Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sera of 260 patients with high serum aspartate aminotransferase (L-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.1.1; AST)/alanine aminotransferase (L-alanine: 2-oxoglutarate aminotransferase, EC 2.6.1.2; ALT) ratio (greater than 2.0) and high serum AST (greater than 45 IU/1) were selected and tested for the presence of immunoglobulin complexed-AST, by using immunoprecipitation reaction and counterimmunoelectrophoresis. The macromolecular AST was confirmed by size-exclusion high-performance liquid chromatography (HPLC). 34 patients out of 260 were found to have AST-immunoglobulin complexes (13.1%). The classes of AST-linked immunoglobulins were identified to be alpha in 28 cases (82.4%, P less than 0.01), mixed type of alpha and gamma in 5 cases (14.7%) gamma in one case (2.9%). Positive frequency was the highest in liver malignancies, either primary (9/26, 34.6%) or metastatic (7/17, 42.2%), followed by other malignancies (6/55, 10.9%) and chronic liver diseases (4/22, 18.2%). Thus, it can be strongly suggested that the immunoglobulin A complexed-AST is frequently found in association with liver malignancies.
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PMID:Incidence and properties of aspartate aminotransferase-immunoglobulin complexes in patients with a high serum aspartate to alanine aminotransferase ratio. 220 38

Three common variants of soluble cytoplasmic L-alanine:2-oxoglutarate aminotransferase (ALT, EC 2.6.1.2), sALT 1, 2-1 and 2, were isolated from normal human liver, and characterized by electrophoretic and kinetic analyses. The isoelectric point of sALT 1 was pH 6.45. sALT 2-1 was focused into three bands with pl 6.1, 6.2 and 6.45; sALT was focused into one band with pl 6.1. The electrophoretic mobilities of sALTs altered to the fast beta-globulin fraction after aging or papain treatment. Ammonia was produced during the latter, and the altered migration was considered to be caused by deamidation of sALT. The relative molecular mass of each of the enzymes was 110,000. Minor differences in the apparent Km values among the multiple forms for both L-alanine and 2-oxoglutarate were observed after incubation with 100 mumol/L of pyridoxal phosphate (PALP). PALP stimulation of the enzyme activities was also different. sALT 1 was more stable than sALT 2-1 and 2 after heat and urea treatments. In human sera from 1065 adult Japanese, sALT 2-1, a heterozygote form of sALT 1 and 2, was dominant.
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PMID:Electrophoretic and kinetic characterization of three variants of soluble cytoplasmic L-alanine:2-oxoglutarate aminotransferase in human liver tissue. 237 27

In vivo studies were performed in the dog to verify if sodium lactate had an important effect on the metabolism of glutamine by the kidney. The animals were infused with 0.6 M sodium lactate to induce acute metabolic alkalosis with plasma bicarbonate of 29.7 mM. During these experiments, it was demonstrated that the renal uptake of glutamine increased by 46%, while the renal production of ammonia was unchanged. The renal production of alanine rose from 6.0 to 16.8 mumol/min. Plasma concentration of lactate increased from 1.3 to 19.2 mM, while that of pyruvate increased from 0.075 to 0.454 mM. In the renal tissue, alpha-ketoglutarate, malate, oxaloacetate, lactate, pyruvate, citrate, and alanine increased significantly. Similar changes were found in the liver and skeletal muscle. The observed changes are best described by transamination of pyruvate and glutamate under the influence of alanine aminotransferase (GPT). It can be calculated that this reaction was responsible for 76% of the production of ammonia from glutamine, the latter being necessary to provide glutamate for the synthesis of alanine. Dogs infused with 0.3 M sodium bicarbonate instead of sodium lactate with the same degree of acute metabolic alkalosis, showed a depression of 40% in the renal uptake of glutamine with a 38% decrease in renal ammoniagenesis and a 20% fall in the production of alanine. The present studies demonstrate that the production of ammonia from glutamine is not necessarily related to changes in acid-base balance, but may be associated with biochemical alterations related to the synthesis of alanine by the kidney.
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PMID:The metabolic response of the kidney to acute sodium lactate alkalosis. 286 25

