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:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe a column-chromatographic method for separating the mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase in human serum. Bed height of the ion exchanger, pH, and salt concentrations in the eluting buffers are shown to be variables affecting the separation of the isoenzymes. Under the optimized conditions selected for this study, a 30% increase in volume was observed in one fraction, associated with changing the salt concentration of the eluting buffer and attributed to a contraction of the DEAE-Sephadex A-50. Elution profiles (enzyme activity vs. fraction number) were examined with highly purified mitochondrial and cytoplasmic isoenzymes of human origin in bovine serum albumin and human serum. Recovery of the enzyme in the eluted fractions averaged 102% (SD, 2.0%) for specimens prepared from the purified isoenzymes and 104% (SD, 10.7%) for 38 human serum specimens. The separation technique showed linearity to catalytic concentrations in excess of 200 U/liter (reaction temperature 30 degrees C) for each isoenzyme. Additional information is presented regarding among-day precision and the effect of specimen dilution.
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PMID:Column-chromatographic separation of isoenzymes of aspartate aminotransferase. 2 23

The response of guinea pig macrophages to migration inhibitory factor (MIF) is altered by several chemical treatments. Treatment of macrophages with the diazonium salt of sulfanilic acid (5 x 10(-6) to 4 x 10(-4) M) significantly increases the response of these cells to MIF. Treatment with acetic anhydride also augments the response of these cells to MIF. The latter finding suggests that alteration of amino, hydroxyl, or sulfhydryl groups is involved in this phenomenon. Treatment of macrophages with sodium periodate (2 x 10(-5) to 10(-3) M) which is known to oxidize cis-glycols and with hydroxylamine (2 x 10(-5) to 2 x 10(-3) M), which reacts with carbonyl groups also increases response to MIF. The following experiments suggest that the significant alteration occurs at the level of the cell surface. Incubation of macrophages with the diazonium salt of sulfanilic acid at 4 degrees C, at which temperature pinocytosis is largely inhibited, is sufficient to increase the MIF response. The activity of the cytoplasmic enzyme aspartate aminotransferase, which in homogenates is susceptible to inactivation by low concentrations of the diazonium salt of sulfanilic acid, is not decreased when intact macrophages are incubated with high concentrations of the diazonium salt of sulfanilic acid. Cumulatively, these findings suggest that modification of different functional groups on the macrophage surface causes the same physiologic effect.
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PMID:Chemical treatment of macrophages increases their responsiveness to migration inhibitory factor (MIF). 18 95

Intravenous administration of the rare earth metal salt, praseodymium nitrate, induced hepatic damage in the rat, as assessed by morphologic examination (light and electron microscopy) and biochemical parameters (serum glutamic-pyruvic transaminase (EC 2.6.1.2) and glutamic-oxalacetic transaminase (EC 2.6.1.1) activity as well as hepatic triglyceride content). Praseodymium hepatotoxicity was only attained with lower doses (10, 20, or 40 mg/kg), whereas a larger dose (80 mg/kg) was inactive in this respect. As detected by electron microscopy, lower doses of the metal salt caused hepatocytic alterations consisting of degranulation and dilatation of rough endoplasmic reticulum, accumulation of smooth endoplasmic reticulum as well as numerous lipid droplets. No abnormalities were detected in the cell organelles following administration of a large dose of the metal salt; however, vacuoles containing markedly electron-dense material were seen in the cytoplasm of the hepatocytes and the sinusoidal Kupffer cells.
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PMID:Effect of praseodymium nitrate on hepatocytes and Kupffer cells in the rat. 19 Nov 66

Several kinds of hydrophilic proteins were examined to determine their interaction with artificial liposomes. Mitochondrial aspartate aminotransferase (m-GOT) [EC 2.6.1.1], as well as cytochrome c, was found to interact strongly with negatively charged liposomes. In each case, an appreciable amount of the protein bound to liposomes remained unreleased after raising the salt concentration in the medium. The m-GOT tightly bound to the liposomes was also found to become latent in its enzymatic activity, and could be reversibly activated by solubilization of the liposomes with detergent. This is also the case for cytochrome c, which ceases to be reducible by external reductant, such as dithionite. Furthermore, the tightly bound m-GOT was not susceptible to the proteolytic action of trypsin, or that of Nagarse. From these observations it can be inferred that these basic proteins interact with acidic liposomes not only electrostatically but also hydrophobically. This kind of hydrophobic interaction was not observed in the combination of positively charged liposomes and acidic proteins, including s-GOT. Mitochondrial GOT was shown to be bound to isolated intact mitochondrial, but the bound enzyme was fully active, in contrast to the case of acidic liposomes. The hydrophobic interaction of water-soluble protein with liposomes is discussed in connection with the penetration of matrix enzyme through mitochondrial membranes.
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PMID:Interaction of mitochondrial aspartate aminotransferase with negatively charged lecithin liposomes. 37

