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)

Rate of incorporation of 1-14C-glycine in total protein and subcellular fractions of rat liver tissue as well as the activity of alanine- and aspartate aminotransferases in blood serum were studied at various periods after treatment with CCl4. The protein synthesis was distinctly decreased in liver tissue and the alanine aminotransferase activity was markedly increased in blood serum with the first days after CCl4 administration. Dissimilar alterations were observed in the rate of the label incorporation into nuclear and mitochondrial fractions after prolonged administration of CCl4. Hepatocyte nuclei proved to be more sensitive to cytoplasmic alterations caused by tetrachlormethane. Incorporation of 1-14C-glycine into both nuclear and mitochondrial fractions was decreased only at later periods. In blood serum the alanine aminotransferase activity was drastically increased after prolonged administration of CCl4, whereas the aspartate aminotransferase activity was increased as compared with control less markedly.
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PMID:[Incorporation of 1-14C-glycine into total protein and subcellular fractions of rat liver at different periods following administration of tetrachlormethane]. 85 28

Incubation of rat brain 4-aminobutyrate aminotransferase with 4-amino-hex-5-enoic acid, a substrate analog of 4-aminobutyric acid, results in a time-dependent irreversible loss of enzymatic activity. In the presence of 0.1 mM inhibitor the half-life of the inactivation process is approximately 6 min. Low concentrations of L-glutamic acid or 4-aminobutyric acid protect against this inactivation, while 2-oxoglutarate prevents this protection, suggesting that only the pyridoxal form of the enzyme is susceptible to inhibition by 4-amino-hex-5-enoic acid. The irreversible inhibition of mammalian 4-aminobutyrate aminotransferase by 4-amino-hex-5-enoic acid is selective. There is no inhibition of this enzyme from Pseudomonas fluorescens with the inhibitor at mM concentrations. Even at 10 mM there is no irreversible inhibition of mammalian glutamate decarboxylase or of aspartate aminotransferase, while alanine aminotransferase is inhibited over 500 times more slowly than rat brain 4-aminobutyrate transaminase.
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PMID:4-amino-hex-5-enoic acid, a selective catalytic inhibitor of 4-aminobutyric-acid aminotransferase in mammalian brain. 85 82

In a group of 113 consecutive patients taken into a coronary care unit on suspicion of acute myocardial infarction, blood samples were taken every 6 h and the following enzyme activities were measured: creatine kinase (S-CK), aspartate aminotransferase (S-ASAT), alanine aminotransferase (S-ALAT) and lactate dehydrogenase (S-LD). All measurements were made according to the Recommendations of the Scandinavian Committee on Enzymes. On all patients S-CK B subunit activity was determined by immunoinhibition with a specific anti CK M-subunit inhibitory antibody. At peak values of the respective total enzyme activities CK and LD isoenzymes were further qualitatively estimated by electrophoresis. The data indicate that even serial determinations of total CK, ASAT, ALAT and LD activities in serum do not provide the information required for a conclusive diagnosis of myocardial infarction in the individual case. In contrast, the positive predictive value (PV) of S-CK B was found to be 1.0 and the negative predictive value was 0.98. S-CK MB showed a PV pos. of 1.0 and also a PV neg. of 1.0. Electrophoretic determination of S-LD isoenzymes was slightly poorer with a PV pos. of 0.96 and PV neg. of 0.98. S-CK, total activity with nearly 9 per cent false positives had a positive predictive value of only 0.91, but a negative one of 1.0.
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PMID:Creatine kinase B-subunit activity in human serum. II. Evaluation of s-ck b-subunit activity in the diagnosis of acute myocardial infarction. 88 49

Feeding a pyridoxine deficient diet, for 2 weeks after hatching, had no effect on post-hatching development of chick brain aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) activity or on cholesterol deposition in the brain, but significantly depressed the development of brain alanine aminotransferase (L-alanine:2-oxoglutarate aminotransferase, EC 2.5.1.2) activity. Feeding a pyridoxine deficient diet from 3 to 8 weeks of age had no effect on any of the three parameters studied.
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PMID:Pyridoxine deficiency and postnatal development of brain aspartate and alanine aminotransferase activities, and cholesterol levels in chicks. 89 57

A modern approach is described for the evaluation of the optimal conditions for two-substrate enzyme reactions. It chiefly involves the determination of the concentration of substrates for the primary reaction and the catalytic concentration of indicator enzymes. The interrelationship between the concentration of the two substrates (concentration pairs) are described mathematically to be hyperbolic, and, in case of competitively inhibited reactions, to be parabolic. Calculated optimum concentrations have been rechecked experimentally for the reactions of aspartate aminotransferase and alanine aminotransferase. For pyridine coenzyme linked indicator reactions it could be demonstrated that they mostly follow zero order kinetics. One of the products of the primary reaction reacts, in its steady state concentration, as the second substrate. This represents the size of the lag phase of the coupled reaction. The Km of this substance must be known in order to calculate the catalytic concentration of the indicator enzyme in relation to that of the primary enzyme. Its concentration can be fixed arbitrarily within certain limits, depending on whether the calculated result actually can be realized; otherwise a larger lag phase must be tolerated. For practical reasons, it is generally possible to measure only a certain percentage of maximum reaction rate.
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PMID:Evaluation of optimum conditions of two-substrate enzyme reactions. 91 39

