The stimulation by salts of hexose phosphate uptake by Escherichia coli

Hexose phosphate uptake in Escherichia coli is stimulated by salts. KCl and MgCl2 stimulate to about the same extent, but Mg2+ is effective at a tenth the concentration of K+. At higher concentrations, both salts inhibit. The stimulation by a series of salts correlates strongly with the hydrated radius of the cation, with small ions more effective than large. There are effects by the anion, but they do not correlate with any simple property. Cells accumulate glucose 6-phosphate to a higher concentration in the presence of KCl than in its absence. The maximum velocity of glucose 6-phosphate uptake is stimulated by KCl, as is the ratio V/Km.