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:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The distribution of L-alanine:glyoxylate aminotransferase (AGT) activities were found in Suncus liver, 55% in particulate fraction and 45% in supernatant. 2. 65% of AGT activities in particulate were dependent on AGT isoenzyme 2 (AGT 2) having molecular weight 210,000, the remainder (35%) of AGT activities were dependent on AGT isoenzyme 1 (AGT 1) which have aminotransferase activity for serine. AGT activities in supernatant were dependent on AGT 1, AGT 2 and alanine:2-oxoglutarate aminotransferase (GPT), and their activity ratios were 10, 15 and 75%, respectively. 3. Km values for alanine were 0.52 mM; AGT 1, 3.3 mM; AGT 2, 0.88 mM; GPT measuring with AGT activity. AGT activity of GPT was inhibited by addition of glutamate and its Ki value was 1.8 mM. 4. Some other properties of AGT 1, AGT 2 and GPT are described.
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PMID:Alanine:glyoxylate aminotransferase activities in liver of Suncus murinus (insectivora). 290 70

A survey of aminotransferase activities present in a cell-free extract of the anaerobic protozoan, Trichomonas vaginalis was performed. 2-Oxoglutarate, oxaloacetate or phenylpyruvate acted as effective amino acceptors with tyrosine, phenylalanine, tryptophan, leucine, valine, isoleucine, aspartate, alanine, ornithine or lysine. Arginine, serine, glutamine, glycine, beta-alanine and gamma-aminobutyrate were not active as amino donors. With pyruvate as acceptor, significant, yet low, activity was seen only with glutamate, lysine or phenylalanine. Partial purification of enzymes catalysing transamination of leucine, valine, isoleucine, alanine, ornithine and lysine were carried out. A single enzyme catalysed the transamination of ornithine and lysine. The substrate specificity of this enzyme is novel. A separate enzyme catalysed the transamination of all three branched chain amino acids. A third enzyme catalysed the alanine aminotransferase reaction. A fourth enzyme catalysing the transamination both of aromatic amino acids and aspartate has previously been purified [Lowe, P.N. and Rowe, A.F. (1985) Biochem. J. 232, 689-695].
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PMID:Aminotransferase activities in Trichomonas vaginalis. 309 39

Escherichia coli strain K28, isolated after nitrosoguanidine mutagenesis, was found to be auxotrophic for serine. It was also temperature sensitive for growth as a result of producing an altered seryl-transfer ribonucleic acid (tRNA) synthetase (EC 6.1.1.11, l-serine: tRNA ligase [AMP]). The auxotrophy was caused by a mutation in the structural gene for phosphohydroxy-pyruvate transaminase (serC), which was distinct from, but closely linked to, the structural gene for seryl-tRNA synthetase (serS). We conclude that the relevant genes are in the order gal-serS-serC-aroA.
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PMID:Close linkage of the genes serC (for phosphohydroxy pyruvate transaminase) and serS (for seryl-transfer ribonucleic acid synthetase) in Escherichia coli K-12. 457 Jul 68

1. Attempts were made to demonstrate the presence of pyridoxal phosphate in the rat liver system catalysing the alphabeta-elimination of l-serine O-sulphate. 2. Methods designed to resolve protein-bound cofactor, spectroscopic examination of a purified enzyme system and attempted reactivation of apo-(alanine aminotransferase) failed to demonstrate the presence of pyridoxal phosphate. 3. The activity of the alphabeta-eliminating system remained constant in vitamin B(6)-deficient animals even though the activities of other pyridoxal phosphate-dependent systems fell markedly. 4. The metabolism of l-serine O[(35)S]-sulphate in vivo appears to be normal in vitamin B(6)-deficient animals. 5. No incorporation of tritium into the alphabeta-eliminating system occurred after administration of tritiated pyridoxine to experimental animals.
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PMID:A rat liver system that catalyses a pyridoxal phosphate-independent alpha beta-eliminto. 581 88

