Planta

, Volume 212, Issue 5–6, pp 835–841

A plasma membrane-bound enzyme of tobacco roots catalyses the formation of nitric oxide from nitrite

  • Christine Stöhr
  • Frank Strube
  • Gisela Marx
  • Wolfram R. Ullrich
  • Peter Rockel

DOI: 10.1007/s004250000447

Cite this article as:
Stöhr, C., Strube, F., Marx, G. et al. Planta (2001) 212: 835. doi:10.1007/s004250000447

Abstract.

Purified plasma membranes (PMs) of tobacco (Nicotiana tabacum L. cv. Samsun) roots exhibited a nitrite-reducing enzyme activity that resulted in nitric oxide (NO) formation. This enzyme activity was not detected in soluble protein fractions or in PM vesicles of leaves. At the pH optimum of pH 6.0, nitrite was reduced to NO with reduced cytochrome c as electron donor at a rate comparable to the nitrate-reducing activity of root-specific succinate-dependent PM-bound nitrate reductase (PM-NR). The hitherto unknown PM-bound nitrite: NO-reductase (NI-NOR) was insensitive to cyanide and anti-NR IgG and thereby proven to be different from PM-NR. Furthermore, PM-NR and NI-NOR were separated by gel-filtration chromatography and apparent molecular masses of 310 kDa for NI-NOR and 200 kDa for PM-NR were estimated. The PM-associated NI-NOR may reduce the apoplastic nitrite produced by PM-NR in vivo and may play a role in nitrate signalling via NO formation.

Key words:Nicotiana (nitrogen assimilation) Nitrate reductase Nitric oxide Nitrite Plasma membrane Root (nitrogen assimilation) 

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Christine Stöhr
    • 1
  • Frank Strube
    • 2
  • Gisela Marx
    • 1
  • Wolfram R. Ullrich
    • 1
  • Peter Rockel
    • 1
  1. 1.Institut für Botanik, Technische Universität, Schnittspahnstrasse 10, 64287 Darmstadt, GermanyDE
  2. 2.Institut für Chemie und Dynamik der Geosphäre (ICG-6) Forschungszentrum Jülich GmbH, 52425 Jülich, GermanyDE

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