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:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The maximal rate (Vmax) of some mitochondrial enzyme activities related to energy transduction (citrate synthase, alpha-ketoglutarate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, NADH-cytochrome c reductase, cytochrome oxidase) and amino acid metabolism (glutamate dehydrogenase, glutamate-pyruvate transaminase and glutamate-oxaloacetate transaminase) are evaluated in non synaptic ("free") and intrasynaptic mitochondria from brain hippocampus. The different mitochondrial populations were isolated from rat subjected to single i.p. treatment with saline solution, almitrine (30 mg/kg) and delta-yohimbine (10 mg/kg). In control rats, the mitochondrial populations exhibit different enzymatic patterns. Acute treatment with almitrine decreases cytochrome oxidase activity in intra-synaptic mitochondria, while acute treatment with delta-yohimbine decreases succinate dehydrogenase activity in both types of free and intra-synaptic mitochondria. NADH-cytochrome c reductase activity is also decreased by acute treatment with almitrine ("free" and "synaptic" mitochondria) and delta-yohimbine (synaptic mitochondria only).
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PMID:Factors involved in drug interference on enzyme activities of three mitochondrial populations from rat hippocampus. 180 34

This study was prompted by the paradox of strong presence of mitochondria in an anaerobic protozoan, recently reclassified from the yeasts. Stemming from publication in 1911 to 1912, Blastocystis hominis has been generally accepted as a harmless intestinal yeast of humans, with short standardized textbook (parasitology) descriptions, even to the present day. Reports since 1967 have changed the classification of B. hominis from yeast to protozoan (Sarcodina), and this has been followed by interest in B. hominis-caused disease, resulting in documentation of disease in humans and other primates. In this study of B. hominis, the basic ultrastructure of the mitochondria was shown by thin-section electron microscopy to be identical to that of an archetypical mitochondrion. There were hundreds of them in large B. hominis cells (100 to 200 microns in diameter). Mitochondria were confined to a peripheral ring of cytoplasm bounded by the outer cell membrane (there is no cell wall) and the membrane of the large, spherical, organelle-free central body that constitutes 75% of the cell's volume. Mitochondria tended to surround the cell's usual two to four nuclei. Rhodamine 123 stained the mitochondria selectively, visualized by fluorescence microscopy. The cell was devoid of cytochromes. Addition of 0.1% cytochrome c to the growth medium increased utilization of glucose by 34% and that of lactate by 17%. Furthermore, it markedly increased the number of mitochondrion-filled cells. At higher concentrations, cytochrome c inhibited the growth of the cells. Despite the presence of large numbers of mitochondria, activities of the mitochondrial enzymes pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, isocitrate dehydrogenase, glutamate dehydrogenase, and cytochrome c oxidase were absent. Thus, the function of the mitochondria in B. hominis remains unknown. Considerable activities of aspartate aminotransferase and alanine aminotransferase were found. Aldolase activity was prominent. Pyruvate decarboxylase was present. Diaphorase and lactate dehydrogenase were detectable but in suspect quantities. Other missing enzymes were gamma glutamyl transpeptidase, alkaline phosphatase (a lysosomal marker), and creatine kinase isoenzymes.
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PMID:Biochemical and ultrastructural study of Blastocystis hominis. 283 9

