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)

The free amino acid concentrations in cotyledons and axes of soybean (Glycine max [L.] Merr. cv. Wells) seedlings were determined by automated single column analysis after germination at 10 and 23 C. After 5 days germination at 10 C, glutamate and aspartate were in high concentration in both cotyledons and axes (38 and 24% of total free amino acids recovered, respectively), whereas the concentrations of their amide derivatives, asparagine and glutamine, were low in cotyledons (4.4%) and high in axes (21%). In contrast, after 5 days germination at 23 C, asparagine and glutamine accounted for 22 and 45% of total free amino acids in cotyledons and axes respectively, and aspartate and glutamate concentrations were low. The activities of glutamine synthetase and asparagine synthetase were considerably lower in tissues from the 10 C treatment than those from the 23 C treatment.Aspartate and glutamate concentrations were nearly equal in all but one sample. Both glutamate oxaloacetate transaminase and glutamate dehydrogenase activities were much higher in axis tissues at 23 C as compared to 10 C. Arrhenius plots of axis glutamate oxaloacetate transaminase and glutamate dehydrogenase activities were biphasic and triphasic, respectively, with energies of activation for both increasing with low temperature. Energies of activation were identical for glutamate oxaloacetate transaminase from 10 and 23 C treatments but much higher for glutamate dehydrogenase from 23 C-treated axes. This indicates a difference in enzyme complement for glutamate dehydrogenase with the two treatments.Hydrolysis of free amino acid sample (basic fraction) aliquots showed large quantities of peptides in 23 C-treated axes at 2 days, while few or no peptides were found in the 10 C treatment. Amino acid residues most prevalent in peptides were aspartate, threonine, serine, glutamate, and glycine.
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PMID:Low Temperature Effects on Soybean (Glycine max [L.] Merr. cv. Wells) Free Amino Acid Pools during Germination. 1666 May 75

L-colitose is a 3,6-dideoxysugar found in the O-antigens of some Gram-negative bacteria such as Escherichia coli and in marine bacteria such as Pseudoalteromonas tetraodonis. The focus of this investigation, GDP-4-keto-6-deoxy-D-mannose-3-dehydratase, catalyzes the third step in colitose production, which is the removal of the hydroxyl group at C3' of GDP-4-keto-6-deoxymannose. It is an especially intriguing PLP-dependent enzyme in that it acts as both a transaminase and a dehydratase. Here we present the first X-ray structure of this enzyme isolated from E. coli Strain 5a, type O55:H7. The two subunits of the protein form a tight dimer with a buried surface area of approximately 5000 A2. This is a characteristic feature of the aspartate aminotransferase superfamily. Although the PLP-binding pocket is formed primarily by one subunit, there is a loop, delineated by Phe 240 to Glu 253 in the second subunit, that completes the active site architecture. The hydrated form of PLP was observed in one of the enzyme/cofactor complexes described here. Amino acid residues involved in anchoring the cofactor to the protein include Gly 56, Ser 57, Asp 159, Glu 162, and Ser 183 from one subunit and Asn 248 from the second monomer. In the second enzyme/cofactor complex reported, a glutamate ketimine intermediate was found trapped in the active site. Taken together, these two structures, along with previously reported biochemical data, support the role of His 188 as the active site base required for catalysis.
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PMID:The structure of GDP-4-keto-6-deoxy-D-mannose-3-dehydratase: a unique coenzyme B6-dependent enzyme. 1694 43

Arsenic and hexavalent chromium toxicity results from their ability to interact with sulfahydryl groups of proteins and enzymes, and to substitute phosphorus in a variety of biochemical reactions. Alanine aminotransferase (ALT; E.C: 2.6.1.2) and Aspartate amino transferase (AST; EC 2.6.1.1) play a crucial role in transamination reactions and can be used as potential biomarkers to indicate hepatotoxicity and cellular damage. While histopathological studies in liver tissue require more time and expertise, simple and reliable biochemical analysis of ALT and AST can be used for a rapid assessment of tissue and cellular damage within 96 h. The main objective of this study was to determine the acute effects of arsenic and hexavalent chromium on the activity of ALT and AST in the Indian major carp, Labeo rohita for 24 h and 96 h. Significant increase in the activity of ALT (P < 0.01) from controls in arsenic exposed fish indicates serious hepatic damage and distress condition to the fish. However, no such significant changes were observed in chromium-exposed fish suggesting that arsenic is more toxic to the fish. These findings indicate that ALT and AST are candidate biomarkers for arsenic-induced hepatotoxicity in Labeo rohita.
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PMID:Effect of arsenic and chromium on the serum amino-transferases activity in Indian major carp, Labeo rohita. 1791 61

