Open AccessChanges in the Cellular Energy State Affect the Activity of the Bacterial Phosphotransferase System
Author(s) -
Rohwer Johann M.,
Jensen Peter Ruhdal,
Shinohara Yasuo,
Postma Pieter W.,
Westerhoff Hans V.
Publication year - 1996
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1996.00225.x
Subject(s) - pep group translocation , phosphotransferase , intracellular , oxidative phosphorylation , biochemistry , glycolysis , atpase , adenosine triphosphate , operon , chemiosmosis , phosphorylation , chemistry , biology , atp synthase , phosphoenolpyruvate carboxykinase , metabolism , escherichia coli , enzyme , gene
The effect of different cellular free‐energy states on the uptake of methyl α‐ d ‐glucopyranoside, an analogue of glucose, by the Escherichia coli phospho enol pyruvate:carbohydrate phosphotransferase system was investigated. The intracellular [ATP]/[ADP] ratio was varied by changing the expression of the atp operon, which codes for the H + ‐ATPase, or by adding an uncoupler of oxidative phosphorylation or an inhibitor of respiration. Corresponding initial phosphotransferase uptake rates were determined using an improved uptake assay that works with growing cells in steady state. The results show that the initial uptake rate was decreased under conditions of lowered intracellular [ATP]/[ADP] ratios, irrespective of which method was used to change the cellular energy state. When either the expression of the atp operon was changed or 2,4‐dinitrophenol was added to wild‐type cells, the relationship between initial phosphotransferase uptake rate and the logarithm of the [ATP]/[ADP] ratio was approximately linear. These results suggest that the cellular free‐energy state, as reflected in the intracellular [ATP]/[ADP] ratio, plays an important role in regulating the activity of the phosphotransferase system.