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)

The mechanism of ammonia assimilation in Methanosarcina barkeri and Methanobacterium thermoautotrophicum was documented by analysis of enzyme activities, 13NH3 incorporation studies, and comparison of growth and enzyme activity levels in continuous culture. Glutamate accounted for 65 and 52% of the total amino acids in the soluble pools of M. barkeri and M. thermoautotrophicum. Both organisms contained significant activities of glutamine synthetase, glutamate synthase, glutamate oxaloacetate transaminase, and glutamate pyruvate transaminase. Hydrogen-reduced deazaflavin-factor 420 or flavin mononucleotide but not NAD, NADP, or ferredoxin was used as the electron donor for glutamate synthase in M. barkeri. Glutamate dehydrogenase activity was not detected in either organism, but alanine dehydrogenase activity was present in M. thermoautotrophicum. The in vivo activity of the glutamine synthetase was verified in M. thermoautotrophicum by analysis of 13NH3 incorporation into glutamine, glutamate, and alanine. Alanine dehydrogenase and glutamine synthetase activity varied in response to [NH4+] when M. thermoautotrophicum was cultured in a chemostat with cysteine as the sulfur source. Alanine dehydrogenase activity and growth yield (grams of cells/mole of methane) were highest when the organism was cultured with excess ammonia, whereas growth yield was lower and glutamine synthetase was maximal when ammonia was limiting.
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PMID:Ammonia assimilation and synthesis of alanine, aspartate, and glutamate in Methanosarcina barkeri and Methanobacterium thermoautotrophicum. 612 78

Pregnant F-344 rats were exposed by intubation to a single dose (35 mg/kg) of 1,2-dimethylhydrazine dihydrochloride or to an acetate buffer on day 14 of gestation. A detailed examination of the effects of this dose of 1,2-dimethylhydrazine on brush border enzymes in the offspring was performed. Changes in the liver and colon levels of the alpha-glycerophosphate and malate/aspartate substrate cycle enzymes were measured during the development; at days 17 and 20 of gestation and at 2, 6, 13, 20, 27, 55, 110 days and 1 year after birth. It is concluded that metabolic energy enzymes, glutamate oxaloacetate transaminase and malate dehydrogenase, are more sensitive to 1,2-dimethylhydrazine treatment than are the brush border hydrolases or NAD- and Fp-linked alpha-glycerophosphate dehydrogenases.
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PMID:Development of rat liver and colon substrate cycle enzymes in offspring with and without prenatal exposure to a carcinogenic dose of 1,2-dimethylhydrazine. 614 Jan 24

The accumulations by axoplasmic transport of selected enzyme activities proximal and distal to a ligature placed on the sciatic nerve were monitored in rats exposed in utero to maternal antibodies to nerve growth factor (NGF) and in control rats. Littermates of the animals exposed to anti-NGF were shown elsewhere to have had a 70% reduction in the number of sensory neurons in dorsal root ganglia and a 90% reduction in number of neurons in superior cervical (sympathetic) ganglion. The accumulation of F(-)-sensitive acid phosphatase activity was depressed 75% both proximal and distal to the tie. Accumulation of F(-)-resistant acid phosphatase activity was depressed nearly 50% proximal to the tie. Distal accumulation of this activity did not occur in either group of rats. Accumulation of acetylcholinesterase activity was depressed 30%. Distal accumulation of the activities of beta-glucuronidase and hexokinase was depressed 50%. In the lumbar dorsal root ganglia, dry weight was reduced 40%, and the activities of peroxide-sensitive, F(-)-resistant acid phosphatase and of the mitochondrial enzymes hexokinase, glutamic dehydrogenase, glutamic-oxalacetic transaminase, and NAD-dependent isocitric dehydrogenase were all reduced a little more, 45--50% per ganglion. However, the activities of the lysosomal enzymes, F(-)-sensitive acid phosphatase and beta-glucuronidase, of the peroxide-resistant, F(-)-resistant acid phosphatase, and of the mitochondrial enzyme glutaminase were all reduced about 60% per ganglion. The results of these measurements were interpreted to suggest that much, and perhaps all, of the F(-)-sensitive acid phosphatase activity in motion in peripheral nerve in rat is confined to sensory axons.
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PMID:Transported enzymes in sciatic nerve and sensory ganglia of rats exposed to maternal antibodies against nerve growth factor. 616 7

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

1. The acute oral LD50 and chronic LC50 toxicity values for ethylene dibromide (EDB) were estimated for japanese quail. 2. Single sub-acute oral and intraperitoneal doses of EDB (1/2 LD50) and chronic oral doses of EDB (1/3 LC50) were administered to quail in order to characterise the sub-lethal effects of EDB residues. 3. At 24 h after sub-acute dosing, relative liver weight, plasma aspartate aminotransferase (AT) [EC 2.6.1.1] and L-iditol (sorbitol) dehydrogenase (SDH) [EC 1.1.1.14] were elevated and decreases were found in hepatic total lipid, total protein, AT and glutamic dehydrogenase (NAD (P)+) (GDH) and plasma cholinesterase (ChE) [EC 3.1.1.8] and total lipid. 4. Following chronic administration, elevations in relative liver weight, plasma ChE and total lipid, haemoglobin and haematocrit were found and hepatic AT, GDH and total lipid were decreased. 5. The changes in hepatic and plasma enzymes and constituents are discussed in relation to possible biphasic effects resulting from EDB exposure.
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PMID:A study on the toxicity and the biochemical effects of ethylene dibromide in the Japanese quail. 702 16

