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)

In glycogen storage disease type III (glycogen debranching enzyme (DE) deficiency), the activities of serum alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase may be strikingly elevated during childhood but are low during adult life. To determine the pattern of the elevated serum enzyme activities in relationship to diet, the biochemical subtype and clinical symptoms, 13 patients with DE deficiency were studied. Activities of serum aspartate and alanine transaminases, lactate dehydrogenase, and alkaline phosphatase were markedly elevated during infancy. Continued elevation of enzyme activities during childhood appeared to be related to DE deficiency in liver, but unrelated to DE deficiency in muscle. Activity elevations correlated inconsistently with diet and poorly with childhood growth rate or the presence of hypoglycaemia. The serum enzyme activities declined around puberty concomitantly with a decrease in liver size. Although periportal fibrosis and micronodular cirrhosis indicated the presence of hepatocellular damage during childhood, the decline in serum enzyme activities with age and the absence of overt hepatic dysfunction suggest that the fibrotic process may not always progress.
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PMID:Glycogen debranching enzyme deficiency: long-term study of serum enzyme activities and clinical features. 129 83

Eleven subjects performed a graded exercise test after 1 week of protein supplementation (PRO) or glucose polymer placebo (CON), randomly assigned in a double blind fashion. The exercise consisted of 3-min graded exercise bouts separated by 10 min of active recovery at zero pedal resistance. Subjects then performed a 30-sec Wingate test (WIN) to assess performance during supramaximal exercise. Blood samples were obtained in the last 15 sec of each exercise and recovery period. PRO resulted in a decrease in blood lactate following 120% VO2max and WIN, an increase in blood alanine at all time points, and lower postexercise muscle lactate and glycogen. Resting muscle GPT activity was 47% higher during the PRO trial. Mean power output during the WIN did not differ between PRO and CON. The WIN fatigue index was not significantly different between PRO and CON. The increased alanine may reflect increased transamination of pyruvate, thereby reducing the accumulation of lactate, which in turn had a marginal effect on performance during supramaximal exercise.
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PMID:The effect of protein supplementation on lactate accumulation during submaximal and maximal exercise. 129

Sera from 209 dialysis patients were tested for antibodies to hepatitis C virus (anti-HCV) by a 2nd generation enzyme-linked immunoassay (ELISA 2) using nonstructural and core antigens. Confirmation of reactivity was obtained by a 2nd generation immunoblot assay (RIBA 2) for antibodies to 4 separate antigens (5-1-1, c100-3, c33c, c22-3). ELISA 2 was positive in 99 sera, 95 of which were confirmed by RIBA 2, thus accounting for an anti-HCV prevalence of 45.5%. Anti-HCV positivity was correlated to longer duration of dialysis therapy (p less than 0.001), higher number of transfusions (p less than 0.001), history of kidney transplant (p less than 0.001) and of serum alanine/aspartate aminotransferase (AST/ALT; p less than 0.001) or gamma-glutamyltransferase (GGT) (p less than 0.001) increments. The most frequent RIBA 2 patterns were: reactivity to all 4 antigens (34 patients) and to c33c and c22-3 (45 patients). The former patients, compared to the latter, had higher values of AST (p less than 0.08), ALT (p less than 0.02), GGT (p less than 0.005), IgG (p less than 0.05). It is possible that the reactivity to all 4 antigens of RIBA 2 is a clue of a greater activity of viral hepatic disease.
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PMID:Confirmation of high prevalence of hepatitis C antibodies in hemodialysis patients by second generation immunoblot assay. 132 87

We have previously reported that Drosophila Kc cells require glutamine for maximal expression of heat shock proteins in stressed conditions (Sanders and Kon: J. Cell. Physiol. 146:180-190, 1991). The mechanism of this effect has been investigated by comparing the metabolic utilization of glutamine in conditions which support hsp expression with that of glutamate in conditions where up to 100-fold less hsp is synthesized. This comparison showed that free ammonia was generated by cells incubated in the presence of glutamine in 37 degrees C (heat shock) conditions, but not at 25 degrees C, and not in the presence of glutamate in either normal or heat shock conditions. There was no difference in the amount of [14C]O2 generated from either [14C]-labeled amino acid in the tricarboxylic acid cycle, but three- to four-fold more alanine was synthesized in cells incubated in glutamine than in glutamate. Treating the cells with aminotransferase inhibitors to artificially increase NH3 release raised hsp expression in the presence of glutamate to maximal levels characteristic of glutamine. This potentiation correlated with inhibition of alanine aminotransferase. Since only NH3 production correlated with hsp expression in heat shock conditions in the presence of glutamine, and NH3 addition to glutamate also resulted in maximal hsp expression, we measured glutamine production in glutamate plus NH3 and observed net glutamine synthesis. The supposition that glutamine itself is responsible for the regulatory changes supporting maximal hsp expression was supported by the finding that the glutamine analog, 6-diazo-5-oxo-L-norleucine (DON), mimicked the effects of glutamine. We conclude that glutamine imposes regulatory changes which alter nitrogen metabolism and support hsp expression in Kc cells.
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PMID:Glutamine and glutamate metabolism in normal and heat shock conditions in Drosophila Kc cells: conditions supporting glutamine synthesis maximize heat shock polypeptide expression. 134 46

