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 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

Proteolytic aspartate and alanine aminotransferase, beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase activities, contents of phosphocreatine, AMP + IMP, ADP, ATP were studied in the rat musculi gastrocnemius after denervation and blockade of axoplasmic flow, the latter being caused by 0.05 M colchicin solution applied to the sciatic nerve. Two weeks after denervation and the axoflow disturbance all the indices (except the N-acetyl-beta-D-glucoseaminidase activity) showed uniform changes. A month following the colchicin blockade the phosphocreatine and adenylates contents became normal. A conclusion is made on significance of the axoplasmic flow as a factor performing the trophic function of the nervous system.
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PMID:[Effect of axoplasmic flow blockade on enzymic activities and components of the rat muscle adenylate system]. 9 36

Treatment of male guinea-pigs daily with an oral dose of 2 mg dehydroepiandrosterone (DHA) sulphate/100 g body weight for 2 weeks significantly reduced the glucose-6-phosphate dehydrogenase (G-6-PDH) activity of erythrocytes, liver, kidney and testis. Lactate dehydrogenase activity in plasma also decreased, but L-aspartate: 2-oxoglutarate aminotransferase (GOT) and L-alanine:2-oxoglutarate aminotransferase (GPT) activity in plasma remained unaffected. In liver and kidney, however, a significant rise in GOT and GPT was observed. A 2- to 3-7-fold increase of C19-steroids was observed in plasma, liver and kidney. In extracts of liver and kidney more than 60% of steroids were isolated from the sulphatide fraction. Only minor changes were detected in the metabolic pattern of C19-steroids, 17-hydroxysteroids prevailing in the free and sulphatide fractions, while 17-oxosteroids predominated in the sulphate and glucuronide fractions. A slight rise of cyclic AMP concentrations in liver and kidney tissue was attributed to the inhibition of phosphodiesterase by the DHA/G-6-PDH system
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PMID:Effects of exogenous dehydroepiandrosterone sulphate on various enzymes and on steroid metabolism in the guinea-pig. 13 7

The effect of carbon-tetrachloride poisoning and the protection caused by AMP were studied. A single dose of CCl4 has resulted in a rapid development of a fatty liver, a considerable increase in serum enzymes, glutamic oxalacetic and pyruvic transaminases as well as serum-alkaline phosphatase. Total serum protein showed a tendency to decrease accompanied by a decrease in A/G ratio. Administration of adenosine-5-monophosphate prevented the increase in serum-alkaline phosphatase and increased the A/G ratio. There was, however, a slight but significant decrease in serum GOT and GPT within the 24-hrs. period of study, but it remained still higher than that of the control. AMP lowered liver fat without complete protection against the development of fatty liver.
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PMID:Effect of AMP on acute carbon-tetrachloride hepatotoxicity. 20 15

1. The metabolism of glutamine and alanine in the lung was studied in rats made septic by a caecal ligation and puncture technique. 2. The blood glucose concentration was not significantly different in septic rats, but blood pyruvate, lactate, glutamine and alanine concentrations were markedly increased as compared with sham-operated rats. Conversely, blood ketone body and plasma cholesterol concentrations were significantly decreased in septic rats. Both plasma insulin and plasma glucagon concentrations were markedly elevated in response to sepsis. Sepsis resulted in a negative nitrogen balance. 3. Sepsis increased the rates of production of glutamine (52.5%, P less than 0.001), alanine (38.9%, P less than 0.001) and glutamate (48.6%, P less than 0.001) by lung slices incubated in vitro. 4. Sepsis increased lung blood flow by 27.6% (P less than 0.05). Blood flow and arteriovenous concentration difference measurement across the lung of septic rats showed an increase in the net exchange rates of glutamine (142.5%, P less than 0.001), alanine (129.4%, P less than 0.001), glutamate (100.9%, P less than 0.001) and ammonia (138.0%, P less than 0.001) as compared with sham-operated control rats. 5. Sepsis produced significant decreases in the lung concentrations of glutamine (36.8%), glutamate (20.8%), 2-oxoglutarate (64.8%) and AMP (18.3%). The lung concentrations of alanine (95.9%), ammonia (67.7%) and pyruvate (89.7%) were increased. 6. The maximal activities of glutamine synthetase (20.4%, P less than 0.05), phosphate-dependent glutaminase (18.9%, P less than 0.05) and alanine aminotransferase (25.5%, P less than 0.05) were increased, but there was no marked change in that of glutamate dehydrogenase, in the lungs of septic rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glutamine and alanine metabolism in lungs of septic rats. 168 36

