[Coupling of energy-dependent H+ and K+ ion fluxes in Streptococcus faecalis]

Grampositive bacteria S. faecalis are capable of uptaking potassium ions during many hours in the media containing glucose. Such behaviour of K+-uptake indicates that this system is not regulated as it takes place in gramnegative bacteria E. coli (1,3). The stoichimetry of DCCD-sensitive exchange between H+ and K+ ions equals 2:1. It is possible that S. faecalis possesses an electrogenic proton-potassium pump which can exchange 2H+ from the cell for external K+.