Na⁺ efflux from Na⁺-loaded cells elicited by an inwardly directed acriflavine gradient.

<p>Cells of <i>E. coli</i> KAM32/pHAP5 or <i>E. coli</i> KAM32/pHY300PLK (control) were diluted with 0.1 M MOPS-TMAH (pH7.0) until approximately 9 mg protein/ml. Na⁺ was loaded to cells via MelB by the addition of Mβgal (the first arrow), and acriflavine (final 200 µM) was added to the assay mixture at the time point indicated by the second arrow. Upward deflection of the curve indicates Na⁺ influx into cells and downward deflection indicates Na⁺ efflux from cells.