Changes in the NAD(P)H concentration caused by addition of nitrogenase 'switch-off' effectors in Rhodospirillum rubrum G-9, as measured by fluorescence.
The effect of nitrogenase 'switch-off' effectors on the concentration of NAD(P)H in Rhodospirillum rubrum G-9 was investigated by fluorescence. A rapid decrease in fluorescence was observed when cells, either N2-grown or nitrogen-starved, were subjected to the effectors, but not when sodium chloride or Tris buffer was added. No effects on the fluorescence were observed in non-nitrogen fixing cultures except when NAD+ was added. The results strongly indicate that the redox state of the pyridine nucleotide pool affects the control of the regulation of nitrogenase activity in R. rubrum.
Norén
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A
Department of Biochemistry, Arrhenius Laboratories for Natural Science, Stockholm University, Sweden.
Nordlund
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S
D000641:Ammonia / Q000494:pharmacology; D003624:Darkness; D005973:Glutamine / Q000494:pharmacology; D008027:Light; D009243:NAD / Q000494:pharmacology; D009249:NADP / Q000378:metabolism*; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology; D012247:Rhodospirillum rubrum / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D013050:Spectrometry, Fluorescence
D005973:Glutamine; D009243:NAD; D009249:NADP; D000641:Ammonia; D009591:Nitrogenase; D010100:Oxygen