Excretion of glutathione by methylglyoxal-resistant Escherichia coli

A methylglyoxal-resistant mutant of Escherichia coli B excreted glutathione into the growth medium, especially during growth on medium containing methylglyoxal. In the presence of methylglyoxal, the total amount of glutathione excreted was increased about 50-fold over that of the wild-type strain. The resistant mutant had high activities of two enzyme systems: a glutathione-forming enzyme system (consisting of gamma-glutamylcysteine synthetase and glutathione synthetase) and a glyoxalase system (consisting of glyoxalase I and glyoxalase II). Methylglyoxal resistance appeared to be due to the simultaneous increase in the activities of these two enzyme systems.