title: Glutamine synthetase activity in Solanaceous cell suspensions accumulating alkaloids or not. 13C NMR and enzymatic assay.
abstract: The metabolism of labelled pyruvate followed by 13C NMR and the measure of glutamine synthetase (GS) showed, according to previous results, a high activity of this enzyme in suspension cells of Nicotiana plumbaginifolia. This activity could derive glutamate from the alkaloid synthesizing pathways. However, a recent work showed that the rate of the GS gene transcription was inversely proportional to the Gln/Glu ratio. The measures of Gln and Glu concentrations in Nicotiana plumbaginifolia cells revealed that high GS activity correlates with the weak value of Gln/Glu ratio. Therefore, the hypothesis of GS dysfunctioning for the non-biosynthesis of alkaloids in N. plumbaginifolia suspension cells can be discarded. This conclusion is strengthened by the results obtained when using a GS inhibitor.
authors.affiliation: Laboratoire de biophysique, faculté de pharmacie, Amiens, France.
authors.forename: F
authors.initials: F
authors.lastname: Mesnard
authors.forename: D
authors.initials: D
authors.lastname: Marty
authors.forename: F
authors.initials: F
authors.lastname: Gillet-Manceau
authors.forename: M A
authors.initials: MA
authors.lastname: Fliniaux
authors.forename: J P
authors.initials: JP
authors.lastname: Monti
mesh_terms: D000470:Alkaloids / Q000096:biosynthesis*; D002478:Cells, Cultured; D013286:Datura stramonium / Q000235:genetics / Q000378:metabolism*; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D005974:Glutamate-Ammonia Ligase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000096:biosynthesis*; D005973:Glutamine / Q000096:biosynthesis*; D009682:Magnetic Resonance Spectroscopy; D008717:Methionine Sulfoximine / Q000494:pharmacology; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010946:Plants, Medicinal; D010947:Plants, Toxic; D013045:Species Specificity; D013535:Suspensions; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis*
chemical_list: D000470:Alkaloids; D004791:Enzyme Inhibitors; D010940:Plant Proteins; D013535:Suspensions; D005973:Glutamine; D008717:Methionine Sulfoximine; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005974:Glutamate-Ammonia Ligase