Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Adaptation of Ehrlich ascites tumor cells to serial cultivation in media with progressively elevated (hypertonic) NaCl content ("high NaCl"-tolerant cells) has resulted in progressive increases of the cellular activities of NAD-dependent glycerol-3-phosphate dehydrogenase (EC 1.1.1.8), NAD-dependent malate dehydrogenase (EC 1.1.1.37), glutamate--oxalacetate transaminase (EC 2.6.1.1), NAD (P)-dependent glutamate dehydrogenase (EC 1.4.1.3), NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42). The activities of glutamate-pyruvate transaminase (EC 2.6.1.2.) and of glycolytic enzymes as phospho-fructokinase (EC 2.7.1.11), glyceraldehydephosphate dehydrogenase (EC 1.2.1.12) and lactate dehydrogenase (EC 1.1.1.27) were only slightly and not in progressive manner (in response to the progressive increase of the environmental NaCl concentration) affected. These changes are discussed with respect to a metabolic pattern of these "high NaCl"-tolerant cells which is compatible with increased energy requirements, especially for active cation transport. It is suggested that these increased cellular enzyme activities reflect an increased transfer of reducing equivalents across mitochondrial membranes (via the "glycerophosphate cycle and the malate-aspartate shuttle") and possibly a stimulated lipid metabolism. These alterations in the level of enzyme activities must be regarded asan adaptive cellular response to the "high NaCl" environment, since readaptation to growth in regular isotonic media resulted in a reversion to the enzyme pattern characteristic of the parent cells.
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PMID:Changes in enzyme pattern of Ehrlich ascites tumor cells following serial cultivation in media with increased (hypertonic) NaCl content. 12 1

The mitochondrial matrix subfractions from rat liver, kidney cortex, brain, heart, and skeletal muscle were isolated and their protein components were resolved by two-dimensional polyacrylamide gel electrophoresis, revealing between 120 and 150 components for each matrix subfraction. Excellent resolution was obtained utilizing a pH 5 to 8 gradient in the first dimension and in 8 to 13% exponential acrylamide gradient in the second dimension, increasing the number of mitochondrial matrix proteins observed 3-fold over one-dimensional systems. Protein components tentatively identified by co-migration with pure enzymes and by known tissue distributions are carbamoyl-phosphate synthetase (EC 2.7.2.5), ornithine transcarbamylase (EC 2.1.3.3), glutamate dehydrogenase (EC 1.4.1.3), pyruvate carboxylase (EC 6.4.1.1), citrate synthase (EC 4.1.3.7), fumarase (EC 4.2.1.2), aconitase (EC 4.2.1.3), alpha-ketoglutarate dehydrogenase (EC 1.2.4.2), dihydrolipoyl transsuccinylase (EC 2.3.1.12), lipoamide dehydrogenase (EC 1.6.4.3), glutamate-aspartate aminotransferase (EC 2.6.1.1), and the two subunits of pyruvate dehydrogenase (EC 1.2.4.1). Protein components unambiguously identified by peptide mapping are citrate synthase, aconitase, and pyruvate carboxylase. The inner membrane subfraction from rat liver mitochondria was also resolved two dimensionally; the alpha and beta subunits of ATPase (F1) (EC 3.6.1.3) were identified by peptide mapping.
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PMID:Resolution of rat mitochondrial matrix proteins by two-dimensional polyacrylamide gel electrophoresis. 44 63

1. The concentration of HCO3- (independent of any change of pH) exerts different effects on glutamine metabolism in rat kidney-cortex tubules, hepatocytes and enterocytes.2. In kidney tubules HCO3- (10.5-50 MM) has no effect on glutaminase (EC 3.5.1.2), whereas glutamate dehydrogenase (EC 1.4.1.3) is inhibited as HCO3- concentration is increased. The result is that flux through the entire glutamate-to-glucose pathway is inhibited by increasing HCO3- concentrations. A large proportion (more than 30%) of the glutamine removed undergoes complete oxidation. 3. In hepatocytes, and to a smaller extent in enterocytes, HCO3- is an accelerator of glutaminase. Synthesis of glucose and urea from glutamine in hepatocytes increases as HCO3- concentration is increased. Calculations show that fumarate, formed via aspartate aminotransferase and arginino-succinate lyase, is the precursor of the glucose. There is no complete oxidation of the carbon skeleton of glutamine in hepatocytes. 4. Leucine at near-physiological concentrations (0.1-1 mM) is an accelerator of glutaminase in hepatocytes, but not in kidney tubules or in enterocytes. 5. The results are discussed in relation to regulation of acid/base balance in vivo.
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PMID:A role for bicarbonate in the regulation of mammalian glutamine metabolism. 54 52