1. The concentrations of alanine, aspartate, glutamate, glutamine and serine plus threonine have been measured by enzymic methods in ;quick-frozen' livers from normal, starved, alloxan-diabetic and phlorrhizin-treated rats. 2. The hepatic concentrations of alanine and serine plus threonine were decreased in rats starved for 48hr. Treatment of these rats with phlorrhizin resulted in a rapid fall (within 2(1/2)hr.) in the concentrations of all the glucogenic amino acids except serine plus threonine, which increased. The pattern for alloxan-diabetic rats was similar to that for phlorrhizin-treated animals, except that here serine plus threonine also decreased in concentration. 3. The effects of anoxia on the hepatic concentrations of the glucogenic amino acids are reported. 4. Inhibition of glutamate-pyruvate transaminase in vivo by l-cycloserine resulted in the accumulation of alanine in situations involving high rates of gluconeogenesis from endogenous amino acids. 5. Measurements of the concentrations of the reactants of the glutamate-pyruvate transaminase and glutamate-oxoglutarate transaminase systems in various metabolic states suggest that they are both at or near equilibrium in rat liver. 6. New enzymic methods are described for the determination of serine plus threonine and alanine.
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PMID:Concentrations of free glucogenic amino acids in livers of rats subjected to various metabolic stresses. 604 91

1. Amino acid metabolism and protein synthesis in a Staphylococcus aureus mutant strain that requires pyrithiamine for optimum growth were studied and compared with those in the thiamine-requiring parent S. aureus. 2. The mutant strain utilized amino acids at a higher rate than did the parent strain. The utilization of glutamic acid, serine and glycine was much stimulated in the mutant strain. 3. The rate of oxidation of glutamic acid, aspartic acid, isoleucine and glycine was higher in the mutant strain. 4. The mutant strain contained serine, glycine, tyrosine, glutamic acid, aspartic acid, arginine and histidine as free amino acids, whereas the parent strain possessed lysine, arginine, histidine, aspartic acid and glutamic acid. 5. The mutant strain possessed slightly higher glutamate-oxalo-acetate transaminase activity, whereas the activities of glutamate-pyruvate transaminase were similar in both strains. 6. The incorporation of (14)C from [2-(14)C]-acetate into individual amino acids of the cell protein was greater in the mutant strain. 7. The incorporation of (14)C-labelled amino acids into the cell proteins of the mutant strain was not much different from that in the parent strain. 8. Induction of beta-d-galactosidase in the mutant strain did not occur, whereas induction of this enzyme is possible in the parent strain. Thiamine or pyrithiamine has no direct effect on the induction of beta-d-galactosidase.
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PMID:Amino acid metabolism and protein synthesis in a pyrithiamine-requiring Staphylococcus aureus mutant. 604 29

Evidence is provided for the utilization of glutamine by calvaria and compact bone of rat. Glutamine was actively transported into calvaria, principally by sodium-dependent mechanisms; its uptake was significantly inhibited by neutral amino acids (alanine, proline, serine, asparagine) and glutamine analogs (L-glutamate-gamma-hydroxamate, albizziin). Glutamine was degraded to ammonia and glutamate by phosphate-dependent glutaminase, a mitochondrial enzyme present in both calvaria and compact bone. The enzyme exhibited an apparent Kmgln of 2.35 mM, a KactPO4 of 25 mM, and a broad pH optimum (7.5-9.5). It was inactivated by incubation of intact calvaria or bone homogenates with the glutamine analogs 6-diazo-5-oxo-L-norleucine (DON) and a 2-amino-4-oxo-5-chloropentanoic acid (chloroketone). Such treatment also severely inhibited (greater than 95%) both ammonia and 14CO2 formation from [U-14C]glutamine. Glutamate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase activities were measured in bone. Amino-oxyacetate, an aminotransferase inhibitor, inhibited 14CO2 formation from [U-14C]glutamine. The data indicate that glutamine can serve as a precursor of ammonia, glutamate, other amino acids (alanine, aspartate, ornithine, proline) and carbon dioxide in bone and that phosphate-dependent glutaminase, transaminases, and citric acid cycle activity contribute to the observed metabolism.
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PMID:Glutamine metabolism in bone. 613 80

