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)

The effects of zinc on the enzymes of hepatic mitochondria were investigated in rats that had been given zinc sulfate (10 mg Zn2+/100 g body wt) p.o. Administration of zinc caused a marked elevation of succinate dehydrogenase, glutamate dehydrogenase, cytochrome c oxidase and ATPase activities, whereas it did not cause significant changes in pyruvate carboxylase, malate dehydrogenase and isocitrate dehydrogenase activities. The effect of zinc as a function of time was greatest on succinate dehydrogenase. Zinc also produced a marked elevation of ATP concentration in the hepatic cytosol and a corresponding increase in ATPase activity in the hepatic mitochondria. Zinc content of the inner membrane of mitochondria was raised significantly by administration of zinc. The removal of zinc by washing in 10 mM EDTA caused a significant decrease of the increased succinate dehydrogenase activity caused by administration of zinc, while it did not lower ATPase activity. The addition of zinc in amounts of 10-10(3) ng Zn2+ per mg protein produced a significant increase in succinate dehydrogenase activity in the inner membrane of mitochondria, whereas ATPase activity was elevated significantly at 10(3)-10(4) ng Zn2+ per mg protein, indicating that zinc activated succinate dehydrogenase more sensitively than ATPase. The present investigation suggests that zinc taken up by hepatic mitochondria stimulates the electron transport system and oxidative phosphorylation and, as a result, increases the ATP concentration in the hepatic cytosol.
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PMID:Role of zinc as an activator of mitochondrial function in rat liver. 621 62

A postulated zinc-taurine complex, with a zinc affinity intermediate between that for glutamic acid dehydrogenase and the calcium binding protein(s), provides an explanation for a series of seemingly unrelated biochemical and physiological effects of taurine. The proposed complex suggests a central mechanism for the action of taurine, such as a bicarbonate and pH dependent influence on calcium and zinc movements (and vice versa), the osmoregulatory role of taurine, and its effect on the excitation threshold.
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PMID:A central mechanism of action for taurine: osmoregulation, bivalent cations, and excitation threshold. 688 56

The role of blastospores in the protection of Aspergillus parasiticus from high levels of aflatoxins was studied. The strain protects itself from aflatoxicity by forming thick-walled blastospores. The formation of blastospores was not observed under conditions of reduced aflatoxin formation, e.g., under zinc and asparagine deficiencies. The germination of blastospores coincided with an increase in the specific activity of glutamate dehydrogenase (NADP) and a simultaneous decrease in the specific aflatoxin production.
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PMID:Role of blastospores in protecting Aspergillus parasiticus NRRL 3240 from high levels of aflatoxins. 713 1

Glutamate dehydrogenase (L-glutamate: NAD+ oxidoreductase (deaminating) EC 1.4.1.2) has been purified to homogeneity from Lemna minor and seeds of Pisum sativum. As established by polyacrylamide gel electrophoresis the Pisum-enzyme constitutes a multiple pattern of seven charge isoenzymes whereas the Lemna enzyme shows one single protein band. Molecular weights of 230 000 were calculated for both enzymes by sedimentation equilibrium measurements. (Pisum-enzyme) and comparative gel filtration (Lemna-enzyme). Sodium dodecyl sulfate gel electrophoresis and electron microscopic observations revealed that both enzymes are composed of four identical subunits (molecular weight 58 500) arranged in a tetraedric structure. The amino acid compositions of both enzymes are similar to those of various hexameric glutamate dehydrogenases. The N-terminal amino acid of the Pisum-enzyme is alanine. Both enzymes require Ca2+ for maximal catalytic activity. For the Lemna-enzyme the K0.5 values for Ca2+ are 22 microM (NAD+-dependent reaction), respectively. Ca2+ which to some extent can be replaced by Zn2+ does not affect the enzyme aggregation but seems to govern a reversible equilibrium between catalytically active and inactive enzyme forms.
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PMID:Plant NAD-dependent glutamate dehydrogenase. Purification, molecular properties and metal ion activation of the enzymes from Lemna minor and Pisum sativum. 738 42

