D.
abstract: Electrochemical impedance spectroscopy (EIS) was used to the study of gramicidin D (GD) dimerization and to transport of monovalent cations across lipid bilayers by the dimers. Phosphatidylcholine (PC) membranes were studied, unmodified and modified with very low GD concentrations in the presence of various potassium ion concentrations. A new method was proposed to determine the parameters used to describe the gramicidin dimer: gramicidin surface concentration (c(GG)), area occupied by individual channel (A(G)) and gramicidin dimerization equilibrium constant (K(GG)). It was shown that electrochemical impedance spectroscopy measurements of lipid bilayer membranes yielded the K(GG) and A(G) values of the same order of magnitude as other measurement techniques.
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: Zbigniew
authors.initials: Z
authors.lastname: Figaszewski
mesh_terms: D019281:Dimerization; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D006096:Gramicidin / Q000737:chemistry*; D007473:Ion Channels; D017136:Ion Transport; D008051:Lipid Bilayers / Q000737:chemistry*; D008564:Membrane Potentials; D010713:Phosphatidylcholines / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry; D013057:Spectrum Analysis
chemical_list: D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D006096:Gramicidin; D011188:Potassium