Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intraperitoneal administration to rats of D- or DL-alpha-hydrazinoimidazolylpropionic acid was found to produce a substantial inactivation of hepatic histidine ammonia-lyase (EC 4.3.1.3) in vivo. Proportional to this loss in enzyme activity was an impairment of the ability of treated rats to oxidize L-[ring-2-14C] histidine to 14CO2. Rats in which hepatic histidine ammonia-lyase activity was either depressed by DL-hydrazinoimidazolylproprionic acid injection or elevated by feeding a high protein diet displayed proportionately altered rates of 3H2O release into plasma water following L-[3-3H] histidine administration. Plasma L-histidine clearance following loading with this amino acid was similarly affected by these treatments. Administration of DL-alphal-hydrazinoimisazolylproprionic acid to rats was also found to inactivate non-specifically pyridoxal 5-phosphate enzymes in vivo; pyridoxine injection was found to reverse the DL-alpha-hydrazinoimidazolylproprionic acid-induced inactivation of hepatic aspartate aminotransferase (EC 2.6.1.1) in vivo, but not that of hepatic histidine ammonia-lyase. These findings demonstrate that histidine ammonia-lyase is the rate-limiting factor in L-histidine degradation in the rat. The potential usefulness of DL-hydrazinoimidazolylproprionic acid in the production of an animal model for histidinemia (hereditary histidine ammonia-lyase deficiency) is discussed.
 ...
PMID:Studies on the production and assessment of experimental histidinemia in the rat. 0 33

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.
 ...
PMID:Interaction of mitochondrial aspartate aminotransferase with negatively charged lecithin liposomes. 37

The effects of three widely spaced levels of bacterial contamination of reagent water on several chemistry, radioimmunoassay, and coagulation procedures were studied. These included determinations of lactate dehydrogenase, creatine kinase, aspartate transaminase, alkaline phosphatase, blood urea nitrogen, total protein, thyroid-stimulating hormone, digoxin, thrombin time, activated partial thromboplastin time, and prothrombin time. Statistical analyses included calculations of means and coefficients of variation, and analysis of variance, as well as correlation coefficients for test results versus logarithm of bacterial contamination. Statistically and clinically significant differences occurred together only for an elevated level of creatine kinase.
 ...
PMID:Effects of bacterial contamination of reagent water on selected laboratory tests. 43 36

Previously, a proteolipid that can bind glutamate with high affinity has been isolated from pig heart mitochondrial membranes. A final affinity chromatography on gamma-methylglutamate-albumin coreticulated on glass fiber was necessary. This procedure includes long dialysis steps which tend to denature the high-glutamate affinity proteolipid. Here is described a new method of isolation which avoids long dialysis steps and yields greater amounts of the high-glutamate affinity proteolipid. The binding of glutamate or aspartate on high-glutamate affinity proteolipid has been studied by gel filtration, by equilibrium dialysis or by a new procedure of rapid centrifugation based on the insolubility of high-glutamate affinity proteolipid in water. The latter method permits the detection of low and high affinity sites for glutamate with a Kd 60 mM and 55 muM, respectively. Among a series of analogues, aspartate appeared to be the best competitor: Kd = 30 muM and two Ki values, 0.37 mM (at high glutamate concentration) and 3.8 muM (at low glutamate concentration). High-glutamate affinity proteolipid binds 0.4 nmol of glutamate but only 0.1 nmol of aspartate per mg protein. The sites for glutamate and aspartate appear to be different but interdependent. In the presence of high-glutamate affinity proteolipid, externally added glutamate stimulated the efflux of aspartate from preloaded liposomes. High-glutamate affinity proteolipid contains cardiolipin, phosphatidyl choline and phosphatidyl ethanolamine the distribution of which is different from that of the inner membrane. The effects of various phospholipases, trypsin, and thiol reagents were studied on the binding of glutamate. High-glutamate affinity proteolipid binds 9 nmol N-ethylmaleimide per mg protein but only 6.1 nmol in the presence of glutamate. The dissociation of high-glutamate affinity proteolipid caused by thiol reagents yielded a soluble protein fraction with higher affinity for glutamate. Electrophoresis and an immunological approach allowed the detection and titration of the glutamate dehydrogenase and aspartate aminotransferase present in high-glutamate affinity proteolipid in inhibited forms, the latter being 26-fold more concentrated than the former.
 ...
PMID:Glutamate transport in pig heart mitochondria. Binding and structural properties of high-glutamate affinity proteolipid: reconstitution studies. 68 5

The purification procedure reported includes fractionation of water extract from chicken hearts with ammonium sulfate, fractional precipitation with ethanol, chromatography on Whatman CM-52 cellulose and crystallization. Specific activity of the pure crystalline enzyme was 234 micromoles.min-1.mg-1, as determined in the coupled assay with malate dehydrogenase (pH 7.5; 25 degrees). The amino acid composition of the enzyme was determined and the circular dichroism spectrum was recorded in the 200-250 nm range. The spectrum shows two negative bands with extrema at 208 and 220 nm. From the circular dichroism data it is estimated that aspartate transaminase contains approximately 40% alpha-helix and 10% beta-structure.
 ...
PMID:[Improved procedure for purification of aspartate transaminase from chicken heart cytosol. Characterization of the enzyme]. 73 31

