Studies of the adenylate and pyridine nucleotide pools during nitrogenase ‘switch-off’ inRhodospirillum rubrum

• DOI: 10.1007/bf02277397
• Publication Date: 2006-01-25T15:00:28Z
• Authors: S. Nordlund; L. Höglund
• Keywords: Rhodospirillum rubrum

When ammonium ions are added to a nitrogen fixing culture ofRhodospirillum rubrum, nitrogenase activity decreases due to inactivation of the Fe-protein. We have studied the adenylate and pyridine nucleotide pools during switch-off using the sensitive bioluminescence method. Immediately after the addition of ammonium ions there is a decrease in the ATP pool which is quickly reversed and no change is seen during the switch-off period. The pyridine nucleotide pools also do not change significantly during the switch-off. Consequently we conclude that changes in the pools studied were not the signal promoting inactivation of the Fe-protein.