Glutamate Dehydrogenases: Enzymology, Physiological Role and Biotechnological Relevance

Santero, Eduardo; Hervás, Ana B.; Canosa, Inés; Govantes, Fernando

doi:10.5772/47767

Cited by 15 publications

(9 citation statements)

References 144 publications

(159 reference statements)

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“…It has been suggested that GDH activity was not necessary for cell growth and functioned only when the ammonium concentration in the environment is extremely high. Under normal circumstances, most of the ammonia is incorporated to glutamate via GS-GOGAT (Santero et al 2012). Therefore, one of the possible reasons for low shoot GDH activity in MR 253 is that GDH was not required to assimilate ammonia.…”

Section: Discussionmentioning

confidence: 97%

Exogenous proline significantly affects the plant growth and nitrogen assimilation enzymes activities in rice (Oryza sativa) under salt stress

Teh

Shaharuddin

et al. 2016

Acta Physiol Plant

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Salinity has been shown to be a major factor contributing to low nitrogen availability in plants. To verify the changes in nitrogen metabolism activity as affected by the exogenous application of proline under salt stress and its relation to salt tolerance, in vitro rice shoot apices were used as a model to study the growth performance and changes in nitrogen assimilation activities in two Malaysian rice cultivars MR 220 and MR 253. Results revealed that salt stress greatly reduced the plant height, shoot nitrate (NO 3 -) content, shoot glutamine synthetase (GS), and root nitrate reductase (NR) activities in both cultivars. Supplementation of proline significantly increased the plant height, number of roots, root NO 3 -content, root NR, and root GS activities under salt stress in both cultivars with greater enhancement in MR 253 than MR 220. The results also indicated that MR 253 possessed higher nitrite reductase (NiR) and glutamate synthase (NADH-GOGAT) activities as compared with MR 220 in all tested treatments. It was suggested that the NO 3 -content, NR, and GS activities played important roles in regulating nitrogen metabolism under salt stress. Taken together, it was concluded that the ability of proline in

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Section: Discussionmentioning

confidence: 97%

Exogenous proline significantly affects the plant growth and nitrogen assimilation enzymes activities in rice (Oryza sativa) under salt stress

Teh

Shaharuddin

et al. 2016

Acta Physiol Plant

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“…Glutamate in bacteria can be synthesized by two alternative routes. One route involves the reductive amination of 2-OG by glutamate dehydrogenase under conditions of nitrogen excess (>1 mM NH 4 + ), as it has a high K m for ammonium and this activity is repressed by NtrC (Hervás et al , 2010; Santero et al , 2012). The disadvantage of this pathway is its extra energy requirement.…”

Section: Discussionmentioning

confidence: 99%

Hierarchical management of carbon sources is regulated similarly by the CbrA/B systems in Pseudomonas aeruginosa and Pseudomonas putida

et al. 2014

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The CbrA/B system in pseudomonads is involved in the utilization of carbon sources and carbon catabolite repression (CCR) through the activation of the small RNAs crcZ in Pseudomonas aeruginosa, and crcZ and crcY in Pseudomonas putida. Interestingly, previous works reported that the CbrA/B system activity in P. aeruginosa PAO1 and P. putida KT2442 responded differently to the presence of different carbon sources, thus raising the question of the exact nature of the signal(s) detected by CbrA. Here, we demonstrated that the CbrA/B/CrcZ(Y) signal transduction pathway is similarly activated in the two Pseudomonas species. We show that the CbrA sensor kinase is fully interchangeable between the two species and, moreover, responds similarly to the presence of different carbon sources. In addition, a metabolomics analysis supported the hypothesis that CCR responds to the internal energy status of the cell, as the internal carbon/nitrogen ratio seems to determine CCR and non-CCR conditions. The strong difference found in the 2-oxoglutarate/glutamine ratio between CCR and non-CCR conditions points to the close relationship between carbon and nitrogen availability, or the relationship between the CbrA/B and NtrB/C systems, suggesting that both regulatory systems sense the same sort or interrelated signal.

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“…via the reductive amination of α-ketoglutarate to L-Glu catalysed by glutamate dehydrogenase (GDH) or via the glutamine synthetase (GS), glutamate synthase (glutamine oxoglutarate aminotransferase; GOGAT) pathway. [56][57][58] Glu is of central importance to the biosynthesis of new proteins as other AAs are synthesised from Glu, using it as a substrate for the amination of appropriate αketoacid C skeletons. The fast rise in the δ 15 N values of Glu reflects the initial incorporation of 15 [NH 4 ] + , with the subsequent decline after 2 days reflecting redistribution of the 15 N into newly synthesised AAs, hence their δ 15 N values rise.…”

Section: Pathways Of Assimilation Of Different N-containing Substratesmentioning

confidence: 99%

Compound-Specific Amino Acid 15N Stable Isotope Probing of Nitrogen Assimilation by the Soil Microbial Biomass Using Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry

Charteris

2019

15N Tracing of Microbial Assimilation, Partitioning and Transport of Fertilisers in Grassland Soils

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RATIONALE: Organic nitrogen (N) greatly exceeds inorganic N in soils, but the complexity and heterogeneity of this important soil N pool make investigations into the fate of N-containing additions and soil organic N cycling challenging. This paper details a novel approach to investigate the fate of applied N in soils, generating quantitative measures of microbial assimilation and of newly synthesized soil protein. METHODS:Laboratory incubation experiments applying 15 N-ammonium, 15 N-nitrate and 15 N-glutamate were carried out and the high sensitivity and selectivity of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) exploited for compound-specific 15 N stable isotope probing ( 15 N-SIP) of extracted incubation soil amino acids (AAs; as N-acetyl, O-isopropyl derivatives). We then describe the interpretation of these data to obtain a measure of the assimilation of the applied 15 N-labelled substrate by the soil microbial biomass and an estimate of newly synthesised soil protein. RESULTS:The cycling of agriculturally relevant N additions is undetectable via bulk soil N content and δ 15 N values and AA concentrations. The assimilation pathways of the three substrates were revealed via patterns in AA δ 15 N values with time, reflecting known biosynthetic pathways (e.g. ammonium uptake occurs first via glutamate) and these data were used to expose differences in the rates and fluxes of the applied N substrates into the soil protein pool (glutamate > ammonium > nitrate). CONCLUSIONS: Our compound-specific 15 N-SIP approach using GC/C/IRMS offers a number of insights, inaccessible via existing techniques, into the fate of applied 15 N in soils and is potentially widely applicable to the study of N cycling in any soil, or indeed, in any complex ecosystem.

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Glutamate Dehydrogenases: Enzymology, Physiological Role and Biotechnological Relevance

Cited by 15 publications

References 144 publications

Exogenous proline significantly affects the plant growth and nitrogen assimilation enzymes activities in rice (Oryza sativa) under salt stress

Exogenous proline significantly affects the plant growth and nitrogen assimilation enzymes activities in rice (Oryza sativa) under salt stress

Hierarchical management of carbon sources is regulated similarly by the CbrA/B systems in Pseudomonas aeruginosa and Pseudomonas putida

Compound-Specific Amino Acid 15N Stable Isotope Probing of Nitrogen Assimilation by the Soil Microbial Biomass Using Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry

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