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)

The activities of serum aspartate aminotransferase (EC 2.6.1.1, L-aspartate: 2-oxoglutartate aminotransferase, ASAT) and alanine aminotransferase (EC 2.6.1.2, L-alanine: 2-oxoglutarate aminotransferase, ALAT) were determined in the sera of 1484 apparently healthy subjects using kinetic methods according to the Scandinavian recommendation (33). In the adult sera the mean activity of ASAT was 21.4
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PMID:Activities of aspartate and alanine aminotransferases and alkaline phosphatase in sera of healthy subjects. 115 24

The influence of bovine somatotropin in acute CCl4 poisoning was studied in rabbits. Somatotropin was injected subcutaneously in doses of 2.5 mg/kg. Liver damage was assessed on the basis of alanine and aspartate aminotransferase and aldolase activities. STH injected during 10 experimental days or 5 days preceding experimental poisoning with CCl4 did not increase the degree of liver damage in comparison with the group of animals injected only with carbon tetrachloride.
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PMID:Influence of bovine somatotropin on the liver experimentally damaged with carbon tetrachloride. 116 53

1. In order to assess whether the potential ability of heart ventricular muscle and liver to metabolise substrates such as alanine, aspartate and lactate varies as the sheep matures and its nutrition changes, the activities of the following enzymes were determined in tissues of lambs obtained at varying intervals between 50 days after conception to 16 weeks after birth and in livers from adult pregnant ewes: lactate dehydrogenase (EC 1.1.1.27), alanine aminotransferase (EC 2.6.1.2), pyruvate kinase (EC 2.7.1.40), pyruvate carboxylase (EC 6.4.1.1), phosphoenolpyruvate carboxykinase (GTP)(EC 4.1.1.32), malate dehydrogenase (EC 1.1.1.37), aspartate aminotransferase (EC 2.6.1.1) and citrate (si)-synthase (EC 4.1.3.7). 2. In the heart a most marked increase in alanine aminotransferase activity was found throughout development. During this period the activities of citrate (si)-synthase, lactate dehydrogenase and pyruvate carboxylase also increased. There were no substantial changes in the activities of aspartate aminotransferase, malate dehydrogenase or pyruvate kinase. Pyruvate kinase activities were five times greater in the heart compared with those found in the liver. No significant activity of phosphoenolpyruvate carboxykinase (GTP) was detected in heart muscle. 3. In the liver the activities of both alanine aminotransferase and aspartate aminotransferase increased immediately following birth although the activity of alanine aminotransferase was lower in livers of pregnant ewes than in any of the lambs. As with alanine aminotransferase the highest activities of lactate dehydrogenase were found during the period of postnatal growth. No marked changes were observed in malate dehydrogenase or citrate (si)-synthase activities during development. A small decline in pyruvate kinase activity occurred whilst the activities of pyruvate carboxylase and phosphoenolpyruvate carboxykinase (GTP) tended to rise during development.
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PMID:Activities of enzymes concerned with pyruvate and oxaloacetate metabolism in the heart and liver of developing sheep. 117 28

1. Bicarbonate stimulates the activity of rat brain cytoplasmic and mitochondrial alanine aminotransferase (EC 2.6.1.2) probably due to the enhanced affinity for its substrates. 2. Under the same conditions, the activity of crystalline aspartate aminotransferase was inhibited. 3. The role of bicarbonate buffer in regulation of alanine aminotransferase activity and synthesis of alanine are discussed.
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PMID:Effect of bicarbonate buffer on the activity of cytoplasmic and mitochondrial alanine aminotransferase. 117 9

The sequences of the coenzyme-binding peptide of both cytoplasmic and mitochondrial aspartate aminotransferases from sheep liver were determined. The holoenzymes were treated with NaBH4 and digested with chymotrypsin; peptides containing bound pyridoxal phosphate were then isolated. One phosphopyridoxyl peptide was obtained from sheep liver cytoplasmic aspartate aminotransferase. Its sequence was Ser-Ne-(phosphopyridoxyl)-Lys-Asn-Phe. This sequence is identical with that reported for the homologous peptide from pig heart cytoplasmic aspartate aminotransferase. Two phosphopyridoxyl peptides with different RF values were isolated from the sheep liver mitochondrial isoenzyme. They had the same N-terminal amino acid and similar amino acid composition. The mitochondrial phosphopyridoxyl peptide of highest yield and purity had the sequence Ala-Ne-(phosphopyridoxyl)-Lys-Asx-Met-Gly-Leu-Tyr. The sequence of the first four amino acids is identical with that already reported for the phosphopyridoxyl tetrapeptide from the pig heart mitochondrial isoenzyme. The heptapeptide found for the sheep liver mitochondrial isoenzyme closely resembles the corresponding sequence taken from the primary structure of the pig heart cytoplasmic aspartate aminotransferase.
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PMID:The sequences of the coenzyme-binding peptide in the cytoplasmic and the mitochondrial aspartate aminotransferases from sheep liver. 118 Aug 94

