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PubMed1999

[Management of asymptomatic elevated serum aminotransferase levels, particularly in nonalcoholic steatohepatitis].

At routine determination of serum activities of transaminases (aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) increased levels are frequently found. An algorithm may be used in the analysis of elevated transaminase levels: after elimination of the most frequent causes of hepatitis (alcoholic hepatitis, chronic hepatitis B and C) and some rare conditions (autoimmune hepatitis, alpha 1-antitrypsin deficiency, haemochromatosis and Wilson's disease), the diagnosis will often be nonalcoholic steatohepatitis. Although nonalcoholic steatohepatitis is considered a stable disease, recent literature shows a progression to cirrhosis in 8-17%. So far, no effective therapeutic strategies are available for nonalcoholic steatohepatitis.

Adult↗
PubMed1975

Evaluation of the new "System Olli 3000" kinetic ultraviolet analyzer for measuring aspartate ana alanine aminotransferase and lactate dehydrogenase activities in serum.

A new fast kinetic analyzer, System Olli 3000, is evaluated as an instrument for the routine clinical laboratory measurement of the activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in serum. The System Olli 3000 consists of dispensers for simultaneous multiple dispensing of sample and reagents, incubators, vortex-type shakers, and a photometer with quartz fibre optics connected to a computer, allowing cycling measurements of 24 cuvets 24 times in 2 min. An unique slope search algorithm is described. The system shows a high degree of precision and a wide linearity range; activities of at least 10-fole the normal upper limit for all three of these enzymes can be measured without diluting the serum sample. As many as 380 analyses per hour (including calibration and blanks) can be carried out by one technician. For comparison, enzyme measurements were also made with an LKB 8600 Reaction Rate Analyzer and a Pye Unicam SP 8005 spectrophotometer coupled on-line to an IBM 1800 computer. Results obtained with the different instruments correlated well, especially in the region of main interest, i.e., above the normal upper limit. We conclude that the new instrument has many potentialities in kinetic analyses of nonenzymatic constituents in biological fluids.

Alanine Transaminase↗
PubMedDate not supplied

The effect of X-irradiation on the alanine--and aspartate aminotransferase activity in the liver, kidney and spleen of mouse.

The effect of X-irradiation on the alanine- and aspartate aminotransferase activity in the liver, kidney and spleen of mouse. Acta Physiol. Pol. 1975, 26 (1): 95-101. The alanine- and aspartate aminotransferase (GOT and GPT) activities and the protein content were measured in the liver, kidney and spleen homogenates of mice exposed to a single whole body X-irradiation with a 900 r dose. The assays were performed in 6 h intervals during the first day and 24 h intervals from the 2nd until the 6th day after the exposure. Significant differences in the enzymatic activity were found in the course of 24 h in control animals and a marked increase of this activity was found after irradiation. This may be explained by changes in the permeability of the mitochondrial membrane for enzyme molecules.

Alanine Transaminase↗
PubMedDate not supplied

[Aspartate aminotransferase from chicken heart cytosol. Characterization of SH-groups].

Homogeneous aspartate aminotransferase has been prepared from chicken heart cytosol. The purification procedure includes fractionation with NH4-sulfate and with ethanol, chromatography on ion-exchange cellulose DE-32 and on hydroxylapatite. Crystallization of the enyme is described. The enzyme was shown to contain 4 SH-groups per protein subunit of molecular weight 50 000. Two of the SH-groups are fully buried, they can be blocked with thiol reagents only upon denaturation of the protein. One exposed SH-group is readily modified at alkaline pH by iodoacetamide, N-ethymaleimide or tetranitromethane, without any inhibition of enzymic activity; this group readily reacts also with 5,5,-ditthiobis (2-nitrobenzoate) and p-mercuribenzoate. One SH-group is semi-buried: it is inaccessible to the above-mentioned reagents at pH 8, but can be blocked by p-mercuribenzoate at pH about 5. Blocking with p-mercuribenzoate of two SH-groups-the exposed and the semi-buried one-lowers enzymic activity to 70% of the initial value. Syncatalytic modication of a SH-group observed in aspartate aminotransferase from pig heart cytosol does not occur in chicken enzyme.