1. The apparent Michaelis constants of the glutamate dehydrogenase (EC 1.4.1.3), the glutamate-oxaloacetate transaminase (EC 2.6.1.1) and the glutaminase (EC 3.5.1.2) of rat brain mitochondria derived from non-synaptic (M) and synaptic (SM2) sources were studied. 2. The kinetics of oxygen uptake of both populations of mitochondria in the presence of a fixed concentration of malate and various concentrations of glutamate or glutamine were investigated. 3. In both mitochondrial populations, glutamate-supported respiration in the presence of 2.5 mM-malate appears to be biphasic, one system (B) having an apparent Km for glutamate of 0.25 +/- 0.04 mM (n=7) and the other (A) of 1.64 +/- 0.5 mM (n=7) [when corrected for low-Km process, Km=2.4 +/- 0.75 mM (n=7)]. Aspartate production in these experiments followed kinetics of a single process with an apparent Km for glutamate of 1.8-2 mM, approximating to the high-Km process. 4. Oxygen-uptake measurement with both mitochondrial populations in the presence of malate and various glutamate concentrations in which amino-oxyacetate was present showed kinetics approximating only to the low-Km process (apparent Km for glutamate approximately 0.2 mM). Similar experiments in the presence of glutamate alone showed kinetics approximating only to the high-Km process (apparent Km for glutamate approximately 1-1.3 mM). 5. Oxygen uptake supported by glutamine (0-3 mM) and malate (2.5 mM) by the free (M) mitochondrial population, however, showed single-phase kinetics with an apparent Km for glutamine of 0.28 mM. 6. Aspartate and 2-oxoglutarate accumulation was measured in 'free' nonsynaptic (M) brain mitochondria oxidizing various concentrations of glutamate at a fixed malate concentration. Over a 30-fold increase in glutamate concentration, the flux through the glutamate-oxaloacetate transaminase increased 7--8-fold, whereas the flux through 2-oxoglutarate dehydrogenase increased about 2.5-fold. 7. The biphasic kinetics of glutamate-supported respiration by brain mitochondria in the presence of malate are interpreted as reflecting this change in the relative fluxes through transamination and 2-oxoglutarate metabolism.
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PMID:Comparative studies on glutamate metabolism in synpatic and non-synaptic rat brain mitochondria. 88 64

Changes in serum enzyme levels, liver histology and liver function tests have been correlated to determine the usefulness of these tests in assessing liver status. The effects of carbon tetrachloride administration on these parameters has been determined in a group of 20 sheep. Normal levels, elevated levels after injury and the effect of elapsed time after injury are reported for serum glutamic dehydrogenase, sorbitol dehydrogenase, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, lactate dehydrogenase, fructose-1-phosphate adlolase, alkaline phosphatase, cholesterol and proteins. Variation in the time of elevation of enzyme activities may be useful in determining the elapsed time between acute injury and serum sampling. In comparison to sheep fed an adequate diet, a diet with a restricted protein intake was associated with increased severity of histological lesions and decreased liver function.
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PMID:A comparison of parameters used to assess liver damage in sheep treated with carbon tetrachloride. 92 59

This study belongs to a series of comparative biochemical and semiquantitative-histological investigations in renal tissue fractions of pyelonephritis patients (human PN) and of different types of experimental pyelonephritis (experimental PN). The experiments aim at more detailed knowledge on the interrelationship of intermediary cell metabolism and histopathological changes during the different phases of human and experimental PN. The results concerning acid and alkaline phosphatase activities as well as concerning glutaminase I and glutamic dehydrogenase activities were earlier reported (Exp. Path. vols. 8, 9, 10 and 12). In the present study the author has analyzed the activities of aspartate aminotransferase (E.C.2.6.1.1. AspAT) the synonym of which is glutamic oxaloacetic transaminase (GOT).
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PMID:[Aspartate aminotransferase activities in renal tissue during experimental and human chronic pyelonephritis]. 92 89

