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:1.4.3.11 (glutamate dehydrogenase)
4,437 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors have studied the enzymhistochemical and ultrastructural pictures of tenocytes of adult human tendons. High succinate dehydrogenase, cytochrome oxidase, TPN-diaphorase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity were found, as indicated both oxidativ, anaerobic and pentose-phosphate shung activity. Phosphorylase and glutamate dehydrogenase activity was medial, lipase and alcaline phosphatase activity was slight. In tenocytes well developed rough endoplasmic reticulum and GOLGI apparatus, large amount of free ribosomes were found.
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PMID:Histochemical and ultrastructural study of adult human tendon. 23 84

A 250- to 300-fold purification of a nicotinamide adenine denucleotide phosphate (NADP)-dependent glutamate dehydrogenase (GDH, E.C. 1.4.1.4) with a yield of 60% from a thermophilic bacillus is described. More than one NADP-specific GDH was detected by polyacrylamide gel electrophoresis. The enzyme is of high molecular weight (approximately 2 X 10-6), similar to that of the beef and frog liver GDH. The pI of the thermophilic GDH is at pH 5.24. The enzyme is highly thermostable at the pH range of 5.8 to 9.0. The purified GDH, unlike the crude enzyme, was very labile at subzero temperatures. An unidentified factor(s) from the crude cell-free extract prevented the inactivation of the purified GDH at -70 C. Various reactants of the GDH system and D-glutamate also protected, to some extent, the enzyme from inactivation at -70 C. From the Michaelis constants for glutamate (1.1 X 10-2M), NADP (3 X 10-4M), ammonia (2.1 X 10-2M), alpha-ketoglutarate (1.3 X 10-3M), and reduced NADP (5.3 X 10-5M), it is suggested that the enzyme catalyzes in vivo the formation of glutamate from ammonia and alpha-ketoglutarate. The amination of alpha-ketoglutarate and deamination of glutamate by the thermophilic GDH are optimal at the pH values of 7.2 and 8.4, respectively.
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PMID:Purification and properties of glutamate dehydrogenase from a thermophilic bacillus. 23 42

Both the changes in the activities of nitrogenase, glutamine synthetase and glutamate dehydrogenase and in the extracellular and intracellular NH4+ concentrations were investigated during the transition from an NH4+ free medium to one containing NH4+ ions for a continuous culture of Azotobacter vinelandii. If added in amounts causing 80-100% repression of nitrogenase, ammonium acetate, lactate and phosphate are absorbed completely, whereas chloride, sulfate and citrate are only taken up to about 80%. After about 1-2 hrs the NH4+ remaining in the medium is absorbed too, indicating the induction or activation of a new NH4+ transport system. One of the new permeases allows the uptake of citrate in the presence of sucrose. Addition of inorganic NH4+ level leads to a reversible rise in the glutamine synthetase activity which is not prevented by chloramphenicol, and to a reversible decrease in nitrogenase activity. During these measurements glutamate dehydrogenase activity remains close to zero. The intracellular NH4+ level of about 0.6 mM does not change when extracellular NH4+ is taken up and repression of nitrogenase starts.
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PMID:Ammonium uptake by nitrogen fixing bacteria I. Azotobacter vinelandii. 23 60

1. It is shown by limited tryptic digestion of beef liver glutamate dehydrogenase under native conditions that the amino terminus of the polypeptide chain is located at the surface of the molecule. End-group analysis after trypsin treatment yields aspartic acid as the new N-terminal amino acid while the C-terminal threonine remains unchanged. 2. NADH, especially in the presence of 2-oxoglutarate, protects the enzyme against tryptic degradation. In the absence of the coenzyme, glutamate dehydrogenase is rapidly inactivated. 3. The regulatory effects of ADP and GTP are only slightly altered by trypsin. A small shift of the pH dependence of the activation by ADP is observed. 4. The quaternary structure of the unimer of the enzyme is not affected by limited tryptic digestion indicating that the N-terminal part of the polypeptide chain is not located in the contact domains between the polypeptide chains. The association of the hexamer to large associated particles is reduced but not abolished. 5. It is shown by treatment of the enzyme with iodo[2(-14)C]acetic acid as well as with Ellman's reagent that the six - SH groups of the polypeptide chain are buried and not accessible to these reagents in phosphate buffer. In Tris buffer they become exposed and react in the order 89, 55, 197, 115, 270, 319. This together with the result that in Tris buffer the rat of inactivation caused by trypsin is higher than in phosphate buffer indicates that Tris buffer changes drastically the properties of the enzyme. 6. Cross-linking of the enzyme molecule with bifunctional reagents and subsequent dodecylsulfate-polyacrylamide electrophoresis shows that the six identical polypeptide chains are arranged in two groups of three. 7. The implications of these results for the tertiary and quaternary structure of beef liver glutamate dehydrogenase are discussed.
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PMID:Studies of glutamate dehydrogenase: analysis of functional areas and functional groups. 24 Jun 78