Tyrosine aminotransferase (TAT), glutamic-pyruvic transaminase (GPT), glutamic-oxaloacetic transaminase (GOT), and alkaline phosphatase (ALP) were measured in the serum and livers of Microtus montanus infected with Trypanosoma brucei gambiense. Only liver TAT and serum ALP showed significant changes. In addition, blood glucose, pyruvate and lactate, and liver glycogen levels were assayed. All four compounds showed significant changes, strongly suggesting increased glycogen mobilization and increased catabolic activity. Interestingly, the serum ketone levels were very low and no significant changes were observed. These chronically infected animals had an organic aciduria in which pyruvate, lactate, beta-hydroxybutyrate, alpha-ketoglutarate, phenylpyruvate, and p-hydroxyphenylpyruvate were significantly increased. The possible significance of these observations is discussed.
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PMID:Further biochemical characterization of chronic Trypanosoma brucei gambiense-Microtus montanus infection. 288 86

The total production of alpha-ketoglutarate from glutamate and isocitrate was estimated in isolated rat liver mitochondria. Mitochondrial alanine aminotransferase converts glutamate to alpha-ketoglutarate [A.K. Groen et al. (1982) Eur. J. Biochem. 122, 87-93], thus participating in the net formation of the tricarboxylic acid cycle intermediates from glutamate. The present investigation indicates a significant contribution of the alanine aminotransferase reaction to glutamate oxidation by isolated rat liver mitochondria in the presence of bicarbonate. It amounted to 41-74 and 7-31% of the total utilization of glutamate in States 4 and 3, respectively, in various conditions in vitro, at pyruvate concentrations in the range of 0.1-10 mM. The participation of glutamate in the total production of alpha-ketoglutarate at physiological concentrations of glutamate, citrate, and isocitrate varied in the range of 72-82%. It was calculated that alpha-ketoglutarate formation by the reaction of alanine aminotransferase amounted to 30 and 5% of the total mitochondrial alpha-ketoglutarate production in States 4 and 3, respectively, at physiological concentrations of its precursors and in the presence of 0.5 mM malate and 0.1 mM pyruvate. It constituted 77-97% of the net production of the tricarboxylic acid cycle intermediates from glutamate in rat liver mitochondria. The importance of alpha-ketoglutarate production via the alanine aminotransferase reaction under various physiological conditions is discussed.
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PMID:Significance of the alanine aminotransferase reaction in the formation of alpha-ketoglutarate in rat liver mitochondria. 289 86

The changes in the contents of the main tricarboxylic acid cycle intermediates and related amino acids under total ischemia and subsequent reperfusion of isolated guinea pig heart were studied. The decrease in ATP and phosphocreatine during 30 min ischemia was accompanied by alanine formation and approximately stoichiometric glutamate loss. The increase in malate in ischemic myocardium corresponded to the anaplerotic flux aspartate----oxaloacetate----malate. The succinate production was commensurable to alpha-ketoglutarate formation in the alanine aminotransferase reaction. The release of bulk amount of lactate, alanine and succinate into the myocardial effluent was observed during an early phase of the reperfusion using 1H NMR. In contrast to these metabolites, malate release was not observed in the reperfusion. By the 30th min of the reperfusion the decrease in lactate, alanine, malate and succinate tissue contents to the preischemic values was accompanied by the recovery of ATP and phosphocreatine. The results suggest that the formation and the release of succinate and alanine from the heart, complementary to that of lactate, reflect profound disturbances in energy metabolism.
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PMID:Metabolism of the tricarboxylic acid cycle intermediates and related amino acids in ischemic guinea pig heart. 289 8

The metabolism of [15N]glutamate was studied with gas chromatography-mass spectrometry in rat brain synaptosomes incubated with and without glucose. [15N]Glutamate was taken up rapidly by the preparation, reaching a steady-state level in less than 5 min. 15N was incorporated predominantly into aspartate and, to a much lesser extent, into gamma-aminobutyrate. The amount of [15N]ammonia formed was very small, and the enrichment of 15N in alanine and glutamine was below the level of detection. Omission of glucose substantially increased the rate and amount of [15N]aspartate generated. It is proposed that in synaptosomes (a) the predominant route of glutamate nitrogen disposal is through the aspartate aminotransferase reaction; (b) the aspartate aminotransferase pathway generates 2-oxoglutarate, which then serves as the metabolic fuel needed to produce ATP; (c) utilization of glutamate via transamination to aspartate is greatly accelerated when flux through the tricarboxylic acid cycle is diminished by the omission of glucose; (d) the metabolism of glutamate via glutamate dehydrogenase in intact synaptosomes is slow, most likely reflecting restriction of enzyme activity by some unknown factor(s), which suggests that the glutamate dehydrogenase reaction may not be near equilibrium in neurons; and (e) the activities of alanine aminotransferase and glutamine synthetase in synaptosomes are very low.
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PMID:Glucose and synaptosomal glutamate metabolism: studies with [15N]glutamate. 290 Aug 79

