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)

CBA mice, inoculated intravenously with large doses of adenovirus type 5, showed raised levels of serum aspartate aminotransferase (SAAT; EC 2.6.I.I) and died within a few days from histologically demonstrable hepatic necrosis. After inoculation of I LD50, virus was rapidly taken up by the tissues where infectivity then declined greatly. Organ titres then increased about 100-fold by 48 h p.i. but, in the liver, which showed intranuclear inclusion bodies, and by electron microscopy, scattered intranuclear and intracytoplasmic adenovirions, the increase was 10000- to 100000-fold. P antigen was detected by single radial diffusion in liver extracts, and by immunofluorescence in 80% of liver cells at 36 h p.i. Hexon, penton base and fibre antigens appeared later and in fewer cells. The maximum amount of hexon, of demonstrable type 5 specificity, was shown by radioimmunoassay to be equivalent to up to 5 x 1011 whole adenovirions/g liver. It is concluded that human adenovirus type 5 undergoes an abortive but lytic infection in most liver cells but that replication may proceed to completion in a few.
J Gen Virol 1978 Jul
PMID:Infection of mouse liver by human adenovirus type 5. 21 Nov 82

Injection with pharmacological doses of dexamethasone (5 mg/kg) and/or bovine glucagon (1 mg/kg) exerts pronounced effects on toadfish liver compared with vehicle-treated control fish. Affected parameters include hepatic levels of glycogen and the activities of glutamate dehydrogenase, aspartate aminotransferase, malate dehydrogenase, and enzymes involved in NADPH generation as well as the kinetics of pyruvate kinase. Activities of tyrosine aminotransferase, however, a prime target for hormonal induction in mammals, remain unchanged in Opsanus. In subsequently isolated toadfish hepatocytes, metabolite concentrations and flux through gluconeogenesis are altered as are in vitro responses to epinephrine and catfish glucagon in previously injected fish. Contrary to existing mammalian models, short-term regulation of urea cycle activity can be ruled out for toadfish, since hormone treatments fail to influence the activity of two ornithine-urea cycle enzymes or the rate of hepatocyte-urea synthesis. Treatment-dependent increases in hepatic glutamine synthetase, the unique feeder enzyme for ammonia "nitrogen" in fish urea cycle, indicate a potentially pivotal role for this enzyme in longer-term regulation of ureogenesis.
Gen Comp Endocrinol 1992 Feb
PMID:Metabolic actions of glucagon and dexamethasone in liver of the ureogenic teleost Opsanus beta. 160 Dec 63

We have isolated an alfalfa leaf cDNA clone that encodes aspartate aminotransferase (AAT, EC 2.6.1.1) by direct complementation of an Escherichia coli aspartate auxotroph with a plasmid cDNA library. DNA sequence analysis of the recombinant plasmid, pMU1, revealed that a 1514 bp cDNA was inserted in the correct orientation and in-frame with the start of the lacZ coding sequence in the vector, pUC18. The resulting fusion protein is predicted to be 424 amino acids in length with a molecular weight of 46387 Daltons. The cDNA-encoded protein has a characteristic pyridoxal phosphate attachment site motif and has substantial amino acid sequence homology to both animal and bacterial AATs. Plasmid pMU1 encodes an AAT with a Km for aspartate of 3.3 mM, a Km for 2-oxoglutarate of 0.28 mM, and a pH optimum between 8.0 and 8.5. Several lines of evidence including Western blot analysis, the isoelectric point of the encoded protein, and the effect of pH on the activity of the fusion protein, suggest that the cDNA encodes the isozyme AAT-1 rather than AAT-2. Northern blot analysis showed that the aat-1 clone hybridized to a 1.6 kb transcript present in alfalfa leaves, roots and nodules. The relative concentrations of aat-1 mRNA in these tissues were 1:2:5, respectively. Thus, transcription of aat-1 appears to be induced during nodule development. Southern blot analysis suggested that AAT-1 in alfalfa is encoded by either a single-copy gene or a small, multigene family.
Mol Gen Genet 1991 Dec
PMID:Isolation and analysis of a cDNA clone that encodes an alfalfa (Medicago sativa) aspartate aminotransferase. 175 49

