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)

Treatment of rats with cefazolin in vivo significantly suppressed activity of alanine and aspartate aminotransferases in serum and in the liver, brain, kidney, and heart. Simultaneous administration of pyridoxal further reduced enzyme activity except in the liver, where there was no change. Pyridoxal 5'-phosphate partly reversed the decreased enzyme activity in the serum, liver, and kidney, but did not return it to the amount observed in the control animals; enzyme activity remained suppressed in the brain and heart. The effect of cefazolin was dose related, but there was no sex-related difference. In contrast to its action on am-notransferase activity, cefazolin elicited no effect on alkaline phosphatase (pyridoxal-5'-phosphate hydrolase) in serum or on pyruvate carboxylase in the liver, heart, and kidney. Cefazolin exposed to the hepatic microsomal mixed-function oxidase system in vitro was partly converted into metabolites that inhibited serum alanine aminotransferase activity in vitro. The latter inhibition was reversed by the addition of pyridoxal 5'-phosphate.
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PMID:Decreased aminotransferase activity of serum and various tissues in the rat after cefazolin treatment. 45 47

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

1. In order to assess whether the potential ability of heart ventricular muscle and liver to metabolise substrates such as alanine, aspartate and lactate varies as the sheep matures and its nutrition changes, the activities of the following enzymes were determined in tissues of lambs obtained at varying intervals between 50 days after conception to 16 weeks after birth and in livers from adult pregnant ewes: lactate dehydrogenase (EC 1.1.1.27), alanine aminotransferase (EC 2.6.1.2), pyruvate kinase (EC 2.7.1.40), pyruvate carboxylase (EC 6.4.1.1), phosphoenolpyruvate carboxykinase (GTP)(EC 4.1.1.32), malate dehydrogenase (EC 1.1.1.37), aspartate aminotransferase (EC 2.6.1.1) and citrate (si)-synthase (EC 4.1.3.7). 2. In the heart a most marked increase in alanine aminotransferase activity was found throughout development. During this period the activities of citrate (si)-synthase, lactate dehydrogenase and pyruvate carboxylase also increased. There were no substantial changes in the activities of aspartate aminotransferase, malate dehydrogenase or pyruvate kinase. Pyruvate kinase activities were five times greater in the heart compared with those found in the liver. No significant activity of phosphoenolpyruvate carboxykinase (GTP) was detected in heart muscle. 3. In the liver the activities of both alanine aminotransferase and aspartate aminotransferase increased immediately following birth although the activity of alanine aminotransferase was lower in livers of pregnant ewes than in any of the lambs. As with alanine aminotransferase the highest activities of lactate dehydrogenase were found during the period of postnatal growth. No marked changes were observed in malate dehydrogenase or citrate (si)-synthase activities during development. A small decline in pyruvate kinase activity occurred whilst the activities of pyruvate carboxylase and phosphoenolpyruvate carboxykinase (GTP) tended to rise during development.
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PMID:Activities of enzymes concerned with pyruvate and oxaloacetate metabolism in the heart and liver of developing sheep. 117 28

Fat-cells were prepared from rat and guinea-pig epididymal adipose tissue and compared on the basis of the intracellular distributions and activities of enzymes and with respect to their utilization of various U-(14)C-labelled substrates for lipogenesis. 1. Compared with the rat, guinea-pig extramitochondrial enzyme activities differed in that aconitate hydratase, alanine aminotransferase, ATP-citrate lyase, lactate dehydrogenase, NAD-malate dehydrogenase, NADP-malate dehydrogenase and phosphoenolpyruvate carboxykinase activities were appreciably lower, whereas aspartate aminotransferase, glucose 6-phosphate dehydrogenase, NADP-isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase activities were appreciably higher. Mitochondrial activities of citrate synthase, NADP-isocitrate dehydrogenase and pyruvate carboxylase were appreciably lower, whereas mitochondrial activities of aspartate aminotransferase, glutamate dehydrogenase, NAD-malate dehydrogenase and phosphoenolpyruvate carboxykinase were higher in the guinea pig compared with the rat. 2. In general guinea-pig fat-cells incorporated acetate and lactate into fatty acids more readily than rat fat-cells, whereas rat fat-cells incorporated glucose and pyruvate more readily than guinea-pig fat-cells. 3. Acetate stimulated the incorporation of glucose into fatty acids in rat fat-cells, but had no appreciable effect upon this process in guinea-pig fat-cells. Acetate greatly decreased the incorporation of lactate into fatty acids in cells from both species. 4. Lactate/pyruvate ratios produced by incubation of guinea-pig cells with glucose+insulin were very low compared with those found with rat cells under the same conditions. 5. With glucose (+insulin) or with glucose+acetate (+insulin) as substrates guinea-pig cells produced enough NADPH by the hexose monophosphate pathway to satisfy the NADPH requirements of lipogenesis. In rat fat-cells under the same conditions, hexose monophosphate-pathway NADPH provision was not sufficient to meet the requirements of lipogenesis. 6. These results are discussed, particularly in relationship to the disposition of cytosolic reducing equivalents in the cells.
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PMID:Lipogenesis in rat and guinea-pig isolated epididymal fat-cells. 415 67