Three groups of isolated rat livers were perfused at 35 C with Krebs-Ringer bicarbonate buffer containing commercial bovine serum albumin (BSA) which had been purified by gel filtration on a column of Sephacryl S-200 and used within 12 hr of purification, or BSA which had been purified by gel filtration and stored at -70 C until used. The ability of livers to produce bile, retain potassium, and to maintain a constant level of glucose in the perfusate was greatly improved in the presence of purified albumin which had not been frozen. Such livers also showed the highest rates of urea synthesis, but the rate of release of aspartate aminotransferase (GOT) from cells and the bile salt content of the bile produced were similar to those found with unpurified BSA. Livers perfused with purified albumin which had been stored in the frozen state were slightly inferior to those perfused with nonfrozen albumin in their ability to produce bile and urea, to retain potassium and GOT within cells, and to maintain a constant concentration of glucose in perfusates. The concentration of bile salts in the bile produced by this group was also lower than that found with the other two groups. Overall, isolated rat livers benefited from perfusion with purified albumin, although freeze storage of this material rendered it slightly inferior to the nonfrozen material in its ability to support the liver.
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PMID:Improved performance of the isolated rat liver when perfused with purified bovine serum albumin. 46 29

1. For methods of vitamin E and selenium supplementation were evaluated using thirty-nine pregnant ewe-lambs fed on a ration containing 0.043 mg Se/kg and 25 mg vitamin E/kg. Treatments were control, fortified mineral mix (ESe salt) (300 mg vitamin E, 3 mg Se), ruminal Se pellets (505 mg Se), drench (300 mg vitamin E, 3 mg Se) and intramuscular injection (600 mg vitamin E, 3 mg Se). Only ewes supplemented, commencing approximately 50 d before parturition. 2. Birth weights were similar for all treatments and live-weight gains of lambs to 56 d of age were improved in all supplemented groups (P less than 0.05). There were no clinical cases of nutritional muscular dystrophy. 3. Se concentrations in whole blood were more than doubled in both lambs and ewes drenched or injected; responses to ESe salt and pellets were much smaller. 4. Plasma tocopherol levels were increased in injected dams and their lambs (P less than 0.001). 5. Haemoglobin concentration and erythrocyte counts were significantly higher (P less than 0.01) in control ewes and lambs than in treated lambs. 6. Lactate dehydrogenase (EC 1.1.1.27), creatine kinase (EC 2.7.3.2) and aspartate aminotransferase (EC 2.6.1.1) activities were increased in lambs from control, ESe salt and pellet groups (P less than 0.001). Glutathione peroxidase (EC 1.11.1.9) activity responded to Se supplementation in both ewes and their lambs (P less than 0.001) and the response was highest in the injected group, followed in order, by the drench, pellet, Ese salt and control groups. 7. These studies indicated that in terms of the haematological and blood chemistry changes investigated, the intramuscular injection was most effective, followed by the oral drench. Ruminal pellets and fortified salt were less satisfactory.
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PMID:Haematological and blood chemistry changes in ewes and lambs following supplementation with vitamin E and selenium. 69 59

Sources of variation in assays of aspartate aminotransferase (EC 2.6.1.1) activity were examined in an interlaboratory survey and through an examination of materials used as calibration materials in these assays. Four highly stable lyophilized specimens containing human cytoplasmic enzyme, with activities of 0, 22, 46, and 96 U/liter at 30 degrees C and optimal substrate concentrations, were assayed by 319 laboratories. Mean values obtained on these specimens by laboratories using 2,4-dinitrophenylhydrazine kits varied among manufacturers and deviated from values expected from this procedure. The average coefficient of variation (CV) with these kits was greater than 20%. Automated continuous-flow procedures with use of diazonium salt showed the best precision (av CV, less than 10%). However, the automated continuous-flow malate dehydrogenase/NADH coupled method produced an average CV greater than 20%. Results from each of the automated methods were related to a reference malate dehydrogenase/NADH coupled continuous kinetic assay method by temperature relationships alone. Mean values from manual diazonium salt procedures were 1.7-fold greater than similar reference values (av CV was 18%). The higher results were attributed to the use of poorly-defined units and to an artifact caused by chromophore stabilizers in this procedure when aqueous samples are used. The average CV in continuous kinetic methods varied among kit manufacturers, ranging from 6 to 28% for the specimen of highest activity. Variations in results were much larger at 366 nm than at 340 nm than at 340ity. Variations in results were much larger at 366 nm than at 340 nm. Interassay relationships of these methods are presented. Concentrations of pyruvate in commercially available calibration materials differed between manufacturers, varied in stability, and deviated from the expected concentration. For some colorimetric assays the precision attained on reported absorbance values for the enzyme specimens was of the same order of magnitude as that for pyruvate standards. Other sources of error are revealed by the interlaboratory survey. The value of commercially available sources of enzyme activity as calibration or control materials was assessed by evaluating the following properties: activity at suboptimal concentrations of L-aspartate or 2-oxoglutarate, temperature effects, preincubation lability owing to aspartate and phosphate, pyridoxal phosphate saturation, contamination with glutamate dehydrogenase, and manufacturer's rated activity. These properties are compared to those of human cytoplasmic enzyme in a human serum matrix.
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PMID:Interlaboratory proficiency, intermethod comparison, and calibrator suitability in assay of serum aspartate aminotransferase activity. 113 21

