Inhibition of K+ transport and metabolism of escherichia coli by ethacrynic acid

1. Aerobic K+ transport in E. coli is independent of membrane ATPase (E.C.3.6.1.3.) 2. Ethacrynic acid reduces the intracellular K+ concentration of E. coli by a decrease in the rate constant for influx which is produced by inhibition of energy metabolism (respiration) and by a smaller increase of the efflux. 3. The inhibition of K+ transport by ethacrynic acid is greatly enhanced by H+ and NaCl. 4. A K+ dependent mutant of E. coli is specifically about ten times more sensitive to inhibition by ethacrynic acid than the wildtype.