1. The activities of gluconeogenic and glycolytic enzymes and the concentrations of citrate, ammonia, amino acids, glycogen, glucose 6-phosphate, acetyl-CoA, lactate and pyruvate were measured in kidney cortex of normal, diabetic, cortisone-treated and growth hormone-treated rats. 2. In kidney cortex of diabetic, cortisone-treated and growth hormone-treated rats the activities of glucose 6-phosphatase (EC 3.1.3.9), fructose 1,6-diphosphatase (EC 3.1.3.11) and phosphopyruvate carboxylase (EC 4.1.1.32) were increased. 3. The activities of glutamate dehydrogenase (EC 1.4.1.3), alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.10) and pyruvate carboxylase (EC 6.4.1.1) were increased in diabetic and cortisone-treated rats. In growth hormone-treated rats the activity of aspartate aminotransferase was depressed but those of the other three enzymes were unchanged. 4. The activity of hexokinase (EC 2.7.1.1) was not altered in any of these conditions. Phosphofructokinase (EC 2.7.1.11) activity was depressed only in growth hormone-treated rats. Pyruvate kinase (EC 2.7.1.40) activity was depressed in cortisone-treated and growth hormone-treated rats but unchanged in diabetic rats. 5. Amino acids, acetyl-CoA and glucose 6-phosphate contents were increased in rat kidneys in all these three conditions. Ammonia content was increased in diabetic and cortisone-treated rats but was markedly diminished in growth hormone-treated rats. 6. The [lactate]/[pyruvate] ratio was elevated in diabetic and cortisone-treated rats but unchanged in growth hormone-treated rats. Citrate content was increased in the kidney cortex of diabetic and growth hormone-treated rats but was unchanged in cortisone-treated rats. The activity of ATP citrate lyase (EC 4.1.3.8) was depressed in diabetic and growth hormone-treated rats but was increased in cortisone-treated rats. 7. Glycogen content was moderately elevated in growth hormone-treated rats and markedly elevated in diabetic rats, whereas no change in glycogen content was observed in cortisone-treated rats. Glycogen synthetase (EC 2.4.1.11) activity was unchanged in all these three conditions. Phosphorylase (EC 2.4.1.1) activity was not affected in cortisone-treated rats but was depressed in diabetic and growth hormone-treated rats.
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PMID:Evaluation of the rate-limiting steps in the pathway of glucose metabolism in kidney cortex of normal, diabetic, cortisone-treated and growth hormone-treated rats. 434 56