Ammonium sulfate fractionation of proteins from extremely halophilic bacteria on Sepharose 4B, carboxymethylcellulose, diethylaminoethylcellulose, and hexamethylenediamine-Agarose is described. Halophilic proteins are absorbed on these gels at 2.5 M ammonium sulfate and eluted by decreasing concentration gradients of this salt. The method has enabled the separation of malate dehydrogenase from glutamate dehydrogenase and aspartate aminotransferase on Sepharose 4B and the additional 15-fold purification of glutamate dehydrogenase on DEAE-cellulose. The technique is simple and convenient, operates at low cost, and possesses great power of resolution. The mechanism of adsorption is discussed and compared to previous instances of "hydrophobic chromatography". It is concluded that the retention of halophilic proteins on the polysaccharide gels at 2.5 M ammonium sulfate is due to hydrophobic interactions.
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PMID:Hydrophobic chromatography and fractionation of enzymes from extremely halophilic bacteria using decreasing concentration gradients of ammonium sulfate. 127 45

A method has been developed which allows isolation of 0.3--0.5 g of mitochondrial aspartate aminotransferase in five days starting from 10 pig hearts; the method does not involve initial preparation of mitochondria. Mitochondrial malate dehydrogenase and the cytoplasmic aspartate aminotransferase may conveniently be recovered from side fractions. The product mitochondrial aspartate aminotransferase is homogeneous as judged by various electrophoretic techniques and by N-terminal analysis. Crystals of the enzyme have been obtained both from concentrated, essentially salt-free, solutions and from solutions of ammonium sulphate. The amino acid composition, N and C-terminal amino acid sequences and subunit molecular weight have been determined; these characteristic properties are compared with those of the cytoplasmic isozyme from the same source.
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PMID:Large-scale purification and some properties of the mitochondrial aspartate aminotransferase from pig heart. 127 71

Ursodiol is a hydrophilic, non-hepatotoxic bile salt indicated for the medical treatment of cholesterol gallstones. This pilot study explored the use of prophylactic ursodiol in an attempt to decrease the incidence and severity of veno-occlusive disease (VOD) of the liver following allogeneic bone marrow transplantation (BMT). Between February 1991 and January 1992, 22 consecutive patients undergoing BMT for hematologic malignancies received the BU(4)/CY(2) preparative regimen and CSA/MTX for GVHD prophylaxis. Ursodiol, 600-900 mg daily by mouth was begun at least 1 day prior to beginning the preparative regimen. Results for this pilot group were compared to a control group of 28 consecutive patients transplanted between June 1989 and January 1991 with the same regimen without ursodiol. There were no significant differences in disease or clinical status between the groups pretransplant. However, mean baseline AST levels were significantly higher in the ursodiol group, 28.0 U/l vs 18.1 U/l in the control group (p = 0.001). The median maximum bilirubin observed post-transplant was 2.35 mg/dl (range 0.9-45) in the ursodiol group, and 5.05 mg/dl (range 0.7-29.4) in controls. The incidence of VOD was 2/22 (9.1%) in the ursodiol group and 18/28 (64.3%) in controls (p = 0.0001). Death due to VOD occurred in 1/22 patients (4.5%) in the ursodiol group and in 6/28 (21.4%) controls (p = 0.12). Our data suggest that ursodiol may decrease the incidence of VOD in allogeneic BMT patients.
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PMID:Pilot trial of prophylactic ursodiol to decrease the incidence of veno-occlusive disease of the liver in allogeneic bone marrow transplant patients. 142 93


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