title: Studies on the effect of NAD(H) on nitrogenase activity in Rhodospirillum rubrum.
abstract: The effect of NAD(P) and analogs of this nucleotide on nitrogenase activity in Rhodospirillum rubrum has been studied. Addition of NAD+ to nitrogen fixing Rsp. rubrum leads to inhibition of nitrogenase. NADP+ has the same effect but NADH or analogs modified in the nicotinamide portion do not cause inhibition. In contrast to ammonium ions, addition of NAD+ leads to inhibition of nitrogenase in cells that have been N-starved under argon. The inhibitory effect of NAD+ is more pronounced at lower light intensities. Addition of NAD+ also leads to inhibition of glutamine synthetase, a phenomenon also occurring when "switch-off" is produced by the addition of effectors such as ammonium ions or glutamine. It is also shown that NAD+ is taken up by Rsp. rubrum cells.
authors.affiliation: Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, University of Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Soliman
authors.forename: S
authors.initials: S
authors.lastname: Nordlund
mesh_terms: D009243:NAD / Q000031:analogs & derivatives / Q000494:pharmacology*; D009591:Nitrogenase / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D012247:Rhodospirillum rubrum / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D009243:NAD; D009591:Nitrogenase