Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Subjects with abnormalities in a number of laboratory tests were shown to have higher than usual probabilities of being heavy drinkers. Quantitative estimates have been made of the probabilities of heavy drinking from the results of the following tests: gamma-glutamyl transpeptidase, mean corpuscular volume, uric acid, triglyceride, and aspartate aminotransferase. In men, but not in women, there was a clear increase in this probability with increasing test results for these five tests, which may prove useful in the detection of individuals who are at risk from their drinking habits.
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PMID:Estimation of alcohol intake from laboratory results. 3 27

The activity of the red blood cell enzymes transketolase, glutathione reductase, and aspartate transaminase, and their activation by the coenzymes thiamine, riboflavin, and pyridoxine, the pyruvate tolerance test, the leucocyte vitamin C concentration, and the activity in serum of gamma-glutamyl transferase were measured in a series of 35 patients with alcohol-related illness. The incidence of thiamine deficiency was 31% as assessed by the activation of transketolase, and 55% as assessed by the pyruvate tolerance test. The incidence of riboflavin deficiency was 23% and of ascorbic acid deficiency 91%. No cases of pyridoxine deficiency were detected. The pyruvate tolerance test was found to be a more sensitive test of thiamine deficiency than the transketolase activation, and the activation of red blood cell aspartate transaminase was found to be a poor indicator of pyridoxine deficiency. There was a poor correlation of the gamma-glutamyl transferase activity with the degree of vitamin deficiency, suggesting that alcohol exposure is only partly responsible for the observed vitamin deficiency.
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PMID:Detection and incidence of B and C vitamin deficiency in alcohol-related illness. 3 28

Increased serum activities of the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) occurred in 12 out of 19 patients with idiopathic parkinsonism when they were treated with the ergot derivative lergotrile at an oral dose varying from 50 to 150 mg daily. Hepatocellular injury was confirmed by microscopic examination of liver biopsies obtained from 3 of these patients when the serum activities of ALT and AST were appreciably elevated. Light microscopy revealed features of mild acute hepatocellular injury, and electron microscopy showed proliferation of the smooth endoplasmic reticulum and apparently unique mitochondrial changes in hepatocytes. This is the first report of pathological changes in the liver associated with the therapeutic use of an ergot derivative. The presence of a potentially reactive cyanide group in the lergotrile molecule could be causally related to the observed hepatocellular injury. It is suggested that serum ALT and AST activities should be monitored carefully when the therapeutic potential of any new ergot derivative is assessed.
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PMID:Hepatocellular injury with distinctive mitochondrial changes induced by lergotrile mesylate: a dopaminergic ergot derivative. 3 55

A method for the purification of mitochondrial isoenzyme of sheep liver aspartate aminotransferase (EC 2.6.1.1) is described. The final preparation is homogeneous by ultracentrifuge analyses and polyacrylamide-gel electrophoresis and has a high specific activity (182 units/mg). The molecular weight determined by sedimentation equilibrium is 87,100 +/- 680. The amino acid composition is presented; it is similar to that of other mitochondrial isoenzymes, but with a higher content of tyrosine and threonine. Subforms have been detected. On isoelectric focusing a broad band was obtained, with pI 9.14. The properties of the mitochondrial aspartate aminotransferase are compared with those of the cytoplasmic isoenzyme. The Km for L-aspartate and 2-oxoglutarate for the cytoplasmic enzyme were 2.96 +/- 0.20 mM and 0.093 +/- 0.010 mM respectively; the corresponding values for the mitochondrial form were 0.40 +/- 0.12 mM and 0.98 +/- 0.14 mM. Cytoplasmic aspartate aminotransferase showed substrate inhibition by concentrations of 2-oxoglutarate above 0.25 mM in the presence of aspartate up to 2mM. The mitochondrial isoenzyme was not inhibited in this way. Pi at pH 7.4 inhibited cytoplasmic holoenzyme activity by up to about 60% and mitochondrial holoenzyme activity up to 40%. The apparent dissociation constants for pyridoxal 5'-phosphate were 0.23 micrometer (cytoplasmic) and 0.062 micrometer (mitochondrial) and for pyridoxamine 5'-phosphate they were 70 micrometer (cytoplasmic) and 40 micrometer (mitochondrial). Pi competitively inhibited coenzyme binding to the apoenzymes; the inhibition constants at 37 degree C were 32 micrometer for the cytoplasmic isoenzyme and 19.5 micrometer for the mitochondrial form.
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PMID:Some kinetic and other properties of the isoenzymes of aspartate aminotransferase isolated from sheep liver. 3 56

