Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.1.2 (glutamate dehydrogenase)
 4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our objective was to determine the respective roles of the couple glutamine synthetase/glutamate synthase (GS/GOGAT) and glutamate dehydrogenase (GDH) in ammonium and amino acid metabolism during germination and post-germinative growth in the model legume Medicago truncatula Gaertn. For this aim, amino acids were analyzed by HPLC and changes in gene expression of several enzymes involved in N and C metabolism were studied by real-time quantitative reverse transcription-polymerase chain reaction. Among the enzymes studied, GDH showed the highest increase in gene expression (80-fold), specifically in the embryo axis and concomitant with the increase in ammonium content during post-germinative growth. In cotyledons, GDH gene expression was very low. Although in vitro GDH aminating activity was several times higher than its deaminating activity, in vivo 15NH4 incorporation into amino acids was completely inhibited by methionine sulfoximine, a GS inhibitor, indicating that GDH is not involved in ammonium assimilation/detoxification. Changes in the expressions of GS and GOGAT isoforms revealed that GS1b (EC 6.3.1.2) in concert with NADH-dependent GOGAT (EC 1.4.1.14) constitute the major route of assimilation of ammonium derived from reserve mobilization and glutamic acid/glutamine synthesis in germinating M. truncatula seeds. However, during post-germinative growth, although germination was held in darkness, expression of GS2 and Fd-GOGAT (EC 1.4.7.1) increased and expression of GS1b decreased in cotyledons but not in the embryo axis. 2-Oxoglutarate, the substrate of the transamination reaction, was provided by the cytosolic isoform of isocitrate dehydrogenase (EC 1.1.1.42). We suggest that GDH during post-germinative growth, specifically in the developing embryo axis, contributes to ammonium delivery to GS for glutamine synthesis in the absence of primary NO3- assimilation. Interestingly, this reaction also produces reducing power (NADH) in organs deprived of photosynthesis.
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PMID:Respective roles of the glutamine synthetase/glutamate synthase cycle and glutamate dehydrogenase in ammonium and amino acid metabolism during germination and post-germinative growth in the model legume Medicago truncatula. 1499 6

Toxic doses of zinc and cadmium inhibit shoot growth but increase the capacity of several leaf enzymes in dwarf beans (Phaseolus vulgaris L.). Both effects were studied as a function of the metal concentration applied to the plant. There was a linear relationship between the metal content of the primary leaf and the nutrient solution. When leaf metal content exceeded a toxic threshold value, shoot growth became inhibited and an increase in capacity of the following enzymes was measured in the leaf: glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase, malic enzyme, glutamate-oxaloacetate transminase, peroxidase. The threshold values were similar for growth inhibition as well as for enzyme capacity induction. Both effects were strongly correlated to each other, especially under conditions of toxic zinc treatment. Measurement of enzyme capacity might therefore provide a useful criterion for the evaluation of the phytotoxicity of soils, contaminated by zinc and/or cadmium.
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PMID:Induction of enzyme capacity in plants as a result of heavy metal toxicity: dose-response relations in Phaseolus vulgaris L., treated with zinc and cadmium. 1509 10

