Effect of Glutathione and Some of Its Components on the Response of Escherichia Coli to Penicillin

Abstract

Glutathione (GSH) has little effect on the growth of Escherichia coli ATCC 6522 in the chemically defined medium that was used, but when penicillin also is present favors the early onset of action of the antibiotic. Of the component moieties of GSH, in the absence of penicillin, glutamic acid appreciably stimulates and glycine slightly stimulates early growth, while cysteine markedly prolongs the lag phase. Glutamic acid nullifies the depressing effect of cysteine, but glycine does not. In the presence of penicillin, glutamic acid and glycine, singly or together, seem to favor earlier evidence of the growth-depressing effect of the antibiotic than is produced by penicillin alone. The effect of cysteine on the reaction of the organisms to penicillin is difficult to interpret, but there was no evidence for inhibition of penicillin, such as might have been expected from some of the reports in the literature. In the presence of penicillin, organisms respond quite differently to GSH and to an equivalent (concentrationwise) mixture of the component moieties of GSH.