1. A cereal-based diet containing 16 mg copper/kg was fed ad lib. to a group of laying hens for 35 d. Five other groups were given this control diet to which was added 120, 240, 480, and 1920 mg Cu/kg (as copper sulphate). 2. Records were kept of daily food intake, water intake and egg production. 3. After 35 d the hens were slaughtered and blood haemoglobin, packed cell volume, Cu and aspartate aminotransferase (EC 2.6.1.1) levels assayed. Liver, oviduct, kidney and breast muscle Cu and iron concentrations were measured. 4. Food and water intakes were depressed by the two highest levels of dietary Cu and water intake was increased by the diet with 240 mg added Cu/kg. Both food and water intake showed a quadratic relationship with the level of added dietary Cu. 5. Body-weight loss was increased by the addition of Cu and showed a significant linear relationship with the concentration of added Cu in the diet. Liver and oviduct weights were depressed at the two highest levels of Cu addition. 6. Liver and oviduct Cu and Fe concentrations were significantly increased by high dietary Cu and mean total liver and kidney Cu and Fe showed an increase although for the liver this was not statistically significant.
 ...
PMID:The effect of dietary copper sulphate on laying performance, nutrient intake and tissue copper and iron levels of the mature, laying, domestic fowl. 88 76

Two new methods of activation were developed to graft enzymes on collegen films. They involved chemical modifications of surface groups of collagen either by Woodward's reagent "K" or by EDC, a water-soluble derivative of carbodiimide. EDC was a better coupling agent and a detailed study was conducted with this agent. It could be used either in a global method of activation and coupling, or in a two-step procedure of activation of collagen, followed by spontaneous coupling of enzyme. All enzymes tested were successfully bound: malate dehydrogenase, lactate dehydrogenase, aspartate aminotransferase, urease, creatine kinase, hexokinase. The influence on the yield of grafted enzyme, of pretreatment of films, time and temperature of EDC activation, concentration of EDC and enzyme, protecting agents was studied. Stability of enzyme activity on storage was greatly increased after grafting. A co-grafted dual system creatine kinase/heoxkinase, was achieved which exhibited a good efficiency. A striking renaturing process at 0-4degreesC after thermal denaturation, was observed with hexokinase.
 ...
PMID:Grafting of enzymes on collagen films using Woodward's reagent "K" and a water-soluble carbodiimide derivative. 95 53

Because of the difficulties in drawing blood for clinical chemistry in small laboratory animals there exist many methods for sampling blood and the preparation of serum, none of which is generally accepted or well standardised. It was the aim of this study to investigate the effects of sampling techniques on normal values of enzyme activities in the serum of rat and mouse. The activities of the following enzymes were determined: sorbitol dehydrogenase, lactate dehydrogenase, malate dehydrogenase, glutamate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, pyruvate kinase, creatine kinase, myokinase, alkaline phosphatase and leucine aminopeptidase. In addition plasmaproteins, urea and inorganic phosphorus were measured. In rats blood was obtained from the following sites: retroorbital venous plexus, jugular vein, heart and ventral aorta. In mice blood was sampled from the jugular vein and the ventral aorta. Shifts of water from the interstitial to the intravascular space due to hypovolemia occurring during the experimental procedure were followed up by measuring the hematocrit and the distribution of radioiodide labelled albumin. In rats the activities of lactate dehydrogenase, malate dehydrogenase, aspartate aminotransferase, pyruvate kinase, creatine kinase and myokinase found in blood serum obtained from the retroorbital venous plexus and the ventral aorta were too high compared to the other sampling sites. Activities of alkaline phosphatase and alanine aminotransferase were slightly elevated when blood was sampled from the punctured retroorbital venous plexus. Small differences in plasmaproteins and hematocrit values were found to be due to acute shifts of water within the extracellular space. In mice the activities of lactate dehydrogenase, malate dehydrogenase, aspartate aminotransferase and myokinase were found to be too high in blood serum obtained from the ventral aorta. Efflux of enzymes from damaged cells and the interstitial space ive caused erroneous results too, but only to a minor extent. The most reliable method for blood sampling in rat and mouse is the cannulation of the jugular vein. The heart puncture can be recommended too. Attention should be paid, however, to the possibility of aspirating disrupted muscle cells through the inserted needle.
 ...
PMID:[Effects of blood sampling on enzyme activities in the serum of small laboratory animals (author's transl)]. 108 84

Biochemical variables have been measured in a group of volunteers during and after a long-distance run. Plasma glucose levels remained relatively constant and a significant decrease in plasma bicarbonate was noted. Plasma sodium, chloride, total protein, albumin and calcium showed significant increased of an order compatible with water losses occurring during the run. Plasma potassium, urea, creatinine, uric acid, phosphate and bilirubin all show much more marked and variable increases. The plasma enzymes alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase and creatine kinase likewise increased significantly throughout the run. Whilst most constituents showed a tendency to return to normal at 20-30 hours after the run, gross increases were observed for aspartate aminotransferase and creatine kinase.
 ...
PMID:The effect of long-distance running on some biochemical variables. 119 11

Release and binding of aspartate aminotransferase, malate dehydrogenase and protein from and to water-shocked vesicles obtained from rat liver mitochondria was shown to occur. The characteristics of this phenomenon were shown to depend on the effectors used. They were in some way different from those observed with whole mitochondria under similar conditions.
 ...
PMID:Release and binding of protein and enzymes from and to water-shocked vesicles obtained from rat liver mitochondria. 122 17


1 2 3 4 5 6 7 8 9 10 Next >>