Animals↗
PubMed1975

[The influence of pyridoxal 5'-phosphate on the temperature relationships of aspartate aminotransferase isoenzymes].

The relationship between temperature and the behaviour of aspartate aminotransferase was investigated in the presence of pyridoxal 5'-phosphate. The addition in vitro of pyridoxal 5'-phosphate caused an increase in the activity and altered the thermal behaviour of aspartate aminotransferase. In choosing the temperature for the determination of enzymic activity, the concentration of the coenzyme must therefore also be considered.

Aspartate Aminotransferases↗
PubMed1975

[Ultrastructural location of aspartate aminotransferase in the cerebellum of mice].

The histochemical location of aspartate aminotransferase by ultrastructural observation in the mouse cerebellum has been investigated. The enzymatic activity was observed specifically in the fibre endings of basket cells and in the probable terminations of golgi cells axons. This observation suggests the intervention of aspartate aminotransferase in the specific function of the cerebellum inhibitor axons.

Animals↗
PubMedDate not supplied

[Activity of aspartate carbamoyltransferase, alanine and aspartate aminotransferases in loach embryos after incubation of zygotes in solutions of bioorganic compounds].

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.

Adenine↗
PubMedDate not supplied

Labilization of the phosphoester linkage in enzyme-inhibitor complexes of aspartate aminotransferase.

Individual enzyme-inhibitor complexes with characteristic absorption spectra have been obtained as a result of the reaction of the apoenzyme of aspartate aminotransferase with Nalpha-(5'-phosphopyridoxyl)-L-glutamic acid, Nalpha-(5'-phosphopyridoxyl)-D-glutamic acid, and Nalpha-(5'-phosphopyridoxyl)-L-pyroglutamic acid. The stability of the enzyme-inhibitor complexes has been investigated under various conditions, viz., reactivation by the coenzyme, denaturation by urea, variations in the pH. It has been shown that the complexes formed by the last two inhibitors are reactivated by pyridoxal-5'-phosphate and that the inhibitor can be released under mild conditions. The enzyme-inhibitor complex formed by Nalpha-(5'-phosphopyridoxyl)-L-glutamic acid, on the other hand, was not reactivated by the coenzyme. Pyridoxylglutamic acid has been isolate in attempts to release the inhibitor. The dephosphorylation of the inhibitor has been associated both with the hydrolysis of a phosphate bond involving the enzyme and with the phosphorylation of aspartate aminotransferase. A 32P peptide containing 13 amino acids has been isolated from the tryptic hydrolysate of the enzyme-inhibitor complex (formed by a 32P inhibitor). The data obtained have been interpreted on the basis of an assumption that the phosphate group of the coenzyme has an active role in the enzymatic transamination reaction.

Apoenzymes↗
PubMed2004

Sequential changes of serum aminotransferase levels in patients with severe acute respiratory syndrome.

Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease. To describe the hepatic injury caused by this disease, we report the sequential changes of serum transaminase in probable SARS patients during a hospital outbreak in southern Taiwan. From April to June, 2003, 52 probable SARS patients were hospitalized. Serial serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were retrospectively analyzed and hepatitis B surface antigen (HBsAg) was also evaluated to correlate with the progression of this disease. Fifty-three percent of the patients had abnormal liver function during hospitalization. More than 70% of abnormal transaminase levels were mildly elevated. Most elevated levels were noted during the second week after onset of fever. Neither transaminase elevation nor HBsAg was related to the prognosis of SARS, and only advanced age was an independent predictor of poor outcome. Our study suggested that coronavirus causing SARS might induce liver damage.

Adult↗
PubMedDate not supplied

[Supermolecular organization of aminotransferases and dehydrogenases of alpha-ketoacid from rat brain mitochondria].