Response characteristics are presented for a dual-enzyme fiber-optic biosensor for glutamate. An enzyme layer composed of glutamate dehydrogenase (GDH) and glutamate-pyruvate transaminase (GPT) is used to produce reduced nicotinamide adenine dinucleotide (NADH) at the tip of a fiber-optic probe. NADH luminescence is monitored through this probe and the measured fluorescence intensity is related to the concentration of glutamate. GDH catalyzes the formation of NADH, and GPT drives the GDH reaction by removing a reaction product and regenerating glutamate. Optimal response is obtained in a pH 7.4 Tris-HCl buffer maintained at 25 degrees C in the presence of 4 mM NAD+ and 10 mM L-alanine. The temperature profile reveals a strong negative temperature effect which is attributed to the temperature dependency of NADH luminescence. Under optimal conditions, the sensor sensitivity is 0.127 nA/microM over the 1-10 microM concentration range, the detection limit is 0.13 microM, and response times range from 4 to 8 min. The sensor response is stable for 12 days when stored at 4 degrees C. Selectivity for glutamate is excellent over most of the common amino acids as well as ascorbic acid, uric acid, taurine, and GABA. Only slight responses were observed for glutamine and lysine. The effect of ammonia on the glutamate response was found to be minimal at total ammonia nitrogen concentrations as high as 200 microM.
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PMID:Dual-enzyme fiber-optic biosensor for glutamate based on reduced nicotinamide adenine dinucleotide luminescence. 135 Apr 33

The activities of aspartate and alanine aminotransferases in biological samples were assessed through a novel and sensitive procedure, based on the conversion of [U-14C]2-ketoglutarate to L-[U-14C]glutamate. In human plasma, the generation of L-[U-14C]glutamate was proportional to the volume of plasma (20-60 microL) and to the length of incubation (30-90 min). The reaction velocity was related to the temperature with a Q10 close to 1.7 for aspartate aminotransferase and 2.0 for alanine aminotransferase. At 37 degrees C, the 95% confidence interval in healthy subjects ranged from 5.1-18.8 U/mL (mean value 11.9 U/L) for aspartate aminotransferase and from zero to 20.1 U/L (mean value 9.9 U/L) for alanine aminotransferase. The intra-assay coefficient of variation did not exceed 2.5%. The present method was also applied to homogenates prepared from rat pancreatic islets, liver, heart, parotid glands, and erythrocytes, using no more than 40 micrograms wet weight of tissue per sample, and could thus be used in small biological samples, such as those obtained by needle biopsy.
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PMID:Radioisotopic assay of aspartate and alanine aminotransferase. 135 85