Crush syndrome develops due to muscle crush injury often found in patients extricated from prolonged compression after disasters. It leads to rhabdomyolysis, kidney failure and hypovolemic shock, followed by decreased blood supply, to tissue under compression and general body parts including brain. In the present study, experimental model of crush syndrome in albino rats was induced by, 2h of compression followed by 48 h of decompression, of femoral muscle tissue. Aspartate and alanine aminotransferase activities of rat brain regions during crush syndrome were investigated. After exposure to 2h compression in comparison to normal/control levels, both cytosolic AST and ALT activities reduced. Cytosolic AST activity reduced by 31.2%, 26.1% and 19.4% in olfactory lobes, cerebral cortex and cerebellum, respectively, whereas cytosolic ALT activity decreased by 51.1%, 52.4%, 47.4% and 36.9% in olfactory lobes, cerebral cortex, cerebellum and medulla oblongata, respectively.
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PMID:Aspartate aminotransferase and alanine aminotransferase activities of rat brain during crush syndrome. 1883 29

Alfalfa (Medicago sativa, Siwa 1) seeds were subjected to drought stress during germination by using polyethylene glycol (PEG 4000) for studying the changes in some enzyme activities involved in nitrogen metabolism and the content of nitrogenous compounds during the first four days of growth after putrescine (Put) treatment. Decreasing the external water potential reduced activities of glutamate-pyruvate transferase (GPT), glutamate-oxaloacetate transferase (GOT) and RNase. Some free amino acids such as proline and glycine increased, while alanine and aspartic acid decreased. Nucleic acids content also decreased. Polyamines e.g., spermidine (Spd) and spermine (Spm) increased at the water potential -0.4 MPa. Put treatment increased activities of GOT, GPT and RNase. Furthermore, Put treatment increased nucleic acids content and the endogenous polyamines under drought stress. Drought stress was imposed during seedling stage by decreasing soil moisture content. GOT, GPT and RNase activities increased in leaves of alfalfa seedlings under drought stress. Soluble nitrogenous compounds accumulated under drought stress, while nucleic acids content decreased. Except glutamic acid, all free amino acids detected increased under drought stress. Put treatment decreased activities of GOT, GPT and RNase, as well as reduced the accumulation of the total soluble nitrogenous compounds, but increased DNA, RNA and protein contents.
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PMID:Alterations in nitrogen metabolites after putrescine treatment in alfalfa under drought stress. 1906 67

The Pseudomonas dacunhael-aspartate-beta-decarboxylase (ABDC, aspartate 4-decarboxylase, aspartate 4-carboxylyase, E.C. 4.1.1.12) is a pyridoxal-5'-phosphate (PLP)-dependent enzyme that catalyzes the beta-decarboxylation of l-aspartate to produce l-alanine and CO(2). This catalytically versatile enzyme is known to form functional dodecamers at its optimal pH and is thought to work in conjunction with an l-Asp/l-Ala antiporter to establish a proton gradient across the membrane that can be used for ATP biosynthesis. We have solved the atomic structure of ABDC to 2.35 A resolution using single-wavelength anomalous dispersion phasing. The structure reveals that ABDC oligomerizes as a homododecamer in an unknown mode among PLP-dependent enzymes and has highest structural homology with members of the PLP-dependent aspartate aminotransferase subfamily. The structure shows that the ABDC active site is very similar to that of aspartate aminotransferase. However, an additional arginine side chain (Arg37) was observed flanking the re-side of the PLP ring in the ABDC active site. The mutagenesis results show that although Arg37 is not required for activity, it appears to be involved in the ABDC catalytic cycle.
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PMID:The crystal structure of the Pseudomonas dacunhae aspartate-beta-decarboxylase dodecamer reveals an unknown oligomeric assembly for a pyridoxal-5'-phosphate-dependent enzyme. 1926 5

Cisplatin is one of the most potent chemotherapeutic antitumor drugs. Oxidative stress has been proven to be involved in cisplatin-induced toxicity. Therefore, the present study was undertaken to examine the antioxidant potential of grape seed proanthocyanidin extract (GSPE) against the toxicity of cisplatin in male rats. Cisplatin treated animals revealed a significant elevation in plasma, heart, kidney and liver thiobarbituric acid reactive substances (TBARS), while the activities of antioxidant enzymes (GST, SOD, CAT and GSH-Px, and the levels of glutathione (GSH) were decreased. Aspartate and alanine transaminases (AST and ALT), creatine kinase and lactate dehydrogenase were significantly increased in plasma, while liver AST and ALT were significantly decreased. Cisplatin significantly increased the levels of plasma total lipid, cholesterol, urea and creatinine, and the relative weight of kidney. On the other hand, plasma total protein and albumin, and body weight were significantly decreased. GSPE reduced cisplatin-induced the levels of TBARS in plasma, heart, kidney and liver, TL, cholesterol, urea and creatinine, and liver AST and ALT. Moreover, it ameliorated cisplatin-induced decrease in the activities of antioxidant enzymes, and GSH, total protein and albumin. Therefore, the present results revealed that GSPE exerts a protective effect by antagonizing cisplatin toxicity.
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PMID:Protective effect of grape seed proanthocyanidin extract against oxidative stress induced by cisplatin in rats. 1942 35

