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 previous studies it was found that: (a) aspartate aminotransferase increases the aspartate dehydrogenase activity of glutamate dehydrogenase; (b) the pyridoxamine-P form of this aminotransferase can form an enzyme-enzyme complex with glutamate dehydrogenase; and (c) the pyridoxamine-P form can be dehydrogenated to the pyridoxal-P form by glutamate dehydrogenase. It was therefore concluded (Fahien, L.A., and Smith, S.E. (1974) J. Biol. Chem 249, 2696-2703) that in the aspartate dehydrogenase reaction, aspartate converts the aminotransferase into the pyridoxamine-P form which is then dehydrogenated by glutamate dehydrogenase. The present results support this mechanism and essentially exclude the possibility that aspartate actually reacts with glutamate dehydrogenase and the aminotransferase is an allosteric activator. Indeed, it was found that aspartate is actually an activator of the reaction between glutamate dehydrogenase and the pyridoxamine-P form of the aminotransferase. Aspartate also markedly activated the alanine dehydrogenase reaction catalyzed by glutamate dehydrogenase plus alanine aminotransferase and the ornithine dehydrogenase reaction catalyzed by ornithine aminotransferase plus glutamate dehydrogenase. In these latter two reactions, there is no significant conversion of aspartate to oxalecetate and other compounds tested (including oxalacetate) would not substitute for aspartate. Thus aspartate is apparently bound to glutamate dehydrogenase and this increases the reactivity of this enzyme with the pyridoxamine-P form of aminotransferases. This could be of physiological importance because aspartate enables the aspartate and ornithine dehydrogenase reactions to be catalyzed almost as rapidly by complexes between glutamate dehydrogenase and the appropriate mitochondrial aminotransferase in the absence of alpha-ketoglutarate as they are in the presence of this substrate. Furthermore, in the presence of aspartate, alpha-ketoglutarate can have little or no affect on these reactions. Consequently, in the mitochondria of some organs these reactions could be catalyzed exclusively by enzyme-enzyme complexes even in the presence of alpha-ketoglutarate. Rat liver glutamate dehydrogenase is essentially as active as thebovine liver enzyme with aminotransferases. Since the rat liver enzyme does not polymerize, this unambiguously demonstrates that monomeric forms of glutamate dehydrogenase can react with aminotransferases.
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PMID:Effect of aspartate on complexes between glutamate dehydrogenase and various aminotransferases. 1 47

Serum gamma glutamyl transpeptidase (GGTP), isocitrate dehydrogenase (ICD), ornithine carbamoyl transferase (OCT), alanine aminotransferase (AlT), aspartate aminotransferase (AsT), and alkaline phosphatase (ALP) activities were assayed in 67 alcoholics and 40 drug dependent patients. Bilirubin, total protein, albumin, and globulin were also measured. GGTP elevation was observed in 48% of alcoholics and in 50% of drug dependents. The incidences of elevated levels of other enzymes were: ICD 39 and 38-7%; OCT 23-7 and 36-1%; AlT 30 and 33%; AsT 24-2 and 21-7%; ALP 10-4 and 5% respectively. Measurement of GGTP is thus more useful as a screening test for involvement of the liver in alcoholics and drug dependent patients than that of the other enzymes.
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PMID:Serum enzyme levels in alcoholism and drug dependency. 23 23

South Louisiana crude oil was fed to duckling mallards (Anas platyrhynchos) in concentrations of 0.025, 0.25, 2.5, and 5.0% of the diet from hatching to 8 weeks of age to assess the effects of chronic oil ingestion during early development. Growth was depressed in birds receiving a diet containing 5% oil but there was no oil-related mortality. Diets containing 0.25, 2.5, and 5.0% oil impaired avoidance behavior of 6-day-old mallard ducklings when compared with controls or ducklings fed 0.025% oil, but had no effect on open-field behavior of 7-day-old ducklings. Liver hypertrophy and splenic atrophy were gross evidence of the pathological effects of oil in birds on the 2.5 and 5.0% oil diets. Biochemical lesions that occurred included elevation of plasma alanine aminotransferase and ornithine carbamyl transferase activity. Hepatocyte hypertrophy and bile duct proliferation in the liver were noted in birds fed the 2.5 and 5.0% oil diets and tubular inflammation and degeneration in the kidney were noted in birds fed the 5.0% oil diet.
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PMID:Effects of chronic ingestion of south Louisiana crude oil on mallard ducklings. 31 28