Administration of thyroxine toxic doses to rats results in a considerable increase in the alanine aminotransferase and aspartate aminotransferase activity in nuclear, mitochondrial and supernatant fractions of the rat heart. The hormone action is more pronounced in the mitochondrial fraction. A simultaneous administration of thyroxine and actinomycin D decreases the hormone effect in case of nuclear and supernatant enzymes. The enzymes of mitochondrial fractions do not change after actinomycin D injection. It is possible to suggest that in mitochondria there occurs a synthesis of some enzymes.
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PMID:[Thyroxine induction of aminotransferases in subcellular fractions of rat heart]. 91 49

Neddle biopsies of the liver were performed in 121 cases of sarcoidosis. Granulomas compatible with sarcoidosis were seen in 24 percent of the cases. Liver function tests (serum alkaline phosphatase, serum aspartate aminotransferase, serum alanine aminotransferase, and bromsulphthalein clearance test) were performed on 325 patients with sarcoidosis and on 132 with non-sarcoid erythema nodosum (EN). Pathological findings were seen especially in patients with extensive EN, without any correlation with the disease responsible for the eruption. Hepatic granulomas were found more often in patients with sarcoid changes in lung parenchyma than in those with bilateral hilar adenitis only. There were no other definite correlations between hepatic granulomas and other clinical and laboratory findings. The incidence of pathological results in this study was clearly lower than, e.g., in the USA, thus reflecting the good prognosis of sarcoidosis in the Scandinavian countries.
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PMID:The liver in sarcoidosis. 92 Feb 48

Comparative determinations of aspartate aminotransferase and alanine aminotransferase activities were made with so-called "optimised" methods introduced in the G.D.R., G.F.R. and Scandinavia. By means of the paired t-test significant differences could be established. These differences are partly due to different reaction conditions. For practical clinical aspects these differences should be of little relevance. In comparison with above-mentioned activites determined at 37 degrees C, aspartate aminotransferase activities measured with the IFCC reference method are lower by about 30 percent.
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PMID:Comparative determinations of aminotransferase activities in serum with so-called "optimised" methods. 92 5

The method for the determination of enzymic activity in turbid, lipaemic sera, which involves clearing by polyanion precipitation with heparin and magnesium chloride, was critically reviewed. In the diagnosis of diseases of the liver and pancreas, which are frequently associated with hyperlipoproteinaemia, only residual enzyme activities are measured in the cleared serum after polyanion treatment. In the measurement of glutamate dehydrogenase and in the Phadebas test for alpha-amylase, the enzymes are inactivated by treatment with heparin and magnesium chloride. On the other hand, as a result of polyanion precipitation gamma-glutamyl transferase is transferred, together with lipoproteins and chylomicrons, to the lipid-rich supernatant. Acid phosphatase also exhibits only residual activity in cleared serum. The activity of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, leucine arylamidase, cholinesterase, creatine kinase, lactate dehydrogenase, and alpha-hydroxybutyrate dehydrogenase, and the activity of alpha-amylase in the Merckotest are not affected by polyanion treatment of the serum.
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PMID:[Enzyme diagnosis in lipaemic sera before and after polyanion precipitation with heparin and magnesium chloride (author's transl)]. 92 35

The rate of distribution of cell enzymes between the intravascular and extravascular space was studied, following a sudden decrease of enzyme activities in plasma. This rapid decrease of enzyme activities was achieved in rats by a rapid exchange of the blood with a twofold volume of a suspension of homologous erythrocytes in isoosmolar bovine serum albumin solution. After this plasmapheresis, the activities of seven cell enzymes in the plasma were decreased to 14 to 22% of their original values. The subsequent increase in activities showed different kinetics, depending on the enzyme. After 120 min, creatine kinase had reached the starting activity; malate dehydrogenase and aldolase reached their original activities after 180 min. Aspartate aminotransferase, glutamate dehydrogenase, alanine aminotransferase and pyruvate kinase increased more slowly and they had still not reached their starting values after 240 min. Repetition of the plasmapheresis after 90 min had no obvious effect on the kinetics of the subsequent activity increase. During the first minutes after plasmapheresis the adjustment of the activity equilibrium between the interstitial and the intravascular compartments depends mainly on the capillary permeability. It is therefore possible to determine half-life constants for the distribution of enzymes within the extracellular space. The constants for malate dehydrogenase and aldolase are almost identical with those determined by intravenous injection, whereas there are discrepancies in the constants for the remaining enzymes. The constants for pyruvate kinase and glutamate dehydrogenase are significantly lower, while those for aspartate aminotransferase, alanine aminotransferase and creatine kinase are significantly higher, than those determined after intravenous injection. Possible reasons for these differences are disucssed.
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PMID:[Plasmapheresis as an experimental model for studies on the extracellular distribution of enzymes. Distribution and transport of cell enzymes within the extracellular space. IV (author's transl)]. 93 47


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