Crimean-Congo haemorrhagic fever (CCHF) is a potentially fatal viral disease. In this study, the aim was to investigate the prognostic factors affecting the patient's survival and risk factors to fatality. At Ondokuz Mayis University Faculty of Medicine, a tertiary referral centre near the CCHF epidemic region, patients with typical clinical findings and indicative microbiological results for IgM and/or reverse transcriptase-polymerase chain reaction of CCHF virus were enrolled in the study, from 2004 to 2007. Patients were divided into two subgroups according to their survival outcomes; group I (n = 44) survived patients and group II (n = 6) consisted of fatal cases. The median platelet count was significantly lower in the fatal group (11000/mm(3)) when compared to the survived group (49500/mm(3)). Aspartate transferase and alanine transferase (ALT) levels were significantly higher in group II, when compared to group I. Also, the median range of serum lactic dehydrogenase (LDH) and creatinine phosphokinase (CPK) levels were much more elevated, and prothrombin time (PT) and activated partial thromboplastin time (aPTT) were prolonged in fatal cases. There was also a significant difference in median age of these two groups. Advanced age, late admission, low platelet count, increased AST, ALT, CPK and LDH levels, and prolonged PT and aPTT could be an early indicator of poor prognosis in patients with CCHF.
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PMID:Risk factors for fatality in patients with Crimean-Congo haemorrhagic fever. 1953 53

To determine the effect of metabolic acidosis on expression of L-Gln, L-Glu, and L-Asp metabolizing enzymes and transporters, the relative content of mRNA, protein, or mRNA and protein, of 6 enzymes and 5 transporters was determined by real-time reverse transcription-PCR and immunoblot analyses in homogenates of kidney, skeletal muscle, and liver of growing lambs fed a common diet supplemented with canola meal (control; n = 5) or HCl-treated canola meal (acidosis; n = 5). Acidotic sheep had a 790% greater (P = 0.050) expression of renal Na(+)-coupled neutral AA transporter 3 mRNA and a decreased expression of renal glutamine synthetase mRNA (47% reduction, P = 0.037) and protein (57% reduction, P = 0.015) than control sheep. No change in renal cytosolic phosphoenolpyruvate carboxykinase (protein and mRNA), glutaminase (mRNA), or L-Glu dehydrogenase (protein) was found. In skeletal muscle, acidotic sheep had 101% more (P = 0.026) aspartate transaminase protein than did control sheep, whereas no change in the content of 3 Na(+)-coupled neutral AA transporters (mRNA) or 2 high-affinity L-Glu transporter proteins was found. In liver, no change in the content of any assessed enzyme or transporter was found. Collectively, these findings suggest that tissue-level responses of sheep to metabolic acidosis are different than for nonruminants. More specifically, these results indicate the potential capacity for metabolism of L-Asp and L-Glu by skeletal muscle, and L-Gln absorption by kidneys, but no change in hepatic expression of L-Gln metabolism, elaborates previous metabolic studies by revealing molecular-level responses to metabolic acidosis in sheep. The reader is cautioned that the metabolic acidosis model employed in this study differs from the increased plasma lactate-induced metabolic acidosis commonly observed in ruminants fed a highly fermentable grain diet.
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PMID:Metabolic acidosis in sheep alters expression of renal and skeletal muscle amino acid enzymes and transporters. 1982 50

A pregnant Thai woman with mild hypochromic microcytic anemia caused by alpha- and beta- globin defects is described. The proband was a 26-year-old pregnant woman discovered through our ongoing thalassemia screening program. Initial hemoglobin (Hb) high performance liquid chromatography (HPLC) analysis revealed a homozygosity for an unknown variant at the D window, inconsistent with results of family analyses. Further Hb analysis using automated capillary zone electrophoresis identified that the proband was in fact a compound heterozygote for Hb E [beta26(B8)Glu-->Lys, GAG>AAG] and another beta chain variant. DNA analysis demonstrated that she carried the Hb Korle-Bu mutation [beta73(E17)Asp-->Asn (GAT>AAT)] in trans to the Hb E and an alpha-thalassemia-1 (alpha-thal-1) with the Southeast Asian (- -(SEA)) deletion. Family studies identified that her father and sister were double heterozygotes for Hb Korle-Bu and alpha-thal-1, whereas her mother was a double heterozygote for Hb E/Hb Constant Spring [Hb CS; alpha142, Term-->Gln (TAA>CAA in alpha2)]. The genotype-phenotype relationship observed in this Thai family with complex hemoglobinopathies and methods for characterization are presented.
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PMID:Complex interaction of Hb E [beta26(B8)Glu-->Lys], Hb Korle-Bu [beta73(E17)Asp-->Asn] and a deletional alpha-thalassemia-1 in pregnancy. 1995 98


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