Sélectivité du transport de Ca2+/Mg2+ à travers une membrane liquide par A•23187 (calcimycine) et son dérivé N-méthyle

Abstract

Operating in a cell of water/CHCl3/water, it is shown that there is a preferential transport of Ca2+/Mg2+ by A.23187. On the basis of measurements of flux of extraction and of flux of liberation in a half-cell of water/CHCl3, it is shown that the selectivity of the transport is related to the kinetics of liberation, which is markedly different for the two ions and which could be explained by the structure of the complex dimers that are formed, according to the corresponding crystallographic studies. The methylation of the —NHCH3 entails an inversion of the selectivity in the transport