Twenty calves were infected with 1000 metacercariae of Fasciola hepatica, the activities of 10 enzymes in plasma or serum were assayed and concentrations in serum of proteins, urea and bilirubin were determined. These values were compared with control data obtained from 14 uninfected calves. Aspartate aminotransferase, lactate dehydrogenase, sorbitol dehydrogenase, glutamate dehydrogenase, ornithine carbamoyl transferase and gamma-glutamyl transpeptidase activities increased in infected calves. Total serum protein increased, albumin decreased, globulin increased and the albumin/globulin ratio was decreased in infected calves. Plasma alanine aminotransferase, leucine aminopeptidase, alkaline phosphatase and cholinesterase activities and serum concentration of urea and bilirubin were unaffected. It was concluded that glutamate dehydrogenase and gamma-glutamyl transpeptidase were the most sensitive indicators of liver cell damage in fascioliasis.
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PMID:Biochemical indicators of liver injury in calves with experimental fascioliasis. 83 11

In order to assess the extent to which metabolism within the sheep placenta may influence the transfer of metabolites between mother and foetus at different stages of gestation the activities of enzymes concerned with some aspects of carbohydrate, amino acid and keton body metabolism were determined in placental cotyledons resected from ewes during the last three months of pregnancy. The activities of pyruvate kinase (EC 2.7.1.40), lactate dehydrogenase (EC 1.1.1.27), malate dehydrogenase (EC 1.1.1.37), ATP citrate (pro-3S)-lyase (EC 4.1.3.8), citrate (si)-synthase (EC 4.1.3.7), acetyl-CoA synthetase (EC 6.2.1.1), acetyl-CoA acetyltransferase (EC 2.3.1.9) and 3-keto acid CoA-transferase (EC 2.8.3.5) per gram wet weight cotyledon do not change during the period studied. The activities of alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.1), isocitrate dehydrogenase (NADP+) (EC 1.1.1.42), ornithine-oxoacid aminotransferase (EC 2.6.1.13) and 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) show an increase in activity between the third and fourth months of pregnancy whilst the activities of arginase (EC 3.5.3.1) and possibly pyruvate carboxylase (EC 6.4.1.1) show an increase in activity between the fourth and final months of pregnancy. Ornithine decarboxylase (EC 4.1.1.17) activity declines to one tenth of its activity during this later period. The absence of detectable activities of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) and ornithine carbamoyltransferase (EC 2.1.3.3) indicate that gluconeogenesis and urea synthesis from ammonia do not occur in the sheep placenta. It appears that the ability of the placenta to metabolise several substrates is achieved by the time the placenta reaches its maximum size at approximately 90 days.
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PMID:Enzyme activities in the sheep placenta during the last three months of pregnancy. 84 73

The activities of ornithine carbamyl transferase, arginase and glutamic-pyruvic transaminase increase in the liver of the rat if the biological value of the dietary protein decreases. Experiments with pigs revealed in the blood serum an analogous high correlation between the biological value of the dietary protein and the activities of arginase, glutamic-pyruvic transaminase, leucine aminopeptidase and glutamic-oxalacetic transaminase. The most favourable possibility of protein evaluation on the basis of criteria of the intermediary protein metabolism consists in the determination of the blood urea concentration provided that the protein carrier supply is standardized. This procedure which has been elaborated by BERGNER and co-workers in 1968 for the determination of the protein quality was confirmed by TAYLOR and co-workers in 1974 on healthy individuals as a reliable and elegant measuring technique with highly significant correlation. It is concluded that the true biological value of protein carriers or protein mixtures which are intended for human nutrition can on principle be determined only in studies with healthy individuals.
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PMID:[Protein evaluation based on intermediary protein metabolism criteria]. 122 18

The synthesis and release of alanine and glutamine have been studied in the intact rat epitrochlaris skeletal muscle preparation. Aspartate, cysteine, leucine, valine, methionine, isoleucine, serine, theronine, and glycine increased significantly the formation and release of alanine from muscle. Cysteine, leucine, valine, methionine, isoleucine, tyrosine, lysine, and phenylalanine increased the rate of glutamine synthesis. Only ornithine, arginine, and tryptophan were without effect on the synthesis of either alanine or glutamine. Half-maximal stimulation of alanine and glutamine formation by added amino acids was observed with concentrations ranging between 0.5 and 1.0 mM. Increases in alanine and glutamine formation were not accompanied by changes in pyruvate production or glucose uptake. The progressive decline in alanine and glutamine synthesis noted on prolonged incubation was prevented by the addition of amino acids to the incubation medium. Stimulation of alanine synthesis by added amino acids was unaffected by inhibition of glycolysis with iodoacetate. Inhibition of alanine aminotransferase with aminooxyacetate significantly decreased alanine formation. Pyruvate and ammonium chloride did not increase further the rate of either alanine or glutamine formation above that produced by added amino acids. These data indicate that most amino acids are precursors for alanine and glutamine synthesis in skeletal muscle. A general mechanism is presented for the de novo formation of alanine from amino acids in skeletal muscle, and the importance of proteolysis for the supply of amino acid precursors for alanine and glutamine synthesis is discussed.
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PMID:Alanine and glutamine synthesis and release from skeletal muscle. II. The precursor role of amino acids in alanine and glutamine synthesis. 124 59

