Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

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

1)The time course of changes in concentration of renal metabolites in response to a non-toxic load of NH4 as NH4 Cl or NH4HCO3 were measured in fasted rats. 2) Following a NH4Cl load, decrease of renal concentration of 2-oxoglutarate occurs but this change is delayed in relation to the peak of the blood ammonia concentration and persists after disappearance of the hyperammoniemia. 3) Following a NH4HCO3 load, the oxoglutarate concentration changes are less marked and more transient. 4) No close relationship between the mitochondrial free NAD/NADH ratio calculated from the glutamate dehydrogenase and the 3-hydroxybutyrate dehydrogenase systems were seen during alteration of the ammonia concentration. 5) Contrary to the observations in the liver under similar circumstances (BROSNAN, J.T. et al.: Biochem.J. 138, 453, 1974), no increase in kidney tissue or renal venous blood alanine or aspartate concentration are seen. 6) A constant infusion of NH4HCO3 resulted only in an increase in tissue and renal venous blood glutamine concentration. 7) The infusion of NH4 together with a carbon source (malate) resulted in a similar increase in tissue glutamine concentration and more striking increase in renal venous glutamine concentration. No accumulation of aspartate nor alanine were seen. 8) In vitro studies indicate that the net flux through both the aspartate aminotransferase and the glutamate dehydrogenase reactions is dependent on the concentration of the reactants as expected for a near-equilibrium system. 9) It is concluded that the kidney response to an ammonia load differs from that of the liver despite the existence of a similar network of near-equilibrium reactions of (1) a lack of local availability of oxaloacetate, (2) a lower activity of alanine aminotransferase, (3) a greater in vivo activity of glutamine synthetase.
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PMID:Effect of an ammonia load on the kidney near-equilibrium systems in the rat in vivo. 18 80

A trial was performed in 204 healthy calves (heifers) of the Bohemian Spotted breed in the post-natal period from birth to the age of four months. The activities of the following enzymes in blood plasma were determined: L-aspartate: 2-oxoglutarate: aminotransferase, EC.2.6.1.1. (GOT), L-alanine: oxoglutarate: aminotransferase, EC.2.6.1.2. (GPT), L-lactate: NAD oxidoreductase, EC.1.1.1.27 (LDH), and orthophosphoric acid monoester phosphohydrolase, EC.3.1.3.1. (alkaline phosphatase). The calves were divided into age categories according to the date of birth with an interval of one week. GOT activity in blood plasma increased significantly until the age of eight weeks (from the original value of 1.1708 +/- 0.2598 micronmol ml-1 to 1.8150 +/- 0.6362 micronmol ml-1, with the maximum of 2.0317 +/- 0.7777 micronmol ml-1 of plasma in the sixth week). In the subsequent period the GOT curve has not a characteristic course. While the activity of GOT increased in the first weeks after birth, the activity of GPT showed a significant drop (from the original level of 0.9000 +/- 0.3364 micronmol ml-1 to the minimum of 0.3675 +/- 0.1901 micronmol ml-1 of plasma in the seventh week); from the 10th week on the values rise so that at the end of the period of study they reach almost the same levels as in calves in the first postnatal week. The activity of LDH in blood plasma remains at almost the same level in the first five weeks after birth (between 43.4025 +/- 8.4893 micronmol ml-1 and 46.3792 +/- 14.8952 micronmol ml-1 of plasma); it was at a statistically significantly higher level only in a short period between the 7th and 10th week after birth. The highest values of alkaline phosphatase in blood plasma were recorded at the age of two or three weeks (maximum in the second week 23.9833 +/- 9.0945 micronmol ml-1 of plasma); from the fourth week on, the values of alkaline phosphatase are significantly lower until the end of the test period, ranging betweek 5.3133 +/- 1.6017 micronmol ml-1 and 7.5425 +/- 2.2437 micronmol ml-1 of plasma. Changes conditioned by postnatal development were observed in the development of all the enzymatic activities under study, the greatest changes being observed in alkaline phosphatase.
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PMID:[The development of transaminase activity (SGOT and SGPT), lactate dehydrogenase and alkaline phosphatase in the blood plasma of calves up to the age of 4 months]. 82 94

Fasting serum bile acid (SBA) was measured by the enzymic fluorimetric method coupled with the NAD-resazurin system in 23 controls, 35 asymptomatic carriers of HIs antigen including 4 e antigen carriers and 91 patients with various liver diseases. All GHBs and e antigen carriers showed SBA within the normal range. SBA was most significantly correlated with serum bilirubin (gamma=0.74) and was a more sensitive index for impaired liver function than bilirubin or alkaline phosphatase in 164 radomly chosen samples from the liver disease group. In serial determinations of SBA with reference to GOT, GPT, changing patterns of these two parameters were classified into the parallel type and the discrepant type. Thirty two out of 40 cases with chronic liver disease belonged to the parallel type. SBA remained abnormal even after the normalization of transaminase in 12 out of 20 resolving episodes in cases of the parallel type, regardless of diagnosis. Since SBA changes according to the stage of the disease activity, serial and simultaneous estimation of SBA and GOT, GPT was found to be helpful in the observation of liver diseases. Maximum values of SBA elevation in an endogenous bile acid tolerance test after eating two egg yolks were higher than controls in 4 out of 7 cases with liver disease, who were associated with normal fasting SBA.
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PMID:Evaluation of fluorimetrically estimated serum bile acid in liver disease. 84 3

