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)

The activity of the aspartate-, alanine-, tyrosine-, phenylalanine- and tryptophane aminotransferases in the rat organes in development have been investigated by quantitative histochemical methods. The isoenzymes have also been examined. The variable increase of the aminotransferase activity has been observed in the liver, brain, heart, skeletal muscle and kidney. In spite of the differences of the aspartate aminotransferase activity in the organs, the increase up to the 7th postnatal day, the reduction after that and the repeated increase after the 14th day reaching the level of the adult animals is evident as a common trend. A considerable increase of the alanine aminotransferase activity has been observed in the late postnatal period. While the difference in the activity of the aromatic aminotransferases in the embryonic organs is small, the changes of the 3 enzymes are different in the postnatal development. The number and the intensity of the isoenzymes of the aspartate- and alanine aminotransferases increase in the development. The isoenzyme spectrum of aromatic aminotransferases in the embryo proves an equal in number and intensity of fractions. In the development this similarity is preserved only with regard to cathode isoenzymes, while with anode once some differences appear.
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PMID:Histochemical evidence of aminotransferases. 82 67

Data are provided which indicate that pyruvate and/or acetaldehyde can reverse the inhibition of alanine aminotransferase and aspartate aminotransferase by amino-oxyacetate. It was shown that acetaldehyde could reverse the inhibition of gluconeogenesis from alanine and that pyruvate could reverse the inhibition of urea synthesis by amino-oxyacetate.
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PMID:Re-evaluation of amino-oxyacetate as an inhibitor. 84 92

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

The present study was undertaken to test the hypothesis that muscle phosphorylase may function as a repository for vitamin B6 in the animal. Since a repository would be expected to accumulate surplus material, one would predict that phosphorylase, which contains stoichio-metric amounts or pyridoxal phosphate, would increase in muscle of animals surfeited with the vitamin. Rats were fed a vitamin B6-free diet supplemented with pyridoxine providing levels 10, 1.0 and 0.1 of those recommended by the National Research Council (NRC). At the high intake level, muscle phosphorylase and total muscle vitamin B6 increased steadily and in almost constant ratio for at least 6 weeks, whereas both alanine and aspartate transaminase increased initially, but reached a plateau within 2 weeks. At the intermediate level of pyridoxine intake, muscle phosphorylase also increased, but less rapidly than in rats fed the higher level. When vitamin B6 intake was restricted to 10% of the NRC-recommended level, no increase in phosphorylase concentration occurred during a period of 10 weeks. These results support the hypothesis that muscle phosphorylase acts as a reservoir for vitamin B6 in the animal and provide experimental evidence that muscle enzyme content expands as vitamin is accumulated during high dietary intake.
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PMID:Increased muscle phosphorylase in rats fed high levels of vitamin B6. 90 52

The pyridoxal form of both cytosolic and mitochondrial aspartate aminotransferase is irreversibly inactivated consequent to its interaction with the beta,gamma-unsaturated substrate analogue vinylglycine. Per catalytic cycle, 90% of the enzyme molecules are inactivated while 10% escape inactivation by transamination to the pyridoxamine form. In the presence of vinylglycine plus 2-oxoglutarate, inactivation is complete because of retransamination of the pyridoxamine form to the susceptible pyridoxal form. Peptide analyses after inactivation with [1-14C]vinylglycine showed that vinylglycine alkylates the active-site lysine residue 258 which forms the internal aldimine with the coenzyme pyridoxal 5'-phosphate. The coenzyme itself is left intact; resolution of the inactivated enzyme by base or trichloroacetic acid yields pyridoxal-5'-P. The absorption spectrum of the inactivated enzyme (lambdamax 335 nm) suggests that the cofactor is bound as a substituted aldimine. The proposed pathway of alkylation of Lys-258 involves abstraction of the alpha proton from vinylglycine, isomerization to the alpha,beta-unsaturated enamine, and subsequent nucleophilic attack of the epsilon-amino group of the lysyl residue at the beta carbon of the inhibitor. The determination of the amino acid sequence around the coenzyme-binding lysyl residue in the mitochondrial isoenzyme from chicken gave Ala-(epsilon-Pxy)Lys-Asn-Met-(Gly,Leu,Tyr) which is identical with the other mitochondrial transaminases examined so far.
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PMID:Active-site labeling of aspartate aminotransferases by the beta,gamma-unsaturated amino acid vinylglycine. 91 93

This report summarizes a one year evaluation of Abbott's ABA 100, with respect to mechanical parts (syringe plates, precision and linearity of photometry, band width of several filters, multicuvet precision, temperature control) and the reliability of several methods (endpoint procedures: determination of the glucose concentration with hexokinase- and the glucose dehydrogenase method, and of the protein concentration; enzyme activities: alanine and aspartate aminotransferase, creatine kinase, alkaline phosphatase). The critical batch size was estimated as an indicator of economy (about 40 samples per day for the glucose concentration). Various aspects of the instrument are discussed with respect to its use in clinical chemistry.
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PMID:Evaluation of the Abbott Bichromatic Analyzer 100 (A proposal for an evaluation scheme). 95 29

