Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.4.1.4 (glutamate dehydrogenase)
4,358 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activity of the nicotinamide adenine dinucleotide-dependent glutamate dehydrogenase in Bacillus subtilis was influenced by the carbon source, but not the nitrogen source, in the growth medium. The highest specific activity for this enzyme was found when B. subtilis was grown in a minimal or rich medium that contained glutamate as the carbon source. It is proposed that glutamate dehydrogenase serves a catabolic function in the metabolism of glutamate, is induced by glutamate, and is subject to catabolite repression.
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PMID:Regulation of glutamate dehydrogenase in Bacillus subtilis. 611 56

Glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. Glutamate synthase activity has been determined in a number of Neurospora crassa mutant strains with various defects in nitrogen metabolism. Of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutamate requiring) background. These mutants, i and en-am, are so-called enhancers of am; they have been redesignated herein as en(am)-1 and en(am)-2, respectively. Although glutamate synthase levels in en(am)-1 were essentially wild type, the en(am)-2 strain was devoid of glutamate synthase activity under all conditions examined, suggesting that en(am)-2 may be the structural locus for glutamate synthase. Regulation of glutamate synthase occurred to some extent, presumably in response to glutamate requirements. Glutamate starvation, as in am mutants, led to enhanced activity. In contrast, glutamine limitation, as in gln-1 mutants, depressed glutamate synthase levels.
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PMID:Glutamate synthase levels in Neurospora crassa mutants altered with respect to nitrogen metabolism. 615 51

In mouse pancreatic islets the kinetics of insulin secretion and O2 uptake in response to the non-metabolizable leucine analogue (+/-)-BCH (2-endo- aminonorbornane -2-carboxylic acid) were compared. In addition, the fuel-mobilizing effect of (+/-)-BCH was studied with a mitochondrial fraction from islets. (1) Within 2 min 20 mM-(+/-)-BCH markedly enhanced insulin release or O2 consumption by islets respiring in the absence of exogenous fuels. During prolonged exposure to 20 mM-(+/-)-BCH secretion declined more rapidly than O2 uptake. (2) L-Glutamine (10 mM) prevented the decrease of both insulin release and O2 uptake of islets exposed to 20mM-(+/-)-BCH. During the second phase of insulin release in response to 20 mM-(+/-)-BCH + 10 mM-L-glutamine, kinetics of secretion and respiration correlated closely. (3) Initial peaks were consistently seen in the (+/-)-BCH-induced secretory profiles, but never in the respiratory profiles. (4) In contrast with L-glycerol 3-phosphate, L-malate or pyruvate, L-glutamine or L-glutamate maintained low rates of oxidative phosphorylation in B-cell mitochondria. The effects of L-glutamine or L-glutamate were potentiated severalfold by (+/-)-BCH. (5) The effects of other branched-chain amino acids on oxidative phosphorylation resembled their effects on insulin release, redox state of nicotinamide nucleotides and glutamate dehydrogenase activity. (6) The results support the view that (+/-)-BCH stimulates insulin secretion via a primary enhancement of hydrogen supply to the respiratory chain of B-cell mitochondria.
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PMID:Regulation of insulin secretion by energy metabolism in pancreatic B-cell mitochondria. Studies with a non-metabolizable leucine analogue. 637 87

Interaction of the electrolytically prepared dimers of nicotinamide adenine nucleotide, (NAD)2, and nicotinamide adenine nucleotide phosphate, (NADP)2, with lactate, alcohol, glyceraldehyde 3-phosphate, alpha-glycerophosphate, glutamate and glucose-6-phosphate dehydrogenase has been studied using the quenching of protein fluorescence, kinetics of inhibition and the stopped-flow method. It has been shown that these enzymes are able to bind dimers preserving their coenzyme specificity. The most efficient binding of (NAD)2 has been observed in the case of glutamate and lactate (bovine heart) dehydrogenase, the dissociation constants being 6 and 8 microM, respectively. (NADP)2 affinity to glutamate and glucose-6-phosphate dehydrogenase is also fairly high. More detailed studies on the interactions of dimers with alcohol and glutamate dehydrogenase have shown that the binding to the coenzyme binding site is the prerequisite for the association. However, some additional stabilizing interactions with other enzyme groups are not excluded, though (NAD)2 does not bind to the known binding sites of these enzymes, such as the substrate pocket of alcohol dehydrogenase and the regulatory binding sites for ADP and GTP of glutamate dehydrogenase.
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PMID:Binding of NAD and NADP dimers to NAD- and NADP-dependent dehydrogenases. 637 55

