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:1.4.1.2 (glutamate dehydrogenase)
4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several aspects on regulation of rat brain glutamate dehydrogenase when the enzyme catalyses the reaction of glutamate degradation have been studied. The 2-oxo-glutarate is a competitive inhibitor against glutamate and NADH competes with NAD. The enzyme seems to have three sites of binding for glutamate, two of them bind the alpha and gamma carboxylic groups and the other the NH2-group of glutamate. Between the binding of two -COO- groups, the site on the enzyme which binds the gamma -COO- group of glutamate seems to be more important than the alpha one.
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PMID:[Glutamate dehydrogenase from rat brain. Properties of the enzyme when acting in the direction of glutamate degradation]. 612 74

Experiments were designed to examine the early events in the initiation of glutamate deamination in kidney. Perfused kidneys from methionine sulfoximine-treated rats formed ammonia from [15N]glutamate via the purine nucleotide cycle. The turnover of the 6-amino group of adenine nucleotides to yield ammonia occurred at the rate of 0.30 mumol/g of kidney/min. This rate is 3-4 times larger than in liver and is in agreement with published rates of the purine nucleotide cycle in kidney. The addition of 0.1 mM fluorocitrate to glutamate perfusions stimulated ammonia formation 3 1/2-fold. The turnover of the 6-amino group of adenine nucleotides increased during the first 5 min after adding fluorocitrate to form ammonia predominately from tissue glutamate and aspartate. This turnover correlates with a 3 1/2-fold increase in kidney tissue IMP levels. As the ATP/ADP ratio fell the purine nucleotide cycle was inhibited and glutamate dehydrogenase was stimulated to form ammonia stoichiometric with glutamate taken up from the perfusate. Ammonia formation via glutamate dehydrogenase occurred at a rate of 1.0 mumol/g of kidney/min. Fluorocitrate completely blocked ammonia formation from aspartate in perfusions. The perfused kidney formed ammonia from aspartate via the purine nucleotide cycle at a rate of 1.0 mumol/g of kidney/min. The results indicate a discrete role for aspartate in renal metabolism. Ammonia formation via the purine nucleotide cycle can occur at significant rates and equal to the rate of ammonia formation from glutamate via glutamate dehydrogenase.
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PMID:Early events in the initiation of ammonia formation in kidney. 613 Oct 71

The effect of 3-mercaptopicolinate, an inhibitor of phosphoenolpyruvate carboxykinase [GTP:oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.32], was tested on NH3 formation via the purine nucleotide cycle and glutamate dehydrogenase (EC 1.4.1.2). NH3 excretion in rats increased 70-fold after 48 h of NH4Cl feeding, from 12.2 +/- 4.5 to 862 +/- 190 mumol/mg of creatinine. At 4 h after a single intraperitoneal injection of 3-mercaptopicolinate into NH4Cl-fed rats, NH3 excretion was inhibited by 93%. Kidneys of NH4Cl-fed plus 3-mercaptopicolinate-treated rats, compared with those of NH4Cl-fed rats, showed a 3.5-fold increase in the content of IMP, 5-fold increase in adenylosuccinate, 4-fold increase in aspartate, and a 30% increase in AMP. 3-Mercaptopicolinate completely inhibited NH3 and glucose formation from glutamate in tubules from acidotic rats and NH3 formation from aspartate in kidney perfusion experiments. When transamination in tubules was prevented by 2-amino-4-methoxy-trans-but-3-enoic acid, formation of glucose, but not of NH3, from glutamate was inhibited. 3-Mercaptopicolinate completely inhibited NH3 formation from aspartate in the presence of the aminotransferase inhibitor in kidney tubules. The data show that NH3 can be formed via glutamate dehydrogenase and the purine nucleotide cycle at significant and approximately equal rates. 3-Mercaptopicolinate has no direct effect on NH3 formation via glutamate dehydrogenase, but inhibits that via the purine nucleotide cycle. We conclude that gluconeogenesis is not regulatory for NH3 formation in kidney.
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PMID:The relationship between glutamate deamination and gluconeogenesis in kidney. 613 15

