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)

1. The concentration of HCO3- (independent of any change of pH) exerts different effects on glutamine metabolism in rat kidney-cortex tubules, hepatocytes and enterocytes.2. In kidney tubules HCO3- (10.5-50 MM) has no effect on glutaminase (EC 3.5.1.2), whereas glutamate dehydrogenase (EC 1.4.1.3) is inhibited as HCO3- concentration is increased. The result is that flux through the entire glutamate-to-glucose pathway is inhibited by increasing HCO3- concentrations. A large proportion (more than 30%) of the glutamine removed undergoes complete oxidation. 3. In hepatocytes, and to a smaller extent in enterocytes, HCO3- is an accelerator of glutaminase. Synthesis of glucose and urea from glutamine in hepatocytes increases as HCO3- concentration is increased. Calculations show that fumarate, formed via aspartate aminotransferase and arginino-succinate lyase, is the precursor of the glucose. There is no complete oxidation of the carbon skeleton of glutamine in hepatocytes. 4. Leucine at near-physiological concentrations (0.1-1 mM) is an accelerator of glutaminase in hepatocytes, but not in kidney tubules or in enterocytes. 5. The results are discussed in relation to regulation of acid/base balance in vivo.
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PMID:A role for bicarbonate in the regulation of mammalian glutamine metabolism. 54 52

A study of cardiovascular risk factors in middle-aged twin men provided an opportunity to test for genetic variability in the SMA 12/60 (Technicon) battery of clinical chemistry tests. Classical twin methodology was used to analyze the variation of monozygotic and dizygotic twins. In addition, frequency of co-twin contact was used to control for effects of differences in shared environment. Genetic variability played a definite role in controlling four of the 11 reported tests: one-hour serum glucose, serum urea nitrogen, uric acid, and bilirubin. No genetic variation was found for lactate dehydrogenase, phosphorus, and alkaline phosphatase. Significantly higher means for calcium, total protein, albumin, and aspartate aminotransferase in monozygotic twins precluded any statement about heredity and environment for these tests.
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PMID:Genetic variability of clinical chemical values. 55 78

Blood serum of pygmy goats (both sexes, and castrated males) was analyzed to establish biochemical reference values. Influence of age on reference values was also studied. Serum biochemical analyses were made for urea nitrogen, creatinin, bilirubin, lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase, glucose, uric acid, and total lipids. These serum values for pygmy goats were similar to those reported for man, except as follows: Aspartate aminotransferase activities were slightly higher than those reported for man. Glucose concentrations in pygmy goats were slightly lower than in human beings, and uric acid levels were significantly lower than the values for man. Female and castrated male goats had lower total lipid concentrations than did human beings, whereas intact males had higher concentrations. Thus, of the 9 measured variables for pygmy goats, 5 were comparable to human values. This, together with other attributes, including the small size which conduces to economics of maintenance and enhances the desirability of using pygmy goats in research.
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PMID:Serum biochemistry values in normal pygmy goats. 59 8

The expert group "Drug Interference in Clinical Chemistry" of the Bureau of Reference, Directorate General for Research, Science and Education of the Commission of the European Communities, consisting of one participant of each member of the European Communities, presents this first report on the final results of its activities. Within the framework of a first stage basic program, the paper describes interferences of therapeutic and elevated doses of ascorbic acid on commonly used clinical chemical methods. This is the result of a bipartite study that was jointly planned, carried out and evaluated. Local and personal influences have been eliminated, as have variations due to methodology, measurement equipment and reagents, in order to be able to present distinct causal effects of ascorbic acid. No definite influence of ascorbic acid on analytical values for urea, cholesterol, calcium, protein, bilirubin, aspartate aminotransferase and alkaline phosphatase could be detected. At therapeutic concentrations, ascorbic acid distinctly interferes with the analysis of glucose, uric acid, creatinine and inorganic phosphate. The extent and direction of interferences vary, depending on the type of reaction, kit and apparatus. In some cases the influence of ascorbic acid results in severe disturbance of the analytical methods leading to useless values.
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PMID:Drug interference in clinical chemistry: studies on ascorbic acid. 62 9

Isocitrate lyase (EC 4.1.3.1) and malate synthase (EC 4.1.3.2), the two enzymes characteristic of the glyoxylate cycle, were demonstrated in promastigotes of five species of Leishmania (L. brasiliensis, L. donovani, L. mexicana, L. tarentolae, and L. tropica). Both enzymes were present in cells grown in a medium containing 10 mM glucose. Substitution of glucose with 20 mM acetate did not enhance enzyme levels. Acetate was readily taken up and metabolized by the cells. The distribution of label from acetate into various intermediary metabolites indicates a functional glyoxylate cycle and its role in gluconeogenesis/glyconeogenesis. The glyoxylate cycle in conjunction with alanine-glyoxylate aminotransferase and glyoxylate-aspartate aminotransferase could also be important in providing glyoxylate, the precursor for glycine biosynthesis.
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PMID:Evidence for a functional glyoxylate cycle in the leishmaniae. 69 79