1. A method is described for extracting separately mitochondrial and extramitochondrial enzymes from fat-cells prepared by collagenase digestion from rat epididymal fat-pads. The following distribution of enzymes has been observed (with the total activities of the enzymes as units/mg of fat-cell DNA at 25 degrees C given in parenthesis). Exclusively mitochondrial enzymes: glutamate dehydrogenase (1.8), NAD-isocitrate dehydrogenase (0.5), citrate synthase (5.2), pyruvate carboxylase (3.0); exclusively extramitochondrial enzymes: glucose 6-phosphate dehydrogenase (5.8), 6-phosphogluconate dehydrogenase (5.2), NADP-malate dehydrogenase (11.0), ATP-citrate lyase (5.1); enzymes present in both mitochondrial and extramitochondrial compartments: NADP-isocitrate dehydrogenase (3.7), NAD-malate dehydrogenase (330), aconitate hydratase (1.1), carnitine acetyltransferase (0.4), acetyl-CoA synthetase (1.0), aspartate aminotransferase (1.7), alanine aminotransferase (6.1). The mean DNA content of eight preparations of fat-cells was 109mug/g dry weight of cells. 2. Mitochondria showing respiratory control ratios of 3-6 with pyruvate, about 3 with succinate and P/O ratios of approaching 3 and 2 respectively have been isolated from fat-cells. From studies of rates of oxygen uptake and of swelling in iso-osmotic solutions of ammonium salts, it is concluded that fat-cell mitochondria are permeable to the monocarboxylic acids, pyruvate and acetate; that in the presence of phosphate they are permeable to malate and succinate and to a lesser extent oxaloacetate but not fumarate; and that in the presence of both malate and phosphate they are permeable to citrate, isocitrate and 2-oxoglutarate. In addition, isolated fat-cell mitochondria have been found to oxidize acetyl l-carnitine and, slowly, l-glycerol 3-phosphate. 3. It is concluded that the major means of transport of acetyl units into the cytoplasm for fatty acid synthesis is as citrate. Extensive transport as glutamate, 2-oxoglutarate and isocitrate, as acetate and as acetyl l-carnitine appears to be ruled out by the low activities of mitochondrial aconitate hydratase, mitochondrial acetyl-CoA hydrolyase and carnitine acetyltransferase respectively. Pathways whereby oxaloacetate generated in the cytoplasm during fatty acid synthesis by ATP-citrate lyase may be returned to mitochondria for further citrate synthesis are discussed. 4. It is also concluded that fat-cells contain pathways that will allow the excess of reducing power formed in the cytoplasm when adipose tissue is incubated in glucose and insulin to be transferred to mitochondria as l-glycerol 3-phosphate or malate. When adipose tissue is incubated in pyruvate alone, reducing power for fatty acid, l-glycerol 3-phosphate and lactate formation may be transferred to the cytoplasm as citrate and malate.
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PMID:The intracellular localization of enzymes in white-adipose-tissue fat-cells and permeability properties of fat-cell mitochondria. Transfer of acetyl units and reducing power between mitochondria and cytoplasm. 439 82

1. The metabolism of L-alanine was studied in isolated guinea-pig kidney-cortex tubules. 2. In contrast with previous conclusions of Krebs [(1935) Biochem. J. 29, 1951-1969], glutamine was found to be the main carbon and nitrogenous product of the metabolism of alanine (at 1 and 5 mM). Glutamate and ammonia were only minor products. 3. At neither concentration of alanine was there accumulation of glucose, glycogen, pyruvate, lactate, aspartate or tricarboxylic acid-cycle intermediates. 4. Carbon-balance calculations and the release of 14CO2 from [U-14C]alanine indicate that oxidation of the alanine carbon skeleton occurred at both substrate concentrations. 5. A pathway involving alanine aminotransferase, glutamate dehydrogenase, glutamine synthetase, pyruvate dehydrogenase, pyruvate carboxylase and enzymes of the tricarboxylic acid cycle is proposed for the conversion of alanine into glutamine. 6. Strong evidence for this pathway was obtained by: (i) suppressing alanine removal by amino-oxyacetate, and inhibitor of transaminases, (ii) measuring the release of 14CO2 from [1-14C]alanine, (iii) the use of L-methionine DL-sulphoximine, an inhibitor of glutamine synthetase, which induced a large increase in ammonia release from alanine, and (iv) the use of fluoroacetate, an inhibitor of aconitase, which inhibited glutamine synthesis with concomitant accumulation of citrate from alanine. 7. In this pathway, the central role of pyruvate carboxylase, which explains the discrepancy between our results and those of Krebs (1935), was also demonstrated.
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PMID:The conversion of alanine into glutamine in guinea-pig renal cortex. Essential role of pyruvate carboxylase. 733 38

