[Accumulation of K+ in E. coli grown in aerobic conditions]

The character of K+ accumulation in E. coli grown aerobilcally in the salt medium with succinate was studied. K+ uptake via the Trk system has Km 3.4 mM and Vmax 0.45 mM X g+1 X min-1. The initial rates of K+ uptake were not changes at different pH from 6.0 to 8.3 and temperature 17-37 degrees C. DCC did not block, protonophores and arsenate blocked the operation of Trk system. Valinomycin increased (or had no effect) K+ accumulation. K+ distribution is in good conformity with the measured membrane potential. The Trk system works at the utilization of lactic acid and glucose as well as of succinate. The Trk system is described. K+ ionophore by using the membrane potential and ATP regulates functioning of this system.