THE 15N LABELLED L-GLUTAMIC ACID: EXPERIMENTAL AND COMPUTATIONAL NMR STUDIES

N-15 labelled L-glutamic acid is synthesized by the reductive amination of a-ketoglutarate, in the presence of glutamate dehydrogenase (GDH), nicotinamide adenine dinucleotide (NADH) as cofactor and (NH4Cl)-N-15 as source of isotope N-15. The reaction mixture includes glucose dehydrogenase (GlcDH) and glucose, as electron donor, for NADH regeneration, too. We are also interested in the theoretical calculation of NMR parameters for this compound; the C-13 chemical shifts and coupling constants were calculated by B3LYP (hybrid Becke 3 Lee Yang Parr) density functional method with 6-311+G(d,p) basis set. For chemical shifts and coupling constants prediction the GIAO (Gauge-Induced Atomic Orbital) approximation and the keyword NMR=spinspin respectively were used. Comparison between the experimental and theoretical results indicates that DFT/B3LYP/6-311+G(d,p) method is in good agreement with the experimental data.