Glucocorticoid(GC)-induced hepatopathy in the dog is characterized by abnormal liver morphology and increases in serum alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), and the liver alkaline phosphatase isoenzyme (LALP) and by the appearance of an unusual isoenzyme of alkaline phosphatase known as the corticosteroid-induced alkaline phosphatase isoenzyme (CALP). It has not been shown whether the increases in serum ALT, GGT, and LALP are as a result of an increase in production of these enzymes or as a result of the GC-induced hepatocellular swelling and possible membrane alterations. Also, it has been assumed that the mechanism of production of CALP is via GC-induced gene derepression and de novo protein synthesis; however, this hypothesis has not been directly tested. Using isolated dog hepatocytes maintained in a confluent monolayer culture in the presence and absence of GC or cyclic AMP, no statistical increase in serum ALT, GGT, or LALP was observed. A combination of GC and cyclic AMP also caused no statistical increase in ALT and GGT; however, we demonstrate that these conditions clearly stimulated the de novo synthesis of LALP. These conditions do not induce the synthesis of CALP as determined by a sensitive immunoassay. The data obtained using this in vitro model suggest that the primary mechanism(s) of the in vivo increase of serum ALT and GGT in GC treated dogs may be other than that of de novo protein synthesis. Likewise, in vitro production of CALP may be a mechanism more complex than the conditions tested in this study.
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PMID:Effect of glucocorticoids on alkaline phosphatase, alanine aminotransferase, and gamma-glutamyltransferase in cultured dog hepatocytes. 197 72

The viability of the graft after liver transplantation is considered to be expressed as the sum of the hepatocellular activity by re-flowing of the hepatic blood flow after transplantation and the hepatocellular injury derived from the cold ischemia of the liver which is indispensable for transplantation. In order to elucidate the hepatocellular injury in ischemic liver graft cold ischemic liver model without hepatectomy was prepared and liver functions, serum insulin, glucagon and cyclic AMP after glucagon loading were measured. The following results were obtained. 1) Influence of anoxia due to ischemia of the liver expressed by s-GOT, disappeared 2 days after operation but it lasted for long time by s-GPT. Re-elevation of s-GOT, s-GPT observed after 2 days or more was considered to be derived from the hepatocellular necrosis due to rejection. Incidentally, Al-phosphatase was useful for judging the rejection, but s-total bilirubin, s-total cholesterol and albumin were considered to be not useful as parameters for evaluating the viability of the graft. 2) The rejection and the hepatocellular necrosis had not influence on serum insulin, but serum glucagon corresponded to the hepatocellular necrosis and was useful index for the judgment of the hepatocellular damage in the graft. 3) The level of c-AMP after glucagon loading and the c-AMP response corresponded very well to the hepatocellular activity of the graft, and they were considered to be useful indices for evaluating the viability of the graft.
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PMID:[Experimental study of orthotopic liver transplantation in dog--with reference to change of hepatic function, serum insulin, glucagon, c-AMP after liver transplantation and the viability of the graft]. 284 4

1. Changes in the concentrations of ammonia, glutamine, glutamate, 2-oxoglutarate, 3-hydroxybutyrate, acetoacetate, alanine, aspartate, malate, lactate, pyruvate, NAD(+), NADH and adenine nucleotides were measured in freeze-clamped rat liver during ischaemia. 2. Although the concentrations of most of the metabolites changed rapidly during ischaemia the ratios [glutamate]/[2-oxoglutarate][NH(4) (+)] and [3-hydroxybutyrate]/[acetoacetate] changed equally and the value of the expression [3-hydroxybutyrate][2-oxoglutarate][NH(4) (+)]/[acetoacetate][glutamate] remained approximately constant, indicating that the 3-hydroxybutyrate dehydrogenase and glutamate dehydrogenase systems were at near-equilibrium with the mitochondrial NAD(+) couple. 3. The value of the expression [alanine][oxoglutarate]/[pyruvate][glutamate] was about 0.7 in vivo and remained fairly constant during the ischaemic period of 5min, although the concentrations of alanine and oxoglutarate changed substantially. No explanation can be offered why the value of the ratio differed from that of the equilibrium constant of the alanine aminotransferase reaction, which is 1.48. 4. Injection of l-cycloserine 60min before the rats were killed increased the concentration of alanine in the liver fourfold and decreased the concentration of the other metabolites measured, except that of pyruvate. During ischaemia the concentration of alanine did not change but that of aspartate almost doubled. 5. After treatment with l-cycloserine the value in vivo of the expression [alanine][oxoglutarate]/[pyruvate][glutamate] rose from 0.7 to 2.4. During ischaemia the value returned to 0.8. 6. The effects of l-cycloserine are consistent with the assumption that it specifically inhibits alanine aminotransferase. 7. Most of the alanine formed during ischaemia is probably derived from pyruvate and from ammonia released by the deamination of adenine nucleotides and glutamine. The alanine is presumably formed by the combined action of glutamate dehydrogenase and alanine aminotransferase. 8. The rate of anaerobic glycolysis, calculated from the increase in the lactate concentration, was 1.3mumol/min per g fresh wt. 9. Although the concentrations of the adenine nucleotides changed rapidly during ischaemia, the ratio [ATP][AMP]/[ADP](2) remained constant at 0.54, indicating that adenylate kinase established near-equilibrium under these conditions.
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PMID:Effects of ischaemia on metabolite concentrations in rat liver. 431 90

