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:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inflammation of the rat bile duct induced by administration of turpentine into it has been used to study the influence of the impaired duct on liver function. Turpentine was dissolved in olive oil 1:1000 and 1:500. A 2 h ligation of the bile duct was used to promote a local effect. Contemporary groups of intact, sham-operated, control rats (given 0.9% NaCl by intrabiliary injection) and animals with total chronic obstruction were compared to assess the significance of changes. Serum concentrations of total and conjugated bilirubin, cholesterol and creatinine, activities of S-alanine-aminotransferase, S-aspartate aminotransferase and alkaline phosphatase, mortality of rats, and also total body weight compared with the weight of the liver, were investigated on days 1, 4, 8, 12, 16, 32 and 64 after surgery and turpentine, or following ligation of the bile duct. An increase in bilirubin and cholesterol, an augmentation of enzymatic activity and the histological changes were indicative of hepatotoxicity or cholestasis. The turpentine concentration--effect, manifested in body-weight change, suggests some specificity of the effect. There were no changes in serum creatinine arterial blood pressure, heart rate or portal blood pressure, when turpentine was administered by the intrabiliary route. These results suggest primary liver damage.
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PMID:Liver damage induced by intrabiliary turpentine in rats. 197 95

Five groups of five weanling rats were each fed a Torula yeast-based diet either unsupplemented or supplemented with 30 mg beta-carotene/kg, 30 IU vitamin E/kg, 1 mg selenium/kg or 30 mg coenzyme Q10/kg. Elevated levels of plasma aspartate aminotransferase and alanine aminotransferase are sensitive indicators of liver damage. The former enzyme was lower (P less than 0.01) in the vitamin E-, selenium- and beta-carotene-supplemented groups than in the unsupplemented control group, and the latter enzyme was lower in the vitamin E- and selenium-supplemented groups, suggesting a relatively equal effectiveness of these three antioxidants against liver damage. Erythrocytes were tested for protection against uninduced oxidative damage or that induced by 1 mmol/L bromotrichloromethane (BrCl3C) by measuring thiobarbituric acid-reactive substances (TBARS), hemoglobin, hemolysis, protein precipitation, alanine release and several enzyme activities. In untreated erythrocytes, selenium, beta-carotene and coenzyme Q10 exhibited protection by lowering (P less than 0.05) TBARS and alanine release, but only vitamin E protected against hemolysis. In BrCl3C-treated erythrocytes, vitamin E, selenium and beta-carotene protected by decreasing (P less than 0.05) protein precipitation, whereas selenium and beta-carotene decreased alanine release. The results of this study suggested that, in a manner analogous to vitamin E and selenium, beta-carotene and coenzyme Q10 function as antioxygenic nutrients.
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PMID:Comparative antioxidant effectiveness of dietary beta-carotene, vitamin E, selenium and coenzyme Q10 in rat erythrocytes and plasma. 199 57

Two hundred eighty-one alcoholic patients were prospectively evaluated by clinical, biochemical, and histologic parameters during a 4-yr period to assess their prognosis. They were stratified into four categories of injury: 1) fatty liver (26 patients), 2) acute alcoholic hepatitis (106), 3) cirrhosis (39), and 4) cirrhosis with superimposed alcoholic hepatitis (111). The rate of survival and variables correlating with survival varied according to the group. At 48 months, 70% of the patients with fatty liver were alive, 58% in the alcoholic hepatitis group, 49% in cirrhosis, and 35% in alcoholic hepatitis superimposed upon cirrhosis. Within group one, deaths were due to causes unrelated to liver disease. In the alcoholic hepatitis group, factors significantly correlating with survival were ascites, alanine amino-transferase levels, grams of alcohol consumed, continuation of alcohol intake, and clinical severity of disease. Survival in patients of group three correlated significantly with prothrombin time and histologic severity score. Patients with combined cirrhosis and alcoholic hepatitis exhibited the worst prognosis, with the most significant predictors of survival being age, grams of alcohol consumed, the ratio of serum aminotransferases (AST:ALT) and the histologic and clinical severity of the disease. Although a different pattern of correlates was observed for each pathologic level of injury, knowledge of the various correlates aids in prognostic assessment.
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PMID:Prognostic factors in alcoholic liver disease. VA Cooperative Study Group. 199 35

