IMPORTANCE OF GLUTATHIONE FOR GROWTH AND SURVIVAL OF ESCHERICHIA-COLI-CELLS - DETOXIFICATION OF METHYLGLYOXAL AND MAINTENANCE OF INTRACELLULAR K+

The role of the tripeptide glutathione in the growth and survival of E scherichia coli cells has been investigated. Glutathione-deficient mut ants leak potassium and have a reduced cytoplasmic pH. These mutants a re more sensitive to methylglyoxal th an the parent strain, indicating that in the absence of glutathione-dependent detoxification, acidific ation of the cytoplasm cannot fully protect cells. However, increasing the intracellular pH of the glutathione-deficient strain resulted in enhanced sensitivity to methylglyoxal. This suggests that acidificatio n of the cytoplasm can provide some protection to E. coli cells in the absence of glutathione. In the presence of the Kdp system, glutathion e-deficient mutants are highly sensitive to methylglyoxal. This is due to the higher intracellular pH in these cells. In the absence of meth ylglyoxal, the presence of the Kdp system in a glutathione-deficient s train also leads to an extended lag upon dilution into fresh medium. T hese data highlight the importance of glutathione for the regulation o f the Kf pool and survival of exposure to methylglyoxal.