The state of binding of intracellular K + in Halobacterium cutirubrum.

Intracellular K+ in lysed freeze-thawed cell pastes of the extreme halophile, H. cutirubrum, diffused readily against a concentration gradient during equilibrium dialysis, whereas the intracellular Mg2+ was not readily diffusible. The K+ activity in the lysed cell pastes, determined directly by K+ ion-specific electrode, was comparable to the total K-content of the cells, as determined by atomic absorption. This finding and the results of the dialysis experiment suggest that the intracellular K+ in H. cutirubrum is not bound.