14C-labeled bicarbonate was incorporated into trichloroacetic acid-insoluble material by cell suspensions of A. viscosus strain M100 and also into the four-carbon fermentation product, succinate, but not into the three-carbon fermentation product, lactate. The initial step in the conversion of 14C-labeled bicarbonate into both trichloroacetic acid-insoluble material and succinate was catalyzed by the enzyme phosphoenolypyruvate carboxylase, which served to convert the glycolytic intermediate, phosphoenolpyruvate, and bicarbonate to the four-carbon compound, oxalacetate. The metabolic fate of oxalacetate was its conversion to either trichloroacetic acid-insoluble material or succinate. One pathway by which oxalacetate may be metabolized into acid-insoluble material is via its conversion to the biosynthetic precursor aspartate by the action of glutamate aspartate aminotransferase. One source of the alpha-amino group of aspartate was the ammonium ion, which could be incorporated into glutamate, the substrate of the glutamate aspartate aminotransferase reaction, by the action of a reduced nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase whose reducing equivalents could be derived from the nicotinamide adenine dinucleotide phosphate-dependent oxidative reactions of the hexose monophosphate pathway catalyzed by glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Alternatively, oxalacetate was converted to the fermentation product, succinate, through the sequential action of malate dehydrogenase, fumarase, and succinic dehydrogenase. The resolution and partial purification of phosphoenolpyruvate carboxylase, glutamate aspartate aminotransferase, glutamate dehydrogenase, malate dehydrogenase, fumarase, and succinic dehydrogenase are also reported.
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PMID:Carbon dioxide metabolism by Actinomyces viscosus: pathways for succinate and aspartate production. 676 22

The relationship between oxidized nicotinamide adenine dinucleotide (phosphate) [NAD(P)+] transhydrogenase (EC 1.6.1.1) and NAD(P)+ glutamate dehydrogenase in several enteric bacteria which differ slightly in their regulation of nitrogen metabolism was studied. Escherichia coli strain K-12 was grown on glucose and various concentrations of NH4Cl as the sole nitrogen source. In the range of 0.5 to 20 mM NH4Cl, the energy-independent transhydrogenase increased two to threefold. Comparable changes occurred in NAD(P)+-linked glutamate dehydrogenase. NH4Cl concentrations of 20 to 60 mM resulted in relatively constant specific activities for both enzymes. Higher exogenous NH4Cl, however, led to a decline in both activities. Isocitrate dehydrogenase, another potential source of cellular NADPH, was insensitive to NH4Cl limitation. Similar studies in the presence of glutamate and different exogenous NH4Cl concentrations again showed concerted effects on both enzymes. Growth on glutamate as the sole nitrogen source led to severe repression of both transhydrogenase and glutamate dehydrogenase. In Salmonella typhimurium, both enzymes were unaffected by limiting NH4Cl or growth on glutamate as the sole nitrogen source. Both were, however, repressed by growth on aspartate, a potential source of cellular glutamate. Coordinate changes in glutamate dehydrogenase and transhydrogenase were also evident in Klebsiella aerogenes, particularly under conditions in which glutamate dehydrogenase was regulated inversely to glutamate synthetase. Coordinate changes in glutamate dehydrogenase and transhydrogenase in enteric bacteria are discussed in terms of the possible involvement of the latter enzyme as a direct source of NADPH in the ammonia assimilation system.
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PMID:Coregulation of oxidized nicotinamide adenine dinucleotide (phosphate) transhydrogenase and glutamate dehydrogenase activities in enteric bacteria during nitrogen limitation. 678 21

