The in vivo nitrogen isotope discrimination among organicplant compounds

摘要: Abstract The bulk δ 15 N-value of plant (leaf) biomass is determined by that the inorganic primary nitrogen sources NO 3 − , NH 4 + and N 2 isotope discriminations on their uptake or assimilation. from these transferred into “organic N” mainly glutamine synthetase reaction. involved kinetic effect does not become manifest, because turnover quantitative. From product any further conversion proceeds in a “closed system”, where effects only efficient connection with metabolic branching. central most important corresponding process GOGAT-reaction, de novo binding recycling processes like phenylpropanoid biosynthesis photorespiration. reaction yields relatively N-depleted glutamate remaining glutamine, source N-enriched amide-N heteroaromatic compounds. Glutamate provides for all amino acids some other compounds different N-abundances. An equilibration connected to transamination; relative individual tasks. Relative cell, proteins are generally N-enriched, secondary products chlorophyll, lipids, sugars alkaloids depleted N. Global N-values N-patterns several N-atoms can be calculated those precursors biosyntheses.