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)

Ethanol metabolism in rat hepatocytes isolated either from the periportal (pp) or the perivenous (pv) area by collagenase gradient perfusion was compared to reveal metabolic factors that could be associated with the development of perivenous alcoholic liver damage. Cells were also isolated from rats given ethanol (E) chronically by addition to the drinking fluid. One group (EM) received in addition the alcohol dehydrogenase inhibitor 4-methylpyrazole, which potentiated the ethanol treatment by causing sustained elevated diurnal blood ethanol levels. Fatty degeneration ensued in only one-third of the E rats but in all of the EM rats. The periportal/perivenous activity distributions of alanine aminotransferase (ALAT) and glutamate dehydrogenase (GLDH) were 2.2 and 0.75, respectively. Both ethanol treatments significantly decreased the ALAT and increased the GLDH activities, but did not change their pp/pv distributions. Ethanol treatment also increased ethanol and acetaldehyde oxidation, but to the same extent in pp and pv cells. The increase was more marked in cells from EM rats despite their more severe liver fatty degeneration. Ethanol incubation also increased the lactate/pyruvate ratio to the same extent in pp and pv cells both from control or ethanol-treated rats. Our results indicate that periportal and perivenous hepatocytes convert ethanol via acetaldehyde to acetate equally well and with similar effects even after chronic ethanol treatment. Consequently, preferential damage of the perivenous area after chronic ethanol intake is not caused by inherent or acquired differences in ethanol metabolism between perivenous and periportal hepatocytes. Rather, sinusoidal gradients only established in the intact liver may exaggerate the metabolic imbalance by ethanol in the perivenous area, thus explaining its greater vulnerability to damage by alcohol abuse.
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PMID:Comparison of ethanol metabolism in isolated periportal or perivenous hepatocytes: effects of chronic ethanol treatment. 390

Previous observations that valproic acid (VPA) causes hepatic damage prompted us to investigate the effect of large doses of the drug (0.6, 1.2 and 1.8 mmol/kg/day) on a number of liver enzymes located on different subcellular fractions. In mitochondria, glutamate dehydrogenase, aspartate aminotransferase and ornithine carbamoyltransferase were significantly increased (1.8 mmol/kg/day). In microsomes, gamma-glutamyltransferase activity increased significantly (1.8 mmol/kg) and cytochrome P-450 content decreased significantly (1.2 and 1.8 mmol/kg). In cytosol, both aspartate and alanine aminotransferase activities were increased at all dose levels. These results indicate that VPA induces dose-dependent changes in some liver enzyme activities.
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PMID:Effect of sodium valproate on subcellular fraction enzymes in rat liver. 393 26

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

We measured the activities of two mitochondrial enzymes, the mitochondrial form of aspartate aminotransferase (EC 2.6.1.1) and glutamate dehydrogenase (EC 1.4.1.2), in the serum of apparently healthy persons (n = 84) and patients suffering from chronic liver diseases (n = 43). The distribution of activities for glutamate dehydrogenase, but not mitochondrial aspartate aminotransferase, was sex-dependent. The upper limits of the reference intervals (99th percentile) at 37 degrees C were 3.2 U/L for mitochondrial aspartate aminotransferase, 6.4 U/L for glutamate dehydrogenase (women), and 11.0 U/L for glutamate dehydrogenase (men); there was a weak correlation between the activities of both mitochondrial enzymes (r = 0.439). In patients with chronic liver diseases we found a greater increase in the activity of glutamate dehydrogenase than of mitochondrial aspartate aminotransferase and the correlation between the two mitochondrial enzymes was stronger. The diagnostic sensitivity and specificity of either mitochondrial enzyme was less than that of total aspartate aminotransferase, alanine aminotransferase (EC 2.6.1.2), or gamma-glutamyltransferase (EC 2.3.2.2).
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PMID:Mitochondrial enzymes in human serum: comparative determinations of glutamate dehydrogenase and mitochondrial aspartate aminotransferase in healthy persons and patients with chronic liver diseases. 396 54

Isoenzymes of human red cell glutamate-pyruvate transaminase (GPT) were resolved by isoelectric focusing (IEF) of hemolysates in polyacrylamide gels at pH 5.0-7.0. The bands of enzyme activity required both alpha-ketoglutarate and L-alanine in the staining mixture for visualization, indicating that the bands were not lactate dehydrogenase or glutamate dehydrogenase. Phenotyping of 41 individuals by IEF, including types GPT 1, 2A, 1-2A, 1-2B, and 2A-2B, agreed with the typing results obtained by electrophoresis in starch gels and in polyacrylamide gels at acid and alkaline pH. Analysis of one kindred demonstrated autosomal codominant transmission of the rare GPT*2B gene through 3 generations. IEF facilitates phenotyping by permitting identification of the GPT types on a single gel with a considerable reduction in time and cost. Although no new variants were found in this investigation, IEF may be more powerful for the recognition of presently undetected variants of GPT.
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PMID:Identification of human red cell glutamate-pyruvate transaminase (GPT) phenotypes by isoelectric focusing. 397 56

We examined 17 lots of 2-oxoglutarate (seven acid forms, three K salt forms, and seven Na salt forms), obtained from eight commercial suppliers, for suitability for measuring aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) in human serum. Measurements of the catalytic activity concentrations of these two aminotransferases with each of these 17 preparations were not sufficiently sensitive to distinguish good from poor-quality material. Thus, we ranked these lots for purity, by specific analysis with glutamate dehydrogenase and by liquid chromatography, and determined the water content, acid content, and spectral characteristics of each. On the basis of a 2-oxoglutarate assay value by glutamate dehydrogenase of 98% or greater, we considered seven of the preparations acceptable and 10 unacceptable. The molar absorptivities (L X mol-1 X cm-1, mean +/- SD) of the seven acceptable lots in 1 mol/L HCl were: epsilon 325 nm = 9.12 +/- 0.02 (CV = 0.2%), epsilon 279 nm = 2.63 +/- 0.23 (CV = 9.9%), and epsilon 245 nm = 37.9 +/- 4.1 (CV = 10.9%). Use of these spectrophotometric limits alone unambiguously distinguished the inferior lots of 2-oxoglutarate. We urge the inclusion of detailed spectrophotometric specifications for 2-oxoglutarate in Reference Methods for aminotransferase measurements.
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PMID:Comparisons of 17 lots of 2-oxoglutarate, and specifications for use of this substrate in reference methods. 399 57