A fraction of coarse mitochondria from the rat brain was deposited after short-term effect of supersound to obtain "metabolones". Activity of dehydrogenases of alpha-ketoacids, succinate dehydrogenase, aspartate-, alanine- and GABA-alpha-ketoglutarate amino-transferases has been determined in the supernatant liquid and in "metabolones". It is shown that dehydrogenase activity is mainly (93-100%) localized in "metabolones", while the level of aminotransferase activity in the latter is lower (72-94%). Nonproportionally high activity of aminotransferases in the supernatant liquid is found to considerably suprpass a decrease in activity of these enzymes in "metabolones" against a background of extremely scanty losses of protein (within 5%) induced by the supersound effect. A hypothetic model of a "metabolone" containing the enzymes of the Krebbs cycle and GABA-shunt is suggested.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1990

Alanine and aspartate aminotransferase activities in muscles of diabetic rats.

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.

Alanine Transaminase↗
PubMedDate not supplied

[Role of adrenoreceptors in regulating aspartate aminotransferase isoenzyme activity in albino rat hearts].

Cytoplasmic (c) and mitochondrial (m) isoenzymes of aspartate aminotransferase (AAT, EC 2.6.1.1.) were isolated from rat heart extracts by electrophoresis in agar gel. Their pH optima and Km values were estimated; optimal conditions for estimation of the enzymatic activities are reported. Isadrine activated and adrenaline inhibited the cAAT activity. Noradrenaline did not affect the activity of both isoenzymes. Phentolamine, as contrary to obsidane which decreased the activity of both isoenzyme, activated the isoenzymes; the effect was partially decreased by obsidane. Phentolamine did not alter the noradrenaline effect on either mAAT or cAAT; it decreased significantly the free form of the mAAT activity only. Results of the experiments with administration of adrenomimetic drugs suggested that adrenaline and noradrenaline-isadrine had different sites of attachment through which they mediated their action on aspartate aminotransferase in rat heart mitochondria.

Animals↗
PubMed1989

[Role of the serum level of mitochondrial aspartate aminotransferase as marker of alcoholic intoxication in cirrhotic patients].

The purpose of this study was to assess the diagnostic value of serum mitochondrial aspartate aminotransferase activity (mAST) and of the mitochondrial aspartate aminotransferase/total aspartate aminotransferase ratio (mAST/t AST) as markers of chronic alcoholism in cirrhotic patients. Sixty-three hospitalized cirrhotic patients (35 drinkers, 28 abstainers) were investigated. Ninety-six per cent of abstainers had normal values of mAST activity, while 89 per cent of drinkers had high levels of mAST activity. Cirrhotic patients were better divided into drinkers and abstainers by mAST activity (92 per cent) than by mean globular corpuscular volume (MCV) (81 per cent, NS) or by gamma-glutamyltransferase activity (GGT) (75 per cent, P less than 0.01). When the hospital costs of these markers were taken into account, MCV had a better "quality/price" ratio (Q/P) defined as diagnostic value/mean hospital cost (Q/P = 2.5) than MCV plus GGT (diagnostic value 61 per cent, Q/P = 1.2). The measurement of mAST activity in patients with high MCV value or with discrepancy between MCV and GGT values increased the diagnostic value of the other laboratory measurement to 89 per cent, but at a higher cost (Q/P = 0.8). Mitochondrial AST activity is a sensitive and specific marker of chronic alcoholism in cirrhotic patients. However, owing to its high cost, it should be proposed as a second marker after MCV and GGT.

Alcoholism↗
PubMed1985

Effect of chronic ethanol or acetaldehyde on hepatic alcohol and aldehyde dehydrogenases, aminotransferases and glutamate dehydrogenase.

Ethanol or acetaldehyde orally administered (15% and 2% respectively in drinking water) to male Wistar rats for three months induced alterations in the main liver enzymes responsible for ethanol metabolism, aspartate and alanine aminotransferases and NAD glutamate dehydrogenase. Ethanol produced a significant decrease in the activity of soluble alcohol dehydrogenase, while acetaldehyde induced alterations both in soluble and mitochondrial aldehyde dehydrogenases: soluble activity was significantly higher than in the control and ethanol-treated groups, and mitochondrial activity was significantly diminished. Both soluble aspartate and alanine aminotransferases showed pronounced increases by the chronic effect of acetaldehyde, while mitochondrial activities were practically unchanged by the effect of ethanol or acetaldehyde. Mitochondrial NAD glutamate dehydrogenase showed a rise in its activity both by the effect of chronic ethanol and acetaldehyde consumption. The level of metabolites assayed in liver extracts showed marked differences between ethanol and acetaldehyde treatment which indicates that ethanol produced a remarkable increase in glutamate, aspartate and free ammonia together with marked decrease in pyruvate and 2-oxoglutarate concentrations. Acetaldehyde consumption induced a significant decrease in 2-oxoglutarate and pyruvate concentrations. These observations suggest that ethanol has an important effect on the urea cycle enzymes, while the effect of acetaldehyde contributes to the impairment of the citric acid cycle.