In aspartate aminotransferase (AspAT), His143 is located within a hydrogen-bonding distance to Asp222 that forms a strong ion pair with the ring nitrogen of the coenzyme, pyridoxal 5'-phosphate (PLP) or pyridoxamine 5'-phosphate (PMP). His143 of Escherichia coli AspAT was replaced by Ala or Asn. The mutant enzyme H143A showed a slight increase in the maximum velocity of the overall transamination reaction between aspartate and 2-oxoglutarate, while H143N AspAT showed a decrease to 60% in the maximum rate of the overall reactions in both directions. In all of the half-transamination reactions with four substrates, aspartate, glutamate, oxalacetate, and 2-oxoglutarate, the catalytic competence as defined by kmax/Kd decreased by 3-18-fold upon replacing His143 by either Ala or Asn. The extent of the decrease varied from one substrate to another; it was largely contributed to by the decrease in affinities for all substrates. The equilibrium constants, [PMP-form] [keto acid]/[( PLP-form] [amino acid]), decreased by over 10-fold upon the mutations at position 143. Both H143A and H143N AspATs exhibited a considerably decreased affinity for 2-methylaspartate, an external-aldimine-forming substrate analogue, yet without appreciable alteration in the affinity for succinate and glutarate, which are non-aldimine-forming analogues. All these findings suggest that, although His143 is not essential for catalysis, it might assist the formation of enzyme-substrate complex.
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PMID:The role of His143 in the catalytic mechanism of Escherichia coli aspartate aminotransferase. 200 66

Tryptophanase (tryptophan: indole-lyase) from Escherichia coli has been isolated in the holoenzyme form and its absorption spectra and acid-base chemistry have been reevaluated. Apoenzyme has been prepared by dialysis against sodium phosphate and L-alanine and molar absorptivities of the coenzyme bands have been estimated by readdition of pyridoxal 5'-phosphate. The spectrophotometric titration curve, whose midpoint is at pH 7.6 in 0.1 M potassium phosphate buffers, indicates some degree of cooperativity in dissociation of a pair of protons. Resolution of the computed spectra of individual ionic forms of the enzyme with lognormal distribution curves shows that band shapes are similar to those of model Schiff bases and of aspartate aminotransferase. Using molar areas from the latter we estimated amounts of individual tautomeric species. In addition to ketoenamine and enolimine or covalent adduct the high pH form also appears to contain approximately 18% of a species with a dipolar ionic ring (protonated on the ring nitrogen and with phenolate -O-). We suggest that this may be the catalytically active form of the coenzyme in tryptophanase. The equilibrium between tryptophanase and L-alanine has also been reevaluated.
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PMID:Equilibria and absorption spectra of tryptophanase. 203 39

Serum activities of alanine-aminotransferase (ALAT, EC 2.6.1.2), aspartate-aminotransferase (ASAT, EC 2.6.1.1), lactate dehydrogenase (LDH, EC 1.1.1.27), and alkaline phosphatase (AP, EC 3.1.3.1) were increased significantly after a dose of 0.16 g/kg/b. w. (ip.) carbon tetrachloride (tetrachloromethane) in rats pretreated with 10% (v/v) ethanol for one and 10 weeks in comparison with water/carbon tetrachloride-treated animals. At the end of 30 and 52 weeks of ethanol consumption these levels were very slightly increased or not detectable. Ethanol treatment alone did not cause an increase in serum enzyme activities or histological liver damage, but caused a diminished intake of fluid and food and in some cases also a reduction of weight gain in the animal body. Significant decrease in body weight after carbon tetrachloride was more evident in rats pretreated with ethanol (1 week greater than 10 greater than or equal to 52 weeks) than in water drinking animals, the lethality caused by carbon tetrachloride was also higher after one and 10 weeks than after 30 to 52 weeks of ethanol pretreatment. The results indicate a decrease of carbon tetrachloride toxicity with increased duration of ethanol pretreatment. This phenomenon could be attributed to reduced sensibility to those alcohol effects which are responsible for increase of carbon tetrachloride toxicity.
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PMID:Influence of ethanol pretreatment of differing duration on toxic effects of carbon tetrachloride in rats. 208 Sep 8