Abnormal lysyl residues can be detected in aspartate transaminase by following the rate of reaction of amino groups with KN14CO and the rate of enzymatic inactivation. Peptide isolation subsequent to carbamylation of the apoenzyme produces a peptide which is absent in the carbamylated holoenzyme. The composition of the carbamylated peptide matches that of a tryptic peptide containing the active site Lys-258. The holoenzyme retains full catalytic activity after carbamylation of its NH2-terminal alanine and lysyl residues other than Lys-258, which is protected by aldimine formation with pyridoxal phosphate. Apoenzyme prepared from KNCO-treated holoenzyme (apoenzyme') is susceptible to further carbamylation at Lys-258 with irreversible loss of catalytic activity. Carbamylation of the active site lysyl residue is 25 to 50 times more rapid than that of the other 18 lysyl residues of aspartate transaminase. The kinetics of inactivation by KNCO at different pH values served to determine the pH-independent second order rate constant (k) and the pK of the amino group of Lys-258. These values are pK = 7.98 +/- 0.08 and k = 146 +/- 5 M-1S-1, which are similar to the values determined for carbamylation of the NH2- terminal groups of human hemoglobin (Garner, M. H., Bogardt, R. A., and Gurd, E. R. N. (1975) J. Biol. Chem. 250, 4398-4404). The pK value for Lys-258 is as low as that for a group in the active site region which can perturb a 19F nuclear magnetic resonance probe inserted into that region (Martinez-Carrion, M., Slebe, J. C., Boettcher, B., and Relimpio, A. M. (1976) J. Biol. Chem. 251, 1853-1858). Apoenzyme carbamylated at Lys-258 can accept pyridoxal phosphate at the active site even though no Schiff base in formed. Furthermore, this active site carbamylated holoenzyme will form spectroscopically detectable enzyme-substrate complexes with amino acids. The complexes slowly convert to species with absorbance identical with that of enzyme in the pyridoxamine phosphate form.
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PMID:Carbamylation of aspartate transaminase and the pK value of the active site lysyl residue. 96 83

The activity of enzymes of glycine and alanine synthesis (glutamate-pyruvate aminotransferase, aspartate-beta-decarboxylase, threonine aldolase, serine hydroxymethyltransferase, alanine-glyoxylate aminotransferase, aspartate aminotransferase) is studied in haemolymph, fat body, fibroin and sericine divisions of silk gland of silkworm Bombyx mori at terminal period of larva development. Alanine-glyoxylate aminotransferase activity in fibroin division of silk gland (34,6 mu mole of glycine/mg of protein/min-10(-3)), alanine aminotransferase--in sericine division (36,0 mu mole of alanine/mg of protein/min-10(-3)) aspartate aminotransferase 27,3 mu mole of glutamic acid/mg of protein/min-10(-3)) and alanine aminotransferase (35,8 mu mole of alanine/mg of protein/min-10(-3)) on fat body. The ratio of alanine-glyoxylate aminotransferase/glutamate-pyruvate aminotransferase activities in posterior division of silk gland is near to glycine/alanine ratio in silk fibroin. The character of the enzymes activity in silkworm tissues correlates with the silk formation rate.
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PMID:[Glycine and alanine synthesis enzymes in the tissues of the silkworm during its development]. 99 78

Forty male guinea pigs were exposed to nitrogen dioxide in a concentration of 2 mg/m3, 8 hours daily for a period of 180 days. Forty male animals were used as a control group. The following changes were found in intoxicated animals: the decrease of total protein and seromucoid concentration in blood serum and the decrease of total protein, perchloric acid-soluble proteins, protein-bound hexosamines and sialic acids content, in liver tissue. Electrophoretic examination of the serum proteins showed the increase of alpha 1- and beta 2-globulins and the decrease of albumin concentration. Changes in the level of glycoproteins fractions and protein-bound carbohydrates in blood serum were described also. Estimation of enzymes activity showed the decrease of alanine and aspartate transaminase activity in blood serum caused by the strong decrease of the cytoplasmic fraction of these enzymes. However the simultaneous increase of the mitochondrial fraction of transaminases activity was observed. The decrease of the activity of choline esterase was found also. Similar changes of enzymes activity were found in liver tissue. Histopathological studies were done for the further clearing the influenze of nitrogen dioxide on serum and liver proteins concentration and enzymes activity. It was found that after long-term exposure to nitrogen dioxide the destruction processes may be observed in the liver. The possible mechanism of the nitrogen dioxide-induced damage of protein metabolism is discussed.
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PMID:Studies on the effect of long-term exposure to nitrogen dioxide on serum and liver proteins level and enzyme activity in guinea pigs. 100 97

In women employed in an industrial plant in direct contact with epoxide resins and their hardeners, the following biochemical parameters were determined in blood: total protein, seromucoid, haptoglobin, hemoglobin variants, methemoglobin, alpha1-inhibitor of trypsin, lactate dehydrogenase, aspartate and alanine aminotransferases, alkaline and acid phosphatase, gamma-glutamyl transpeptidase, leucylaminopeptidase, and alanine aminopeptidase. Depending on duration of work, Hb A2 fraction and lactate dehydrogenase increased significantly, and aspartate aminotransferase, acid and alkaline phosphatase activities decreased. In pregnant women, leucylaminopeptidase activity and isozyme of placental alkaline phosphatase were decreased.
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PMID:Evaluation of the influence of epoxide resins and their hardeners on the female body. II. Biochemical studies. 101 94


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