1. A simple, facile one-step method has been devised to measure the stereospecificity of NADP+-linked oxidoreductases. The procedure involves coupling the test enzymes to enzymes of known stereospecificity in the presence of deuterated substrates. The regenerated NADP+ in the coupled reactions is analyzed by PMR for its deuterium content at the carbon-4 position of the nicotinamide ring. 2. It is found that malate dehydrogenase (EC 1.1.1.37), lactate dehydrogenase (EC 1.1.1.27) and glycerate dehydrogenase (EC 1.1.1.29) are A-side stereospecific whereas glutamate dehydrogenase (EC 1.4.1.3) and glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) are B-side stereospecific. 3. Enzymes which can utilize both NAD+ and NADP+ have the same stereospecificity with respect to the coenzyme.
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PMID:A one-step PMR determination of hydrogen transfer stereospecificity of NADP+-linked oxidoreductases. 682 14

beta-Oxidation of polyunsaturated fatty acids was studied with isolated rat liver mitochondria in state 3 or uncoupled conditions. 1. Incubation of mitochondria with docosahexaenoyl-, linolenoyl- or gamma-linolenoylcarnitine resulted in an increase of the absorbance at 340 minus 385 nm. This increased absorbance was due to an accumulation of beta-oxidation intermediates of the polyunsaturated fatty acids, and not to the reduction of nicotinamide nucleotides. 2. Experiments carried out with soluble fractions of liver mitochondria incubated with docosahexaenoyl-CoA and gamma-linolenoyl-CoA indicated that this ultraviolet light-absorption was at least partly caused by acyl-CoA esters having a 2,4(,7)-di(tri)enoyl-CoA structure. 3. The addition of glutamate to mitochondria oxidizing gamma-linolenoylcarnitine decreased the absorbance at 340 minus 385 nm, and simultaneously stimulated respiration. With liver mitochondria isolated from fasted rats, 6 mM glutamate increased the rate of acetoacetate production from gamma-linolenoylcarnitine by 130 and 210% under state 3 and uncoupled conditions, respectively. Glutamate did not have any significant effect on the degradation of oleoylcarnitine. The proposed explanation for these findings is that the glutamate dehydrogenase reaction can function as a source of NADPH for 2,4-dienoyl-CoA reductase. 4. The degradation of gamma-linolenoylcarnitine to ketone bodies was augmented in mitochondria isolated from rats treated with clofibrate or partially hydrogenated marine oil. 5. We conclude that 2,4-dienoyl-CoA reductase is an important auxiliary enzyme in the beta-oxidation of polyunsaturated fatty acids. Induction of this enzyme by clofibrate or by certain high-fat diets increases mitochondrial capacity for the degradation of polyunsaturated fatty acids.
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PMID:Beta-oxidation of polyunsaturated fatty acids having double bonds at even-numbered positions in isolated rat liver mitochondria. 686 Jun 98

Transferred nuclear Overhauser enhancement was used to examine the conformation of NAD+ and NADP+ bound to glucose-6-phosphate dehydrogenase and glutamate dehydrogenase and of NAD+ bound to lactate dehydrogenase. The results demonstrate that the conformation of the nicotinamide-ribose bond is anti for dehydrogenases with A stereospecificity and syn for dehydrogenases with B stereospecificity. In those dehydrogenases that bind both NAD+ and NADP+, significant differences occur in the conformations of the bound nicotinamide coenzymes.
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PMID:Conformations of nicotinamide coenzymes bound to dehydrogenases determined by transferred nuclear Overhauser effects. 687 Nov 63

When ammonia was removed from Chlorella sorokiniana cells, which contain an ammonium-inducible nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH), the activity of this enzyme decayed with a half-life of approximately 8 min. By use of rocket immunoelectrophoresis, indirect immunoprecipitation, and indirect immunoadsorption (coupled with pulse-chase experiments with 35S-labeled sulfate), the rapid initial loss in activity was shown to be due to enzyme inactivation rather than degradation of NADP-GDH antigen. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of immunoprecipitates obtained with anti-NADP-GDH immunoglobulin G showed that enzyme inactivation is accompanied by the conversion of enzyme subunits (Mr = 59,000) to a protein with a molecular weight of 118,000. Because this protein was stable during boiling and in the presence of sodium dodecyl sulfate and high concentrations of mercaptoethanol or dithiothreitol, it was tentatively assumed to be a covalently linked dimer of enzyme subunits. Pulse-chase experiments showed that total NADP-GDH antigen was subject to rapid degradation (t 1/2 = 88 min) in induced cells, and the same degradation rate was maintained after removal of ammonia from induced cells.
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PMID:Turnover of ammonium-inducible glutamate dehydrogenase during induction and its rapid inactivation after removal of inducer from Chlorella sorokiniana cells. 720 42


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