In amino acid production by coryneform bacteria, study on relationship between change in enzyme activities and production of a target amino acid is important. In glutamate production, Kawahara et al. discovered that the effect of decrease in 2-oxoglutamate dehydrogenase complex (ODHC) on glutamate production is essential (Kawahara et al., Biosci. Biotechnol. Biochem. 61(7) (1997) 1109). Significant reduction of the ODHC activity was observed in the cells under the several glutamate-productive conditions in Corynebacterium glutamicum. Recent progress in metabolic engineering enables us to quantitatively compare the flux redistribution of the different strains after change in enzyme activity precisely. In this paper, relationship between flux redistribution and change in enzyme activities after biotin deletion and addition of detergent (Tween 40) was studied in two coryneform bacteria, C. glutamicum and a newly isolated strain, Corynebacterium efficiens (Fudou et al., Int. J. Syst. Evol. Microbiol. 52(Part 4) 1127), based on metabolic flux analysis (MFA). It was observed that in both species the specific activities of isocitrate dehydrogenase (ICDH) and glutamate dehydrogenase (GDH) did not significantly change throughout the fermentation, while that of the ODHC significantly decreased after biotin depletion and Tween 40 addition. Flux redistribution clearly occurred after the decrease in ODHC specific activity. The difference in glutamate production between C. glutamicum and C. efficiens was caused by the difference in the degree of decrease in ODHC specific activity. The difference in Michaelis-Menten constants or K(m) value between ICDH, GDH, and ODHC explained the mechanism of flux redistribution at the branch point of 2-oxoglutarate. It was found that the K(m) values of ICDH and ODHC were much lower than that of GDH for both strains. It was quantitatively proved that the ODHC plays the most important role in controlling flux distribution at the key branch point of 2-oxoglutarate in both coryneform bacteria. Flux redistribution mechanism was well simulated by a Michaelis-Menten-based model with kinetic parameters. The knowledge of the mechanism of flux redistribution will contribute to improvement of glutamate production in coryneform bacteria.
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PMID:Comparative study of flux redistribution of metabolic pathway in glutamate production by two coryneform bacteria. 1578 16

In rice roots, transient and cell-type-specific accumulation of both mRNA and protein for NADH-dependent glutamate synthase (NADH-GOGAT) occurs after the supply of NH(4) (+) ions. In order to better understand the origin of 2-oxoglutarate for this reaction, we focused on mitochondrial NAD-dependent isocitrate dehydrogenase (IDH) and glutamate dehydrogenase (GDH) in rice roots. Six rice cDNAs encoding a single catalytic (OsIDHa) and two regulatory (OsIDHc;1, OsIDHc;2) IDH subunits and three GDH proteins (OsGDH1-3) were isolated. These genes, except OsGDH3, were expressed in the roots. Real-time PCR analysis showed that OsIDHa and OsIDHc;1 transcripts, but not OsGDH1 and OsGDH2 transcripts, accumulated in a similar manner to NADH-GOGAT mRNA along the crown roots after the supply of different forms of inorganic nitrogen. Furthermore, immunolocalization studies revealed the NH(4) (+) induction of IDHa protein in two cell layers of the root surface, i.e. epidermis and exodermis, where NADH-GOGAT also accumulated. The possible relationship between NADH-GOGAT, IDH and GDH is discussed.
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PMID:Localization of NAD-isocitrate dehydrogenase and glutamate dehydrogenase in rice roots: candidates for providing carbon skeletons to NADH-glutamate synthase. 1612 Jun 87

Utilization of fatty acids such as oleic acid as sole carbon source by the yeast Saccharomyces cerevisiae requires coordinated function of peroxisomes, where the fatty acids are degraded, and the mitochondria, where oxidation is completed. We identified two mitochondrial oxodicarboxylate transporters, Odc1p and Odc2p, as important in efficient utilization of oleic acid in yeast [Tibbetts et al., Arch. Biochem. Biophys. 406 (2002) 96-104]. Yet, the growth phenotype of odc1delta odc2delta strains indicated that additional transporter(s) were also involved. Here, we identify two putative transporter genes, YMC1 and YMC2, as able to suppress the odc1delta odc2delta growth phenotype. The mRNA levels for both are elevated in the presence of glycerol or oleic acid, as compared to glucose. Ymc1p and Ymc2p are localized to the mitochondria in oleic acid-grown cells. Deletion of all four transporters (quad mutant) prevents growth on oleic acid as sole carbon source, while growth on acetate is retained. It is known that the glutamate-sensitive retrograde signaling pathway is important for upregulation of peroxisomal function in response to oleic acid and the oxodicarboxylate alpha-ketoglutarate is transported out of the mitochondria for synthesis of glutamate. So, citric acid cycle function and glutamate synthesis were examined in transporter mutants. The quad mutant has significantly decreased citrate synthase activity and whole cell alpha-ketoglutarate levels, while isocitrate dehydrogenase activity is unaffected and glutamate dehydrogenase activity is increased 10-fold. Strains carrying only two or three transporter deletions exhibit intermediate affects. 13C NMR metabolic enrichment experiments confirm a defect in glutamate biosynthesis in the quad mutant and, in double and triple mutants, suggest increased cycling of the glutamate backbone in the mitochondria before export. Taken together these studies indicate that these four transporters have overlapping activity, and are important not only for utilization of oleic acid, but also for glutamate biosynthesis.
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PMID:Mitochondrial transporters involved in oleic acid utilization and glutamate metabolism in yeast. 1614 Feb 54

