PubMed · 8236437
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
B T Kaufman. 1993. Why NADP?. https://doi.org/10.1016/0968-0004(93)90033-j
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
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.
Phenylmethanesulfonyl fluoride (PMSF) enabled vanadate to catalyze the oxidation of NADH. Superoxide dismutase and manganese inhibited the oxidation, suggesting that superoxide anion played a crucial role. Since PMSF is widely used to protect enzymes from proteolytic cleavage when they are purified, attention should be paid when the toxicity of vanadate on the enzyme, whose activities are monitored by the oxidation of NADH, is evaluated or when vanadate dependent NADH oxidase is purified and assayed.
Explore the source record for details and available documents.