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)

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

1. Factors regulating the release of alanine and glutamine in vivo were investigated in starved rats by removing the liver from the circulation and monitoring blood metabolite changes for 30 min. 2. Alanine and glutamine were the predominant amino acids released into the circulation in this preparation. 3. Dichloroacetate, an activator of pyruvate dehydrogenase, inhibited net alanine release: it also interfered with the metabolism of the branched-chain amino acids valine, leucine and isoleucine. 4. L-Cycloserine, an inhibitor of alanine aminotransferase, decreased alanine accumulation by 80% after functional hepatectomy, whereas methionine sulphoximine, an inhibitor of glutamine synthetase, decreased glutamine accumulation by the same amount. 5. It was concluded that: (a) the alanine aminotransferase and the glutamine synthetase pathways respectively were responsible for 80% of the alanine and glutamine released into the circulation by the extrasplanchnic tissues, and extrahepatic proteolysis could account for a maximum of 20%; (b) alanine formation by the peripheral tissues was dependent on availability of pyruvate and not of glutamate; (c) glutamate availability could influence glutamine formation subject, possibly, to renal control.
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PMID:Factors regulating amino acid release from extrasplanchnic tissues in the rat. Interactions of alanine and glutamine. 0 55

In the nerve tissue with proliferating macroglia cells were observed a lowered oxygen consumption, an increased aerobic glycolysis and alanine formation and a higher alanine aminotransferase and glutamate dehydrogenase activity than in the control tissue in the homogenates and in the cell sap fraction. The substrate saturation curves, apparent Km and pH optimum values in the tissue with proliferating macroglia and in the control did not differ from one another. The authors assume that a higher alanine aminotransferase activity in the tissue with macroglia proliferation can reflect either a higher synthesis of the enzyme in the altered tissue, or a predominance of glial elements in the altered tissue possessing a higher alanine aminotransferase activity than the nerve cells.
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PMID:Alanine formation and alanine aminotransferase activity in the nerve tissue with proliferating macroglia. 0 40

The cerebral metabolic effects of 2.5, 5, 7.5, 10, 20, 30 and 60 min exposure to 1% CO were studied in lightly anesthetized rats by measurement of cerebral cortical contents of selected glycolytic and citric acid cylce intermediates, as well as tissue energy phosphates. The initial change in the glycolytic sequence occurred at 2.5 min with decreases in tissue glucose and glucose-6-phosphate and increases in fructose-1-6-diphosphate which indicated an activation of phosphofructokinase and hexokinase. The "crossover" pattern between glucose-6-phosphate and fructose-1,6-diphosphate was present at 5, 7.5 and 10 min, but not at 20, 30 and 60 min and thus confirmed previous observations that detection of phosphofructokinase activation in acute unifactorial cerebral hypoxia requires tissue study during the early phases of the experimental exposure. The initial activation of phosphofructokinase occurred in the absence of detectable changes in the tissue content of ATP, ADP, AMP or phosphocreatine and therefore suggested that an imbalance of tissue energy homeostasis is not a prerequisite for the activation of glycolysis in CO intoxication. One percent CO resulted in an increasing malate/oxaloacetate ratio at 5 min, followed by a decrease in alpha-ketoglutarate and aspartate at 7.5 min which suggested a shift in the aspartate aminotransferase reaction towards the replenishment of oxaloacetate removed via the malate dehydrogenase reaction. Subsequent increases in alpha-ketoglutarate at 10, 20, 30 and 60 min were associated with increases in alanine, indicating a contributing role for a secondary shift of the alanine aminotransferase reaction in the replenishment of alpha-ketoglutarate. A comparison of the CO induced changes in the glycolytic and citric acid cycle pathways with those seen in acute hypoxemia indicates no basic qualitative differences in the metabolic responses of brain tissue to the two conditions.
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PMID:Cerebral carbohydrate metabolism during acute carbon monoxide intoxication. 1 62

In an earlier report from this laboratory, one of the early manifestations of hypervitaminosis A was shown to be a marked stimulation of hepatic gluconeogenesis. In the present study, effects of feeding 30,000 IU of retinyl palmitate to young rats (80-100 g), once daily, for 2 days on the incorporation of 14C-labeled precursors into glucose and glycogen by liver slices, levels of amino acids in blood and tissues, and activities of some important amino acid catabolizing enzymes in the liver were investigated. A stimulation of hepatic gluconeogenesis in hypervitaminosis A was indicated by the increased incorporation of 14C-labeled alanine and bicarbonate into glucose and glycogen by liver slices. Excessive intake of retinol caused a marked increase in the activities of hepatic alanine aminotransferase and ornithine aminotransferase and a decrease in that of tryptophan pyrrolase, without affecting those of tyrosine aminotransferase and serine dehydratase. The ratio of NADH:NAD in the livers of rats fed excess retinol was significantly increased. It is suggested that enhancement of glucoeogenesis in hypervitaminosis A is caused by a stimulation of gluconeogenic activity of the liver.
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PMID:Early effects of hypervitaminosis A on gluconeogenic activity and amino acid metabolizing enzymes of rat liver. 2 Apr 86

Biochemical studies on the two transaminases GOT and GPT of swine kidney worm Stephanurus dentatus have been made. GOT has been found much more active than GPT. Enzyme activities are based on the formation of oxaloacetate (GOT) or pyruvate (GPT) from aspartic acid and alanine respectively with oxoglutarate. A linear relationship is observed between the enzyme concentration and activity. GOT shows a maximum activity at pH 8.0 and Michaelis constant 9 X 10(-3) M for male and 2.9 X 10(-3) M for female. GPT has an optimum pH of 7.5 and a Michaelis constant 19 X 10(-3) M for male and 8 X 10(-3) M for female. The optimum temperature for both GOT and GPT was 60 degrees C.
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PMID:Studies on glutamic-oxalacetic (GOT) and glutamic-pyruvic (GPT) transaminases of swine kidney worm Stephanurus dentatus (Diesing, 1839). I. Assay and general properties. 2 9

