PHENOXYACETIC ACID INDUCES GLUTATHIONE-DEPENDENT DETOXIFICATION AND DEPLETES THE GLUTATHIONE POOL IN PENICILLIUM-CHRYSOGENUM

Enzymes of the glutathione-dependent detoxification pathway (glutathio ne S-transferase and gamma-glutamyltranspeptidase)(1)) were induced, a nd the glutathione pool was completely depleted by phenoxyacetic acid in Penicillium chrysogenum mycelia incubated for 15 h in a culture med ium containing lactose as a carbon source and sodium glutamate as a ni trogen source. A significant increase in both the oxidised glutathione concentrations and the glutathione reductase activities were also obs erved. 1-Chloro-2,4-dinitrobenzene - a potent substrate and inducer of glutathione S-transferase - initiated very similar physiological chan ges but no p-lactam production could be detected in this case. When (N H4)(2)HPO4 was used as a nitrogen source the penicillin biosynthesis w as repressed and the induction of gamma-glutamyltranspeptidase by phen oxyacetic acid was hindered considerably.