The pesticide dichlorvos inhibits not only cholinesterase but also alkaline phosphatase, lactate dehydrogenase and glutamate dehydrogenase competitively. A mixed type inhibition of glutamic-oxaloacetic transaminase is in contrast to the increased activity of glutamic-pyruvic transaminase after dichlorvos application. The activity of leucine aminopeptidase is not affected by the substance. After administering rats an acutely toxic dose of dichlorvos (70 mg per kg b.w.) in vitro-inhibitions other than that of cholinesterase could not be found.
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PMID:Enzyme activities after in vitro and in vivo application of dichlorvos. 400 35

Discriminant analysis was used to discriminate between Reye syndrome (RS) patients and non-RS cases based either on conventional blood chemistry data obtained upon admission, or on the activities of hepatic mitochondrial enzymes in biopsy or necropsy tissue. The control group for blood chemistry measurements contained children with upper respiratory tract infections, varicella, etc. who did not develop RS, as well as healthy children. Subjects with no liver disorder (e.g., accidental death, sudden infant death, etc.) or with non-RS liver disorders were used as controls for hepatic enzyme studies. Hepatic damage indicators (aspartate aminotransferase, AST; alanine aminotransferase, ALT; and bilirubin) correctly classified 86-96% of non-RS cases and 61-71% of RS. By contrast, AST and ALT had little prognostic value (63% overall correct). Ammonia effectively classified favorable outcome cases (95% correct) but not unfavorable (14% correct). However, when ammonia was included with stage of coma information 88% of the favorable and 85% of the unfavorable outcome cases were correctly classified. Discriminant analysis of hepatic enzymes (glutamate dehydrogenase and monoamine oxidase activity) for a RS and a non-RS group correctly classified 80% of non-RS and 95% of RS specimens. The function was suitable for the direct evaluation of RS-like mitochondrial enzyme changes in rat liver.
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PMID:Prognosis and diagnosis of Reye syndrome by discriminant analysis. 404 46

Combined enzymodiagnostic program--estimation of total activity of blood serum enzymes aspartate aminotransferase (AST), alanine aminotransferase (AAT), alkaline phosphatase (AP), gamma-glutamyl transferase (gamma-GT), glutamate dehydrogenase (GDH), acetyl cholinesterase (ACE), butyryl cholinesterase (BCE)--was studied to evaluate its diagnostic validity in surgical clinic. In mechanical jaundice of various origin mean values of the enzymatic activities studied as well as the enzymatic coefficients were distinctly altered as compared with control values: AST/AAT, gamma-GT/AST as well as the newer coefficients BCE/ACE, AP/gamma-GT, (formula; see text). The jaundices of tumoral and non-tumoral genesis caused markedly dissimilar alterations in the coefficients AST/AAT and (formula; see text). The data of enzymological analysis may be used for differential diagnosis in jaundices.
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PMID:[Enzyme diagnosis of mechanical jaundice]. 409 Mar 51

Fat-cells were prepared from rat and guinea-pig epididymal adipose tissue and compared on the basis of the intracellular distributions and activities of enzymes and with respect to their utilization of various U-(14)C-labelled substrates for lipogenesis. 1. Compared with the rat, guinea-pig extramitochondrial enzyme activities differed in that aconitate hydratase, alanine aminotransferase, ATP-citrate lyase, lactate dehydrogenase, NAD-malate dehydrogenase, NADP-malate dehydrogenase and phosphoenolpyruvate carboxykinase activities were appreciably lower, whereas aspartate aminotransferase, glucose 6-phosphate dehydrogenase, NADP-isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase activities were appreciably higher. Mitochondrial activities of citrate synthase, NADP-isocitrate dehydrogenase and pyruvate carboxylase were appreciably lower, whereas mitochondrial activities of aspartate aminotransferase, glutamate dehydrogenase, NAD-malate dehydrogenase and phosphoenolpyruvate carboxykinase were higher in the guinea pig compared with the rat. 2. In general guinea-pig fat-cells incorporated acetate and lactate into fatty acids more readily than rat fat-cells, whereas rat fat-cells incorporated glucose and pyruvate more readily than guinea-pig fat-cells. 3. Acetate stimulated the incorporation of glucose into fatty acids in rat fat-cells, but had no appreciable effect upon this process in guinea-pig fat-cells. Acetate greatly decreased the incorporation of lactate into fatty acids in cells from both species. 4. Lactate/pyruvate ratios produced by incubation of guinea-pig cells with glucose+insulin were very low compared with those found with rat cells under the same conditions. 5. With glucose (+insulin) or with glucose+acetate (+insulin) as substrates guinea-pig cells produced enough NADPH by the hexose monophosphate pathway to satisfy the NADPH requirements of lipogenesis. In rat fat-cells under the same conditions, hexose monophosphate-pathway NADPH provision was not sufficient to meet the requirements of lipogenesis. 6. These results are discussed, particularly in relationship to the disposition of cytosolic reducing equivalents in the cells.
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PMID:Lipogenesis in rat and guinea-pig isolated epididymal fat-cells. 415 67


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