Determination of stability constants of valinomycin complexes with ammonium and alkali metal ions by capillary affinity electrophoresis

Capillary affinity electrophoresis (CAE) has been employed to investigate quantitatively the interactions of valinomycin, macrocyclic depsipeptide antibiotic ionophore, with univalent cations, ammonium and alkali metal ions, K⁺, Cs⁺, Na⁺, and Li⁺, in methanol. The study involved measuring the change...

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Bibliographic Details
Published in:Electrophoresis 2008-02, Vol.29 (3), p.652-657
Main Authors: Ehala, Sille, Kašička, Václav, Makrlík, Emanuel
Format: Article
Language:English
Subjects:
Alkali metal cations
Alkalies - chemistry
Anti-Bacterial Agents - chemistry
Binding constant
Capillary affinity electrophoresis
Cations, Monovalent - chemistry
Drug Stability
Electrophoresis, Capillary - methods
Ionophores - chemistry
Quaternary Ammonium Compounds - chemistry
Stability constant
Valinomycin
Valinomycin - analogs & derivatives
Valinomycin - chemistry
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Summary:Capillary affinity electrophoresis (CAE) has been employed to investigate quantitatively the interactions of valinomycin, macrocyclic depsipeptide antibiotic ionophore, with univalent cations, ammonium and alkali metal ions, K⁺, Cs⁺, Na⁺, and Li⁺, in methanol. The study involved measuring the change in effective electrophoretic mobility of valinomycin while the cation concentrations in the BGE were increased. The corresponding apparent stability (binding) constants of the valinomycin-univalent cation complexes were obtained from the dependence of valinomycin effective mobility on the cation concentration in BGE using a nonlinear regression analysis. The calculated apparent stability constants of the above-mentioned complexes show the substantially higher selectivity of valinomycin for K⁺ and Cs⁺ ions over Li⁺, Na⁺, and NH₄⁺ ions. CAE proved to be a suitable method for the investigation of both weak and strong interactions of valinomycin with small ions.
ISSN:0173-0835
1522-2683
DOI:10.1002/elps.200700583