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

1. A cereal-based diet containing 7.6 mg copper/kg was fed ad lib. to laying hens for up to 48 d. Four other groups were given the control diet to which was added hydrated copper sulphate to provide 250, 500, 1000 and 2000 mg added Cu/kg. 2. Hens were killed on day 0 and after 3, 6, 12, 24 and 48 d. Records were kept of body-weight, food consumption, egg production and egg weight. 3. After slaughter blood haemoglobin, packed cell volume, serum Cu and aspartate aminotransferase (AAT; EC 2.6.1.1) were measured. The liver, kidneys, a sample of breast muscle, oviduct, ovary and gizzard were weighed. Gizzard, spleen, liver and kidney tissue were examined histologically. 4. The Cu, zinc and iron concentrations of liver, kidneys and breast muscle and the manganese concentrations of liver and kidneys were determined. 5. Body-weight loss occurred at 500-2000 mg added Cu/kg diet. Egg production was depressed by level of added Cu and period of time on the Cu-containing diets. 6. Mean liver, kidney, oviduct and ovarian weights per unit body-weight were depressed by Cu in the diet and the effect increased with period of time on the diets. Mean gizzard weight per unit body-weight was increased by dietary added Cu and by time. 7. Cu concentrations in the liver were increased by dietary level of added Cu and period of time on the diet. Zn concentration in liver increased at 1000 and 2000 mg added Cu/kg diet and liver Fe concentration was increased at these levels. Histological examination of the gizzard indicated that the Cu content of the gizzard lining increased with dietary added Cu.
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PMID:Effects of level of dietary copper sulphate and period of feeding on the laying, domestic fowl, with special reference to tissue mineral content. 737 Feb 11

The three-dimensional structure of D-amino acid aminotransferase (D-AAT) in the pyridoxamine phosphate form has been determined crystallographically. The fold of this pyridoxal phosphate (PLP)-containing enzyme is completely different from those of any of the other enzymes that utilize PLP as part of their mechanism and whose structures are known. However, there are some striking similarities between the active sites of D-AAT and the corresponding enzyme that transaminates L-amino acids, L-aspartate aminotransferase. These similarities represent convergent evolution to a common solution of the problem of enforcing transamination chemistry on the PLP cofactor. Implications of these similarities are discussed in terms of their possible roles in the stabilization of intermediates of a transamination reaction. In addition, sequence similarity between D-AAT and branched chain L-amino acid aminotransferase suggests that this latter enzyme will also have a fold similar to that of D-AAT.
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PMID:Crystal structure of a D-amino acid aminotransferase: how the protein controls stereoselectivity. 762 35

Five aspartate aminotransferase (EC 2.6.1.1; AAT) isozymes were identified in soybean seedling extracts and designated AAT1 to AAT5 based on their rate of migration on non-denaturing electrophoretic gels. AAT1 was detected only in extracts of cotyledons from dark-grown seedlings. AAT3 and AAT4 were detected in crude extracts of leaves and in cotyledons of seedlings grown in the light. AAT2 and AAT5 were detected in all tissues examined. A soybean leaf cDNA clone, pSAT17, was identified by hybridization to a carrot AAT cDNA clone at low stringency. pSAT17 had an open reading frame which could encode a 50,581 Da protein. Alignment of the deduced amino acid sequence from the pSAT17 open reading frame with mature AAT protein sequences from rat disclosed a 60 amino acid N-terminal extension in the pSAT17 protein. This extension had characteristics of a plastid transit peptide. A plasmid, pEXAT17, was constructed which encoded the mature protein lacking the putative chloroplast transit polypeptide. Transformed Escherichia coli expressed a functional soybean AAT isozyme, which comigrated with the soybean AAT5 isozyme during agarose gel electrophoresis. Differential sucrose gradient sedimentation of soybean extracts indicated that AAT5 specifically cofractionated with chloroplasts. Antibodies raised against the pEXAT17-encoded AAT protein specifically reacted with the AAT5 isozyme of soybean and not with any of the other isozymes, indicating that the soybean cDNA clone, pSAT17, encodes the chloroplast isozyme, AAT5.
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PMID:Isolation and characterization of a soybean cDNA clone encoding the plastid form of aspartate aminotransferase. 768 17

