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Electrochemical Elucidation of the Facilitated Ion Transport Across a Bilayer Lipid Membrane in the Presence of Neutral Carrier Compounds
Author(s) -
Onishi Jun,
Shirai Osamu,
Kano Kenji
Publication year - 2010
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200900481
Subject(s) - chemistry , valinomycin , ion , electrolyte , ion transporter , electrochemistry , ionic bonding , cyclic voltammetry , hydroxide , electrochemical potential , lipid bilayer , inorganic chemistry , analytical chemistry (journal) , membrane , electrode , chromatography , organic chemistry , biochemistry
The ion transport facilitated by neutral carrier compounds (valinomycin, nonactin) has been investigated by cyclic voltammetry in the several electrolyte solutions (KF, KCl, KBr, KNO 3 , KSCN, KClO 4 ), and we demonstrated the effect of the counter anions on the facilitated transport of K + from the viewpoint of electroneutrality. Voltammograms for the ion transport were generated at steady state and the current density between W1 and W2, j W1–W2, increased with the absolute value of the applied membrane potential, E W1–W2 . Then, the magnitude of j W1–W2 at a certain E W1–W2 increased with the hydrophobicity of the counter anion. It was proved that the logarithm of | j W1–W2 |at a certain E W1–W2 is almost proportional to the hydration energy of the counter anion. This indicates that not only K + but also the counter anion distributes into the BLM. Therefore, the magnitude of j W1–W2 at a certain E W1–W2 increased with an increase of pH, because the hydroxide ion was served as a counter anion. Based on the variation of the zero‐current potential in case of various asymmetrical ionic compositions, it is found that the amount of cation transport is much larger than that of anion transport.