In various populations of the cultivated and weedy amaranth species, the electrophoretic patterns of alcohol dehydrogenase (ADH), glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH) and malic enzyme (Me) were studied. In total, 52 populations and two varieties (Cherginskii and Valentina) have been examined. Allozyme variation of this material was low. Irrespective of species affiliation, 26 populations and two varieties were monomorphic for five enzymes; a slight polymorphism of three, two, and one enzymes was revealed in three, nine, and fourteen populations, respectively. A single amaranth locus, Adh, with two alleles, Adh F and Adh S, controls amaranth ADH. Two alleles, common Gdh S and rare Gdh F, control GDH; no heterozygotes at this locus were found. The MDH pattern has two, the fast- and slow-migrating, zones of activity (I and II, respectively). Under the given electrophoresis conditions, the fast zone is diffuse, whereas slow zone is controlled by two nonallelic genes, monomorphic Mdh 1 and polymorphic Mdh 2 that includes three alleles: Mdh 2-F, Mdh 2-N, and Mdh 2-S. Low polymorphism of IDH and Me was also found, though their genetic control remains unknown.
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PMID:[Isozyme analysis in a genetic collection of amaranths (Amaranthus L)]. 1639 55

Isozyme phenotypes were determined for 101 strains of Gibberella fujikuroi and 2 strains of Gibberella nygamai that represent seven biological species (mating populations) isolated from a variety of plant hosts in dispersed geographic locations. Fourteen enzymes were resolved in one or more of three buffer systems. Two of the enzymes, arylesterase and acid phosphatase, were polymorphic within two or more biological species and are suitable for intraspecific studies of population variation. Six enzymes, alcohol dehydrogenase, aspartate aminotransferase, glucose-6-phosphate dehydrogenase, mannitol dehydrogenase, phosphoglucomutase, and phosphogluconate dehydrogenase, were monomorphic in all of the isolates examined. The remaining six enzymes, fumarase, glucose phosphate isomerase, glutamate dehydrogenase (NADP), isocitrate dehydrogenase (NADP), malate dehydrogenase, and triose-phosphate isomerase, could potentially be used to distinguish the different biological species. Mating populations C and D are the most similar, since the mating population C isolates examined had the same isozyme phenotype as did a subset of the isolates in mating population D. Mating population E is the least similar to the other taxa examined. Unique isozyme phenotypes are present but are composed of banding patterns shared among the biological species. This finding supports the hypothesis that these biological species, with the possible exception of mating populations C and D, are reproductively isolated from one another and that no significant gene flow is occurring between them. Isozyme analysis is a useful method to distinguish these closely related biological species. Examination of isozyme phenotypes is more rapid than the present technique, which is based on sexual crosses; can be applied to strains that are not sexually fertile; and is more sensitive than traditional morphological characters, which cannot distinguish more than three or four morphological groups among the seven biological species. While emphasizing the discreteness of the mating populations as biological entities, our isozyme data also reaffirm the close genetic relationship among these groups.
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PMID:Isozyme Variation among Biological Species in the Gibberella fujikuroi Species Complex (Fusarium Section Liseola). 1653 23

Soybean cell suspension cultures grew on defined media with ammonium as the sole nitrogen source if Krebs cycle acids were added. Satisfactory growth was obtained with ammonium salts of citrate, malate, fumarate, or succinate, when compared with the regular medium containing nitrate and ammonium. Little or no growth occurred when ammonium salts of shikimate, tartrate, acetate, carbonate, or sulfate were used. The cells also grew well with l-glutamine as nitrogen source. The specific activities of glutamine synthetase and isocitrate dehydrogenase (nicotinamide adenine dinucleotide phosphate) were lower than in cells grown on a nitrate medium, but ammonium enhanced the activity of glutamate dehydrogenase. Cells of soybean, wheat, and flax have been cultured for an extended period on the ammonium citrate medium.
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PMID:The culture of plant cells with ammonium salts as the sole nitrogen source. 1665 50