The relationship between chloramphenicol production and nitrogen metabolism in Streptomyces venezuelae was examined in stirred jar cultures under pH control. Nitrogen sources that supported rapid biomass accumulation gave low rates of antibiotic synthesis during growth. This was consistent with a general incompatibility between fast growth and high yields of chloramphenicol. In media where the growth rate was reduced below the attainable maximum by the rate at which nitrogen could be assimilated, chloramphenicol production was associated with biomass accumulation. Enzymes that are potentially associated with nitrogen assimilation pathways were assayed in cultures supplied with nitrogen sources supporting markedly different growth rates. The results indicated that glutamine synthetase and alanine dehydrogenase levels were relatively insensitive to changes in growth rate and nitrogen source depletion. Glutamate dehydrogenase and glutamate synthase, on the other hand, showed high activity in cultures assimilating ammonium nitrogen and markedly decreased activity with poorer nitrogen sources or when ammonium was depleted. If chloramphenicol biosynthesis is coordinately controlled by mechanisms that regulate nitrogen assimilation, glutamate synthase and glutamate dehydrogenase are the most likely enzymes that manifest the regulatory linkage.
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PMID:Nitrogen metabolism and chloramphenicol production in Streptomyces venezuelae. 614 5

The comparative studies are continued on the influence of two tertiary amines, procaine and nicotinoyl-procaine, on isolated heart and skeletal muscle cells in culture. A daily addition of these substances to cell cultures produces an increase in the specific activities of glutamate dehydrogenase and glutamate-oxaloacetate transaminase and an inhibition of alteration in the isoenzyme pattern of lactate dehydrogenase. The presence of procaine or nicotinoyl-procaine, resp., inhibits thymidine incorporation by cells in culture, whereas the incorporation of thymidine is increased after pretreatment of cells with these substances. These results support the findings of an influence of said tertiary amines on the metabolism of cells in culture.
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PMID:[Influence of procaine and nicotinoyl-procaine on enzyme activities, nucleic acid and protein synthesis in primary cultures of heart and skeletal muscle cells of rats (author's transl)]. 615 98

A Neurospora spheroplast assay was used to study the cytotoxicity and mutagenicity of cis platin (cis dichlorodiammine platinum II) in a eukaryote. Mutagenicity was measured by using reversion of several alleles of the am (NH3 assimilatory glutamate dehydrogenase) gene. A mutation (uvs-2) that disables a DNA repair pathway in Neurospora resulted in reduced sensitivity to and elimination of mutability by cis platin. The implications for other eukaryotic systems (including human cells) are discussed.
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PMID:Cytotoxicity and mutagenicity of cis platin assayed in neurospora. 623 55

The metabolism of glucose and glutamine in freshly prepared resting and concanavalin A-stimulated rat thymocytes was studied. Concanavalin A addition enhanced uptake of both glucose and glutamine and led to an increase in oxidative degradation of both substrates to CO2. With variously labelled [14C]glucose, it was shown that the pathways of glucose dissimilation were equally stimulated by the mitogen. A disproportionately large percentage of the extra glucose taken up was converted into lactate, but concanavalin A also caused an increase in the oxidation of pyruvate as judged by the enhanced release of 14CO2 from [2-14C]-, [3,4-14C]- and [6-14C]-glucose. Addition of glutamine did not affect glucose metabolism. The major end products of glutamine metabolism by resting and mitogen-stimulated rat thymocytes were glutamate, aspartate, CO2 and NH3. Virtually no lactate was formed from glutamine. Concanavalin A enhanced the formation of all end products except glutamate, indicating that more glutamine was metabolized beyond the stage of glutamate in the mitogen-activated cells. Addition of glucose caused a significant decrease in the rates of glutamine utilization and conversion into aspartate and CO2 in the absence and in the presence of concanavalin A. In the presence of glucose, almost all nitrogen of the metabolized glutamine was accounted for as NH3 released via the glutaminase and/or glutamate dehydrogenase reactions. In the absence of glucose, part (18%) of the glutamine nitrogen was metabolized by the resting and to a larger extent (38%) by the mitogen-stimulated thymocytes via a transaminase or amidotransferase reaction.
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PMID:Glucose and glutamine metabolism in rat thymocytes. 633 20

