Binding to 14-3-3 proteins is not sufficient to inhibit nitrate reductase in spinach leaves.
To assess the role of 14-3-3 proteins in the magnesium-dependent inhibition of nitrate reductase (NR) we tested the effect of magnesium on NR binding to 14-3-3s by coimmunoprecipitation and gel filtration. The stability of the 14-3-3 complex of NR was, unlike its activity, unaffected by magnesium. We therefore conclude that binding to 14-3-3s per se does not inhibit NR. Magnesium inhibited 14-3-3-bound NR much more strongly than 14-3-3-free NR. 14-3-3s possibly reinforce NR inhibition by magnesium.
Weiner
H
H
Julius-von-Sachs-Institut für Biowissenschaften, Lehrstuhl Botanik I, Molekulare Pflanzenphysiologie und Biophysik, Würzburg, Germany. weiner@botanik.uni-wuerzburg.de
Kaiser
W M
WM
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000818:Animals; D008274:Magnesium / Q000378:metabolism*; D008969:Molecular Sequence Data; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018515:Plant Leaves / Q000201:enzymology; D011485:Protein Binding; D011817:Rabbits; D018724:Spinacia oleracea / Q000201:enzymology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D048948:14-3-3 Proteins; D014446:Tyrosine 3-Monooxygenase; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D008274:Magnesium