The RS-isomers of beta-mercapto-alpha-ketoglutarate, beta-methylmercapto-alpha-ketoglutarate and beta-methylmercapto-alpha-hydroxyglutarate have been synthesized. Beta-Mercapto-alpha-ketoglutarate was a potent inhibitor, competitive with isocitrate and noncompetitive with NADP+, of the mitochondrial NADP-specific isozyme from pig heart (Ki = 5 nM; Km (DL-isocitrate)/Ki(RS-beta-mercapto-alpha-ketoglutarate) = 650) and pig liver, the cytosolic isozyme from pig liver (I0.5 = 23 nM), and the NADP-linked enzymes from yeast (Ki = 58 nM) and Escherichia coli (Ki = 58 nM) at pH 7.4 and with Mg2+ as activator. beta-Mercapto-alpha-ketoglutarate was also an effective inhibitor of NADP-isocitrate-dehydrogenase activity in intact liver mitochondria. beta-Mercapto-alpha-ketoglutarate was a much less potent inhibitor for heart NAD-isocitrate dehydrogenase (Ki = 520 nM) than for the NADP-specific enzyme. beta-Methylmercapto-alpha-ketoglutarate (I0.5 = 10 microM) was a much less effective inhibitor than the beta-mercapto derivative for heart NADP-isocitrate dehydrogenase. The beta-sulfur substituted alpha-ketoglutarates were substrates for the oxidation of NADPH by heart NADP-isocitrate dehydrogenase without requiring CO2. beta-Methylmercapto-alpha-hydroxyglutarate, the expected product of reduction of beta-methylmercapto-alpha-ketoglutarate, did not cause reduction of NADP+ but it was an inhibitor competitive with isocitrate for NADP-isocitrate dehydrogenase. The beta-sulfur substituted alpha-ketoglutarate derivatives were alternate substrates for alpha-ketoglutarate dehydrogenase and the cytosolic and mitochondrial isozymes of heart aspartate aminotransferase but had no effect on glutamate dehydrogenase or alanine aminotransferase.
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PMID:beta-Sulfur substituted alpha-ketoglutarates as inhibitors and alternate substrates for isocitrate dehydrogenases and certain other enzymes. 394 94

Metabolism of the glutamate group of amino acids--glutamic acid, gamma-amino-butyric acid, glutamine, aspartic acid and alanine--was studied in the brain of rat as a function of age. The levels of glutamic acid, glutamine and aspartic acid decreased while those of gamma-aminobutyric acid, and alanine increased with age. The results on the activity of the twelve enzymes involved in the metabolism showed that five of them (glutamate dehydrogenase, glutamine synthase, gamma-aminobutyric acid transaminase, succinic semialdehyde dehydrogenase and NAD+-isocitrate dehydrogenase) decreased, while four of them (glutaminase, glutamotransferase, glutamic acid decarboxylase, and alpha-ketoglutarate dehydrogenase) increased. The other three enzymes (aspartate aminotransferase, alanine aminotransferase and NADP+-isocitrate dehydrogenase) did not show any significant change in activity. An age-related increase was seen in alpha-ketoglutarate and ammonia, the intermediates involved in the metabolism of these amino acids. The changes in the level of these amino acids are discussed in relation to the altered energy metabolism during aging.
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PMID:Metabolism of the glutamate group of amino acids in rat brain as a function of age. 614 62

The activities of the mitochondrial FAD-linked glycerophosphate dehydrogenase (m-GDH), glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, glutamate-pyruvate transaminase (GPT) and glutamate-oxaloacetate transaminase were measured in islet and liver homogenates from fetal, neonatal, adult male, adult female, pregnant and lactating rats. Either parallel or dissociated ontogenic changes were observed in islet and liver homogenates. The activity of islet m-GDH was slightly, albeit not significantly, lower in neonates than in adult rats, comparable in male and female adult animals, unaffected by pregnancy, and increased during lactation. It was much higher in fetal or adult islets cultured for 7 days than in freshly isolated islets from adult rats. In cultured islets from adult rats, the increase in m-GDH activity coincided with a dramatic decrease of GPT activity, a situation the mirror image of that found in several animal models of non-insulin-dependent diabetes mellitus. The intrinsic properties of m-GDH, as judged by comparison of measurements made by either a radioisotopic or a colorimetric procedure, were not identical in islet and liver homogenates and differed between fetal and adult islets, suggesting the existence of distinct iso-enzymes. These findings illustrate adaptive changes of islet enzymes, with exclusive or partial mitochondrial location, in ontogenic situations characterized by a remodelling of fuel homeostasis.
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PMID:Ontogeny of FAD-linked glycerophosphate dehydrogenase in rat pancreatic islets. 879 9

