MECHANISM OF ALKALI CATION TRANSPORT IN BULK MEMBRANES USING MACROTETROLIDE ANTIBIOTICS

The transport of potassium ions in a potential gradient across a bulk membrane containing macrotetrolide antibiotics is studied using 14C-labelled macrotetrolide. It is shown that this transport of potassium ions across the membrane is accompanied by an equal transport of macrotetrolide within the membrane indicating that potassium ions are transported as the 1:1 macrotetrolide complex. Since exchange of ligands is shown to occur during the transport, a carrier relay mechanism accounting for all experimental results is proposed. © 1969.