Octanoate and L-palmitylcarnitine inhibited the synthesis of P-enolpyruvate from alpha-ketoglutarate and malate by isolated guinea pig liver mitochondria. A 50% reduction in P-enolpyruvate formation was obtained with 0.1 to 0.2 mM octanoate or with 0.06 to 0.10 mM L-palmitylcarnitine. At these concentrations, oxidative phosphorylation remained intact and only much higher concentrations of fatty acids altered this process. The addition of NH4Cl in the presence of malate and increasing concentrations of alpha-ketoglutarate (or vice versa) enhanced the formation of glutamate, aspartate, and P-enolpyruvate. The addition of increasing concentrations of NH4Cl in the presence of fixed amounts of malate and alpha-ketoglutarate had a similar effect. Furthermore, the inhibition of P-enolpyruvate synthesis by fatty acids and the reduction of the acetoacetate to beta-hydroxybutyrate ratio were reversed by the addition of NH4Cl. Cycloheximide, which blocks energy transfer at site 1 of the respiratory chain, decreased P-enolpyruvate formation. When cycloheximide and either octanoate or L-palmitylcarnitine were added together, there was an even greater reduction in P-enolpyruvate synthesis from either malate or alpha-ketoglutarate than was noted with either fatty acid alone. Since cycloheximide lowers the rate of ATP synthesis this may in turn reduce P-enolpyruvate formation by a mechanism independent of changes in the mitochondrial NAD+/NADH ratio caused by fatty acids. In the isolated perfused liver metabolizing lactate, the inhibitory effect of octanoate on gluconeogenesis was partially relieved by the addition of 1 mM NH4Cl, but remained unchanged in the presence of 2 mM NH4Cl, despite a highly oxidized NAD+/NADH ratio in the mitochondria. In contrast to glucose synthesis, urea formation was markedly increased during the infusion of 1 mM as well as 2 mM NH4Cl. After cessation of NH4Cl infusion, there was an increase in glucose production, to a rate as high as that observed in the absence of octanoate. This increase was accompanied by the disappearance of alanine, aspartate, and glutamate which had been stored in the liver during NH4Cl infusion. Urea synthesis also decreased progressively. These results indicate that gluconeogenesis in guinea pig liver is regulated, in part, by alterations in the mitochondrial oxidation-reduction state. However, the modulation of this effect by changing the concentrations of intermediates of the aspartate aminotransferase reaction indicates competition for oxalacetate between the aminotransferase reaction and P-enolpyruvate carboxykinase.
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PMID:Regulation of hepatic gluconeogenesis in the guinea pig by fatty acids and ammonia. 119 71

Untrained rats were subjected to a single intense physical effort. In the plasma the activity of alanine aminotransferase, aspartate aminotransferase, and the concentrations of amino acids: glycine, cystine, alanine and leucine with isoleucine were measured. The results were compared with the data obtained in a control group. Despite lack of statistically significant differences in the activity of aminotransferases and concentration of amino acids between these groups a correlation was found between the activity of AIAT and alanine concentration in the animals after exercise. The concentration of alpha-amino nitrogen was decreased statistically significantly in the group of animals subjected to intensive exercise.
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PMID:The effect of a single intense effort on the activity of aminotransferases and concentration of free amino acids in the plasma of rats. 119 42

