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)

1. The effects of protein concentration and ionic strength on the adsorption of the individual glycolytic enzymes to F-actin and F-actin--trypomyosin--troponin have been studied. 2. Appreciable association was demonstrated under conditions of physiological ionic strength and high protein concentration, and tropomyosin--troponin established as an important and generalized component of these interactions. 3. Phosphofructokinase, aldolase, pyruvate kinase, lactate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase and glucose-6-phosphate isomerase were strongly bound under these conditions, while triosephosphate isomerase, phosphoglycerate kinase, phosphoglycerate mutase, enolase and hexokinase displayed less adsorption to the structural proteins. 4. The influence of a number of parameters on the adsorption phenomena was examined. Ca2+ and fructose 1,6-diphosphate increased the adsorption of aldolase, lactate dehydrogenase and pyruvate kinase, while decreasing the adsorption of the enzymes of the constant-proportion group. 5. Of the other major enzymic components of skeletal muscle, creatine kinase, adenylate kinase and malate dehydrogenase showed no adsorption to F-actin--tropomyosin--troponin under the experimental conditions. Some adsorption was evident, however, in the case of aspartate aminotransferase, (NADP) isocitrate dehydrogenase and alpha-glycerolphosphate dehydrogenase. 6. These results have been discussed in relation to their functional significance and the roles of enzyme compartmentation in the cell.
 ...
PMID:On the association of glycolytic enzymes with structural proteins of skeletal muscle. 111 88

A total of 407 Leishmania and other Leishmania-like isolates obtained from patients, other vertebrates, sand fly vectors, and other arthropods from Kenya and other countries were characterized and compared with several World Health Organization and other well-characterized reference strains of Leishmania, Trypanosoma, Crithidia, Herpetomonas, and Leptomonas by cellulose acetate electrophoresis (CAE), using 20 enzyme systems. Analysis of the isoenzyme banding patterns (IBP) of the isolates generated isoenzyme profiles that were resolved as zymodemes and tabulated. Isolates that produced similar isoenzyme profiles in all 20 enzyme systems were placed into a particular Leishmania isoenzyme taxon, with the zymodeme designated numerically as Zn. A total of 66 zymodemes were recorded for the 407 isolates studied. To obviate the need to draw all 66 representative IBP for each of the 20 enzyme systems, the 66 zymodemes (Z1-Z66) were again placed into similarity groups represented by pattern number or Pn. This resulted in 23-50 IBP (Pn) per enzyme system. The highest number of IBP scored was for malate dehydrogenase (MDH) (P1-50) and the lowest score was for glucose-6-phosphate isomerase (GPI) (P1-23). From these different isoenzyme profiles or zymodemes, IBP of 14 (MDH, GPI, nucleoside hydrolase, phosphoglucomutase, malic enzyme, isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, mannose-6-phosphate isomerase, 6-phosphogluconate dehydrogenase, glutamate oxaloacetate transferase/aspartate aminotransferase, glutathione reductase, superoxide dismutase, fumarase, and glyceraldehyde-3-phosphate dehydrogenase) of the 20 enzyme systems were selected for computer-calculated numerical taxonomy. Consistent individual isoenzyme bands with similar relative mobilities of the 14 enzyme systems were scored into groups (allelomorphs, allozymes, or electromorphs) and used in cluster analysis. For each pattern in every profile, the presence of a consistent band was entered as 1 and its absence as 0. A total of 419 allozyme characters (variables) were scored for the 14 enzyme systems. Lastly, all different zymodemes sharing a particular IBP (Pn) within an enzyme system were counted and the total number was shown as a zymodeme frequency (Zf). Final analysis of the CAE isoenzyme profiles and cluster-dendrograms resulted in the identification of several potentially new species and subspecies of Leishmania and other Leishmania-like isolates from patients, sand flies, and animal reservoir hosts collected from Kenya and other locations in Africa. Zymodeme analysis of the Kenyan visceral and cutaneous leishmaniasis isolates resulted in the identification of 11 subpopulations of the L. donovani species complex and six subpopulations of the L. tropica species complex endemic to different geographic areas of Kenya.
 ...
PMID:Biochemical characterization and zymodeme classification of Leishmania isolates from patients, vectors, and reservoir hosts in Kenya. 147 44

