Changes in the de novo glutathione (GSH) synthesis (GSH producing activity; GPA), in the χ-glutamyltranspeptidase (γGT) and GSH reductase (GR) activities as well as in the GSH pools were measured in a high β-lactam producing strain of Penicillium chrysogenum in the presence of different nitrogen, sulphur and carbon sources. When (NH4)2HPO4 was used as a nitrogen source both the specific GPA and the specific γGT activity were significantly lower than those observed with Na-Glu, meanwhile nitrogen starvation increased the γGT activity only. Although neither the addition of ammonium ions nor the withdrawal of nitrogen sources influenced the GSH pool during a 10 h cultivation the addition of the sulphur containing amino acids cysteine (Cys) or methionine (Met) at a concentration of 20 mM increased considerably both the specific GPA and the intracellular GSH levels. Nevertheless, GPA decreased significantly when either Cys or Met was added at a three times higher concentration. When glucose was replaced by lactose as a carbon source or during carbon starvation the GPA values and the GSH concentrations were higher while the GR activities were lower than those observed with glucose. Nevertheless, no changes in either the enzyme activities or the GSH levels were detected when glucose was replaced with 2-deoxy-D-glucose or glucose together with caffeine was added to the culture media.
|Number of pages||6|
|Journal||Journal of basic microbiology|
|Publication status||Published - 1998|
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology