Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Kynurenine transaminase activity in rat liver was found in both the mitochondrial and supernatant fractions. The mitochondrial and supernatant fractions contained (a) kynurenine-pyruvate transaminase, which showed a preference for pyruvate as amino acceptor and a pH optimum between 8.0 and 8.5, and (b) kynurenine-alpha-oxoglutarate transaminase, with a preference for alpha-oxoglutarate and a pH optimum between 6.0 and 6.5. Possible roles of these enzymes in tryptophan metabolism in the liver are discussed.
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PMID:Subcellular distribution and properties of kynurenine transaminase in rat liver. 446 56

The potential cholestatic effect of amino acids and metabolites of tryptophan were evaluated by use of seven daily intraperitoneal injections to suckling and weanling rat pups. Of the amino acids present in parenteral nutrition solutions, only tryptophan (given at a dose of 4 mM/kg) produced a significant (p less than 0.01) elevation of serum cholylglycine (12.8 +/- 1.0 microM/liter) as determined by radioimmunoassay, compared to 4.9 +/- 0.4 microM/liter in saline-treated control animals. Total serum conjugates of cholic acid, as determined by radioimmunoassay, were similarly elevated, as was serum alanine aminotransferase. Tryptophan injection resulted in elevated cholylglycine concentrations only at doses of 3 mM/kg/day or higher. Animals more than 2 weeks old did not demonstrate elevation of serum cholylglycine. Injection of light-exposed tryptophan in suckling animals caused a greater elevation of cholylglycine (39.0 +/- 8.6 microM/liter) than freshly prepared tryptophan solutions (p less than 0.005). Tryptophan and its spontaneous degradation products could contribute to the cholestatic liver changes observed during parenteral nutrition therapy.
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PMID:Cholestatic effect of intraperitoneal administration of tryptophan to suckling rat pups. 643 84

After administration of D-galactosamine-HCl alterations in liver cells - histologically resembling hepatitis - occur. During this process several biochemical changes are demonstrable. The formation of these alterations may be prevented by combined administration of nicotinamide + L-methionine or DL-tryptophan + L-methionine. This had been confirmed by histology as well as by determination of GOT and GPT activity in the serum.
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PMID:The influence of nicotinamide, tryptophan, and methionine upon galactosamine-induced effects in the liver. 645 26

The substrate specificity of aspartate aminotransferase (ASAT, E.C. 2.6.1.1.) from Leishmania was examined following observations of artefacts on gels stained for alanine aminotransferase (ALAT, E.C. 2.6.1.2.) after thin-layer starch-gel electrophoresis. Leishmanial ASAT acted on L-aspartate, L-alanine, L-tryptophan and L-tyrosine. Interpretation of ALAT zymograms must thus take into account the presence of interfering ASAT bands, and the need is emphasized for rigorous controls in isoenzyme electrophoresis.
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PMID:Aspartate aminotransferase in Leishmania is a broad-spectrum transaminase. 646 33

Fed and fasted rats were injected with L-tryptophan (12.5 mg/100 g body weight) and the specific activities of L-glutamic: NAD oxidoreductase (deaminating) (EC 1.4.1.2) (GDH), L-aspartic-2-ketoglutaric aminotransferase (EC 2.6.1.1) (GOT) and L-alanine-2-ketoglutaric aminotransferase (EC 2.6.1.2) (GPT) from hepatic mitochondria and cytosol were compared. L-tryptophan results in a decrease of mitochondrial GDH activity by 22% and of cytosolic GPT and GOT by 42% and 38% respectively in the liver of fasted rats. Xanthurenate is a potent inhibitor of purified extramitochondrial GPT, whereas anthranilate and quinolinate are less potent inhibitors. L-tryptophan, 5-OH-tryptophan and indole exert a slight inhibition. Kynurenine, 5-OH-tryptamine, tryptamine, picolinic acid, nicotinic acid and indoloacetic acid do not show any inhibition of GPT. It is suggested that L-tryptophan injection inhibits extramitochondrial GPT by its transformation to xanthurenate and anthranilate.
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PMID:Effect of L-tryptophan injection in rats on some enzymes of amino acid metabolism in liver. I. In vitro studies of the effect of L-tryptophan and its metabolites on the extramitochondrial L-alanine: 2-ketoglutaric aminotransferase. 722 74

Experimental studies have demonstrated preferential injury to the sinusoidal endothelium during liver preservation with University of Wisconsin (UW) or Euro-Collins solution. This endothelial cell injury has an unclear pathogenesis, and it has not yet been studied in the human liver. Therefore, we analyzed the effluent of 21 human liver allografts after cold storage. Markers of hepatocellular and nonparenchymal cell injury were assessed. After preservation with UW solution, early effluent samples contained 1823 +/- 1494 U/l lactate dehydrogenase (LDH), 493 +/- 516 U/l alanine aminotransferase (ALT) and 132 +/- 97 U/l creatine kinase (CK; 92 +/- 92 U/l CK-BB). The effluent of livers preserved in histidine-tryptophan-ketoglutarate (HTK) solution contained 3681 +/- 2009 U/l LDH, 1139 +/- 599 U/l ALT and 282 +/- 120 U/l CK (165 +/- 91 U/l CK-BB). Comparison of effluent enzyme activities with liver tissue enzyme activities indicates that the release of the endothelial cell/nonparenchymal cell marker creatine kinase was higher, by a factor of 7-8, than the release of hepatocellular enzymes. Effluent thrombomodulin concentrations were 123 +/- 248 ng/ml (UW) and 604 +/- 299 ng/ml (HTK), and effluent glucose concentrations, 40.3 +/- 27.0 mM (726 +/- 486 mg/dl; UW) and 10.4 +/- 4.5 mM (187 +/- 81 mg/dl; HTK). We conclude that prominent endothelial cell injury also occurs in human liver grafts after preservation with UW solution or HTK solution. This endothelial cell injury is unlikely to be caused by hypoxia-induced energy deficiency, as it affects a cell type with a high glycolytic capacity in the presence of high glucose levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nonparenchymal cell and hepatocellular injury to human liver grafts assessed by enzyme-release into the perfusate. 793 84

Serum amino acid (AA) profiles are altered in epilepsy. It is not clear whether this is due to the disease process itself or to other variables such as seizure type, seizure frequency, duration of illness, medication, or altered liver function. We investigated serum AA profiles and liver enzymes in 73 epileptic patients and 90 healthy subjects and evaluated the data by analysis of variance to discriminate between age, sex, seizure type, duration of illness, seizure frequency, antiepileptic drug (AED) and increased serum liver enzyme levels, and their putative interaction with the serum AA profile. There was no correlation between the changes in the AA profile and age, duration of illness, seizure frequency, and seizure type. Seventy-two percent of the AED-treated patients and 33% of the unmedicated patients showed an increase in one or several serum liver enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST), and/or gamma-glutamyl transferase (gamma-GT)]; particularly gamma-GT. We observed a significant increase in serum concentrations of glutamine and glycine and decreased levels of taurine, threonine, serine, valine, methionine, isoleucine, leucine, phenylalanine, histidine, tryptophan, and arginine in AED-treated patients but not in unmedicated patients. These results show that the changes in the serum AA profiles of epileptic patients treated with AEDs occur in patients with alteration of serum liver enzymes; whether this implies a causal relation is still uncertain.
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PMID:Serum amino acids, liver status, and antiepileptic drug therapy in epilepsy. 809 92

Tyrosine aminotransferase was purified to homogeneity from epimastigotes of Trypanosoma cruzi by a method involving chromatography on DEAE-cellulose, gel filtration on Sephacryl S-200 and chromatography on Mono Q in an f.p.l.c. system. The purified enzyme showed a single band in SDS/PAGE, with an apparent molecular mass of 45 kDa. Since the apparent molecular mass of the native enzyme, determined by gel filtration, is 91 kDa, the native enzyme is a dimer of similar subunits. The amino-acid composition was determined, as well as the sequences of three internal peptides obtained by CNBr cleavage at Met residues. Both criteria suggest considerable similarity with the tyrosine aminotransferases from rat and from human liver. The enzyme contains nine 1/2 Cys residues, three free and the others forming three disulphide bridges. The enzyme is not N-glycosylated. The isoelectric point is 4.6-4.8. The optimal pH for the reaction of the enzyme with tyrosine as a substrate is 7.0. The apparent Km values for tyrosine, phenylalanine and tryptophan, with pyruvate as a co-substrate, were 6.8, 17.9 and 21.4 mM, respectively, whereas those for pyruvate, alpha-oxoglutarate and oxaloacetate, with tyrosine as a substrate, were 0.5, 38 and 16 mM respectively. The purified tyrosine aminotransferase acts as an alanine aminotransferase as well and the activity seems to reside in the same enzyme molecule. The results suggest that the enzyme is a general aromatic-amino-acid transaminase, with high sequence similarity to tyrosine aminotransferases from rat and human liver.
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PMID:Purification and partial structural and kinetic characterization of tyrosine aminotransferase from epimastigotes of Trypanosoma cruzi. 810 Apr 16