In contrast to previous reports, an increase in glutamate dehydrogenase activity and no change in arginase activity were observed in rats fed a zinc-deficient diet for 15 weeks. The discrepancies could be due to a difference in degree and duration of zinc-deficiency.
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PMID:Zinc-deficiency and activities of urea cycle-related enzymes in rats. 744 13

We have isolated the NIL1 gene, whose product is an activator of the transcription of nitrogen-regulated genes, by virtue of the homology of its zinc-finger domain to that of the previously identified activator, the product of GLN3. Disruption of the chromosomal NIL1 gene enabled us to compare the effects of Gln3p and of Nil1p on the expression of the nitrogen-regulated genes GLN1, GDH2, and GAP1, coding respectively for glutamine synthetase, NAD-linked glutamate dehydrogenase, and general amino acid permease. Our results show that the nature of GATAAG sequence that serve as the upstream activation sequence elements for these genes determines their abilities to respond to Gln3p and Nil1p. The results further indicate that Gln3p is inactivated by an increase in the intracellular concentration of glutamine and that Nil1p is inactivated by an increase in intracellular glutamate.
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PMID:Role of the GATA factors Gln3p and Nil1p of Saccharomyces cerevisiae in the expression of nitrogen-regulated genes. 756 52

Three prepubertal gilts were each given 100 mg of endotoxin (ET) in their ordinary feed rations, twice daily for 6 days; 3 other gilts received standard feed. Following ET feeding, all animals were injected intravenously (i.v.) with ET (1.0 microgram/kg b.w.) once daily for 5 days. Blood samples were collected and analysed for hematology and total serum bile acids (S-BA), glutamate dehydrogenase (S-GLDH), calcium (S-Ca), iron (S-Fe), zinc (S-Zn) and a blood plasma metabolite (15-ketodihydro-PGF2a; P-PG) of prostaglandin F2a. The animals showed no apparent clinical symptoms following ET-feeding, neither did the blood analyses reveal effects of oral ET. However, when iv ET injections were given, the ET-fed animals showed fewer clinical signs of endotoxemia following the 2nd to 5th injection. S-BA and S-GLDH increased markedly in the standard-fed group following the first injection, while the ET-fed animals showed a much smaller increase in S-BA and no change in S-GLDH on that day. The difference in response may be explained by a direct uptake of ET from the gastrointestinal tract in the ET-fed pigs, making them less sensitive to the injected ET.
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PMID:Reduced response to intravenous endotoxin injections following repeated oral administration of endotoxin in the pig. 814 94

Pyrococcus furiosus is a strictly anaerobic archaeon that grows optimally at 100 degrees C by a fermentative-type metabolism in which complex peptide mixtures such as yeast extract and Tryptone, and also certain sugars, are oxidized to organic acids, H2 and CO2. Enzymes involved in the utilization of peptides such as proteases, aromatic amino transferases, and glutamate dehydrogenase have been previously purified from this organism. It is shown here that P. furiosus also contains significant cytoplasmic concentrations of a new enzyme termed indolepyruvate ferredoxin oxidoreductase (IOR). This catalyzes the oxidative decarboxylation of aryl pyruvates, which are generated by the transamination of aromatic amino acids, to the corresponding aryl acetyl-CoA. IOR is a tetramer (alpha 2 beta 2) of two identical subunits (66,000 and 23,000 Da) with a molecular weight of 180,000. The enzyme contains one molecule of thiamine pyrophosphate and four [4Fe-4S]2+,1+ and one [3Fe-4S]0,1+ cluster, as determined by iron analyses and EPR spectroscopy. Significant amounts of other metals such as copper and zinc were not detected. IOR was virtually inactive at 25 degrees C and exhibited optimal activity above 90 degrees C (at pH 8.0) and at pH 8.5-10.5 (at 80 degrees C). The enzyme was sensitive to inactivation by O2, losing 50% of its activity after exposure to air for 20 min at 23 degrees C, and was quite thermostable, with a half-life of activity at 80 degrees C (under anaerobic conditions) of about 80 min. The Km values (in microM) for indolepyruvate, p-hydroxyphenylpyruvate, phenylpyruvate, CoASH, and P. furiosus ferredoxin, the physiological electron carrier, were 250, 110, 90, 17, and 48, respectively. IOR was inhibited by KCN (apparent Ki = 7.5 mM), but not by CO (1 atm). An enzyme analogous to IOR has not been reported previously. Curiously, it has few properties in common with the pyruvate ferredoxin oxidoreductase of P. furiosus, even though the two enzymes catalyze virtually identical reactions. In fact, of known ketoacid oxidoreductases, the catalytic mechanism of IOR appears to be most similar to that of the pyruvate ferredoxin oxidoreductase from the hyperthermophilic bacterium Thermotoga maritima.
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PMID:Indolepyruvate ferredoxin oxidoreductase from the hyperthermophilic archaeon Pyrococcus furiosus. A new enzyme involved in peptide fermentation. 820 94

