Planta

, Volume 125, Issue 3, pp 201–211

The control of glutamine synthetase level in Lemna minor L.

  • David Rhodes
  • G. A. Rendon
  • G. R. Stewart
Article

DOI: 10.1007/BF00385596

Cite this article as:
Rhodes, D., Rendon, G.A. & Stewart, G.R. Planta (1975) 125: 201. doi:10.1007/BF00385596

Summary

The specific activity of glutamine synthetase (E.C. 6.3.1.2) of Lemna minor L. is markedly reduced when either ammonium ions or glutamine are present in the growth medium. Combinations of 5 mM ammonia and 5 mM glutamic acid or 5 mM ammonia and 5 mM glutamine as nitrogen source, lead to a 4–5 fold reduction of the maximum activity measurable on 5 mM γ-aminobutyric acid. Analyses of the soluble pool of nitrogen indicate that the reduction in enzyme level is associated with an increase in the pool of glutamine. There is an inverse correlation between the apparent rate of synthesis of glutamine synthetase and the intracellular concentration of glutamine, and this relationship suggests that the glutamine synthetase of Lemna minor is subject to end product repression by the endogenous pool of glutamine.

Copyright information

© Springer-Verlag 1975

Authors and Affiliations

  • David Rhodes
    • 1
  • G. A. Rendon
    • 1
  • G. R. Stewart
    • 1
  1. 1.Department of BotanyThe UniversityManchesterUK