- Repetitive batch as an efficient method for preparative scale enzymic synthesis of 5-azido-neuroaminic acid and 15N-L-glutamic acid
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Syntheses of both title compounds have been achieved on a multigram scale by enzymic synthesis. For multiple use the enzymes were recovered by means of ultrafiltration. 5-Azido-neuraminic acid was obtained by enzymic aldol condensation starting from 2-azido-2-deoxy-D-mannose and pyruvic acid with N-acetylneuraminic acid aldolase. 15N-L-glutamic acid was obtained by reductive amination with glutamate dehydrogenase and regeneration of the cofactor. For both systems optimization of reaction conditions led to simplified downstream processing. HPLC-analysis was used to follow the reactions and to verify optical purity.
- Kragl,Godde,Wandrey,Kinzy,Cappon,Lugtenburg
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Read Online
- The 15N labelled L-glutamic acid: Experimental and computational NMR studies
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15N labelled L-glutamic acid is synthesized by the reductive amination of α-ketoglutarate, in the presence of glutamate dehydrogenase (GDH), nicotinamide adenine dinucleotide (NADH) as cofactor and 15NH4Cl as source of isotope 15N. 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 13C 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.
- Vulcu, Adriana,Berghian Grosan, Camelia,Chiriac, Maria,Almasan, Valer
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experimental part
p. 667 - 674
(2012/04/23)
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- Chemo-enzymatic synthesis of specifically stable-isotope labelled L-glutamic acid and 2-oxoglutaric acid
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(3-13C)-(4-13C)-,(5-13C)- and (3,4-13C2)-2-oxoglutaric acid were prepared starting from the simple 13C-enriched compounds: ethyl bromoacetate and paraformaldehyde, via a single reaction scheme on the gram scale in high yield.This reaction scheme allows specific 13C enrichment of every carbon position and any combination of positions. (3-13C)-,(4-13C)-, (5-13C), (3,4-13C2) and (15N)-L-glutamic acid were prepared by converting the corresponding 2-oxoglutaric acids via an enantioselective enzymatic conversion.The labelled L-glutamic acids and 2-oxoglutaric acids were characterized by 1H NMR, 13C NMR and mass spectrometry.
- Cappon, J. J.,Baart, J.,Walle, G. A. M. van der,Raap, J.,Lugtenburg, J.
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p. 158 - 166
(2007/10/02)
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