Summary
The partition of alkali cations and anions between an aqueous and an immiscible organic phase has been studied in the absence and presence of neutral and carboxylic ionophores of the valinomycin and nigericin types, respectively. Cation extraction into the organic phase was augmented considerably by the ionophores, and a cation specificity of K+≧Rb+>Cs+≫Na+ was found for all the neutral ionophores tested. Evidence is given that the actual values of ion specificity are a function of the solvent polarity, especially for valinomycin where an inversion of the K+/Rb+ specificity was observed. The ionophores examined have the following rank order of effectiveness for K+ extraction into a standard organic phase consisting of 70% toluene-30%n-butanol: valinomycin>18-crown-6≫trinactin>enniatin B≈dinactin>monactin>nonactin. The ion affinity and selectivity data thus obtained have been compared with data previously reported.
In a toluene-butanol solvent, extraction of cations in the absence of ionophores occurs as ion pairs. On the other hand, the neutral ionophores extract the cations by the mechanism of complexation, with the lipophilic anions coextracted as free gegenionic species at lower ionophore complex concentrations. When the concentration of extracted cations exceeds 1×10−4 m, ion pairing between the ionophore complex and the anion occurs, and this tendency increases with increasing concentration and decreasing polarity of the organic phase. Anion pairing with the complexed cations is much less than for the free cations and this effect appears to be due to the larger distance of closest approach of the anion for the complexed cation.
Similar content being viewed by others
References
Bonne, D.J., Kowalsky, A. 1974. Ion pairing of ionophore potassium complexes: NMR studies with paramagnetic anions.Biochemistry 13:731
Ciani, S., Eisenman, G., Szabo, G. 1969. A theory for the effects of neutral carriers such as the macrotetralide actin antibiotics on the electric properties of bilayer membranes.J. Membrane Biol. 1:1
Diebler, H., Eigen, M., Ilgenfritz, G., Massa, G., Winkler, R. 1969. Kinetics and mechanism of reactions of main group metal ions with biological carriers.Pure Appl. Chem. 20:93
Eisenman, G., Ciani, S., Szabo, G. 1969. The effects of the macrotetralide actin antibiotics on the equilibrium extraction of alkali metal salts into organic solvents.J. Membrane Biol. 1:294
Eisenman, G., Szabo, G., McLaughlin, S.G.A., Ciani, S. 1973. Molecular basis for the action of macrocyclic carriers on passive ionic translocation across lipid bilayer membranes.Bioenergetics 4:93
Frensdorff, H.K. 1971. Salt complexes of cyclic polyethers: Distribution equilibria.J. Amer. Chem. Soc. 93:4684
Grell, E., Funck, T. Eggers, F. 1972. Dynamic properties and membrane activity of ion specific antibiotics.In: Molecular Mechanisms of Antibiotic Action on Protein Biosynthesis and Membranes, Proc. of a Symposium, Granada. E. Muñoz, F. García-Ferrándiz, and D. Vázquez, editors, pp. 646–685
Haynes, D.H. 1970. Equilibrium and Kinetic Properties of Ionophores of the Valinomycin Type in Model Systems and Biological Membranes. Ph. D. Thesis. University of Pennsylvania, Philadelphia, Pa., p. 246
Haynes, D.H. 1972. The kinetics of potassium ion complexation by ionophores.FEBS Letters 20:221
Haynes, D.H., Kowalsky, A., Pressman, B.C. 1969. Application of nuclear magnetic resonance to the conformational changes in valinomycin during complexation.J. Biol. Chem. 244:502
Haynes, D.H., Wiens, T., Pressman, B.C. 1974. Turnover numbers for ionophorecatalyzed cation transport across the mitochondrial membrane.J. Membrane Biol. 18:23
Ivanov, V.T., Laine, I.A., Abdulaev, N.D., Senyavina, L.B., Popov, E.M., Ovchinnikov, Y.A., Shemyakin, M.M. 1969. The physicochemical basis of the functioning of biological membranes: The conformation of valinomycin and its K+ complex in solution.Biochem. Biophys. Res. Commun. 34:803
Johnson, J.R., Christan, S.D., Affsprung, H.E. 1966. The molecular complexity of water in organic solvents. Part II.J. Chem. Soc. (A) 1966:77
Ohnishi, M., Urry, D.W. 1969. Temperature dependence of amide proton chemical shifts: The secondary structures of gramicidin S and valinomycin.Biochem. Biophys. Res. Commun. 36:194
Ovchinnikov, Y.A., Ivanov, V.T., Evstratov, A.V., Bystrov, V.F., Abdullaev, N.D., Popov, E.M., Lipkind, G.M., Arkhipova, S.F., Efremov, E.S., Shemyakin, M.M. 1969. The physicochemical basis of the functioning of biological membranes: Dynamic conformational properties of enniatin B and its K+ complex in solution.Biochem. Biophys. Res. Commun. 37:668
Parsegian, A. 1969. Energy of an ion crossing a low dielectric membrane: Solutions to four relevant electrostatic problems.Nature 221:344
Pressman, B.C. 1968. Ionophorous antibiotics as models for biological transport.Fed. Proc. 27:1283
Pressman, B.C., Harris, E.J., Jagger, W.S., Johnson, J.H. 1967. Antibiotic-mediated transport of alkali ions across lipid barriers.Proc. Nat. Acad. Sci. 58:1949
Pressman, B.C., Haynes, D. H. 1970. Ionophorous agents as mobile ion carriers.In: The Molecular Basis of Membrane Function. D.C. Tosteson, editor. p. 221–246. Prentice-Hall, Englewood Cliffs, N.J.
Prestegard, J.H., Chan, S.I. 1970. Proton magnetic resonance studies of the cation-binding properties of nonactin. II. Comparison of the sodium ion, potassium ion, and cesium ion complexes.J. Amer. Chem. Soc. 92:4440
Szabo, G., Eisenman, G., Ciani, S. 1969. The effects of the macrotetralide actin antibiotics on the electrical properties of phospholipid bilayer membranes.J. Membrane Biol. 1:346
Traube, J. 1904. Theorie der Osmose und Narkose.Pflüg. Arch. Ges. Physiol. 105:541
Wipf, H.K., Pioda, L.A.R., Stafanac, A., Simon, W. 1968. Komplexe von Enniatinen und anderen Antibiotica mit Alkalimetall-Ionen.Helv. Chim. Acta 51:377
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Haynes, D.H., Pressman, B.C. Two-phase partition studies of alkali cation complexation by ionophores. J. Membrain Biol. 18, 1–21 (1974). https://doi.org/10.1007/BF01870099
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01870099