The effects of 2 liquid formula diets differing in protein source were evaluated in orphan foals. The response of 7 foals fed a diet containing casein as the protein source, and 6 foals fed a diet containing a combination of whey and casein, was compared with the response in a reference group of 8 mare-raised foals. Orphaned foals were fed 150 kcal/kg of body weight/d, divided into 6 equal feedings of 25 kcal/kg. Formula intake was comparable among the experimental groups, and foals fed the liquid formula diet grew as well as mare-raised foals. There was no difference among groups in mean daily body weight gain, wither height, heart girth, body temperature, pulse, respiration rate, capillary refill time, or skin tenting. Insulin and blood glucose concentrations increased in both groups of foals fed formula diets, returning to prefeeding values within 4 hours. Differences among groups were found for serum alkaline phosphatase, alanine transaminase, cholesterol, creatinine, and glucose values; all other serum chemical values were comparable among groups. Plasma amino acid determinations revealed that arginine and ornithine were significantly lower in foals in both experimental groups than in reference foals, suggesting that arginine may have been the limiting amino acid in these diets. Diarrhea developed in foals in all treatment groups, but in most cases was self-limiting. These results suggest that the protein source of liquid formula diets may be less important in foals than in infants.
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PMID:Effect of protein source in liquid formula diets on food intake, physiologic values, and growth of equine neonates. 145 45

Due to the ubiquitous presence of p-xylene in air and the existing uncertainty regarding its hepatotoxic potential, we examined the effect of acute and short-term exposure to inhaled p-xylene on the liver. Male F-344 rats were exposed to 0 or to 1600 ppm p-xylene, 6 h/d, for 1 or 3 d. Exposure to inhaled p-xylene caused no histopathological evidence of hepatic damage and had little or no effect on the serum levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, ornithine carbamyl transferase, alkaline phosphatase, and total bilirubin. Exposure to p-xylene for 1 or 3 d resulted in an increase in relative liver weight on d 1 post-exposure. The concentration of hepatic cytochrome P-450 was increased by both p-xylene exposure regimens on d 1 postexposure and had returned to control levels by d 3 following the single p-xylene exposure and by d 2 following the 3-d exposure. These observations provide consistent evidence that acute and short-term exposure to 1600 ppm p-xylene by inhalation did not produce overt hepatotoxicity but resulted in a significant increase in the concentration of hepatic cytochrome P-450, the principal enzyme system involved in the metabolic biotransformation of xenobiotics.
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PMID:Assessment of the hepatotoxicity of acute and short-term exposure to inhaled p-xylene in F-344 rats. 200 13

Diets containing 0.8, 2.53 and 8.0% field variety morning glory seed were fed to male and female rats (20 per group) in a 90-day subchronic feeding study. Gross clinical observations, body weight, and feed and water intake were recorded weekly. At 90 days, all surviving rats were autopsied, organs were weighed, and blood chemistry analyses, haematology, and bone-marrow evaluation for evidence of clastogenic effects were performed. Tissues from control (0% seed) and high-dose (8.0% seed) rats were examined histologically. Effects of morning glory seed were noted mainly in the high-dose group of both sexes. These included increases in mortality, feed consumption (on a body-weight basis), water consumption, serum alkaline phosphatase and potassium, white blood cell count, and brain and liver weights (as a percentage of body weight); body-weight gain and serum glucose were decreased. Significant changes seen in high-dose females alone were: increased haemoglobin, serum constituents (urea nitrogen, glutamic-pyruvic transaminase, glutamic-oxaloacetic transaminase, and ornithine carbamyl transferase), and organ weights (heart, kidney, spleen and pancreas as a percentage of body weight), and decreases in serum albumin, total protein, albumin:globulin ratio, and calcium. Significant changes occurring in high-dose males alone were: increased testicular weight (as a percentage of body weight), increased serum phosphorus, and decreased serum cholesterol. Liver degeneration in the high-dose females was greater than that in the controls. Mortality at 8.0% seed in the diet was 40% in males and 10% in females. At 0.8% seed, the only parameter that differed significantly from that of the controls was a final body-weight reduction in females without a corresponding reduction in feed consumption.
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PMID:Toxicological evaluation of morning glory seed: subchronic 90-day feeding study. 224 29


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