To elucidate the repression mechanism of ammonium ions on the biosynthesis of tylosin in Streptomyces fradiae NRRL 2702, enzyme activities involved in the metabolism of the aspartate family of amino acids were evaluated in relation to the ammonium ion concentration and tylosin production. It was found that aspartate aminotransferase was essential for both cell growth and tylosin production. However, both threonine dehydratase and valine dehydrogenase were repressed by supplemented ammonium ions at concentrations higher than 50 mM. Threonine dehydratase was purified from cell-free extracts by acetone precipitation, ion-exchange chromatography and gel filtration, and its molecular mass was estimated to be 67,200 Da. The optimum pH and temperature for threonine dehydratase activity were 7.5 and 25 degrees C, respectively, and the Km value for threonine under these optimum conditions was 21 mM. The inhibition pattern of ammonium ions on the activity of threonine dehydratase appeared to be a mixed type.
J Gen Microbiol 1991 Nov
PMID:Relationship between threonine dehydratase and biosynthesis of tylosin in Streptomyces fradiae. 178 1

Cell extracts of the fermentative Mollicutes Acholeplasma laidlawii B-PG9, Acholeplasma morum S2, Mycoplasma capricolum 14, Mycoplasma gallisepticum S6, Mycoplasma pneumoniae FH, Mycoplasma hyopneumoniae J and M. genitalium G-37, and the non-fermentative Mycoplasma hominis PG-21, Mycoplasma hominis 1620 and Mycoplasma bovigenitalium PG-11 were examined for 39 cytoplasmic enzyme activities associated with the tricarboxylic acid (TCA) cycle, transamination, anaplerotic reactions and other enzyme activities at the pyruvate locus. Malate dehydrogenase (EC 4.2.1.2) was the only TCA-cycle-associated enzyme activity detected and it was found only in the eight Mycoplasma species. Aspartate aminotransferase (EC 2.6.1.1) activity was detected in all Mollicutes tested except M. gallisepticum S6. Malate synthetase (EC 4.1.3.2) activity, in the direction of malate formation, was found in the eight Mycoplasma species, but not in any of the Acholeplasma species. Phosphoenolpyruvate (PEP) carboxylase (EC 4.1.1.31) was detected in the direction of oxaloacetate (OAA) formation in both Acholeplasma species, but not in any of the Mycoplasma species. Pyruvate carboxylase (EC 6.4.1.1), pyruvate kinase (EC 2.7.1.40), pyruvate dehydrogenase (EC 1.2.4.1) and lactate dehydrogenase (EC 1.1.1.27) activities were found in all ten Mollicutes tested. No activities were detected in any of the ten Mollicutes for aspartase (EC 4.3.1.1), malic enzyme (EC 1.1.1.40), PEP carboxytransphosphorylase (EC 4.1.1.38), PEP carboxykinase (EC 4.1.1.32) or pyruvate orthophosphate dikinase (EC 2.7.9.1). In these TCA-cycle-deficient Mollicutes the pyruvate-OAA locus may be a point of linkage for the carbons of glycolysis, lipid synthesis, nucleic acid synthesis and certain amino acids. CO2 fixation appears obligatory in the Acholeplasma species and either CO2 fixation or malate synthesis appears obligatory in the Mycoplasma species.
J Gen Microbiol 1988 Mar
PMID:Presence of anaplerotic reactions and transamination, and the absence of the tricarboxylic acid cycle in mollicutes. 314 76

We have previously identified a unique site, pac, from which packaging of precursor concatameric viral DNA into proheads starts during the maturation process of bacteriophage CP-T1. The direction of this packaging was determined from restriction enzyme cleavage patterns of CP-T1 DNA. A restriction enzyme generated fragment containing pac was cloned and the surrounding DNA region sequenced. Analysis of the nucleotide sequence revealed numerous repeat regions related to the consensus sequence PuagttGAT.AAT.aa.t. Within the sequenced region an open reading frame encoding a 12260 Mr protein was also identified. This protein appears to share homology with the binding domains of known DNA binding proteins and may represent a putative Pac terminase possessing the specific endonuclease activity required for cleavage at the pac site. Minicell analysis of deletion derivatives of the pac-containing clone revealed a protein of approximately 12,900 Mr encoded within this same region, confirming that this Pac protein is phage encoded.
Mol Gen Genet 1988 Jun
PMID:Molecular analysis of the packaging signal in bacteriophage CP-T1 of Vibrio cholerae. 341 20

