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)

1. The activities of citrate synthase and NAD+-linked and NADP+-linked isocitrate dehydrogenases were measured in nervous tissue from different animals in an attempt to provide more information about the citric acid cycle in this tissue. In higher animals the activities of citrate synthase are greater than the sum of activities of the isocitrate dehydrogenases, whereas they are similar in nervous tissues from the lower animals. This suggests that in higher animals the isocitrate dehydrogenase reaction is far-removed from equilibrium. If it is assumed that isocitrate dehydrogenase activities provide an indication of the maximum flux through the citric acid cycle, the maximum glycolytic capacity in nervous tissue is considerably greater than that of the cycle. This suggest that glycolysis can provide energy in excess of the aerobic capacity of the tissue. 2. The activities of glutamate dehydrogenase are high in most nervous tissues and the activities of aspartate aminotransferase are high in all nervous tissue investigated. However, the activities of alanine aminotransferase are low in all tissues except the ganglia of the waterbug and cockroach. In these insect tissues, anaerobic glycolysis may result in the formation of alanine rather than lactate.
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PMID:Activities of citrate synthase, NAD+-linked and NADP+-linked isocitrate dehydrogenases, glutamate dehydrogenase, aspartate aminotransferase and alanine aminotransferase in nervous tissues from vertebrates and invertebrates. 0 Oct 3

Alkylation at N-1 of the NADP+ adenine ring with 3,4-epoxybutanoic acid gave 1-(2-hydroxy-3-carboxypropyl)-NADP+. Enzymic reduction of the latter, followed by alkaline Dimroth rearrangement and enzymic reoxidation, gave N6-(2-hydroxy-3-carboxypropyl)-NADP+. On the other hand, bromination at C-8 of the NADP+ adenine ring, followed by reaction with the disodium salt of 3-mercaptroproionic acid, gave 8-(2-carboxyethylthio)-NADP+. Carbodimide coupling of the three carboxylic NADP+ derivatives to polyethyleneimine afforded the corresponding macromolecular NADP+ analogues. The carboxylic and the polyethyleneimine derivatives synthesized have been shown to be co-enzymically active with yeast glucose-6-phosphate dehydrogenase, liver glutamate dehydrogenase and yeast aldehyde dehydrogenase. The degree of efficiency relative to NADP+ with the three enzymes ranged from 17% to 100% for the carboxylic derivatives and from 1% to 36% for the polyethyleneimine analogues. On comparing the efficiences with the three enzymes of the N-1 derivatives to the one of the corresponding N6 anc C-8 analogues, the order of activity was N-1 greater than N6 greater C-8, except in the case of the carboxylic compounds with glutamate dehydrogenase, where this order was inverted. None of these modified cofactors were active with pig heart isocitrate dehydrogenase.
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PMID:Preparation of coenzymic activity of soluble polyethyleneimine-bound NADP+ derivatives. 1 99

Activities of 9 enzymes were determined biochemically in the endometrium. In Trial I (five women) 25 mg progesterone were injected i.m. on day 9 of the cycle; and endometrial biopsy taken 24 hours later was compared with endometrium from day 10 and day 21, taken in two untreated cycles from the same volunteers. Similarly, in Trial II (five women) 50 mg progesterone were injected on day 9, biopsy taken on day 11 and compared with days 11 and 21 from untreated cycles. The specific activites of lactate dehydrogenase, isocitrate dehydrogenase (ICDH), malate dehydrogenase, glutamate dehydrogenase, beta-glucuronidase, acid phosphatase (ACP) and alkaline phosphatase (AP) were significantly higher in the secretory phase. Twenty-five milligrams progesterone (after 24 hours) caused increases of some enzymes, significant only for AP. Fifty milligrams (after 48 hours) increased significantly the activity of ICDH and ACP. Biochemical changes, especially increase of ICDH, can be used for detection of the effect of progesterone on the endometrium.
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PMID:Effect of endogenous and exogenous progesterone on human endometrial enzymes. 3 Jul 6

