Regulation of glutamine synthetase from the white button mushroom Agaricus bisporus.
The regulation of glutamine synthetase (GS) from Agaricus bisporus was studied at the posttranscriptional level using a specific antibody fraction directed against purified GS. The cross-reactivity of the antiserum against various Agaricus species and other fungi was tested and low reactivity with the Ascomycetes was found. GS protein and activity levels were measured in cell-free extracts of mycelium grown on different N sources. In mycelium grown on glutamine or ammonium as N source, the biosynthetic GS activity is higher than the transferase activity. Moreover, the results show a correlation between GS biosynthetic activity, GS protein, and previously reported mRNA levels. Also, after addition of ammonium or glutamine to glutamate-utilizing cultures, transferase activity decreased more rapidly than biosynthetic activity and GS protein level. This suggests a conformational modification which only affects transferase activity.
Kersten
M A
MA
Department of Microbiology and Evolutionary Biology, Faculty of Science, University of Nijmegen, Toernooiveld 1, Nijmegen, NL-6525 ED, The Netherlands. moniquek@sci.kun.nl
Baars
J J
JJ
Op den Camp
H J
HJ
Van Griensven
L J
LJ
van der Drift
C
C
D000364:Agaricus / Q000201:enzymology*; D002457:Cell Extracts / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D007118:Immunoassay; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D002457:Cell Extracts; D000644:Quaternary Ammonium Compounds; D012333:RNA, Messenger; D005973:Glutamine; D005974:Glutamate-Ammonia Ligase