The rabbit kidney does not readily metabolize but synthesizes glutamine at high rates by pathways that remain poorly defined. Therefore, the metabolism of variously labeled [13C]- and [14C]glutamates has been studied in isolated rabbit kidney tubules with and without acetate. CO2, glutamine, and alanine were the main carbon and nitrogenous end products of glutamate metabolism but no ammonia accumulated. Absolute fluxes through enzymes involved in glutamate metabolism, including enzymes of four different cycles operating simultaneously, were assessed by combining mainly the 13C NMR data with a new model of glutamate metabolism. In contrast to a previous conclusion of Klahr et al. (Klahr, S., Schoolwerth, A. C., and Bourgoignie, J. J. (1972) Am. J. Physiol. 222, 813-820), glutamate metabolism was found to be initiated by glutamate dehydrogenase at high rates. Glutamate dehydrogenase also operated at high rates in the reverse direction; this, together with the operation of the glutamine synthetase reaction, masked the release of ammonia. Addition of acetate stimulated the operation of the "glutamate --> alpha-ketoglutarate --> glutamate" cycle and the accumulation of glucose but reduced both the net oxidative deamination of glutamate and glutamine synthesis. Acetate considerably increased flux through alpha-ketoglutarate dehydrogenase and citrate synthase at the expense of flux through phosphoenolpyruvate carboxykinase; acetate also caused a large decrease in flux through alanine aminotransferase, pyruvate dehydrogenase, and the "substrate cycle" involving oxaloacetate, phosphoenolpyruvate, and pyruvate.
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PMID:The rabbit kidney tubule simultaneously degrades and synthesizes glutamate. A 13C NMR study. 903 May 22

The effect of various metabolic inhibitors on the rate of oxygen consumption by procyclic culture forms of Trypanosoma congolense utilizing proline as substrate was investigated. Cyanide inhibited the rate of oxygen consumption by 81.0 +/- 6.7%, malonate inhibited the rate by 51.6 +/- 1.6% and Antimycin A by 73.1 +/- 5.9%. A combination of cyanide and malonate inhibited the rate of oxygen consumption by 84.9 +/- 6.7% while a combination of antimycin A and malonate inhibited the rate by 81.6 +/- 7.6%. Rotenone had no effect on the rate of respiration except when the intact cells were first permeabilized by digitonin after which rotenone decreased the rate of respiration by 20-30%. Salicylhydroxamate (SHAM) did not have any effect on the rate of oxygen consumption. Enzymes involved in the catabolism of proline with high activities were: proline dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, fumarase, NADP-linked malic enzyme, alanine aminotransferase and malate dehydrogenase. Activities of 1-pyrroline-5 carboxylate dehydrogenase, glutamate dehydrogenase, aspartate aminotransferase and NAD-linked malic enzyme were detectable but lower. The end products of proline catabolism were alanine and glutamate. Unlike the case in Trypanosoma brucei brucei aspartate was not detected. Possible pathways of proline catabolism in procyclic culture forms of T. congolense and of electron transfer are proposed.
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PMID:Catabolism of proline by procyclic culture forms of Trypanosoma congolense. 1042 13

Exposure to hyperoxia (500-600 torr) or low pH (4.5) for 72 h or NaHCO(3) infusion for 48 h were used to create chronic respiratory (RA) or metabolic acidosis (MA) or metabolic alkalosis in freshwater rainbow trout. During alkalosis, urine pH increased, and [titratable acidity (TA) - HCO(-)(3)] and net H(+) excretion became negative (net base excretion) with unchanged NH(+)(4) efflux. During RA, urine pH did not change, but net H(+) excretion increased as a result of a modest rise in NH(+)(4) and substantial elevation in [TA - HCO(-)(3)] efflux accompanied by a large increase in inorganic phosphate excretion. However, during MA, urine pH fell, and net H(+) excretion was 3.3-fold greater than during RA, reflecting a similar increase in [TA - HCO(-)(3)] and a smaller elevation in phosphate but a sevenfold greater increase in NH(+)(4) efflux. In urine samples of the same pH, [TA - HCO(-)(3)] was greater during RA (reflecting phosphate secretion), and [NH(+)(4)] was greater during MA (reflecting renal ammoniagenesis). Renal activities of potential ammoniagenic enzymes (phosphate-dependent glutaminase, glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, alanine aminotransferase, phosphoenolpyruvate carboxykinase) and plasma levels of cortisol, phosphate, ammonia, and most amino acids (including glutamine and alanine) increased during MA but not during RA, when only alanine aminotransferase increased. The differential responses to RA vs. MA parallel those in mammals; in fish they may be keyed to activation of phosphate secretion by RA and cortisol mobilization by MA.
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PMID:Renal responses of trout to chronic respiratory and metabolic acidoses and metabolic alkalosis. 1044 55