A Tris-citrate pH 9.5 gel/borate pH 8.2 electrode discontinuous buffer system for starch gel electrophoresis of proteins was developed to resolve iso- and allozymes of aspartate aminotransferase in frogs (Hyla crucifer). This buffer system also enhanced resolution of NADP-dependent malate dehydrogenase and the L-lactate dehydrogenase-A locus in this species. It provided good resolution of NAD-dependent malate dehydrogenase in esocid fishes, and esterases, glycerol-3-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, alcohol dehydrogenase, and S-aconitate hydratase in ambystomatid salamanders. Variation suppressed by other buffers was revealed by this buffer for some enzyme encoding loci, while at other loci, this buffer suppressed electromorph variability. The concentration of tris(hydroxymethyl)aminomethane in gels made with this buffer was much higher than in pH 8.7 "Poulik" gels, but running characteristics of the two gel types were similar. Gels made with this new buffer were less prone to splitting and "warping" than Poulik gels, and were easier to handle. When screening a given taxon for enzyme variability, tests using multiple buffers are essential to maximize the amount of electrophoretically detectable variation.
 ...
PMID:A high pH discontinuous buffer system for resolution of isozymes in starch gel electrophoresis. 279 42

The cerebral metabolic effects of intravenous administration of 1000 mg/kg gamma-hydroxybutyrate (GHB) were studied by sequential measurement of the cerebral contents of selected glycolytic-citric acid cycle intermediates and energy phosphates in lightly anesthetized rats. The initial change in the glycolytic pathway occurred by 2.5 min, with increases of tissue glucose-6-phosphate and decreases of fructose-1,6- diphosphate which indicated an inhibition of phosphofructokinase. This pattern was transient and was replaced at 5--15 min by increasing tissue glucose and decreasing glucose-6-phosphate which indicated an inhibition of hexokinase. The initial inhibition of phosphofructokinase was associated with functional depression, an isoelectric EEG and an increase of the tissue phosphocreatine which suggested that the observed metabolic pattern was an adaptation to the reduced energy needs of neuronal depression. Within 2.5 min of GHB injection tissue alpha-ketoglutarate and aspartate showed significant increases which suggested a shift in the aspartate aminotransferase reaction. Preliminary calculations indicated that the probable cause of this shift was an increase in oxaloacetate content due to GHB oxidation. The cytoplasmic NADH/NAD+ ratio remained unchanged throughout the entire exposure to GHB (2.5--180 min) and thus gave no support for the hypothesis that GHB interfers with glycolysis via the restriction of free cytoplasmic NAD+ required for the glyceraldehyde phosphate dehydrogenase step.
 ...
PMID:Sequential alterations of cerebral carbohydrate metabolism associated with gamma-hydroxybutyrate. 735 98

Nitric oxide (NO) is a readily diffusible, short-lived free radical with a multitude of organ-specific regulatory functions. Within the hepatocyte, NO production is associated with inhibition of mitochondrial electron transport enzyme activity, activation of soluble guanylyl cyclase, and inhibition of glyceraldehyde-3-phosphate dehydrogenase. However, while NO can regulate a number of hepatocyte functions, it is unknown whether NO production is hepatoprotective or hepatotoxic. Using isolated rat hepatocytes in primary short-term culture, we investigated the role of cytokine-mediated NO production in toxin-induced hepatocyte injury. In a model of acetaminophen (AM) hepatotoxicity, inhibition of cytokine-mediated NO production potentiated AM injury. In the presence of an inhibitor of NO synthesis, NG-monomethyl-L-arginine (L-NMMA), hepatocyte release of aspartate aminotransferase was increased twofold in the presence of 4.0 and 8.0 mM AM (P < 0.01). In addition, in the presence of AM, cytokine-mediated NO production was increased by 75% over baseline (P < 0.01). Maximum NO synthesis occurred at an AM concentration of 2 mM. A potential mechanism for the hepatoprotective effect of NO centers on its role in glutathione (GSH) homeostasis. In the presence of increasing concentrations of AM, hepatocyte GSH stores decreased in parallel in both control and cytokine-stimulated hepatocytes (ANOVA, P < 0.01). When cytokine-stimulated hepatocytes were exposed to 50 microM L-NMMA, NO release was ablated, while glutathione levels decreased by threefold in comparison to controls (P < 0.01). In the presence of increasing concentrations of AM, cytokine-treated cells exposed to 50 microM L-NMMA exhibited significant decremental decreases in GSH levels (P < 0.05). These data suggest that inhibition of cytokine-mediated NO production potentiates AM hepatoxicity by modulation of hepatocyte glutathione stores.
 ...
PMID:Nitric oxide decreases oxidant-mediated hepatocyte injury. 801 16