The effects of variation in quality and quantity of dietary protein on certain tissue enzymes in rainbow trout (Salmo gairdneri) were examined. Trout were given for 9 weeks diets containing proteins of different quality (fish-meal, casein and corn gluten) and with protein energy levels ranging from 26 to 74% of total metabolizable energy. In the first experiment, activities of a number of enzymes were monitored by only hepatic serine pyruvate transaminase (SPT) activity changed in response to the dietary treatments--increasing as protein energy level was raised. In the second experiment, opposing glycolytic an gluconeogenic enzyme activities [pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK); phosphofructokinase (PFK) and fructose diphosphatase (FDP)] were measured. Gluconeogenic enzyme activities correlated positively and significantly with dietary protein energy level; glycolytic enzymes correlated negatively and significantly with this parameter for all three proteins. There was no consistent relationship between presumed equilibrium point of opposing enzyme activities and maximum weight gain for the three proteins. It is suggested that hepatic activities of SPT, PFK, PK, FDP and PEPCK will provide useful indices of protein status in trout.
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PMID:Effects of quantity and quality of dietary protein on certain enzyme activities in rainbow trout. 625 69

Effects of varying protein level on hepatic utilization of serine, threonine and glycine were examined by measurements of metabolic fluxes across the liver. Feeding a high protein (HP) diet markedly enhanced hepatic extraction of serine, threonine and glycine, in parallel to alanine. After 20 hours starvation, activity of alanine aminotransferase and serine dehydratase still reflected the induction of these enzymes in fed rats. Thus, in starved rats previously adapted to HP diets, hepatic uptake of serine, threonine and glycine remained very efficient. With a normal diet, gluconeogenesis from alanine may be very active during starvation, in contrast to serine. The present results suggest that serine, and, to a lesser extent glycine, are very efficient glucogenic substrates with HP diets. The serine aminotransferase pathway might be important in rats fed HP diets, particularly for utilization of serine synthesized from glycine in mitochondria. With HP diets, the drop in hepatic alanine, serine and threonine suggest that transport across the plasma membrane might limit their utilization.
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PMID:Control of hepatic utilization of serine, glycine and threonine in fed and starved rats. 640 4

Concurrent treatments of cobalt chloride (CoCl2) and phenobarbital (PB), alone or in combination with lithocholic acid (LCA), were administered to rats for 7 days to assess whether or not a hypoactive hypertrophic smooth endoplasmic reticulum (HHSER) could be induced, as well as investigating the potential role of HHSER in the pathogenesis of cholestasis. LCA given alone slightly reduced hepatic triglycerides, significantly elevated plasma triglycerides and decreased microsomal glucose-6-phosphatase (G6P-ase) activity. PB administered alone significantly increased hepatic phospholipids and microsomal protein, phospholipid and cytochrome P-450 contents, as well as microsomal aminopyrine-N-demethylase (APDM-ase) activity. Functional indicators of liver impairment were associated primarily with CoCl2 treatment, whether given alone or in combination with PB + LCA. These signs included significantly reduced hepatic triglycerides, and increased plasma triglycerides associated with enhanced release of hepatic VLDL-triglycerides, as well as significantly decreased microsomal G6P-ase activity and/or reduced APDM-ase activity and cytochrome P-450 content. Elevated plasma bilirubin levels, and aspartate and alanine aminotransferase activities were also evident with concurrent CoCl2 + PB + LCA treatments. Combined CoCl2 + PB treatments, with or without LCA, caused significant increases in microsomal protein and phospholipid, and decreased activity of the rough endoplasmic reticulum (RER) marker G6P-ase, but no changes in cytochrome P-450 levels and no marked alterations in the activity of the SER marker APDM-ase. The data indicated that simultaneous CoCl2 and PB treatments, whether given alone or in combination with LCA, caused a functional impairment of the RER, and did not induce HHSER membranes.
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PMID:Functional responses of the rat hepatic endoplasmic reticulum to treatment proposed as a model for cholestasis. 668 66


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