15n nuclear magnetic resonance study of ammonium ion assimilation by lemna gibba l
1987
MONSELISE, EDNA BEN‐IZHAK | KOST, DANIEL | PORATH, DAN | Tal, Moshe
¹⁵N Nuclear magnetic resonance (NMR) spectroscopy was used to follow nitrogen assimilation and amino acid production in Lemna gibba L. exposed to 0.4 mM ¹⁵NH₄Cl solution for 24 h. NMR analysis of the ¹⁶N content of the treated plant tissues (aqueous extract) revealed ¹⁵N incorporation into glutamine (N‐amide plus amino‐N or amide‐N only) and glutamic acid and no detectable free ammonium ion. Methionine sulphoximine (MSO), an inhibitor of glutamine synthetase, at 1.0 mM inhibited completely the incorporation of ¹⁵N. In the presence of 0.5 mM azaserine (AZA), a glutamate synthase inhibitor, the incorporation of ¹⁵N was detected only in the amide group of glutamine. The results confirm the involvement of the glutamine synthetase/glutamate synthase (GS/ GOG AT) pathway in the assimilation of ammonium ions.
显示更多 [+] 显示较少 [-]