[Role of putrescine in the antiporter mechanism of potassium transport in Escherichia coli and its role in the regulation of intracellular pH].

The interrelation between the Escherichia coli transport processes of K+ and putrescine+2 was investigated under the inhibition and limitation of the main energy consuming potassium transport systems (Trk, Kdp). It was shown that the potassium addition to the potassium deprived putrescine loaded cells triggers the putrescine exit at the exchange on the potassium. The stoichiometry of putrescine +2/2K+ translocation provide the electroneutrality of this process. The putrescine gradient turnover changes the potassium transport direction on the opposite one. The submitted experimental data are the evidence of putrescine +2/2K+ antiporter existence. The role of this antiporter in the E. coli pH-homeostasis is discussed.