The effect of oral intake of endotoxins was studied in 12 prepubertal gilts. The animals were given 30 or 100 mg of ET each in their regular morning feed ration. Blood samples were collected periodically during 24 h and the clinical status, including rectal temperature, was recorded at the same time. Hematological and clinical chemical analyses that included serum bile acids, glutamate dehydrogenase, alkaline phosphatase, calcium, iron, zinc and a blood plasma metabolite of prostaglandin F2 alpha, were done. The animals showed no obvious clinical symptoms following endotoxin feeding. The major findings were increased bile acid and glutamate dehydrogenase values with the most prominent rises being recorded 10-12 h after endotoxin intake. In a later experiment, 6 animals were injected i.v. with endotoxin in doses in the range 0.1-0.5 micrograms/kg b.w. Blood samples were taken and analysed as in the endotoxin-feeding experiment. Within 1 h of injection, all animals showed symptoms such as vomiting, fever and dyspnea. The clinical signs disappeared within 2-5 h. The injections were followed by increases in bile acids, glutamate dehydrogenase and prostaglandin F2 alpha metabolite. To conclude, this study indicates that clinically healthy prepubertal gilts react to ingested endotoxin in feed but that no apparent clinical disturbances ensue.
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PMID:Effects of oral and intravenous administration of endotoxin in prepubertal gilts. 845 2

Severe iron deficiency results in complex systemic disorders e.g., including metabolism of energy and minerals. To investigate whether also moderate iron depletion may alter the activities of citric cycle enzymes and the cytochrome oxidase, the trace element status, and serum enzymes indicative of cell damage, this experiment was carried out with rats supplied with sub-optimal iron (9, 13 and 18 mg iron per kg diet) over a total of 5 weeks. The study included 3 pair-fed groups and an ad libitum group, fed with 50 mg iron/kg diet. All iron-restricted rats were classified as iron-deficient on the basis of reduced iron concentrations in body and iron-depending blood parameters. Body weight gain and catalase activity in kidney were lowered in rats receiving the lowest dietary iron level, exclusively. Rats fed 9 and 13 mg iron per kg diet had nearly 6- and 3-fold, respectively higher platelet counts in blood than their corresponding pair-fed controls. The activities of transaminases ASAT and ALAT, alkaline phosphatase, glutamate dehydrogenase and lactate dehydrogenase in serum which are indicative of cell damage were also markedly influenced by moderate dietary iron restriction, in which the enzyme levels in serum increased with intensifying iron depletion. Although, moderate iron restriction to young male rats was associated with marked alterations in iron status and serum enzymes, the activities of tricarboxylic acid cycle enzymes including malic dehydrogenase, fumarase, and isocitric dehydrogenase as well as cytochrome oxidase in liver remained largely unaffected. Only hepatic aconitase showed a somewhat reduction with iron depletion. Moreover, iron restriction was also accompanied with an accumulation of copper in liver which was significant for rats fed 9 and 13 mg iron per kg diet, whereas zinc status remained completely unaffected by moderate iron deficiency. It can be concluded, that a short-term moderate iron deficiency with ranging hemoglobin concentrations from 66 and 121 g/L, was accompanied with altered platelet counts, serum enzyme activities indicative of cell damage, and hepatic copper concentrations, but the activities of the tricarboxylic acid cycle enzymes and cytochrome oxidase in liver remained largely unaffected.
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PMID:Effect of different degrees of moderate iron deficiency on the activities of tricarboxylic acid cycle enzymes, and the cytochrome oxidase, and the iron, copper, and zinc concentrations in rat tissues. 980 Mar 17


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