The results of sending specimens through a computerized pneumatic airtransport system and manually delivering specimens were compared for 15 chemical tests and six hematologic procedures. All specimens were collected from inpatients and outpatients into evacuated glass containers. The specimens traversed a maximum of 829 feet (253 meters) involving 16 bends and eight transfer units at 25 feet/second (7.6 meters/second). Only the activity of lactate dehydrogenase exceeded the precision of the test in pneumatically transported specimens. Ruptured erythrocytes in incompletely filled vacuum tubes were the likely source of the increased lactate dehydrogenase activity. Neither the serum sodium, potassium, chloride, carbon dioxide, total protein, albumin, calcium, glucose, creatinine, total bilirubin, alkaline phosphatase, aspartate transaminase, acid phosphatase, uric acid, leukocyte count, erythrocyte count, hemoglobin, hematocrit, nor the prothrombin time and partial thromboplastin time were affected by pneumatic transport. It is concluded that the pneumatic system tested provides a safe, efficient method of transporting the blood specimens tested.
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PMID:Evaluation of a computer-directed pneumatic-tube system for pneumatic transport of blood specimens. 70 6

Inhibition of liver aspartate aminotransferase by L-2-amino-4-methoxy-trans-3-butenoic acid in the suckling newborn rat causes a decrease in all gluconeogenic precursors from phosphoenolpyruvate to glucose and an accumulation of lactate but not of pyruvate. This suggests that the aspartate shuttle is operative and confirms the quantitative importance of lactate as a gluconeogenic precursor at this time during development.
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PMID:Evidence for the participation of aspartate aminotransferase in hepatic glucose synthesis in the suckling newborn rat. 72 14

Measurement in cuvettes with their longitudinal dimension parallel to the light beam, while under the influence of a centrifugal force, has many advantages that are not immediately apparent. This survey summarizes the advantages in comparison to cuvettes standing with their long axis perpendicular to the light beam: in the latter the pathlength is fixed by the geometry, but if the cuvette is lying longitudinal to the light beam the pathlength is given by the filling volume. Because of the dependence of the pathlength on the filling (reaction) volume when cuvettes are lying longitudinal to the light beam, the calculation formulas show that the calculation factors, both for enzyme and substrate determination, become independent of the reagent volume form. This is demonstrated by simple equations and confirmed in practice by use of the (Cobas) Bio centrifugal analyzer in assays for glucose and aspartate aminotransferase.
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PMID:Absorbance measurement in cuvettes lying longitudinal to the light beam. 76 47

Two amino acid solutions were compared at different levels of nitrogen (N) intake for their effectiveness in promoting N retention in normal and in traumatized rats when given as part of a complete diet under total intravenous feeding conditions. An essential amino acid pattern based on that found in whole egg and one with an essential amino acid pattern based on an egg-potatoe mixture, were equally efficacious in promoting N retention in normal, 300-g rats infused with 75 mg of N and 80 kcal/day. Traumatized rats were in positive N balance on infusions of 400 mg of N/day from either the egg or the egg-protein amino acid solution for the first 5 days postinjury. On day 5 the injured animals showed no significant changes in plasma total protein, albumin, glucose, urea N, total bilirubin, and L-aspartate aminotransferase when compared with each other or with orally fed control rats. The two amino acid solutions were satisfactory sources of amino acids when infused as part of a complete intravenous diet for the purpose of studies in the parenterally fed rat. The results of these studies supported the adequacy of the amino acid requirement data for the adult rat of Nasset (J. Nutr. 61, 555-569, 1957) and of Smith and Johnson (Brit. J. Nutr. 21, 17-27, 1967) but suggested that the NRC values calculated from the data of Benditt et all. (J. Nutr. 40, 335-350, 1950) were too high for several amino acids. An improvement in the surgical cannulation technique is also discussed.
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PMID:Comparison of two amino acid solutions for total parenteral nutrition of normal and traumatized hats. 80 95

The values of a number of biochemical variables have been studied before and after a 50-gram load of glucose orally. Reductions which were statistically significant were found for sodium, potassium, urea, total protein, albumin, calcium, phosphorus, urate, bilirubin, alkaline phosphatase, but not for bicarbonate, creatinine, creatine kinase, lactate dehydrogenase, aspartate aminotransferase, cholesterol, triglyceride or chloride. The magnitude of the changes was generally not great, but could be clinically appreciable. The differences may need to be taken into account in comparing population studies.
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PMID:The effect of 50 grams of glucose orally on a number of biochemical variables. 85 60


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