The contributions of NAD-specific and NADP-specific isocitrate dehydrogenases to isocitrate oxidation in isolated intact rat liver mitochondria were examined using DL-threo-alpha-methylisocitrate (3-hydroxy-1,2,3-butanetricarboxylate) to specifically inhibit flux through NADP-specific isocitrate dehydrogenase. Under a range of conditions tested with respiring mitochondria, the rate of isocitrate oxidation was decreased by about 20--40% by inhibition of NADP-isocitrate dehydrogenase, and matrix NADP became more oxidized. (a) For mitochondria incubated with externally added DL-isocitrate and citrate, the rate of isocitrate oxidation obtained by extrapolation to infinite alpha-methylisocitrate concentration was approximately 70% of the uninhibited rate in both state 3 and state 4. (b) With pyruvate plus malate added as substrates of citric acid cycle oxidation and isocitrate generated intramitochondrially, a concentration of alpha-methylisocitrate (400 microM) sufficient for 99.99% inhibition of NADP-isocitrate dehydrogenase inhibited isocitrate oxidation in states 4 and 3 by 21 +/- 6% and 19 +/- 11% (mean +/- SEM), respectively. (c) With externally added isocitrate and citrate, the addition of NH4Cl increased isocitrate oxidation by 3--4-fold, decreased NADPH levels by 30--40% and 2-oxoglutarate accumulation by about 40%. The further addition of 600 microM alpha-methylisocitrate decreased the NH4Cl-stimulated isocitrate oxidation by about 40% and decreased NADPH to about 30% of the level prevailing in the absence of NH4Cl; nevertheless, the rate of isocitrate oxidation was still twice as large in the presence of NH4Cl and alpha-methylisocitrate as in their absence. Experiments were also performed with intact mitochondria incubated with respiratory inhibitors to determine additional factors which might affect the flux through the two isocitrate dehydrogenases. (a) In the coupled reduction of acetoacetate by isocitrate, where the rate of reoxidation of reduced pyridine nucleotides is limited by NAD-specific 3-hydroxybutyrate dehydrogenase, 85--100% of the rate of 3-hydroxybutyrate formation was retained in the presence of 400--900 microM alpha-methylisocitrate. (b) In a system where the rate of isocitrate oxidation is limited by the rate of NADPH reoxidation by glutathione reductase, the rate of glutathione reduction extrapolated to infinite alpha-methylisocitrate concentration was from 20--40% of the uninhibited rate. (c) In the coupled synthesis of glutamate from isocitrate and NH4Cl, where the reoxidation of NADPH and NADH can occur via glutamate dehydrogenase, the rate of glutamate production extrapolated to infinite alpha-methylisocitrate concentration was about 60% of the uninhibited rate.
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PMID:Activities of NAD-specific and NADP-specific isocitrate dehydrogenases in rat-liver mitochondria. Studies with D-threo-alpha-methylisocitrate. 3 61

Tetrahymena pyriformis Wh 14 was grown in Erlenmeyer flasks under continuous stirring at 30 degrees C for three days . After the culture had produced dry matter of about 100 mg HCB was added in acetone at a dose level of 0, 0.001, 0.1 and 1.0 ppm to the culture and incubated for another 7 days. At a dose level of 0.001 ppm the activity of delta-aminolevulinate dehydratase, hexokinase, and pyruvate kinase remained unaffected but was increased for glutamic-oxaloacetic transaminase, glutamic dehydrogenase, isocitrate dehydrogenase, and malate dehydrogenase while 0.1 ppm HCB increased the activity of all enzymes studied, the only exception being glutamic-pyruvic transaminase, the activity of which was depressed by HCB exposure. A concentration of 1.0 ppm HCB depressed the activity of most of the enzymes below control values with the exception of the two mitochondrial enzymes, MDH and ICDH, studied here.
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PMID:Effect of hexachlorobenzene (HCB) on the activity of some enzymes from Tetrahymena pyriformis. 10 53

Influence of ionic strength of incubation medium on the release of adenylate kinase (AK), isocitrate dehydrogenase (IDH) and glutamate dehydrogenase (GDH) from intact and injured rat liver mitochondria has been studied. It has been found that raised ionic strength (mu equal 0.16-0.32) has increased the release of GDH and AK activities - IDH to a lesser degree - for mitochondrial preparations only with damaged inner membrane. Treatment of mitochondria with potassium chloride solution of definite ionic strength has permitted to detect the alteration of these organelles occurring in vivo and in vitro.
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PMID:Influence of ionic strength of incubation medium on the release of some enzymes from rat liver mitochondria. 16 38

Posthepatectomy coma was produced in 13 dogs and the cerebrums were biopsied for analysis of concentrations of glucose, glucose-6-phosphate, dihydroxyacetone-phosphate, phosphoenolpyruvate, pyruvate, lactate, citrate, alpha-ketogulutarate, fumarate, malate, oxaloacetate, adenosinetriphosphate, ammonia, and glutamine as well as for activities of glucokinase, phosphofructokinase, pyruvate kinase, isocitrate dehydrogenase, glutamate dehydrogenase, malate dehydrogenase, and malic enzyme. There were no differences from normal in the brain glycolytic substrate concentrations. Four of the Krebs cycle substrates were significantly reduced, but not differently than in dogs sedated for 24 hours. The glycolytic pathway, Krebs cycle, and related enzyme activities were not significantly altered. Cerebral adenosine triphosphate concentration was unchanged but the concentrations of ammonia and glutamine increased threefold.
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PMID:Effect of total hepatectomy on selected cerebral substrates and enzymes of the glycolytic pathways and Krebs cycle. 17 Jun 98