Escherichia coli strain K28, isolated after nitrosoguanidine mutagenesis, was found to be auxotrophic for serine. It was also temperature sensitive for growth as a result of producing an altered seryl-transfer ribonucleic acid (tRNA) synthetase (EC 6.1.1.11, l-serine: tRNA ligase [AMP]). The auxotrophy was caused by a mutation in the structural gene for phosphohydroxy-pyruvate transaminase (serC), which was distinct from, but closely linked to, the structural gene for seryl-tRNA synthetase (serS). We conclude that the relevant genes are in the order gal-serS-serC-aroA.
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PMID:Close linkage of the genes serC (for phosphohydroxy pyruvate transaminase) and serS (for seryl-transfer ribonucleic acid synthetase) in Escherichia coli K-12. 457 Jul 68

1. Transient and steady-state changes caused by acetate utilization were studied in perfused rat heart. The transient period occupied 6min and steady-state changes were followed in a further 6min of perfusion. 2. In control perfusions glucose oxidation accounted for 75% of oxygen utilization; the remaining 25% was assumed to represent oxidation of glyceride fatty acids. With acetate in the steady state, acetate oxidation accounted for 80% of oxygen utilization, which increased by 20%; glucose oxidation was almost totally suppressed. The rate of tricarboxylate-cycle turnover increased by 67% with acetate perfusion. The net yield of ATP in the steady state was not altered by acetate. 3. Acetate oxidation increased muscle concentrations of acetyl-CoA, citrate, isocitrate, 2-oxoglutarate, glutamate, alanine, AMP and glucose 6-phosphate, and lowered those of CoA and aspartate; the concentrations of pyruvate, ATP and ADP showed no detectable change. The times for maximum changes were 1min, acetyl-CoA, CoA, alanine and AMP; 6min, citrate, isocitrate, glutamate and aspartate; 2-4min, 2-oxoglutarate. Malate concentration fell in the first minute and rose to a value somewhat greater than in the control by 6min. There was a transient and rapid rise in glucose 6-phosphate concentration in the first minute superimposed on the slower rise over 6min. 4. Acetate perfusion decreased the output of lactate, the muscle concentration of lactate and the [lactate]/[pyruvate] ratio in perfusion medium and muscle in the first minute; these returned to control values by 6min. 5. During the first minute acetate decreased oxygen consumption and lowered the net yield of ATP by 30% without any significant change in muscle ATP or ADP concentrations. 6. The specific radioactivities of cycle metabolites were measured during and after a 1min pulse of [1-(14)C]acetate delivered in the first and twelfth minutes of acetate perfusion. A model based on the known flow rates and concentrations of cycle metabolites was analysed by computer simulation. The model, which assumed single pools of cycle metabolites, fitted the data well with the inclusion of an isotope-exchange reaction between isocitrate and 2-oxoglutarate+bicarbonate. The exchange was verified by perfusions with [(14)C]bicarbonate. There was no evidence for isotope exchange between citrate and acetyl-CoA or between 2-oxoglutarate and malate. There was rapid isotope equilibration between 2-oxoglutarate and glutamate, but relatively poor isotope equilibration between malate and aspartate. 7. It is concluded that the citrate synthase reaction is displaced from equilibrium in rat heart, that isocitrate dehydrogenase and aconitate hydratase may approximate to equilibrium, that alanine aminotransferase is close to equilibrium, but that aspartate transamination is slow for reasons that have yet to be investigated. 8. The slow rise in citrate concentration as compared with the rapid rise in that of acetyl-CoA is attributed to the slow generation of oxaloacetate by aspartate aminotransferase. 9. It is proposed that the tricarboxylate cycle may operate as two spans: acetyl-CoA-->2-oxoglutarate, controlled by citrate synthase, and 2-oxoglutarate-->oxaloacetate, controlled by 2-oxoglutarate dehydrogenase; a scheme for cycle control during acetate oxidation is outlined. The initiating factors are considered to be changes in acetyl-CoA, CoA and AMP concentrations brought about by acetyl-CoA synthetase. 10. Evidence is presented for a transient inhibition of phosphofructokinase during the first minute of acetate perfusion that was not due to a rise in whole-tissue citrate concentration. The probable importance of metabolite compartmentation is stressed.
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PMID:Control of the tricarboxylate cycle and its interactions with glycolysis during acetate utilization in rat heart. 544 22


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