1. The distribution of L-alanine:glyoxylate aminotransferase (AGT) activities were found in Suncus liver, 55% in particulate fraction and 45% in supernatant. 2. 65% of AGT activities in particulate were dependent on AGT isoenzyme 2 (AGT 2) having molecular weight 210,000, the remainder (35%) of AGT activities were dependent on AGT isoenzyme 1 (AGT 1) which have aminotransferase activity for serine. AGT activities in supernatant were dependent on AGT 1, AGT 2 and alanine:2-oxoglutarate aminotransferase (GPT), and their activity ratios were 10, 15 and 75%, respectively. 3. Km values for alanine were 0.52 mM; AGT 1, 3.3 mM; AGT 2, 0.88 mM; GPT measuring with AGT activity. AGT activity of GPT was inhibited by addition of glutamate and its Ki value was 1.8 mM. 4. Some other properties of AGT 1, AGT 2 and GPT are described.
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PMID:Alanine:glyoxylate aminotransferase activities in liver of Suncus murinus (insectivora). 290 70

We determined the recovery time courses of muscle oxidases and liver enzymes after iron administration to iron-deficient rats. Female 21-day-old Sprague-Dawley rats were fed an iron-deficient (3 mg Fe/kg) or a control (50 mg Fe/kg) diet for 3 wk. The deficient rats were then injected with 50 mg Fe as iron dextran/kg body wt (Fe-T) or saline (Fe-) intraperitoneally. At 16, 40, 64, 112, and 180 h after injection, blood and tissue samples were taken to determine hemoglobin concentration (Hb), gastrocnemius glycolytic enzyme and oxidase activities, and liver amino acid catabolic enzyme activities. No changes were observed in any parameter across time in either the Fe- or control (Fe+) rats. In the Fe- rats, Hb, pyruvate + malate (P + M), 2-oxoglutarate (2-OG), and succinate oxidases (SO) were depressed to 33, 36, 44, and 7% of Fe+, respectively (P less than 0.05). At 16 h, Fe-T values were significantly elevated compared with Fe- rats but still only 40, 48, 55 and 10% of controls, respectively. Glutamate dehydrogenase (GDH) and alanine aminotransferase (AAT) of Fe- rats were 174 and 134% of control values (P less than 0.05). By the 180-h time point, Hb, P + M, 2-OG, and SO of Fe-T rats increased to 99, 84, 89, and 43% of Fe+ values, whereas GDH and AAT activities declined to 111 and 106% of controls. Glycolytic enzymes showed no systematic changes with iron deficiency or after iron administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reciprocal changes of muscle oxidases and liver enzymes with recovery from iron deficiency. 292 6

In vitro supplementation with the active form of vitamin B6, pyridoxal-phosphate (PLP), increases measurements of both serum aminotransferase enzymes, L-aspartate: 2-oxoglutarate amino transferase, EC 2.6.1.1 (AST) and L-alanine: 2-oxoglutarate aminotransferase, EC 2.6.1.2 (ALT). The plasma PLP level in normal individuals clearly relates inversely to the degree of stimulation of serum AST and ALT. PLP added in vitro increases the reference values but does not decrease the biological variability of AST measurements in healthy individuals. Since B6 deficiency is observed in alcoholics, in some significant percentage of hospitalized patients and in apparently healthy people over age 64, these individuals will show PLP stimulation of their serum amino-transferase enzymes. Patients with liver disease show lesser activation with PLP of AST activity but not ALT activity than patients with heart disease (myocardial infarction). AST isoenzyme measurements in the form of a mitochondrial AST/total AST ratio may discriminate alcoholic hepatitis from all other hepatic diseases. In renal dialysis patients including transplant patients, it may be desirable to measure the aminotransferases with added PLP in order to reflect better the cytolytic state of the liver. While unconfirmed studies suggest the combination of PLP activation and AST isoenzyme measurements may aid in the diagnosis of hepatoma, PLP activation per se does not provide clear cut improved diagnostic value of AST and ALT in liver diseases. However, in view of PLP incorporation into the IFCC reference methods for AST and ALT, and the National Reference System for the Clinical Laboratory, it is recommended that PLP be included in all AST and ALT measurements.
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PMID:Review of pyridoxal phosphate and the transaminases in liver disease. 300 34


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