Rose-bengal-sensitized photooxidation of aspartate transaminase from chicken heart cytosol results in a loss of enzymatic activity which follow first order kinetics down to 70--75% inactivation. 0.9 Histidine, 0.9 tryptophane residues and 1.5 SH groups per enzyme subunit were found to be modified in the photooxidized transaminase, which retained 26% residual activity. Photodestruction of the coenzyme was about 16%. The rate of enzyme photoinactivation is constant in the pH range 6--8, and drastically decreases with lowering pH from 6 to 4. alpha-Ketoglutarate partially protects the holoenzyme from inactivation. The apoenzyme undergoes photoinactivation at a rate almost twice as rapid as the holoenzyme. Photooxidized apotransaminase retains affinity to pyridoxal phosphate and binds as much coenzyme as the native apoenzyme. Photooxidation induces no significant alterations in the circular dichroism pattern of the enzyme in the 200 to 240 nm range. However, positive circular dichroism is markedly increased in the absorption bands of aromatic amino acids (260--300 nm). The affinity of photooxidized holoenzyme for glutarate and alpha-methyl aspartate is greatly decreased. On the other hand, photooxidized enzyme retains its ability to bind alpha-alanine and to catalize the transamination half-reaction between alpha-alanine and the bound coenzyme. These findings imply that photooxidation disturbs the binding of the distal carboxyl group of dicarboxylic substrates. This may be due to a localized conformational change induced by destruction of a photoreactive histidine residue at the active site. A role of the histidine residue in transamination reaction is discussed.
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PMID:[Photooxidation of aspartate transaminase from chicken heart cytosol]. 3 52

In the adult rat kidney, alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.1) and D-amino acid oxidase (EC 1.4.3.3) were measured in glomeruli, 4 parts of the proximal tubule, 2 parts of the distal tubule and in patches from the thin limb area and the papilla. These enzymes were measured in more limited parts of the nephron during postnatal development. Adult aspartate aminotransferase activities (percentage of the highest) ranged from 100 in the distal straight segment to 25 in the late part of the proximal straight segment to 10 in the thin limb and papillary area. Alanine aminotransferase (lower by a factor of 100 in absolute terms) was distributed as the mirror image of aspartate aminotransferase within proximal and distal tubules. D-Amino acid oxidase was 850-fold higher in proximal straight segments than in medullary structures. During development alanine aminotransferase increased 6-fold and D-amino acid oxidase, 4.5-fold in proximal straight tubules but aspartate aminotransferase increased in distal straight tubles 8-fold.
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PMID:Distribution of two aminotransferases and D-amino acid oxidase within the nephron of young and adult rats. 3 98

Liver of rat foetuses from 14 to 19 days of gestation and cultured hepatocytes derived from foetuses of 14 or 15 days gestation show a limited capacity to transaminate tyrosine. This low tyrosine transamination activity can be ascribed to aspartate aminotransferase. Definitive tyrosine aminotransferase can be demonstrated in 1-day-old cultures of hepatocytes taken from 19-day foetuses, but not from 15-day foetuses. However, after 3 days of culture hepatocytes from 15-day foetuses are able to synthesize tyrosine aminotransferase. Induction studies reveal that dexamethasone is capable of increasing tyrosine aminotransferase activity once it is detectable in culture.
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PMID:Hepatocyte differentiation in culture. Appearance of tyrosine aminotransferase. 3 44

Serum gamma-glutamyl transferase (GGT, EC. 2.3.2.2. was measured in 173 patients with diseases of the hepatobiliary system (including metastatic cancer) and in 90 patients who were subsequently shown to have primary diseases of other etiology. All patients had been selected because they had abnormal alkaline phosphatase, aspartate aminotransferase or bilirubin on SMA 12/60 screening. Serum GGT was elevated in 97% of patients with primary hepatobiliary disease. The magnitude of the increase in GGT was variable in all groups and was unhelpful in differential diagnosis, even between medical and surgical cases. Moreover, GGT was abnormal in 69 patients who did not have primary hepatobiliary disease (77%), an incidence higher than that for other enzyme tests performed. We conclude that because GGT was more susceptible than other tests to spurious elevation in the absence of hepatobiliary disease and was unhelpful in differential diagnosis, it has little value apart from monitoring alcohol abuse and enzyme induction.
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PMID:Lack of value of serum gamma-glutamyl transferase in the diagnosis of hepatobiliary disease. 3 86

A middle-aged adult male with a mild form of tyrosinemia II (Richner-Hanhart syndrome) is described. Treatment with a low-tyrosine diet caused a fall in plasma tyrosine and clearing of the hyperkeratosis of the soles. Liver biopsy of this patient revealed low but measurable levels of cytoplasmic tyrosine aminotransferase and elevated levels of the mitochondrial tyrosine-metabolizing enzyme aspartate aminotransferase. It is hypothesized that these enzymes have been induced in sufficient amounts to account for the mild clinical course.
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PMID:Hepatic enzymes of tyrosine metabolism in tyrosinemia II. 4 76

Three harp seal pups, Phoca groenlandica, were captured on the ice of the Gulf of St. Lawrence, and subjected to 3 h of transportation and handling stress. The activities of creatine kinase (CK), aspartate aminotransferase (AspAT), aldolase, alanine aminotransferase, gamma glutamyl transpeptidase, and leucine aminopeptidase were determined in serial blood samples collected for 4 d following the stress episode. Marked elevation of plasma CK activity was observed 3 h after capture. Values returned to normal in 12 h in two seals, and by 24 h in the third. Slight elevations in AspAT were also noted; the remaining enzymes were unaffected. Plasma CK is recommended as a sensitive indicator of handling stress in seals.
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PMID:Effects of handling stress on plasma enzymes in harp seals, Phoca groenlandica. 4 15


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