A soybean leaf cDNA clone, pSAT2, was isolated by hybridization to a carrot aspartate aminotransferase (EC 2.6.1.1.; AAT) cDNA clone at low stringency. pSAT2 contained an open reading frame encoding a 47640 Da protein. The protein encoded by pSAT2 showed significant sequence similarity to AAT proteins from both plants and animals. It was most similar to two Panicum mitochondrial AATs, 81.5% and 82.0% identity. Alignment of the pSAT2-encoded protein with other mature AAT enzymes revealed a 25 amino acid N-terminal extension with characteristics of a mitochondrial transit peptide. A plasmid, pEXAT2, was constructed to encode the mature pSAT2 protein lacking the putative mitochondrial transit peptide. Escherichia coli containing the plasmid expressed a functional AAT isozyme which comigrated with the soybean AAT4 isozyme during agarose gel electrophoresis. Equilibrium sucrose gradient sedimentation of soybean extracts demonstrated that AAT4 specifically cofractionated with mitochondria. Antibodies raised against the pEXAT2-encoded AAT protein reacted with AAT4 of soybean and not with other AAT isozymes detected in soybean tissues, providing further evidence that clone pSAT2 encodes the soybean mitochondrial isozyme AAT4.
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PMID:Characterization of a soybean cDNA clone encoding the mitochondrial isozyme of aspartate aminotransferase, AAT4. 776 91

A clone encoding aspartate aminotransferase (AAT, EC 2.6.1.1) was isolated from an Arabidopsis thaliana leaf cDNA library. This clone contains a 1365 bp open reading frame encoding a polypeptide of 49.8 kDa, designated Ataat1. The clone was shown to contain a chloroplastic isoenzyme as an in organellar protein import assay demonstrated that a radiolabelled transcription/translation product of 49.8 kDa was imported into viable pea chloroplasts and was subsequently processed to yield a mature protein of 45 kDa. The open reading frame corresponding to the predicted mature AAT was manipulated into an expression construct (pEC14). Transformed Escherichia coli cells containing pEC14 expressed up to 16 times more AAT activity than vector only controls, thus demonstrating conclusively that the clone encoded AAT.
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PMID:Isolation, characterisation and expression of a cDNA clone encoding plastid aspartate aminotransferase from Arabidopsis thaliana. 776 5

The substrate specificity of tyrosine aminotransferase (eTAT) from Escherichia coli has been tested by transferring the critically different residues Leu39, Glu141, and Arg293 into equivalent positions of aspartate aminotransferase (eAAT). These residues are not directly involved in the catalytic process. The single mutant eAAT V39L possesses greater values of kcat/KM not only for tyrosine but also for aspartate and glutamate. In contrast, the double mutant eAAT P141E,A293R and also the triple mutant eAAT V39L,P141E,A293R exhibit smaller changes of kcat/KM. The converse mutants of tyrosine aminotransferase, in which critical residues of eAAT (Val39) and of mitochondrial AAT (Ala39, Val37) were transferred into equivalent positions of eTAT, exhibited generally decreased values of kcat/KM for both dicarboxylic and aromatic substrates. On the basis of the known structures of eAAT and eAAT V39L as well as of a refined model of eTAT, these results indicate that the different substrate specificities of eAAT and eTAT are due to multiple side chain differences and minor rearrangements of the backbone. The generally improved catalytic efficiency of the mutant eAAT V39L appears to be due to an indirect effect, namely, the facilitated closure of the active site upon substrate binding.
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PMID:Significant improvement to the catalytic properties of aspartate aminotransferase: role of hydrophobic and charged residues in the substrate binding pocket. 790 77

Indian River male broiler chickens growing from 7 to 28 d of age were fed on diets containing 120, 210 and 300 g crude protein/kg diet and 0, 1.67 or 16.7 g added tryptophan (TRP)/kg diet. The hypothesis tested was that crude protein levels and TRP would affect both growth and neurotransmitter metabolism. Heart, brain and pancreatic neurotransmitter (noradrenaline (NA), dopamine (DA), serotonin (5-HT) and 5-hydroxy-indole-3-acetic acid (5-HIAA)) concentrations were determined by HPLC separation and electrochemical detection. Malate dehydrogenase (2-oxoglutarate decarboxylating) (NADP+) (MDH(NADP+); EC 1.1.1.40), isocitrate dehydrogenase (NADP+) (ICD(NADP+); EC 1.1.1.42) and aspartate aminotransferase (AAT; EC 2.6.1.1) activities were also measured. Supplemental TRP decreased growth and feed intake. Increasing dietary crude protein decreased MDH(NADP+), but increased (ICD(NADP+) and AAT activities. Additional dietary TRP decreased MDH(NADP+) activity, but had no effect on other enzyme activities. Cardiac NA concentrations were directly related to dietary crude protein levels while pancreatic levels were inversely related. An increase in dietary crude protein decreased both brain NA and DA. Supplemental dietary TRP increased both 5-HIAA and 5-HT. Changes in feed intake caused by different levels of both dietary crude protein and TRP are accompanied by altered levels of neurotransmitters. The present study indicates that much larger amounts of TRP are required to make simultaneous changes in feed intake and neurotransmitters.
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PMID:Crude protein and supplemental dietary tryptophan effects on growth and tissue neurotransmitter levels in the broiler chicken. 877 19

