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Co‐ordination of the nitrate and nitrite assimilation, the glutathione and free radical metabolisms, and the pentose phosphate pathway in Penicillium chrysogenum
Author(s) -
Emri Tamás,
Sámi László,
Szentirmai Attila,
Pócsi István
Publication year - 1999
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/(sici)1521-4028(199905)39:2<109::aid-jobm109>3.0.co;2-q
Subject(s) - glutathione , glutathione reductase , chemistry , biochemistry , nitrite reductase , pentose phosphate pathway , nitrate reductase , glutathione peroxidase , nitrite , cumene hydroperoxide , dehydrogenase , nitrate , enzyme , glycolysis , organic chemistry , catalysis
The specific glutathione reductase (GR) and glucose‐6‐phosphate dehydrogenase (G6PD) activities increased significantly in Penicillium chrysogenum grown on glucose in the presence of either nitrate or nitrite. These changes kept the intracellular peroxide levels low and prevented the onset of any glutathione/glutathione disulphide redox imbalances. On the other hand, the specific activity of several other glutathione metabolic enzymes including glutathione peroxidase, glutathione S‐transferase, γ ‐glutamyltranspeptidase and the glutathione producing activity was not effected by NO 3 — and NO 2 — . When P. chrysogenum mycelia were challenged with oxidative stress caused by high concen‐trations of H 2 O 2 , tert ‐butyl hydroperoxide, menadione, diamide or phenoxyacetic acid the intracellular peroxide concentrations increased significantly, and the nitrate reductase and nitrite reductase activities were eliminated. When glucose was replaced with lactose the GR and G6PD activities were not influenced by the nitrogen sources but in this case the intracellular GSH concentration was twice higher than that observed with glucose.