The histochemical study of the consumption of glutamic acid by way of the aspartate aminotransferase and the glutamic dehydrogenase in the cerebellar cortex of several species of animals have demonstrated that in that nerve centre exists some structures in which the mentioned consumption is specially or exclusively realized by means of one way and not for other different one. Is observed, as well, that in the rats, chicken and lizard, the baskets that surround the Purkinje cells are constituted by basket cells axons and by recurrent collaterals of Purkinje axons and that those structures have an intense aspartate aminotransferase activity, but not glutamic dehydrogenase. The aspartate aminotransferase activity was not observed on the other side, in the perikarya of the Purkinje cells of the related animals. However, there exists intense glutamic dehydrogenase activity. On the other hand, in the toad was not observed baskets with aspartate aminotransferase activity but this enzyme was presented on the other side in the perikarya of the Purkinje cells. All these observations have suggested the possibility that this special utilization of the glutamic acid is in some way concerned with the transmission phenomenons of the nerve impulse.
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PMID:Aspartate aminotransferase activity and glutamic dehydrogenase in the cerebellar cortex in several species of animals. A histochemical study. 102 99

In order to gain insight into the metabolic modifications induced in rat brain tissues by helium-neon (He-Ne) laser irradiation, in the research described here, we investigated the variations in the activity of the enzymes aspartate transferase (AST, EC 2.6.1.4), both cytosolic and mitochondrial, glutamate dehydrogenase (GIDH, EC 1.4.1.3), and total superoxide dismutase (SOD, EC 1.15.1.1), in the brain of rats treated with a very small dose (1.08 J) of He-Ne laser radiation. The rats were sacrificed 4 h after the treatment. The enzymes were evaluated spectrophotometrically in brain extracts of irradiated animals and also in untreated rats (controls) and rats that underwent simulated treatment (stressed). The data obtained from 5-10 animals assayed individually showed that, in the in toto brain tissues of the irradiated rats compared to the stressed rats, there was a marked increase of total SOD, together with an appreciable decrease of cytosolic AST, and insignificant variations in mitochondrial AST and GIDH. Stress alone caused a considerable decrease of total SOD and small but statistically significant increases of s-AST, m-AST, and GIDH.
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PMID:Rat brain metabolism enzyme activity variations following He-Ne laser irradiation. 177 92

To study the effects of ethanol on the hepatotoxicity of N-nitrosodimethylamine (NDMA), 5 mg NDMA/kg body weight was injected intraperitoneally 3 times a week for 6 weeks into rats pair-fed liquid diets containing 36% of energy either as ethanol or as additional carbohydrates. Another group of rats was pair-fed with the same diets but injected with saline instead of NDMA. Co-administration of ethanol and NDMA produced much higher elevations of serum alanine and aspartate aminotransferase and glutamic dehydrogenase activities than the administration of either agent alone. The combined treatment also slightly increased focal necrosis, whereas other liver lesions (steatosis and fibrosis) and the functional impairment of mitochondrial respiration were not affected significantly. Microsomal low Km NDMA demethylation, as well as NDMA denitrosation, were inhibited markedly by incubation with an antibody against P450IIE1, suggesting the involvement of this alcohol-inducible P450 in both NDMA bioactivation reactions. The addition of ethanol inhibited P450-dependent demethylation and denitrosation of NDMA in liver microsomes, whereas both activities were enhanced markedly by chronic ethanol administration. At ethanol concentrations similar to those prevailing in the blood of alcohol-fed animals at the time of NDMA administration, hepatic microsomal demethylation and denitrosation remained significantly higher in ethanol-fed rats given NDMA than in controls. Our results suggest that bioactivation plays a critical role in the hepatotoxicity of NDMA and its aggravation by chronic alcohol consumption.
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PMID:Effects of ethanol consumption on bioactivation and hepatotoxicity of N-nitrosodimethylamine in rats. 185 64


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