Activities of alanine and aspartate aminotransferase in different muscle types and in the liver of streptozotocin diabetic rats were studied 1,2 and 3 days after administering of streptozotocin. It was shown that the activity of both enzymes was elevated in the "white" layer of the vastus lateralis, in the liver and in the heart, whereas it remained unchanged in the "red" layer of the same muscle, in the soleus and the diaphragm. It is concluded that the effect of acute insulin deficiency on the aminotransferase activity in skeletal muscles depends on the muscle fiber composition and does not appear in muscles with a high oxidative potential. These results indicate that muscle fiber composition should be taken into account when evaluating the role of insulin in amino acid metabolism in the muscle.
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PMID:Alanine and aspartate aminotransferase activities in muscles of diabetic rats. 213 88

Significant increase in the activity of liver succinate dehydrogenase (SDH) was observed in male Wistar rats, fed Aroclor 1260 (PCB; polychlorinated biphenyl) at 50 and 100 ppm level for 120 days. Lactate dehydrogenase (LDH) activity increased in 50 ppm PCB fed animals and decreased in 100 ppm PCB fed rats. On the other hand, enzymes like alanine and aspartate aminotransferase, alkaline and acid phosphatase showed remarkable decrease in activity in PCB fed animals. Slab gel electrophoresis of LDH isozymes showed remarkable increase in LDH2 and LDH3 and to some extent increase in LDH1 isozymes of livers of 50 ppm PCB fed animals but not in 100 ppm PCB fed groups as compared to controls. In both the PCB fed groups, liver showed centrilobular hypertrophy, hepatocellular damage, hyperplasia, karyolysis and karyorrhexis.
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PMID:Effect of feeding polychlorinated biphenyl (Aroclor 1260) on hepatic enzymes of rats. 216 95

The aim of our work was to assess the performance of tissue polypeptide antigen in detecting hepatocellular carcinoma in cirrhotic patients, while also checking for any influence of liver dysfunction on the serum level of the marker. One hundred and twenty-five consecutive cirrhotic patients, 35 with and 90 without, hepatocellular carcinoma were studied. Tissue polypeptide antigen had a different distribution in the two groups and the best diagnostic accuracy with 48.6% sensitivity and 85.6% specificity was found at the cut-off value of 240 UL-1. In cirrhotic patients significant linear correlations were found between tissue polypeptide antigen and alanine-transaminase, aspartate-transaminase, G-glutamyl-transpeptidase and alkaline phosphatase; there was no correlation with bilirubin or pseudo-cholinesterase. In patients with hepatocellular carcinoma a significant linear correlation was found only with alanine and aspartate transaminase and G-glutamyl-transpeptidase. The analysis of covariance still showed a significant difference between mean tissue polypeptide antigen levels in the two groups also accounting for covariates. These results suggest that: a) the liver dysfunction may be involved in increasing tissue polypeptide antigen values; b) tissue polypeptide antigen has a different distribution in cirrhotic patients with and without hepatocellular carcinoma also accounting for covariates; these findings further support the specificity of tissue polypeptide antigen.
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PMID:The serum tissue polypeptide antigen in the detection of hepatocellular carcinoma in cirrhotic patients. 217 22

Sera of 260 patients with high serum aspartate aminotransferase (L-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.1.1; AST)/alanine aminotransferase (L-alanine: 2-oxoglutarate aminotransferase, EC 2.6.1.2; ALT) ratio (greater than 2.0) and high serum AST (greater than 45 IU/1) were selected and tested for the presence of immunoglobulin complexed-AST, by using immunoprecipitation reaction and counterimmunoelectrophoresis. The macromolecular AST was confirmed by size-exclusion high-performance liquid chromatography (HPLC). 34 patients out of 260 were found to have AST-immunoglobulin complexes (13.1%). The classes of AST-linked immunoglobulins were identified to be alpha in 28 cases (82.4%, P less than 0.01), mixed type of alpha and gamma in 5 cases (14.7%) gamma in one case (2.9%). Positive frequency was the highest in liver malignancies, either primary (9/26, 34.6%) or metastatic (7/17, 42.2%), followed by other malignancies (6/55, 10.9%) and chronic liver diseases (4/22, 18.2%). Thus, it can be strongly suggested that the immunoglobulin A complexed-AST is frequently found in association with liver malignancies.
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PMID:Incidence and properties of aspartate aminotransferase-immunoglobulin complexes in patients with a high serum aspartate to alanine aminotransferase ratio. 220 38


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