1. Isolated hepatocytes were used to establish the reasons for the accumulation of aspartate, previously observed when the isolated rat liver was perfused with ethanol in the presence of alanine or ammonium lactate. 2. The isolated cells did not form aspartate when incubated with alanine and ethanol, but much aspartate was formed on incubation with ammonium lactate and ethanol. 3. Urea was the main nitrogenous product on incubation with alanine, in contrast with the perfused liver, where major quantities of NH4+ are also formed. When the formation of urea was nullified by the addition of urease, alanine plus ethanol caused aspartate formation, indicating that aspartate formation depends on the presence of critical concentrations of NH4+. 4. The accumulated aspartate was present in the cytosol. Ethanol halved the content of 2-oxoglutarate in the cytosol and more than trebled that of glutamate in the mitochondria. 5. The findings support the assumption that 2-oxoglutarate formed by the mitochondrial aspartate aminotransferase is not translocated to the cytosol in the presence of ethanol and NH4+, because it is rapidly converted into glutamate, the dehydrogenation of ethanol providing the required NADH. Aspartate, however, is translocated to the cytosol and accumulates there because of the lack of stoicheiometric amounts of oxoglutarate.
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PMID:The accumulation of aspartate in the presence of ethanol in rat liver. 120 Oct 7

In embryos of loach (Misgurnus fossilis) obtained from zygotes, which were incubated for 30 min in the D,L-aspartate solution the alanine aminotransferase activity is 2-4 times as high as in the control embryos. The most essential influence of this amino acid is found in the gastrula -- from 12 till 18 h after fertilization. The aspartate aminotransferase activity under these conditions does not undergo the essential changes. D,L-alanine and adenine do not affect the activity of the both enzymes during primary stages of development, but adenine as well as cytidine reduce the action of aspartate carbamoyltransferase of embryos 3, 6 and 3 h after the beginning of fertilizatio, respectively. The decrease in the aspartate carbamoyltransferase activity is revealed in the unfertilized eggs after 2 h of incubation in the solutions of estrone and thyroxine. Cytidine alone under these conditions has no definite influence, but removes the inhibitory effect of estrone. The regularities were established in changes of the activity of above mentioned enzymes of embryos under physiological conditions of development.
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PMID:[Activity of aspartate carbamoyltransferase, alanine and aspartate aminotransferases in loach embryos after incubation of zygotes in solutions of bioorganic compounds]. 124 Jun 68

Pulsed Fourier transform proton magnetic resonance spectroscopy was used to study the glutamate-alanine transaminase-catalyzed incorporation of deuterium from solvent deuterium oxide into the alpha and beta positions of L-alanine. It was found that the beta proton resonance signal initially disappears slightly faster than the signal due to the alpha proton, but whereas the alpha proton signal decays exponentially, that due to the beta proton signal does not. Eventually, the rate of decrease of the alpha proton signal becomes greater than that for the beta proton. This change in the relative rates is ascribed to a deuterium isotope effect upon substitution of an alpha proton by a deuteron. Furthermore, as deuterium begins to replace hydrogen, two classes of alanine become distinguishable, i.e. alanine which contains deuterium in the alpha position and hydrogen in the beta position, and alanine which contains hydrogen in the alpha position and deuterium in the beta position. Thus, removal of all 3 beta protons is not contingent upon loss of an alpha proton from the same molecule. The two classes of deuterated alanine may conceivably arise by a scrambling mechanism in which protons are transferred from the alpha to the beta position and vice versa. Present evidence excludes this scramblong mechanism and leads to the conclusion that deuterium incorporation into L-alanine involves, (a) the reversible enzymatic conversion of the classical ketimine enzymes intermediate to an enaminetype structure, and (b) considerable conservation of label during the prototropic shift from the alpha carbon of L-alanine to the C4-position of pyridoxal 5'-phosphate. It is also postulated that alanine binds at the active site in such a way as to bring the beta protons into close contact with a basic group on the enzyme surface. This group is distinct from that used in abstraction of an alpha proton. The beta protons of glutamate are not enzymatically removed; presumably glutamate binds in such a way that the beta protons cannot effectively interact with an enzyme base. Similar studies were carried out on soluble glutamate-aspartate transaminase; no evidence was found for significant enzyme-catalyzed deuterium incorporation into the beta position of L-glutamate, L-aspartate, and L-alanine.
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PMID:Proton magnetic resonance studies of glutamate-alanine transaminase-catalyzed deuterium exchange. Evidence for proton conservation during prototropic transfer from the alpha carbon of L-alanine to the C4-position of pyridoxal 5'-phosphate. 124 68


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