Histometric data obtained by the point counting method, and the enzyme patterns of glycolysis, gluconeogenesis, fatty degradation and energy transfer have been determined in the same muscle specimens of m. vastus lateralis from 12 untrained patients between the ages of 4 and 78 years who suffered no disturbance of the neuromuscular system. Activities of 18 enzymes have been related to pure muscle weight corrected for fatty and connective tissue content, as well as to single fibre weight. A comparable muscle enzyme pattern was found in persons of around 20 years old and around 70 years old when expressed per gram of single fibre weight. However, in terms of grams of pure muscle weight, a significant activity decrease with age was obtained for 6-phosphofructokinase, triosephosphate dehydrogenase and phosphoenolpyruvate carboxykinase, whereas activity of hexose diphosphatase increased with age as also did 3-hydroxyacyl-CoA dehydrogenase activity. Five other cytoplasmic enzyme activities involved in glycolysis and energy transfer did not change significantly with age, nor did lysosomal acid phosphatase. The mitochondrial enzyme activities of gluconeogenesis (for example, pyruvate carboxylase, malic enzyme) were diminished to a lesser extent as also the auxiliary enzymes glutamic-oxaloacetic transminase and glutamic-pyruvic transaminase; glutamate dehydrogenase activity remained unchanged. The findings indicate a distinct disorganization of cytoplasmic glycolysis and gluconeogenesis pathways in presenile human skeletal muscle, confirming the histometric data already described. They cannot be explained by changes with age in numerical or areal ratio of type I and type II fibres.
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PMID:Disorganization of glycolytic and gluconeogenic pathways in skeletal muscle of aged persons studied by histometric and enzymatic methods. 743 2

In the adipose tissue, besides fatty acid synthesis (FA-S) from glucose, which includes several mitochondrial steps, FA-S from glutamate has been demonstrated. FA-S from glutamate takes place in the cytosol through the backward pathway of Krebs cycle (BPKC) and is due to the sequential action of (1) alanine aminotransferase (ALT, EC 2.6.1.2), which is presence of pyruvate converts glutamate to oxoglutarate; (2) isocitrate dehydrogenase (NADP) (ICDH, EC 1.1.1.42), which converts oxoglutarate to isocitrate; (3) aconitate hydratase (ACO, EC 4.2.1.3), which transforms isocitrate to citrate: and (4) ATP citrate-lyase (ATP-CL, EC 4.1.3.8), which splits citrate to yield the acetyl-CoA needed for FA-S. We studied the enzymes involved in BPKC in homogenates of human adipose tissue. In normal subjects, the cytosolic activity (mumol/min/g protein) was: ALT = 10.3 +/- 1.1, ICDH = 29.5 +/- 2.8, ACO = 2.05 +/- 0.23, and ATP-CL = 1.2 +/- 0.2. Mitochondria contained less or no activity, values being 20, 9, 11, and 0% of total for ATL, ICDH, ACO, and ATP-CL, respectively. BPKC enzymes are more active than the enzymes limiting FA-S from glucose, i.e., phosphofructokinase (EC 2.7.1.11), pyruvate carboxylase (EC 6.4.1.1), and pyruvate dehydrogenase (EC 1.2.4.1). In the obese patients, cytosolic ALT and ATP-CL were increased (12.9 +/- 0.7, P < 0.05, and 2.28 +/- 0.27, P < 0.01, respectively) compared to normal, while ICDH was not changed (ACO could not be studied). Similar changes were obtained by expressing enzyme activity per fat cell number.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fatty acid synthesis from glutamate in the adipose tissue of normal subjects and obese patients: an enzyme study. 755 12

The effects of cortisol on hepatic and renal gluconeogenic enzyme activities were investigated in sheep fetuses during late gestation and after experimental manipulation of plasma cortisol levels by fetal adrenalectomy and exogenous infusion of cortisol. Hepatic and renal gluconeogenic enzyme activities increased with increasing gestational age in parallel with the normal rise in fetal cortisol levels towards term (146 +/- 2 days). For the majority of enzymes this increase in activity towards term was prevented when the prepartum cortisol surge was abolished by fetal adrenalectomy and stimulated prematurely in fetuses younger than 130 days by exogenous infusion of cortisol. When the data from all the fetuses were combined irrespective of treatment or gestational age, there were significant positive correlations between the log plasma cortisol concentration in utero and the activities of glucose-6-phosphatase, fructose diphosphatase, phosphoenolpyruvate carboxykinase and aspartate transaminase in the fetal liver and kidney, and pyruvate carboxylase in the fetal liver but not in the kidney. No correlation was observed between log plasma cortisol and alanine aminotransferase activity in either fetal liver or kidney. These findings show that cortisol is a physiological regulator of most of the fetal gluconeogenic enzymes and enhances the glucogenic capacity of the sheep fetus during late gestation.
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PMID:The effects of cortisol on hepatic and renal gluconeogenic enzyme activities in the sheep fetus during late gestation. 832 49


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