Five synthetic, conformationally restricted alpha-ketoglutarate analogues were tested as substrates of a variety of dehydrogenases and aminotransferases. The compounds were found not to be detectable substrates of glutamate dehydrogenase, L-leucine dehydrogenase, L-phenylalanine dehydrogenase, lactate dehydrogenase, malate dehydrogenase, glutamine transaminase K, aspartate aminotransferase, alanine aminotransferase, and alpha-ketoglutarate dehydrogenase complex. However, two thermostable aminotransferases were identified that catalyze transamination between several L-amino acids (e.g., phenylalanine, glutamate) and the alpha-ketoglutarate analogues of interest. Transamination between L-glutamate (or L-phenylalanine) and the alpha-ketoglutarate analogues was found to be 0.13 to 1.08 micromol/h/mg at 45 degrees C. The products resulting from transamination between L-phenylalanine and the alpha-ketoglutarate analogues were separated by reverse-phase HPLC, and the newly formed amino acid analogues were analyzed by LC-MS in an ion selective mode. In each case, the ions obtained were consistent with the expected product and a representative example is provided. The possibility existed that although the alpha-ketoglutarate analogues are not substrates of the dehydrogenases and most of the aminotransferases investigated, they might be good inhibitors. Weak inhibition of aminotransferases and glutamate dehydrogenase was found with some of the alpha-ketoglutarate analogues. The newly available thermostable aminotransferases may have general utility in the synthesis of bulky L-amino acids from the corresponding alpha-keto acids.
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PMID:Analysis of conformationally restricted alpha-ketoglutarate analogues as substrates of dehydrogenases and aminotransferases. 1170 Sep 82

The effect of weaning on a potential metabolic capacity of key enzymes involved in the energy production by porcine enterocytes was investigated. The activity of citrate synthase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase was determined in the small intestine epithelium of piglets during suckling-weaning transition. Investigations were performed on 5-week-old (suckling), 6-week-old (1st week after weaning) and 7-week-old (2nd week after weaning) piglets. The activity of glutamate dehydrogenase decreased (p < 0.05) during the 1st week after weaning, and remained numerically lower during the 2nd week after weaning than in suckling piglets. The activities of isocitrate dehydrogenase and alanine aminotransferase showed the same pattern as the glutamate dehydrogenase activity and decreased numerically during the 1st and 2nd weeks. The activities of citrate synthase and alpha-ketoglutarate dehydrogenase were numerically lower in post-weaned piglets (1st and 2nd weeks) than in suckling piglets. In contrast, the activity of aspartate aminotransferase was high and remained unchanged from week 5 to the 2nd week post-weaning. The activities of alanine and aspartate aminotransferase were positively correlated in suckling piglets (r = 0.98, p < 0.05) and at the 1st week after weaning (r = 0.99, p < 0.01). Also, both aminotransferases were positively correlated to the activity of alpha-ketoglutarate dehydrogenase in suckling piglets (r = 0.95, p < 0.05 and r = 0.95, p < 0.05) and to the activity of isocitrate dehydrogenase during the 1st week after weaning (r = 0.99, p < 0.001 and r = 0.99, p < 0.01). The results indicate additional capacity of the tricarboxylic acid (TCA) cycle for transformation of alpha-ketoglutarate from other sources than acetyl-CoA such as glutamine, glutamate and other amino acids. Further, the high activity of aspartate aminotransferase also suggests a high capacity of porcine small intestinal epithelium to provide the TCA cycle with oxaloacetate during the suckling-weaning transition.
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PMID:Activity of enzymes involved in energy production in the small intestine during suckling-weaning transition of pigs. 1211 42


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