The effects of weak acids on potassium uptake by Escherichia coli K-12 inhibition by low cytoplasmic pH.
The activity of the Escherichia coli K+ transport system TrkA was measured as a function of the cytoplasmic pH of the cell. For this purpose, pHin was decreased by the addition of the weak acids acetic acid, benzoic acid or salicylic acid to K+-depleted cells. Under these conditions, the initial rate of K+ uptake decreased strongly with pHin, and was almost independent of the acid used. This inhibition was due to a strong decrease in the Vmax for K+ uptake, which indicates that low cytoplasmic pH inactivates the TrkA K+ uptake system. The relevance of this inhibition for growth and metabolism at low pHin is discussed.
D000085:Acetates / Q000494:pharmacology; D001565:Benzoates / Q000494:pharmacology; D019817:Benzoic Acid; D004492:Edetic Acid / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011188:Potassium / Q000378:metabolism*; D012459:Salicylates / Q000494:pharmacology; D020156:Salicylic Acid
D000085:Acetates; D001565:Benzoates; D012459:Salicylates; D019817:Benzoic Acid; D004492:Edetic Acid; D020156:Salicylic Acid; D011188:Potassium