Acetaldehyde↗
PubMed1987

Stereospecific labilization of the C-4' pro-S hydrogen of pyridoxamine 5'-phosphate in aspartate aminotransferase. Activators and inhibitors.

Measurement of the stereospecific release of the pro-S proton from C-4' of enzyme-bound pyridoxamine 5'-phosphate provides an experimental means to probe parts of the active site of aspartate aminotransferase independently of substrate turnover (Tobler, H. P., Christen, P., and Gehring, H. (1986) J. Biol. Chem. 261, 7105-7108). The release of pro-S 3H from enzyme-bound [3H]pyridoxamine 5'-phosphate is 30,000 times faster than from free coenzyme. Enzyme-bound [3H]pyridoxine 5'-phosphate is not detritiated suggesting an essential role of the 4'-amino group. Formation of the unproductive complex of the [3H]pyridoxamine 5'-phosphate-enzyme with aspartate or glutamate results in a 400-fold acceleration of 3H release. In contrast, addition of borohydride or cyanoborohydride immediately stops 3H release. Experiments with a fluorescent reporter group and with differential chemical modifications indicate that the activating effect of aspartate on the release of 3H is accompanied by a shift of the so-called open/closed conformational equilibrium of the enzyme (Kirsch, J.F., Eichele, G., Ford, G. C., Vincent, M.G., Jansonius, J.N., Gehring, H., and Christen, P. (1984) J. Mol. Biol. 174, 497-525) toward the closed conformation; the inhibiting effect of borohydride and cyanoborohydride appears to be accompanied by a shift toward the open conformation. Apparently, at least part of the catalytic apparatus of aspartate aminotransferase becomes fully operative only in the closed conformation of the enzyme.

Animals↗
PubMed1987

[Distribution of alanine and aspartate aminotransferases, gamma-glutamyltransferase, lactate dehydrogenase, alkaline phosphatases and creatine kinase in the main organs of adult goats and kids].

In adult ewes, the distribution of enzymes in the liver, kidney, spleen, pancreas, muscle, lung and myocardium was very similar to that in cows or sheep: aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), lactate dehydrogenase (LDH) and creatine kinase (CK) were mainly in skeletal muscles and the myocardium, while gamma-glutamyl transferase (GGT) and alkaline phosphatases (PAL) predominated in the kidneys. Age-related changes of tissue enzyme patterns were dominated by a dramatic decrease of liver ALAT in adults whereas this enzyme was liver-specific in one month old animals; a decrease of muscle LDH and CK, and an increase of kidney GGT and ALP were also observed in adults.

Aging↗
PubMed1989

Greater than expected alanine aminotransferase activities in plasma and in hearts of patients with acute myocardial infarction.

Early increases in the activity of alanine aminotransferase (ALT, EC 2.6.1.2) in plasma are observed in about 7% of patients with acute myocardial infarction (AMI), of whom about half die. Some type of liver injury, secondary to AMI, could be responsible for this phenomenon. However, quantitative analysis shows that the release of ALT in most of these patients conforms to the myocardial release pattern. Moreover, extra release of hepatic aspartate aminotransferase (EC 2.6.1.1) is not observed. These findings suggest that the heart may occasionally contain a high ALT activity. This hypothesis was verified by determination of enzyme activities in 10 hearts obtained from patients who died after AMI. The mean ALT activity in these hearts, 21 (SD 12) U per gram wet weight, significantly (P less than 0.01) exceeds the value of 7.7 (SD 4.9) U/g found for seven control hearts and may reflect increased amino acid metabolism in the energy-depleted heart muscle, as described earlier for skeletal muscle.

Adult↗