Relationships between nitrogenase, glutamine synthetase, glutamine, and energy charge in Azotobacter vinelandii

Autor: D. Kleiner, J. A. Kleinschmidt
Rok vydání: 1981
Předmět:
Zdroj: Archives of Microbiology. 128:412-415
ISSN: 1432-072X
0302-8933
Popis: When continuous cultures of Azotobacter vinelandii were supplied with ammonium or nitrate in amounts, which just repressed nitrogenase synthesis completely, both the intracellular glutamine level and the degree of adenylylation of the glutamine synthetase (GS) increased only slightly (from 0.45–0.50 mM and from 2 to 3 respectively), while the total GS level remained unaffected. Higher amounts of ammonium additionally inhibited the nitrogenase activity, caused a strong rise in the intracellular glutamine concentration and adenylylation of the GS, but caused no change in the ATP/ADP ratio. These results are considered as evidence that in A. vinelandii the regulation of nitrogenase synthesis is not linked to the adenylylation state of the GS and to the intracellular glutamine level, and that the inhibition of the nitrogenase activity as a consequence of a high extracellular ammonium level is not mediated via a change in the energy charge.
Databáze: OpenAIRE