Using rat hepatocytes we confirmed our previous results that glucagon and beta-adrenergic agonists increased the enzyme activity of alanine aminotransferase (AAT) and propranolol abolished their effects. Only the enzyme activity was measured and other parameters like quantity of the enzyme or activation due to modification were not looked for. As in perfusion experiment phenylephrine and phenoxybenzamine (alpha-agonist and alpha-antagonist respectively) also alpha-antagonist respectively) also increased the AAT activity in isolated rat hepatocytes and propranolol reversed these effects. The additive effect of glucagon and phenoxybenzamine on AAT was also persistent in hepatocyte system. Fructose-1:6-bisphosphatase (Fru-P2-ase), another key enzyme in gluconeogenic pathway, was elevated by glucagon and other beta-adrenergic agonists both in liver perfusion and isolated hepatocyte experiments and was brought back to the normal level by propranolol. In this case also only the enzyme activity was measured and no other parameters were looked for. Unlike AAT this enzyme was not stimulated by phenylephrine or phenoxybenzamine. But AAT and Fru-P2-ase activities were increased significantly by adenylate cyclase activators like fluoride or forskolin. Thus, it appears that the regulation of fru-P2-ase by glucagon is purely a b-receptor mediated process whereas AAT activation shows a mixed type of regulation where some well known alpha-agonist and antagonists are behaving as beta-agonists. Results further indicate the presence of phosphodiesterase in hepatocyte membrane which was stimulated by glucagon and brought back to the normal level by propranolol. The different adrenergic compounds stated above, not only modified the activity of the above two enzymes but also stimulated glucose production by hepatocytes from alanine which was in turn abolished by propranolol as well as amino oxyacetate (AOA), a highly specified inhibitor of AAT. This confirm the participation of AAT in gluconeogenesis from alanine in liver. Forskolin and fluoride also increased the glucose production from alanine and showed additive effects with glucagon, phenylephrine and phenoxybenzamine.
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PMID:Effect of adrenergic agonists and antagonists on alanine amino transferase, fructose-1:6-bisphosphatase and glucose production in hepatocytes. 135 93

We determined transaminases in human blood serum with an amperometric glutamate biosensor. The probe was a hydrogen peroxide sensor assembled with appropriate selective membranes to enhance the probe specificity and lifetime. Calibration curves of glutamate were linear in the range 1-1000 mumol/L, with a response time of < 1 min. This probe was subsequently applied to the measurement of activities of aspartate and alanine aminotransferases in human sera. Analytical recovery studies demonstrated the suitability of the glutamate sensor by measuring 91-99% of added glutamate, 92-106% of added aspartate aminotransferase, and 101-105% of added alanine aminotransferase. Transaminase activity measured in 80 sera correlated well with results obtained with a spectrophotometric procedure.
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PMID:Analysis for transaminases in serum with an amperometric glutamate electrode. 135 81

1. The hepatic metabolism of glutamine, alanine, ammonia, urea, glutathione and glucose was studied in rats made septic by caecal ligation and puncture and was compared with that in rats that had undergone sham operation (laparotomy). 2. Sepsis resulted in increases in the plasma activities of gamma-glutamyltransferase (P less than 0.001), alanine aminotransferase (P less than 0.001) and aspartate aminotransferase (P less than 0.001), the serum total and direct bilirubin concentrations (P less than 0.001), and the blood lactate (P less than 0.01), glutamine (P less than 0.05), alanine (P less than 0.001) and urea (P less than 0.05) concentrations, but produced decreases in the blood ketone body (P less than 0.001) and glutathione (P less than 0.05) concentrations and in the plasma cholesterol concentration (P less than 0.05). These changes were associated with marked negative nitrogen balance in septic rats. 3. Sepsis increased total hepatic blood flow (by 22.7%) together with hepatic arterial flow (by 25.8%) and portal venous flow (by 18.7%). Sepsis resulted in marked increases in the net rates of hepatic extraction of glutamine (by 164%), alanine (by 138%) and ammonia (by 259%) with concomitant increases in the net rates of hepatic release of glutamate (by 105%), glutathione (by 87.5%), glucose (by 70.1%) and urea (by 100.4%). 4. Sepsis increased the activities of liver carbamoylphosphate synthase (by 16.4%), ornithine transcarbamylase (by 29.8%), argininosuccinate synthase (by 28.1%) and arginase (by 33.8%). 5. Septic rats exhibited marked increases in hepatic protein (by 46.0%), RNA (by 43.4%) and DNA (by 37.7%) contents. These changes were accompanied by marked increases in the activity of thymidine kinase (by 35.9%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hepatic glutamine metabolism in the septic rat. 137 98

It has been established in experiments on white rats that antituberculous drugs (isoniazid, rifampicin, ethambutol) given in toxic doses affect the liver, its membranes and organelles, inhibit bile production and bioenergy. This is supported by activation of aspartate and alanine aminotransferases, (ALT and AST), alkaline phosphatase in blood serum and acid phosphatase in the liver, by a decrease of the activity of Na(+)-, K(+)-ATPase, succinate dehydrogenase and cytochromoxidase in the liver, lowering of the rate of bile secretion, excretion of bile acids, bilirubin and cholesterol with bile. Provided the drugs are administered in combination, the hepatotoxicity rises, particularly in combination of isoniazid with rifampicin, and especially as isoniazid is combined with rifampicin and ethambutol.
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PMID:[The comparative action of isoniazid, rifampicin and ethambutol on liver function]. 142 54


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