Optical characteristics of enzyme-reduced coenzyme complexes of yeast NADP-specific glutamate dehydrogenase have been investigated in the presence and absence of product (L-glutamate) and in the presence or absence of phosphate. The phosphate effect, pointed out in a previous work, is found again: inorganic phosphate (Pi) destabilizes the binary complex (E - NADPH), the dissociation constant of which is equal to 14 muM, a value much higher than that determined in Tris-HCl buffer: Kd = 0.9 muM. Concerning the role of phosphate some assumptions are drawn up with respect to a similar behaviour of Pi toward yeast glutamate dehydrogenase and ADP toward the beef liver enzyme. In the same way, L-glutamate induces a stabilization of the binary complex; this latter effect is unchanged in the presence of phosphate, yet it is less marked than in the case of beef liver glutamate dehydrogenase. Protein fluorescence, nucleotide fluorescence and circular dichroism measurements allowed the determination of three identical and independent NADPH binding sites per hexameric active unit. In analogy with beef liver enzyme, it seems that yeast glutamate dehydrogenase is a good model to study anticooperativity in ligand binding.
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PMID:Binding studies of NADPH to NADP-specific L-glutamate dehydrogenase from Saccharomyces cerevisiae. 24 Jul 22

The rate of transport of L-amino acids by Saccharomyces cerevisiae epsilon 1278b increased with time in response to nitrogen starvation. This increase could be prevented by the addition of ammonium sulfate or cycloheximide. A slow time-dependent loss of transport activity was observed when ammonium sulfate (or ammonium sulfate plus cycloheximide) was added to cells after 3 h of nitrogen starvation. This loss of activity was not observed in the presence of cycloheximide alone. In a mutant yeast strain which lacks the nicotinamide adenine dinucleotide phosphate-dependent (anabolic) glutamate dehydrogenase, no significant decrease in amino acid transport was observed when ammonium sulfate was added to nitrogen-starved cells. A double mutant, which lacks the nicotinamide adenine dinucleotide phosphate-dependent enzyme and in addition has a depressed level of the nicotinamide adenine dinucleotide-dependent (catabolic) glutamate dehydrogenase, shows the same sensitivity to ammonium ion as the wild-type strain. These data suggest that the inhibition of amino acid transport by ammonium ion results from the uptake of this metabolite into the cell and its subsequent incorporation into the alpha-amino groups of glutamate and other amino acids.
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PMID:Inhibition of amino acid transport by ammonium ion in Saccharomyces cerevisiae. 24 Aug 6

Glutamate dehydrogenase have been obtained in crystalline form from purified ox liver nuclear fractions. The enzyme appeared homogeneous, as judged by several electrophoretic techniques at two pH values. A comparative study with the widely known ox liver mitochondrial glutamate dehydrogenase revealed several common features, such as the allosteric effect of the nucleotides ADP and GTP, the activation at high concentrations of the cofactor NAD+, and the existence of a concentration-dependent reversible monomer-polymer(s) equilibrium. However, the two enzymes differed in many other respects. Inorganic phosphate activated nuclear glutamate dehydrogenase to a much greater extent than the mitochondrial enzyme; the substrate NH4+ showed cooperative homotropic interactions only with nuclear glutamate dehydrogenase; kinetic differences were detected with most of the reaction substrates, as well as different rates of oxidative deamination of other L-amino acids, the nuclear enzyme had a higher anodic mobility and a different chromatographic behavior on anionic exchangers. The latter evidence indicates that the glutamate dehydrogenase activity in liver is associated with two proteins which are structurally different, thus confirming the results of a separate immunological study. Preliminary evidence suggests that the enzyme in nuclei is attached to the nuclear envelope, probably the inner membrane, from which it can be solubilized by the addition of salts.
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PMID:Crystallization and partial characterization of glutamate dehydrogenase from ox liver nuclei. 24 85