The effects of 1-naphthyl-N-methylcarbamate (carbaryl) upon glucose production from several precursors (lactate, glycerol, alanine, fructose and pyruvate) and on activities of gluconeogenic enzymes (glucose-6-phosphatase, lactate dehydrogenase and aspartate aminotransferase) in isolated rat hepatocytes was studied. The results show that carbaryl inhibits lactate-gluconeogenesis at all concentrations of substrate studied. Gluconeogenesis from 10 mM fructose or 10 mM pyruvate or 10 mM alanine is also inhibited by carbaryl 1 mM. However, glycerol-gluconeogenesis is unaffected. Concentrations of carbaryl at 0.01 and 0.1 mM did not significantly modify lactic dehydrogenase activity, but at 1.0 mM this activity was reduced by 38% in relation to the dimethylsulphoxide-treated group. The synthetic activity of glucose-6-phosphatase is enhanced by carbaryl, but the increase is only significant for 1 mM carbaryl. In the study of aspartate aminotransferase activities two fractions, cytoplasmic and mitochondrial, are differentiated; and, it is observed that both fractions are inhibited by 0.1 and 1.0 mM carbaryl. The results indicate that carbaryl produces major decreases of the glucose production by hepatic cells, and suggest that the carbaryl-induced hyperglycemia in the fasted animal would be due to deficiencies in the peripheral utilization of the glucose.
Gen Pharmacol 1984
PMID:The interaction of carbaryl with the metabolism of isolated hepatocytes: II. Effect on gluconeogenesis. 609 5

We have determined the nucleotide sequence at the distal end of the heat-labile enterotoxin subunit A (LT-A) gene (toxA) originating from human enterotoxigenic Escherichia coli. The sequenced region covers the entire LT-A2 region and a part of the LT-A1 region. In confirming our previous prediction based on product analysis of clones toxA regions, the data suggest the overlapping of the distal end (5'-TTA TGA) of toxA with the proximal end (5'-ATG AAT) of the LT subunit B gene (toxB), in the sequences 5'-TTATGAAT. Some additional characteristics of the LT operon as well as of the products are discussed.
Mol Gen Genet 1982
PMID:Overlapping genes in the heat-labile enterotoxin operon originating from Escherichia coli human strain. 675 77

The reference strains Type A and Type B and two equine strains of Acholeplasma laidlawii were examined for a wide range of isoenzymes using thin-layer starch-gel electrophoresis; in addition two isoenzymes were examined in two strains of A. equifetale. The type strains A and B of A. laidlawii were differentiated by their lactate dehydrogenase, phosphoglucomutase and aspartate aminotransferase patterns and the two equine strains by their hexokinase, lactate dehydrogenase and phosphoglycerate kinase patterns. The two pairs of strains differed from one another with respect to hexokinase, phosphoglucomutase, adenylate kinase and glucose-6-phosphate dehydrogenase. The two strains of A. equifetale could be distinguished by their isoenzymes of hexokinase. The two species were differentiated by their hexokinase and phosphoglucomutase patterns.
J Gen Microbiol 1980 Mar
PMID:Isoenzymes in two species of Acholeplasma. 739 17

1. Hepatoprotective activity of an ethanolic extract of Teucrium stocksianum was investigated against paracetamol-induced hepatic damage in mice. 2. Paracetamol at an oral dose of 0.6 g/kg produced about 94% mortality in mice while pretreatment with the plant extract (0.5 and 1 g/kg for 5 days) reduced the death rate to 0%. 3. Paracetamol (0.6 g/kg, orally) produced liver damage as manifested by significant rises in liver weight, plasma aspartate aminotransferase (AST) activity and bilirubin concentration, pentobarbitone-induced sleeping time, and by the significant depletion of reduced glutathione (GSH) in the liver. 4. Pretreatment of mice with T. stocksianum at the above doses significantly ameliorated all the paracetamol-induced signs of liver damage described above. 5. T. stocksianum did not produce any lethality or adverse effects in the livers of treated mice. 6. These results indicate that T. stocksianum ethanolic extract contains hepatoprotective constituents, and suggest further work on the isolation and characterization of these constituents which may potentially be used as hepatoprotective agents.
Gen Pharmacol 1995 Mar
PMID:Effect of Teucrium stocksianum on paracetamol-induced hepatotoxicity in mice. 759 77


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