The only exogenous substrates oxidized by mitochondria isolated from the flight muscle of the Japanese beetle (Popillia japonica) are proline, pyruvate and glycerol 3-phosphate. The highest rate of oxygen consumption is obtained with proline. The oxidation of proline leads to the production of more NH3 than alanine, indicating a functioning glutamate dehydrogenase (EC 1.4.1.2). Studies of mitochondrial extracts confirm the presence of a very active glutamate dehydrogenase, and this enzyme is found to be activated by ADP and inhibited by ATP. These extracts also show high alanine aminotransferase activity (EC 2.6.1.2) and a uniquely active "malic' enzyme (EC 1.1.1.39). The "malic' enzyme is activated by succinate and inhibited by ATP and by pyruvate. It is suggested that the input of tricarboxylate-cycle intermediate from proline oxidation is balanced by the formation of pyruvate from malate, and the complete oxidation of the majority of the pyruvate. Studies of the steady-state concentrations of mitochondrial CoASH and CoA thioesters during proline oxidation show a high succinyl (3-carboxypropionyl)-CoA content which falls on activating respiration with ADP. There is a concomitant rise in CoASH. However, the reverse transition, from state-3 to state-4 respiration, causes only very slight changes in acylation. The reasons for this are discussed. Studies of the mitochondrial content of glutamate, 2-oxoglutarate, malate, pyruvate, citrate and isocitrate during the same phases of proline oxidation give results consistent with control at the level of glutamate dehydrogenase and isocitrate dehydrogenase during proline oxidation, with the possibility of further control at "malic' enzyme. During the oxidation of pyruvate all of the tricarboxylate-cycle intermediates and NAD(P)H follow the pattern of changes described in the blowfly (Johnson & Hansford, 1975; Hansford, 1974) and isocitrate dehydrogenase is identified as the primary site of control.?2OAuthor
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PMID:The nature and control of the tricarboxylate cycle in beetle flight muscle. 120 Sep 85

The subcellular localization of NAD- and NADP-linked glutamate dehydrogenases (GDH-NAD and GDH-NADP), alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT) in epimastigotes of Trypanosoma cruzi was studied by digitonin extraction from whole cells, subcellular fractionation by differential centrifugation and isopycnic ultracentrifugation. All enzymes presented both a cytosolic and a mitochondrial form; in addition, GDH-NADP seems to have a third, still undefined, localization. The results are compatible with the existence of two pathways for the production of L-alanine linked to the reoxidation of glycolytic NADH, one operative in the mitochondrion and the other in the cytosol, and perhaps responsible for the existence of the two alanine pools detected by 13C-nuclear magnetic resonance (B. Frydman et al., Eur. J. Biochem. 192 (1990) 363-368).
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PMID:Subcellular localization of glutamate dehydrogenases and alanine aminotransferase in epimastigotes of Trypanosoma cruzi. 177 28

The amount of L-lactate in biological fluids (serum, plasma and cerebrospinal fluid) was determined by monitoring the reduced form of nicotinamide adenine dinucleotide (NADH) produced by immobilised lactate dehydrogenase (LDH), with bacterial bioluminescent enzymes immobilised on a separate nylon coil. The LDH catalysed the reaction of L-lactate with NAD; this reaction took place in a nylon coil that preceded the coil for the bioluminescent detection. The co-immobilisation of alanine aminotransferase (ALT) with LDH improved the lactate transformation by 117-183%. The response was linear from 0.1 to 50 micron mol l(-1) at 25 degrees C for the LDH - ALT reactor. The intra- and inter-assay coefficients of variation were less than 5% and the recoveries ranged from 93 to 106%. The results agreed well with those obtained with a spectrophotometric method and with the normal reference values.
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PMID:Bioluminescent flow sensor for the determination of L-(+)-lactate. 222 97

Since red cells transport and metabolize acetaldehyde in vivo, the effects of acetaldehyde on human red cell enzyme activities were studied. Incubation of intact red cells or undiluted red cell lysates at 37 degrees C for 4 h with 1-10 mmol/l acetaldehyde decreased only GOT, GPT and aldolase activities among the 26 enzymes tested. No inhibition occurred at 4 degrees C or when acetaldehyde was incubated with dilute hemolysates. Incubation of lysates with other reducing substrates or with acetate inhibited aldolase but not GOT or GPT. Preincubation of lysates with cyanate or fluoride markedly decreased acetaldehyde-mediated transaminase inhibition but not aldolase inhibition. Addition of pyridoxal phosphate, the vitamin B6 transaminase coenzyme, to GOT and GPT assay mixes did not reverse acetaldehyde-mediated transaminase inhibition. These findings suggest that acetaldehyde-mediated aldolase inhibition results from oxidation of acetaldehyde while transaminase inhibition results from nonoxidative acetaldehyde metabolism. When 100-200 mumol/l acetaldehyde is added to lysates at 2-h intervals and when lysates are incubated with ethanol, alcohol dehydrogenase and an NAD-regenerating system, enzyme inhibition occurs at acetaldehyde levels approaching those seen in vivo. Thus, the role of acetaldehyde-mediated enzyme inhibition in the toxicity of alcohol abuse warrants further study.
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PMID:Effects of acetaldehyde on human red cell metabolism: evidence for the formation of enzyme inhibitors. 341 86

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


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