To determine the effect of varying levels of dietary protein with a constant intake of vitamin B-6 (B-6) on B-6 status, nine women were fed diets providing daily intakes of 1.25 mg B-6 and 0.5, 1.0 and 2.0 g protein/kg body weight. After an 8-d adjustment period, the women consumed each level of dietary protein for 14 d in a Latin-square design. Several direct and indirect B-6 status indicators were measured in blood and urine. Significant differences among protein levels were found for urinary 4-pyridoxic acid (4-PA) excretion (P < 0.01), plasma pyridoxal 5'-phosphate (PLP) concentration (P < 0.05), and urinary excretion of volatile amines (VA, kynurenine plus acetylkynurenine) after a 2-g L-tryptophan load (P < 0.05). Nitrogen intake was significantly negatively correlated with urinary 4-PA excretion (r = -0.619, P < 0.001) and plasma PLP concentration (r = -0.549, P < 0.01), and positively correlated with erythrocyte alanine aminotransferase percentage stimulation (r = 0.418, P < 0.05) and urinary post-tryptophan load excretion of xanthurenic acid (r = 0.535, P < 0.05), kynurenic acid (r = 0.563, P < 0.05) and VA (r = 0.626, P < 0.01). Compared with men consuming diets with similar B-6 to protein ratios In a previous study, the women excreted a greater percentage of the B-6 intake as 4-PA, had lower plasma PLP concentrations and excreted greater amounts of postload urinary tryptophan metabolites at all three protein levels. If the Recommended Dietary Allowance (RDA) of vitamin B-6 is to be based on the dietary B-6 to protein ratio, gender differences in response to varying protein intakes should be considered. For the levels of protein intake used in this study and a B-6 intake of 1.25 mg/d, a B-6 to protein ratio of greater than 0.020 mg/g is required for adequate vitamin B-6 status in women.
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PMID:Vitamin B-6 status of women with a constant intake of vitamin B-6 changes with three levels of dietary protein. 868 52

Changes in vitamin B-6 status indicators were evaluated in vitamin B-6-replete subjects. Ten young women consumed diets providing 85 g protein/d and 1.03, 1.33, 1.73, and 2.39 mg vitamin B-6/d for 12 or 15 d during four successive diet periods; in a second study, six women were fed diets providing 85 g protein/d and 0.84, 1.14, and 2.34 mg vitamin B-6/d for 10 or 12 d during three successive diet periods. Vitamin B-6 status indicators showing significant differences among intakes included urinary excretion of 4-pyridoxic acid and total vitamin B-6, pyridoxal 5'-phosphate and total vitamin B-6 in plasma, and xanthurenic acid excretion after a 2-g L-tryptophan load. Significant correlations were found between vitamin B-6 intake and 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, plasma total vitamin B-6, erythrocyte alanine aminotransferase percentage stimulation and postload excretion of xanthurenic acid and volatile amines (kynurenine plus acetylkynurenine). Depending on the indicator, between 20% and 70% of the subjects had inadequate values for 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, and erythrocyte alanine aminotransferase percentage stimulation at a vitamin B-6 intake of 1.33 mg/d (0.016 mg vitamin B-6/g protein). A ratio of dietary vitamin B-6 to protein > 0.016 mg/g is required for adequate vitamin B-6 status in women.
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PMID:Changes in vitamin B-6 status indicators of women fed a constant protein diet with varying levels of vitamin B-6. 939 90


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