5'-p-Fluorosulfonylbenzoyladenosine (5'-FSBA) is a specific affinity label for the inhibitory NADH site of bovine liver glutamate dehydrogenase. Reaction of the enzyme with 5'-FSBA results in the loss of inhibition by high concentrations of NADH with covalent attachment of 0.53 sulfonylbenozyladenosine/subunit, i.e. modification of three subunits of the hexameric enzyme. Equal amounts of N epsilon-(4-carboxybenzenesulfonyl)lysine (Lys-(CBS] and O-(4-carboxybenzenesulfonyl)tyrosine (Tyr-(CBS] are found throughout the course of the reaction (Saradambal, K. V., Bednar, R. A., and Colman, R. F. (1981) J. Biol. Chem. 256, 11866-11872). Modified enzyme, prepared by incubating 2 mg/ml glutamate dehydrogenase with 0.3 mM 3H-labeled 5'-FSBA at pH 8 for 1 h, was carboxymethylated and digested with thermolysin. Two nucleosidyl peptides were isolated by a combination of chromatography on phenyl boronate-agarose, high-performance liquid chromatography in ammonium bicarbonate and high-performance liquid chromatography in trifluoroacetic acid. By comparison of the amino acid analysis and NH2-terminal residue of each isolated peptide with the known amino acid sequence of the enzyme, the peptides were identified as Leu-Gly-Arg-Lys(CBS) and Ile-Gly-His-Tyr(CBS)-Asp. These sequences correspond to residues 417-420 and 187-191, respectively. Lys-420 and Tyr-190 of glutamate dehydrogenase react with 5'-FSBA, and both are apparently located in the NADH inhibitory site.
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PMID:Identification of the lysine and tyrosine peptides labeled by 5'-p-fluorosulfonylbenzoyladenosine in the NADH inhibitory site of glutamate dehydrogenase. 643 99

Previous studies of the amino acid sequence of the NAD-specific glutamate dehydrogenase of Neurospora crassa (EC 1.4.1.2) resulted in the assignments of peptides to four fragments, the longest being the COOH-terminal 669 residues of the protein. A further study of peptides derived by cyanogen bromide cleavage by different separation methods has yielded additional peptides that have provided new information concerning the sequence and has given overlaps of previously known sequences. This has permitted establishment of 313 residues in one sequence (fragment II). This is in addition to a sequence of 43 residues (fragment I) at the NH2-terminal end and a sequence of 669 residues (fragment III) previously established at the COOH-terminal end of the molecule. The present status of our knowledge of the overall sequence is given in the accompanying papers, together with some views regarding the conformation of the protein (Haberland, M.E., Chen, C.-W., and Smith, E.L. (1980) J. Biol. Chem. 255, 7993-8000, and Austen, B.M., Haberland, M.E., and Smith, E.L. (1980) J. Biol. Chem. 255, 8001-8004).
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PMID:Nicotinamide adenine dinucleotide-specific glutamate dehydrogenase of Neurospora crassa. Isolation and sequences of several cyanogen bromide peptides from the NH2-terminal portion of the peptide chain. 644 50

The activity of certain key enzymes involved in glutamic acid metabolism was studied in purified brain mitochondria and in mitochondrial subfractions separated in a discontinuous 1.2--1.6 mol/l sucrose gradient. Alanine aminotransferase and glutamate dehydrogenase were found to be matrix enzymes and aspartate aminotransferase to be associated with the inner mitochondrial membranes. After the purified mitochondria had been separated into 5 subfractions, aspartate aminotransferase and NAD+-dependent isocitrate dehydrogenase were found to be bound to the lighter mitochondrial subfractions settling at the 1.4--1.5 mol/l sucrose boundary while alanine aminotransferase, 4-aminobutyrate transaminase and glutamate dehydrogenase were associated with the heavier subfractions settling below 2.4 mol/l sucrose. The highest specific activity of the given enzymes was found in the subfraction settling at the 1.4--1.5 mol/l sucrose boundary, the only exception being alanine aminotransferase activity, whose maximum was found in the subfractions settling in 1.5 and 1.6 mol/l sucrose. It was concluded that alanine aminotransferase, in conjunction with glutamate dehydrogenase, is linked to NH3 binding and to the oxidation of reduced adenine nucleotides; in addition, alanine aminotransferase is presumed to have the function of transporting glutamate from the mitochondria to the extramitochondrial space.
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PMID:Alanine aminotransferase and some other enzymes in different populations of free brain cortex mitochondria. 645 52


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