Active and passive transport of amino-acid and oligopeptide derivatives by artificial ionophore-K+ complexes

Abstract

Four types of crown ether [the cyclic crown ether (1), the diaza-crown ether (2), the non-cyclic crown ether (3), and the cryptand (4)] have been examined as novel anion transport carriers. They effectively mediated the passive and active transport of amino-acid and oligopeptide derivatives as carboxylate anions, coupled with K⁺ ion transport. Their transport efficiences, selectivities, and directions were essentially controlled by the nature of the crown ether used and of the cations present. They provide a new chemical analogue of biological transport systems, as well as further applications for the separation of biologically important anions.