Modulation of nitrate reductase: some new insights, an unusual case and a potentially important side reaction.
The mechanism of the post-translational modulation of nitrate reductase activity (NR, EC 1.6.6.1) is briefly summarized, and it is shown that by this mechanism nitric oxide production through NR is also rapidly modulated. New and partly unexpected details on the modulation mechanism have been obtained by using immunological techniques. The phosphorylation state of NR has been assessed with peptide antibodies raised against the serine phosphorylation motive of spinach NR. By co-immunoprecipitation experiments, 14-3-3 binding to phospho-NR and the function of Mg(2+) in that process has been elucidated. Conflicting data on the role of NR phosphorylation and 14-3-3 binding in controlling NR proteolysis are discussed. A possible role of other NR inactivating proteins is also briefly considered and the regulation of NR of Ricinus communis is described as an interesting special case that differs from the 'normal' mechanism in several important aspects.
Kaiser
Werner M
WM
Julius-von-Sachs-Institut für Biowissenschaften, Julius-von-Sachs-Platz 2, D-97082 Würzburg, Germany. kaiser@botanik.uni-wuerzburg.de
Weiner
Hendrik
H
Kandlbinder
Andrea
A
Tsai
Chyn-Bey
CB
Rockel
Peter
P
Sonoda
Masatoshi
M
Planchet
Elisabeth
E
D048948:14-3-3 Proteins; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000494:pharmacology; D050895:Nitrate Reductase (NADH); D009565:Nitrate Reductases / Q000235:genetics* / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D009573:Nitrites / Q000494:pharmacology; D030421:Peroxynitrous Acid / Q000096:biosynthesis; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D012278:Ricinus / Q000201:enzymology*; D015398:Signal Transduction; D018724:Spinacia oleracea / Q000201:enzymology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D048948:14-3-3 Proteins; D009573:Nitrites; D017382:Reactive Oxygen Species; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D014446:Tyrosine 3-Monooxygenase; D009565:Nitrate Reductases; D050895:Nitrate Reductase (NADH); D008274:Magnesium