Subcellular distribution and some physicochemical properties of alanine aminotransferase in striated muscles of the crayfish, trout, carp, frog, pigeon and rabbit were studied. It was established that: (1) Alanine aminotransferase activity in all mentioned animals occurred almost entirely in the cytosolic fraction of the muscles. Total activity and activity per mg protein were highest in crayfish and pigeon muscles and lowest in carp and trout muscles. (2) The pH optimum for the muscles of homoiotherms and poikilotherms ranged from 7.5 to 8, Km values for L-alanine were of the order 10(-3)--10(-2) M and those for alpha-ketoglutarate 10(-4) M. (3) A 10 degree C temperature increase of the incubation medium was accompanied by a 70--90% increase in activity. (4) The higher the alanine aminotransferase activity of the muscles, the relatively higher their alanine production during electrical stimulation. (5) From the above results it is concluded that alanine aminotransferase in striated muscles regulates the rate of glycolysis and energy production under conditions of anaerobiosis through the formation of alanine.
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PMID:Subcellular distribution and some properties of alanine aminotransferase in striated muscles of the crayfish, trout, carp, frog, pigeon and rabbit. 3 68

Chronic ammonia toxicity in experimental mice was induced by exposing them for 2 and 5 days to 5 % (v/v) ammonia solution. The enzymes concerned with glutamate metabolism (aspartate-, alanine- and tyrosine aminotransferases, glutamate dehydrogenase and glutamine synthetase) and (Na+ + K+)-ATPase were estimated in the three regions of brain (cerebellum, cerebral cortex and brain stem) and in liver. Glutamate, aspartate, alanine, glutamine and GABA, RNA and protein were also estimated in the three regions of brain and liver. A significant rise in the activity of (Na+ + K+)-ATPase in all the three regions of brain along with a fall in the activity of alanine aminotransferase was noticed. Changes in the activities of other enzymes were also observed. A significant increase in alanine and a decrease in glutamic acid was observed while no change was observed in the content of other amino acids belonging to the glutamate family. As a result of this, changes in the ratios of glutamate/glutamine and glutamate + aspartate/GABA was observed. The results indicated that the brain was in a state of more depression and less of excitation. Under these conditions the liver tissue was showing a profound rise in the activity of the enzymes of glutamate metabolism. The results are further discussed.
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PMID:Chronic metabolic effects of ammonia in mouse brain. 9 19

Alanine aminotransferase activity is present in mitochondria and the cell sap fraction of the rat myocardium. As distinct from the cell sap form, mitochondrial alanine aminotransferase was significantly inhibited by chloride ions, maleate and incubation medium temperatures of over 40 degrees C. Activity of the cell sap enzyme was inhibited by phosphate and stimulated by temperatures of over 40 degrees C. The pH optimum for cell sap alanine aminotransferase was in the region of 8, while for the mitochondrial enzyme it had a wider range (pH 7.3-8.2). D,L-penicillamine, and antagonist of vitamin B6, inhibited alanine aminotransferase activity equally in intact and tritonized mitochondria and in the cell sap fraction. The activity of mitochondrial and cell sap alanine aminotransferease rose in correlation to the stage of ontogenesis, the maximum increase being observed in the cell sap fraction 14-20 days after birth. The addition of coenzyme to the incubation medium did not affect the activity of either mitochondrial or cell sap alanine aminotransferase. The results indicate that there are two different alanine aminotransferase enzymes in the rat heart, with different intracellular localizations and probably with different regulative functions.
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PMID:Some properties of mitochondrial and cell sap alanine aminotransferase of the rat heart. 13 62

1. A reversible transamination reaction between L-glutamate and pyruvate, or L-alanine and 2-oxoglutarate, takes place in the mitochondrial and cell sap fractions of rat brain. 2. The maximum rate of the transamination reaction in both subfractions was observed in the presence of a keto- substrate concentration of 2.5 mM only, but an amino- donor concentration of 20 mM. 3. The apparent Menten-Michaelis constants for pyruvate and 2-oxoglutarate were of a 10(-4) M and for L-glutamate and L-alanine of a 10(-3) M order and were approximately the same for both fractions. 4. The ratio of the initial rate of the L-alanine + 2-oxoglutarate to the L-glutamate + pyruvate transamination reaction in the cell sap and mitochondrial fractions amounted to up to 2. 5. The apparent equilibrium constant derived from the Haldane equation was 7.01 for cell sap alanine aminotransferase and 4 for the mitochondrial enzyme. 6. Increasing pyridoxal-5'-phosphate concentrations in the incubation medium were accompanied by only non-significant stimulation of alanine aminotransferase activity in the mitochondrial and cell sap fractions. 7. A comparison of the kinetic data obtained on mitochondrial and cell sap alanine aminotransferases in vitro with the actual substrate concentrations in the transamination reaction in nervous tissue in vivo indicates that the direction of the transamination reaction in situ seems to be determined simply by compartmentation and by dynamic changes in amino- and keto- substrates in the mitochondrial and cell sap spaces.
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PMID:Kinetics of the alanine aminotransferase reaction in the mitochondrial and cell sap fractions of rat brain. 14 Mar 99


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