Fed and fasted rats were injected with L-tryptophan (12.5 mg/100 g body weight) and the specific activities of L-glutamic: NAD oxidoreductase (deaminating) (EC 1.4.1.2) (GDH), L-aspartic-2-ketoglutaric aminotransferase (EC 2.6.1.1) (GOT) and L-alanine-2-ketoglutaric aminotransferase (EC 2.6.1.2) (GPT) from hepatic mitochondria and cytosol were compared. L-tryptophan results in a decrease of mitochondrial GDH activity by 22% and of cytosolic GPT and GOT by 42% and 38% respectively in the liver of fasted rats. Xanthurenate is a potent inhibitor of purified extramitochondrial GPT, whereas anthranilate and quinolinate are less potent inhibitors. L-tryptophan, 5-OH-tryptophan and indole exert a slight inhibition. Kynurenine, 5-OH-tryptamine, tryptamine, picolinic acid, nicotinic acid and indoloacetic acid do not show any inhibition of GPT. It is suggested that L-tryptophan injection inhibits extramitochondrial GPT by its transformation to xanthurenate and anthranilate.
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PMID:Effect of L-tryptophan injection in rats on some enzymes of amino acid metabolism in liver. I. In vitro studies of the effect of L-tryptophan and its metabolites on the extramitochondrial L-alanine: 2-ketoglutaric aminotransferase. 722 74

1. Erythrocytes (RBC) from control and marginally riboflavin-deficient subjects were fractionated into nine fractions using a discrete density gradient. 2. Glutathione reductase (NAD(P)H: glutathione oxidoreductase; EC 1.6.4.2) activity and aspartate aminotransferase (EC 2.6.1.1) activity (with and without the appropriate co-enzymes) reduced glutathione, methaemoglobin, sulphaemoglobin and oxyhaemoglobin and susceptibility to peroxide were measured in RBC in the different fractions. 3. Glutathione reductase and aspartate aminotransferase activities and concentrations of reduced glutathione and oxyhaemoglobin all declined with age, while methaemogloblin, sulphaemoglobin and susceptibility to peroxide increased with age. 4. The only significant differences noted in the RBC from marginally-riboflavin-deficient subjects by comparison with controls, were lower glutathione reductase activities and higher concentrations of methaemoglobin. 5. The role of riboflavin in those systems controlling RBC integrity is discussed.
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PMID:Riboflavin deficiency in man: effects on haemoglobin and reduced glutathione in erythrocytes of different ages. 728 95

The cerebral metabolic effects of intravenous administration of 1000 mg/kg gamma-hydroxybutyrate (GHB) were studied by sequential measurement of the cerebral contents of selected glycolytic-citric acid cycle intermediates and energy phosphates in lightly anesthetized rats. The initial change in the glycolytic pathway occurred by 2.5 min, with increases of tissue glucose-6-phosphate and decreases of fructose-1,6- diphosphate which indicated an inhibition of phosphofructokinase. This pattern was transient and was replaced at 5--15 min by increasing tissue glucose and decreasing glucose-6-phosphate which indicated an inhibition of hexokinase. The initial inhibition of phosphofructokinase was associated with functional depression, an isoelectric EEG and an increase of the tissue phosphocreatine which suggested that the observed metabolic pattern was an adaptation to the reduced energy needs of neuronal depression. Within 2.5 min of GHB injection tissue alpha-ketoglutarate and aspartate showed significant increases which suggested a shift in the aspartate aminotransferase reaction. Preliminary calculations indicated that the probable cause of this shift was an increase in oxaloacetate content due to GHB oxidation. The cytoplasmic NADH/NAD+ ratio remained unchanged throughout the entire exposure to GHB (2.5--180 min) and thus gave no support for the hypothesis that GHB interfers with glycolysis via the restriction of free cytoplasmic NAD+ required for the glyceraldehyde phosphate dehydrogenase step.
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PMID:Sequential alterations of cerebral carbohydrate metabolism associated with gamma-hydroxybutyrate. 735 98

Some analytical parameters have been investigated for a recently described stabilized liquid coenzyme technology in which water-free NAD is dissolved in 1,2 propanediol. Correlation for 108 specimens assayed for AST, ALT and LD with a reference method in which glycol-based NAD was absent was greater than or equal to 0.998 with near identical reproducibility over a period of at least 107 days. Mean recovery of exogenous serum enzymes in this linear kinetic assay is 103%. With the option of mixing only the volume of reagent needed for the enzymatic assay, waste can be eliminated as compared to more costly preparations stabilized by lyophilization. Hazards from an impure water supply are avoided since no reconstituting volume is required.
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PMID:Utilization of a glycol-stabilized liquid NAD for the measurement of three enzymes on the GEMSAEC. 736 51

The oxidation of glutamate by non-synaptic and synaptic mitochondria from brains of 3-, 12- and 24-month-old rats was studied. With glutamate plus malate as substrates, non-synaptic mitochondria showed higher respiration rates than synaptic mitochondria in all the three age groups studied. The rate of oxidation of L-[1-14C]glutamate and the activities of NAD-glutamate dehydrogenase and aspartate aminotransferase were also higher in non-synaptic mitochondria compared with synaptic mitochondria in three age groups. With glutamate plus malate as substrates, a significant reduction in state 3 respiration was observed in both mitochondrial populations from 12- and 24-month-old rats compared with 3-month-old animals. Although an age-dependent decrease in the oxidation of L-[1-14C]glutamate was observed in both non-synaptic and synaptic mitochondria from aging rats, the oxidation of [1-14C]-2-oxoglutarate was unaltered in non-synaptic and synaptic mitochondria from senescent rats. The activity of NAD-glutamate dehydrogenase was decreased with age in both mitochondrial populations, whereas aspartate aminotransferase was not altered with age. The results indicate that the oxidation rate of glutamate in rat brain mitochondria is decreased during aging.
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PMID:Age-dependent changes in glutamate oxidation by non-synaptic and synaptic mitochondria from rat brain. 741 21


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