Homogenates of specific brain regions of three sensory systems (auditory, olfactory, and visual) were prepared from pigmented Long-Evans Hooded rats and assayed for amino acid concentrations and activities of glutaminase, aspartate aminotransferase (total, cytosolic, and by difference, mitochondrial), malate dehydrogenase, lactate dehydrogenase, and choline acetyltransferase. Comparing the quantitative distributions among regions revealed significant correlations between AAT and aspartate, between glutaminase and glutamate, between glutamate and glutamine, and between AAT plus glutaminase, or glutaminase alone, and the sum of aspartate, glutamate, and GABA, suggesting a metabolic pathway involving the synthesis of a glutamate pool as precursor to aspartate and GABA. Of the inhibitory transmitter amino acids, GABA concentrations routinely exceeded those of glycine, but glycine concentrations were relatively high in brainstem auditory structures.
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PMID:Amino acid concentrations and selected enzyme activities in rat auditory, olfactory, and visual systems. 878 12

Two experiments were conducted with cross-bred barrows to determine the effect of somatotropin administration on liver enzyme activities. In the first experiment, pigs growing from 26 to 55 kg body weight were given two doses of pituitary porcine somatotropin (pST; 0 and 100 micrograms per kg body weight) and three levels of dietary energy (60, 80 and 100% of free choice intake). In the second experiment, pigs growing from 30 to 60 kg body weight were given two doses of recombinant porcine somatotropin (rpST; 0 and 100 micrograms per kg body weight) and five levels of dietary crude protein (110, 150, 190, 230 and 270 g crude protein/kg diet). Liver arginase (ARG, EC 3.5.3.1) and aspartate aminotransferase (AAT, EC 2.6.1.1) activities were then determined in organ samples taken at slaughter time. Dietary energy did not change liver ARG. Activities of both ARG and AAT increased as dietary crude protein increased. Both pST and rpST decreased ARG, AAT and serum utrea nitrogen. There was a lack of interaction between rpST therapy and dietary protein on either ARG or AAT activities, suggesting that set nutritional states are not required for expression of pST effects.
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PMID:Porcine somatotropin, dietary protein and energy effects on arginase and transaminase activities in pigs. 950 51

A soybean cDNA clone, pSAT1, which encodes both the cytosolic and glyoxysomal isozymes of aspartate aminotransferase (AAT; EC 2.6.1.1) was isolated. Genomic Southern blots and analysis of genomic clones indicated pSAT1 was encoded by a single copy gene. pSAT1 contained an open reading frame with ca. 90% amino acid identity to alfalfa and lupin cytosolic AAT and two in-frame start codons, designated ATG1 and ATG2. Alignment of this protein with other plant cytosolic AAT isozymes revealed a 37 amino acid N-terminal extension with characteristics of a peroxisomal targeting signal, designated PTS2, including the modified consensus sequence RL-X5-HF. The second start codon ATG2 aligned with previously reported start codons for plant cytosolic AAT cDNAs. Plasmids constructed to express the open reading frame initiated by each of the putative start codons produced proteins with AAT activity in Escherichia coli. Immune serum raised against the pSAT1-encoded protein reacted with three soybean AAT isozymes, AAT1 (glyoxysomal), AAT2 (cytosolic), and AAT3 (subcellular location unknown). We propose the glyoxysomal isozyme AAT1 is produced by translational initiation from ATG1 and the cytosolic isozyme AAT2 is produced by translational initiation from ATG2. N-terminal sequencing of purified AAT1 revealed complete identity with the pSAT1-encoded protein and was consistent with the processing of the PTS2. Analysis of cytosolic AAT genomic sequences from several other plant species revealed conservation of the two in-frame start codons and the PTS2 sequence, suggesting that these other species may utilize a single gene to generate both cytosolic and glyoxysomal or peroxisomal forms of AAT.
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PMID:Characterization of a single soybean cDNA encoding cytosolic and glyoxysomal isozymes of aspartate aminotransferase. 962 Feb 68


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