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Influence of Nitrogen Availability on Aminotransferases in Lemna minor L

RUTTER, JOHN C. ; ERISMANN, KARL H.

In: Journal of Experimental Botany, 1985, vol. 36, no. 4, p. 583-589

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    Title
    • Influence of Nitrogen Availability on Aminotransferases in Lemna minor L
    Author
    • RUTTER, JOHN C.. Pflanzenphysiologisches Institut der Universität Bern, Altenbergrain 21, CH-3013 BERN, Switzerland
    • ERISMANN, KARL H.. Pflanzenphysiologisches Institut der Universität Bern, Altenbergrain 21, CH-3013 BERN, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Journal of Experimental Botany, 1985, vol. 36, no. 4, p. 583-589. Oxford University Press
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:293863
    Summary
    Protein contents and glutamate: glyoxylate, serine: glyoxylate, alanine: glyoxylate and glutamate: pyruvate aminotransferase activities per gram fresh weight declined sharply when Lemna minor L., previously grown on nitrate medium, was starved of nitrogen. Nitrogen replenishment after 5 d caused complete recovery of these parameters with higher values in ammonium-fed than nitrate-fed plants 7 d after transfer of plants from nitrogen-free medium. Glutamate: glyoxylate and alanine: glyoxylate aminotransferase specific activities (based on total extracted protein) showed little change with nitrogen availability. Serine: glyoxylate aminotransferase increased slowly during nitrogen starvation and decreased following nitrogen replenishment whether with ammonium or nitrate. After 1 d of nitrogen starvation the specific activity of glutamate: pyruvate aminotransferase declined; it increased following nitrogen replenishment and ammonium gave rise to agreater activity than nitrate. The results are discussed in relation to the differences in stability of the various enzymes relative to the overall protein turnover rate