Mature mitochondrial proteins (aspartate aminotransferase, malate dehydrogenase, hydroxyacyl coenzyme A dehydrogenase, creatine kinase) and cytosolic proteins (aldolase, glyceraldehyde-3-phosphate dehydrogenase) with a basic pI were found to bind to isolated mitochondria, electrostatic interactions being mainly responsible for their binding. Mitochondrial aspartate aminotransferase bound with a Kd' of 30 nM in 0.6 M sorbitol, 20 mM Hepes/KOH, pH 7.4, at 25 degrees C. Cytosolic aspartate aminotransferase and glutamate dehydrogenase (a protein located in the mitochondrial matrix) both with an acidic pI, did not bind to mitochondria. Treatment of mitochondria with proteinases did not affect the subsequent binding of imported mitochondrial proteins. Their association with both intact and proteinase-treated mitochondria resulted in a marked increase in their susceptibility toward proteinase K. In contrast, the basic cytosolic proteins tested bound only to intact mitochondria and thereby did not become more susceptible toward proteolytic attack. Treatment of mitochondria with adriamycin, a drug binding to acidic phospholipids, prevented the subsequent association of mitochondrial aspartate aminotransferase with mitochondria and the ensuing conformational labilization. Apparently, the mature moiety of imported mitochondrial proteins is partially unfolded upon interaction with the lipid component of the mitochondrial envelope. Both the binding of the mitochondrial proteins and their conformational labilization is independent of ATP and the electrochemical potential across the inner membrane.
 ...
PMID:The mature form of imported mitochondrial proteins undergoes conformational changes upon binding to isolated mitochondria. 828 42

In islets from adult rats injected with streptozotocin during the neonatal period, both a nonmetabolized analog of L-leucine and 3-phenylpyruvate augmented 14CO2 output from islets either prelabeled with L-[U-14C]glutamine or exposed to D-[2-14C]glucose and D-[6-14C]glucose, in a manner qualitatively comparable to that found in islets from control rats. The islets of diabetic rats differed, however, from those of control rats by their unresponsiveness to both the L-leucine analog and a high concentration of D-glucose in terms of increasing 3HOH generation from [2-3H]glycerol, an impaired sparing action of the hexose upon 14CO2 output from islets prelabeled with [U-14C]palmitate, and, most importantly, by a decreased rate of D-[2-14C]glucose and D-[6-14C]glucose oxidation when either incubated at a high concentration of the hexose (16.7 mM) or stimulated by nonglucidic nutrient secretagogues at a low concentration of D-glucose (2.8 mM). In islet homogenates, the activity of glyceraldehyde phosphate dehydrogenase, glutamate decarboxylase, and NADP-malate dehydrogenase was lower in diabetic than control islets. Such was not the case for glutamate-alanine transaminase, glutamate-aspartate transaminase, or glutamate dehydrogenase. The neonatal injection of streptozotocin thus affected, in the adult rats, the activity of several islet enzymes. Nevertheless, the metabolic data suggest that an impaired circulation in the glycerol phosphate shuttle, as observed in response to stimulation of the islets by either a high concentration of D-glucose or nonglucidic nutrient secretagogues, represents an essential determinant of the preferential impairment of glucose-induced insulin release in this model of non-insulin-dependent diabetes.
 ...
PMID:Metabolic response to nonglucidic nutrient secretagogues and enzymatic activities in pancreatic islets of adult rats after neonatal streptozotocin administration. 848 60