Studies with the seeds of soybean, navy bean, pea, and peanut were made to determine the extent of leakage of intracellular enzymes during imbition. Embryos with intact testae from all four species were found to leak detectable activities of either intracellular enzymes of the cytosol (glucose-6-phosphate dehydrogenase) or enzymes found in both the cytosol and organelles (malate dehydrogenase, glutamate dehydrogenase, glutamate oxaloacetate transaminase, and NADP-isocitrate dehydrogenase) after 6 hours imbition at 25 C. Pea and peanut embryos with testae leaked considerably lower levels of activity for these enzymes than did those of soybean and bean. Leakage of mitochondrial marker enzymes (fumarase, cytochrome c oxidase, and adenylate kinase) was not detected from embryos with testae, suggesting that a differential diffusion of intracellular components out of cells occurred. Soybean and bean embryos without testae leaked high, and proportionally (per cent dry seed basis) similar, levels of all cytosol, cytosol-organelle, and mitochondrial marker enzymes and protein during imbibition, indicating that cell membranes were not differential to leakage and that they had ruptured. Pea and peanut embryos without testae leaked detectable activities of all cytosol and cytosol-organelle enzymes, although fumarase was the only detectable mitochondrial marker enzyme leaked, suggesting that some degree of differential leakage may have occurred in these species. The outermost layers of embryo cells of seeds without testae of all four species absorbed and sequestered the nonpermeating pigment Evan's blue after 5 to 15 minutes imbibition, indicating that membranes had ruptured. This occurred to a much lesser extent in seeds with intact testae. Both soybean and bean embryos without testae were observed to disintegrate during imbibition, whereas those of pea and peanut did not. These data indicate that seeds of certain legumes are susceptible to cellular rupture during imbibition when seed coats are damaged or missing.
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PMID:Role of the testa in preventing cellular rupture during imbibition of legume seeds. 1666 92

Understanding the functional genomics and proteomics of plasmodia underpins the development of new approaches to antimalarial chemotherapy. Although genome databanks (e.g. PlasmoDB) and biocomputing tools (e.g. PlasMit, PlasmoAP, PATS) are useful in providing a global albeit predictive view of the myriad of about 5000 genes, only 40% are annotated, with few cases of endorsed subcellular localizations of the corresponding proteins in animal models. Progress in plasmodial protein trafficking has been hampered by the lack of a simple yet reliable method for studying subcellular localization of plasmodial proteins. In this study, we have used a combination of fluorescent markers, organelle-specific probes, phase contrast microscopy, and confocal microscopy to locate a selection of signal peptides from 10 plasmodial proteins in CHO-K1 cells. These eukaryotic cells serve as an in vitro living system for studying the cellular destinations of four mitochondrial-targeted TCA cycle proteins (citrate synthase, CS; isocitrate dehydrogenase, ICDH; branched chain alpha-keto-acid dehydrogenase E1alpha subunit, BCKDH; succinate dehydrogenase flavoprotein-subunit, SDH), two nuclear-targeted proteins (histone deacetylase, HDAC; RNA polymerase, RPOL), two apicoplast-targeted proteins (pyruvate kinase 2, PK2; glutamate dehydrogenase, GDH), and two cytoplasmic resident proteins (malate dehydrogenase, MDH; glycerol kinase, GK). The respective localizations of these malarial proteins have complied with the selected molecular targets, viz. mitochondrial, nuclear and cytoplasmic. Interestingly, MDH that is widely known to be resident in eukaryotic mitochondria was found to be cytoplasmic, probably due to the absence of molecular target sequences. Since the localization of plasmodial proteins is central to the authentication of their pathophysiological roles, this experimental system will serve as a useful a priori approach.
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PMID:A relevant in vitro eukaryotic live-cell system for the evaluation of plasmodial protein localization. 1683 57


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