Oxidoreductases were studied histochemically in 162 cases of neuroectodermal tumors. In order of decreasing activity in the cytoplasma these enzymes could be arranged as follows: NADH diaphorase, lactate dehydrogenase, NADPH diaphorase, glutamate dehydrogenase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase. The weak activity of Krebs cycle enzymes and the relatively strong activity of other oxidoreductases, particularly of lactate dehydrogenase, permits to conclude that glycolysis prevails over oxidative processes in neuroectodermal tumor cells. But this should not be interpreted as a decrease of the Krebs cycle enzymes in astrocytoma and oligodendroglioma cells as compared with their parent cells because the latter themselves display a weak activity of these enzymes. A real decrease of Krebs cycle enzyme activity was established only for tumors, the parent cells of which are characterized by a strong (in choroid-papillomas) or moderate (in ependymomas) activity of these enzymes. Many neuroectodermal tumors, in particular those of astrocytic origin, demonstrate a certain correlation between the amount of cytoplasm and oxidoreductase activity. This results in enzymatic polymorphism of the tumor tissue. A certain similarity was established of the oxidoreductase activity in tumor cells and in reactive hypertophic astrocytes. This indicates that both tumor cells and reactive astrocytes may in certain conditions utilize similar mechanisms of increased metabolism. The oxidoreductase activity correlates not with the grade of anaplasia but with different directions of anaplasia reflected in different variants of neuroectodermal tumors. The concept "anaplasia" includes not only certain degrees of dedifferentiation of tumor cells but, as it has been shown histochemically, also an increase of metabolic processes in the tumor cell cytoplasma.
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PMID:Histochemistry of oxidoreductases, enzymatic polymorphism and anaplasia of neuroectodermal tumors. 18 68

8-Bromoadenine nucleotides were tested as potential substrates and/or inhibitors of mitochondrial processes in intact or disrupted organelles, as substrates of various phosphotransferases, and as allosteric effectors in the reactions catalyzed by phosphofructokinase, isocitrate dehydrogenase, glutamate dehydrogenase, and fructose-1,6-bisphosphatase. 8-BrATP and 8-BrADP are not recognized by the translocase system located in the inner mitochondrial membrane and cannot be used as usbstrates in oxidative phosphorylation and related reactions catalyzed be beef heart submitochondrial membranes. This confirms the high specificity for adenine nucleotides of the mammalian systems involved in energy-yielding and energy-requiring reactions. However, 8-BrATP and 8-BrADP are able to substitute for the natural adenine nucleotides in reactions catalyzed by many phosphotransferases, although their capacity as phosphate donors and acceptors is generally much reduced. On the other hand, in almost all investigated cases, the 8-bromoadenine nucleotides have lost the capability of the natural adenine nucleotides to act as allosteric effectors, indicating that the structural requirements for allosteric activity are more stringent than those for catalytic activity.
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PMID:Enzymatic properties of 8-bromoadenine nucleotides. 22 99

The hepatocyte and haematopoietic cell contents of the liver of the foetal guinea pig were measured over the latter half of gestation. Hepatocytes represented about 30% of liver volume at mid-gestation and this increased to 70-80% by term; cell volume remained fairly constant until 5-7 days before term, then more than doubled. Haematopoietic cells represented about 5% of liver volume at mid-gestation and this progressively fell to <1% by term. At 75% of gestation hepatocytes and haematopoietic cells were prepared from perfused foetal livers by collagenase digestion. Enzyme activity of the hepatocyte was, without exception, similar to that of the whole liver. In general, enzyme activity in the haematopoietic cells was similar to that in erythrocytes, with relatively low values for aldolase, glycerol 3-phosphate dehydrogenase, phosphoglycerate mutase, enolase, lactate dehydrogenase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, isocitrate dehydrogenase, ;malic' enzyme, glutamate dehydrogenase and aspartate aminotransferase. The haematopoietic cell contribution to total enzyme activity in the foetal liver was usually much less than 10% and could thus not account for the major changes in hepatic enzyme activity over the latter half of gestation. Hepatocytes contained hexokinase isoenzymes I and III, aldolase isoenzymes A and B and pyruvate kinase isoenzymes 1, 2 and 4. The haematopoietic cells contained hexokinase isoenzyme I and two additional bands of activity with slightly greater mobility, aldolase isoenzyme A and pyruvate kinase isoenzymes 2 and 4.
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PMID:The distribution of enzyme and isoenzyme activities between parenchymal and haematopoietic cells in the liver of the foetal guinea pig. 43 88


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