Glutamate dehydrogenase (L-glutamate:NADP+ oxidoreductase [deaminating], EC 1.4.1.4) has been purified from Escherichia coli B/r. The purity of the enzyme preparation has been established by polyacrylamide gel electrophoresis, ultracentrifugation, and gel filtration. A molecular weight of 300,000 +/- 20,000 has been calculated for the enzyme from sedimentation equilibrium measurements. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate and sedimentation equilibrium measurements in guanidine hydrochloride have revealed that glutamate dehydrogenase consists of polypeptide chains with the identical molecular weight of 50,000 +/- 5,000. The results of molecular weight determination lead us to propose that glutamate dehydrogenase is a hexamer of subunits with identical molecular weight. We also have studied the stability and kinetics of purified glutamate dehydrogenase. The enzyme remains active when heat treated or when left at room temperature for several months but is inactivated by freezing. The Michaelis constants of glutamate dehydrogenase are 1,100,640, and 40 muM for ammonia, 2-oxoglutarate, and reduced nicotinamide adenine dinucleotide phosphate, respectively.
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PMID:Glutamate dehydrogenase from Escherichia coli: purification and properties. 24 44

1. The NADP-linked glutamate dehydrogenase purified from epimastigotes of Trypanosoma cruzi was strongly, but not completely, inhibited by sulfhydryl reagents, in the presence of Tris-HCl or phosphate buffers. 2. The enzyme modified by preincubation with o-iodosobenzoate had a kinetic behaviour different from that shown by the enzyme modified with other inhibitors, such as N-ethylmaleimide or p-chloromercuribenzoate. 3. The inhibition by o-iodosobenzoate was additive with the inhibition by the other reagents tested. 4. It is suggested that two or more different sulfhydryl groups, placed probably near the active site, are involved in these effects.
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PMID:Inhibition of the NADP-linked glutamate dehydrogenase from Trypanosoma cruzi by sulfhydryl reagents. 40 Sep 63

As part of a detailed analysis of the specific enzyme metabolism in individual hypothalamic nuclei during different endocrinological and behavioral states, quantitative distribution of a group of enzymes representative of major metabolic pathways was examined. Malic dehydrogenase (MDH), representative of the citric acid cycle, lactic dehydrogenase (LDH), of glycolysis, glutamic dehydrogenase (GDH), of glutamate metabolism, and glucoseo-6-phosphate dehydrogenase (G-6-PDH), of the pentose pathway, were measured in 11 hypothalamic nuclei, the cerebral cortex, and the cerebellum of adult female rats neonatally treated with testosterone propionate (TP). Several significant metabolic changes occurred in specific hypothalamic nuclei following neonatal TP (1 mg) treatment. MDH activity was significantly reduced in the suprachiasmatic (11%), supraoptic (13%), and anterior (9%) nuclei. No statistically significant changes occurred in nuclei of the middle or posterior hypothalamus. LDH was significantly elevated only in the lateral preoptic areas (23%). Several significant increases of G-6-PDH activity occurred in the following nuclei of the anterior hypothalamus: medial preoptic (32%), lateral preoptic (33%), supraoptic (13%), and paraventricular (23%). No statistically significant changes occurred in nuclei of the middle or posterior hypothalamus; these results were similar to those for MDH and LDH. GDH activity was generally elevated in all of the hypothalamic nuclei examined, except in the anterior nucleus. Significant increases of enzyme level were found in each of the major divisions of the hypothalamus. In the anterior hypothalamus, GDH activity in the paraventricular nucleus rose significantly (16%); in the middle hypothalamus, lateral ventromedial and arcuate nuclear levels were elevated (14 and 17%), and medial and posterior nuclear levels were higher than control values (32 and 36%) in the posterior hypothalamus.
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PMID:Quantitative histochemical studies of the hypothalamus: dehydrogenase enzymes following androgen sterilization. 41 65


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