Among progeny of a hybrid (Rana shqiperica x R. lessonae) x R. lessonae, 14 of 22 loci form four linkage groups (LGs): (1) mitochondrial aspartate aminotransferase, carbonate dehydratase-2, esterase 4, peptidase D; (2) mannosephosphate isomerase, lactate dehydrogenase-B, sex, hexokinase-1, peptidase B; (3) albumin, fructose-biphosphatase-1, guanine deaminase; (4) mitochondrial superoxide dismutase, cytosolic malic enzyme, xanthine oxidase. Fructose-biphosphate aldolase-2 and cytosolic aspartate aminotransferase possibly form a fifth LG. Mitochondrial aconitate hydratase, alpha-glucosidase, glyceraldehyde-3-phosphate dehydrogenase, phosphogluconate dehydrogenase, and phosphoglucomutase-2 are unlinked to other loci. All testable linkages (among eight loci of LGs 1, 2, 3, and 4) are shared with eastern palearctic water frogs. Including published data, 44 protein loci can be assigned to 10 of the 13 chromosomes in Holarctic Rana. Of testable pairs among 18 protein loci, agreement between Palearctic and Nearctic Rana is complete (125 unlinked, 14 linked pairs among 14 loci of five syntenies), and Holarctic Rana and Xenopus laevis are highly concordant (125 shared nonlinkages, 13 shared linkages, three differences). Several Rana syntenies occur in mammals and fish. Many syntenies apparently have persisted for 60-140 x 10(6) years (frogs), some even for 350-400 x 10(6) years (mammals and teleosts).
 ...
PMID:Linkage groups of protein-coding genes in western palearctic water frogs reveal extensive evolutionary conservation. 928 85

The ability of synthetic polyanions to suppress thermo-aggregation of the oligomeric enzymes (glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and aspartate aminotransferase) has been established. The ability of the polyanions to reduce the thermo-aggregation increased in the order poly(methacrylic acid) < poly(acrylic acid) < sodium poly(styrene sulphonate), which agreed well with the increase, in the same order, of the charge density of the chains. The lengthening of the chains, as well as the rise in their relative content, resulted in an increase of the ability to reduce thermo-aggregation, mentioned above. Complete prevention of the enzyme aggregation was achieved when highly charged polyanions of a relatively high degree of polymerization were used in a concentration sufficient to solubilize the protein. Complexing with the polyanions prevented thermo-aggregation of the enzymes, but not their thermo-denaturation. The adverse effect of the complexing polyanions on the catalytic activity was reduced by the addition of a synthetic polycation, which resulted in a significant reactivation (up to 40%) of the enzyme. The possibility of preventing the thermo-aggregation of enzyme molecules and then partly restoring the enzyme activity, appears to be of particular interest when studying the aggregation mechanism of proteins that are prone to form the amyloid structures responsible for the development of neurodegenerative diseases like Alzheimer's disease, bovine spongiform encephalopathy and Huntington disease. This finding can also be considered as an important step in the creation of artificial chaperones.
 ...
PMID:Interaction of polyanions with basic proteins, 2(a) : influence of complexing polyanions on the thermo-aggregation of oligomeric enzymes. 1630 32

Density gradient separation of plastids from leaf and root tissue was carried out. The distribution in the gradients of the activity of the following enzymes was determined: nitrite reductase, glutamine synthetase, acetolactate synthetase, aspartate aminotransferase, catalase, cytochrome oxidase, and triosephosphate isomerase. The distribution of chlorophyll was followed in gradients from leaf tissue. The presence of plastids that have retained their stroma enzymes was denoted by a peak of triosephosphate isomerase activity. Coincidental with this peak were bands of nitrite reductase, acetolactate synthetase, glutamine synthetase, and aspartate aminotransferase activity. The results suggest that most, if not all, the nitrite reductase and acetolactate synthetase activity of the cell is in the plastids. The plastids were found to contain only part of the total glutamine synthetase, aspartate aminotransferase, and triosephosphate dehydrogenase activity in the cell. Some evidence was obtained for low levels of glutamate dehydrogenase activity in chloroplasts.
 ...
PMID:The location of nitrite reductase and other enzymes related to amino Acid biosynthesis in the plastids of root and leaves. 1665 26


1 2 Next >>