Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Conditions for accurate measurement of catalytic activity of aspartate aminotransferase and alanine aminotransferase in human serum have been reinvestigated. The basic variables (kind of buffer, buffer concentration, pH, ion effects, and the influence of pyridoxal-5-phosphate) can now be considered optimized. On this basis, the kinetic parameters of both aminotransferases were determined, i.e., Michaelis and inhibitor constants for substrates and reaction products. With a mathematical approach for two-substrate enzyme reactions the substrate concentrations were calculated from the viewpoints "most economical," "most convenient," and "lowest variability." Also the conditions for the indicator reactions have been newly defined with respect to a kinetic model. All calculated data were rechecked experimentally and it can be shown that both approaches fully agree. Furthermore, we show that the mathematical approach allows more precise recommendations for optimized methods. For technical reasons, the catalytic activity of aspartate aminotransferase in human serum can only be measured as a 0.96 fraction of its theoretical maximum velocity, the catalytic activity of alanine aminotransferase as a 0.91 fraction. The assay conditions for a Reference Method are finally described and recommendations are made for optimized routine methods for determination of the catalytic activity of these transferases in human serum.
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PMID:Optimization of methods for aspartate aminotransferase and alanine aminotransferase. 2 9

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

We looked for variables that could serve as indexes of alcohol consumption. We tested iron, gamma-glutamyltransferase, mean erythrocyte volume, mean erythrocyte hemoglobin concentration, urea, uric acid, and alanine aminotransferase, among others, in an unselected population of men, and by principal components analysis we singled out the correlation between the two enzymes and the two hematologic values. On the other hand, calculation of the coefficients of correlation between the total amount of alcohol consumed and the 10 variables studied, together with multiple regression analysis, showed that the three variables that correlated most significantly with alcohol consumption were gamma-glutamyltransferase, mean erythrocyte volume, and the use of tobacco. Critical evaluation of the results leads us to conclude that still more discriminative biological indices msut be sought and that the use of psychosocial data is also desirable.
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PMID:Relations between reported alcohol consumption and certain biological variables in an "unselected" population. 3 2

Subcellular distribution and some physicochemical properties of alanine aminotransferase in striated muscles of the crayfish, trout, carp, frog, pigeon and rabbit were studied. It was established that: (1) Alanine aminotransferase activity in all mentioned animals occurred almost entirely in the cytosolic fraction of the muscles. Total activity and activity per mg protein were highest in crayfish and pigeon muscles and lowest in carp and trout muscles. (2) The pH optimum for the muscles of homoiotherms and poikilotherms ranged from 7.5 to 8, Km values for L-alanine were of the order 10(-3)--10(-2) M and those for alpha-ketoglutarate 10(-4) M. (3) A 10 degree C temperature increase of the incubation medium was accompanied by a 70--90% increase in activity. (4) The higher the alanine aminotransferase activity of the muscles, the relatively higher their alanine production during electrical stimulation. (5) From the above results it is concluded that alanine aminotransferase in striated muscles regulates the rate of glycolysis and energy production under conditions of anaerobiosis through the formation of alanine.
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PMID:Subcellular distribution and some properties of alanine aminotransferase in striated muscles of the crayfish, trout, carp, frog, pigeon and rabbit. 3 68

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

Elevated serum gamma-glutamyl transferase (GGT) levels were found in 29% of 155 chronic alcoholics undergoing detoxification treatment. Alkaline phosphatase (AP) was increased in 16%, alanine aminotransferase--SGPT (ALT) in 12% of the patients, while 23% had elevations of either AP or ALT or both. Of the foregoing parameters, GGT was the best single indicator of liver involvement. In course of the follow-ups GGT/ALT correlation improved, but GGT/AP correlation deteriorated. In 9 patients, abstinence during follow-up was associated with progressive decrease in previously elevated serum GGT. Because of its unique sensitivity, GGT may be useful as a screening and/or monitoring aid in alcoholism.
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PMID:Dynamic changes of serum gamma-glutamyl transferase in chronic alcoholism. 3 48

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

Biotin deficiency in Aspergillus nidulans resulted in a 70% increase of the protein content and increased levels of free and bound aspartate, glutamate, serine, leucine and methionine. Likewise, the activities of NADP+ glutamate dehydrogenase, NAD+ gluatmate dehydrogenase, aspartate aminotransferase and alanine aminotransferase were significantly increased. The total RNA content increased while the DNA content was unaffected. The rRNA/tRNA ratio remained higher in biotin-deficient cells. Supplementation of glutamate, aspartate, serine, leucine and methionine to the culture medium raised the rRNA/tRNA ratio, and the difference observed in the qualitative and the quantitative patterns of protein and dry cell mass between normal and biotin-deficient cultures was abolished.
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PMID:Factors affecting protein synthesis during biotin deficiency in Aspergillus nidulans. 4 77

We have determined the distribution in cord blood from healthy newborns of six enzymes: creatine kinase, lactate dehydrogenase, aspartate and alanine aminotransferase, alkaline phosphatase and gamma-glutamyltransferase. The concentration of enzymes were determined according to the methods recommended by the Scandinavian Committee on Enzymes. The distribution of isoenzymes and of enzymes in blood from women at delivery was investigated also. All distributions were positively skewed. The upper reference limits of cord blood exceeded those found in mother blood by a factor of eight for gamma-glutamyltransferase, and for lactate dehydrogenase and creatine kinase by a factor of two.
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PMID:Reference values for six enzymes in plasma from newborns and women at delivery. 4 84

A prospective study of 181 patients suspected of having liver disease was carried out to determine the relative efficiencies of serum bilirubin (total and direct), alkaline phosphatase (AP), gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) with respect to diagnosis. Liver biopsies, liver scans, abdominal ultrasound, and clinical parameters were also tabulated and used independently to evaluate the patient's hepatic status and to determine the final diagnoses in each case. From the results of these tests for the 60 patients who were diagnosed as having liver disease, and the 87 patients who were felt to be free of liver disease, predictive values of the above tests were established. Data from this study suggests that while direct bilirubin is the most specific test, GGT is the most sensitive and has the fewest false negatives in the diagnosis of liver disease.
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PMID:Predictive values of various liver function tests with respect to the diagnosis of liver disease. 4 85


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