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

---

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

Nonselective and beta 1-selective adrenergic antagonists were tested for their effects on enzymatic adaptation to exercise training in rats as follows: trained + placebo (TC); trained + propranolol (TP); trained + atenolol (TA); and corresponding sedentary groups, SC and SP. Trained rats ran 1 h/d at 26.8 m/min, 15% grade, 5 d/wk, 10 wk. Both beta-antagonists were given at doses that decreased exercise heart rates by 25%. Training increased skeletal muscle citrate synthase, cytochrome c oxidase (Cyt-Ox), carnitine palmitoyltransferase (CPT), beta-hydroxyacyl coenzyme A dehydrogenase, mitochondrial malate dehydrogenase (MDH), and alanine aminotransferase (ALT) activities significantly in the TC group, but not in TP. These enzyme activities, except Cyt-Ox and CPT, were also significantly increased in TA. Hepatic phosphoenolpyruvate carboxykinase activity did not alter with training or beta-blockade. Fructose 1,6-bisphosphatase activity was lower in TC than in SC, but unchanged in TP or TA. Hepatic mitochondrial MDH and ALT activities increased with training only in TC. It is concluded that beta 2-adrenergic mechanisms play an essential role in the training-induced enzymatic adaptation in skeletal muscle.
...
PMID:Enzymatic adaptation to physical training under beta-blockade in the rat. Evidence of a beta 2-adrenergic mechanism in skeletal muscle. 287 82

Livers of starved rats refed for 2 h were perfused in situ by a modification of the dual digitonin pulse technique of Quistorff and Grunnet (Quistorff, B., and Grunnet, N. (1987) Biochem. J. 243, 87-95). A pulse of digitonin (2 mg/ml) was infused first antegrade through the portal vein followed retrograde through the vena cava, or in reverse order, 13 mg of digitonin per zone. Microscopic examination showed that this procedure permeabilized the periportal and perivenous zones of the liver without overlap, with a narrow unaffected band of hepatocytes between the zones. The distribution pattern between periportal and perivenous zones ratio for alanine transaminase, lactate hydrogenase, fructose-1,6-bisphosphatase, and phosphoenolpyruvate carboxykinase ranged from 1.5 to 3. Glucokinase activity was higher in the perivenous zone (periportal/perivenous ratio of 0.7) and glutamine synthetase was exclusively present in that zone. Fructose 2,6-bisphosphate concentration was nearly equal in the two zones.
...
PMID:The zonation of liver and the distribution of fructose 2,6-bisphosphate in rat liver. 289 7

Male Wistar rats aged 75 and 150 days were given high fat diet (36.5 weight % and 30 weight % fat) over a period of 14 days. The growth (PER, NPR) and utilization (NPU, LPU) parameters of protein biological value and liver phosphoenolpyruvate carboxykinase (PEPCK) activity were determined. In another experiment, the time dependence of liver gluconeogenesis enzyme (PEPCK and fructose-1,6-diphosphatase /FDP-ase/) and transaminase (alanine and aspartate aminotransferase /ALT, AST/) activities during 24 days' administration of the diet were determined. A 14 days' high fat intake had a negative effect on protein utilization in the organism of 75- and 150-day-old animals, which was more pronounced in the younger age group (a bigger drop in net protein utilization /NPU/ and greater stimulation of PEPCK activity). In 150-day-old animals the negative effect of a high fat intake was already manifested on the 6th to 10th day of the diet to the same degree as in the younger animals on the 14th day, as seen from the increase in all the enzyme activities. The paper presents findings on differences in the degree of the negative effect of a high fat intake on protein utilization with reference to age.
...
PMID:Influence of the time of intake of a high fat diet on gluconeogenesis. 293 54

Glycosomes and mitochondrial vesicles from cultured promastigotes of Leishmania mexicana mexicana have been separated using isopycnic centrifugation on linear sucrose gradients. Hexokinase (EC 2.7.1.2), glucose phosphate isomerase (EC 5.3.1.9), phosphofructokinase (EC 2.7.1.11), glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12), and phosphoenolpyruvate carboxykinase (EC 4.1.1.49) were recovered largely in association with glycosomes (density; 1.215 g/ml). Phosphoglycerate kinase (EC 2.7.2.3) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) had some small glycosomal activity, but were mostly recovered in the soluble fractions. Malate dehydrogenase (EC 1.1.1.37) showed a broad peak corresponding to that of the mitochondrial marker oligomycin-sensitive ATPase (EC 3.6.1.4) (density; 1.190 g/ml). Glutamate dehydrogenase (EC 1.4.1.3) and alanine aminotransferase (EC 2.6.1.2) both showed small mitochondrial peaks, but most of the activities were recovered elsewhere on the gradient and in the soluble fractions. The subcellular location of enzymes in L.m. mexicana amastigotes was investigated by following the release of soluble enzymes from digitonin-treated amastigotes. This revealed distinct cytosolic, mitochondrial, and glycosomal compartments. The findings give an insight into the organization and control of L.m. mexicana promastigote and amastigote energy metabolism.
...
PMID:Leishmania mexicana: subcellular distribution of enzymes in amastigotes and promastigotes. 315 38

The interactions of nucleotides with phosphoenolpyruvate carboxykinase were studied by using the stereospecific thiophosphate analogues of GDP and GTP. The metal ion dependent stereoselectivity of these analogues was determined by using steady-state kinetics. The RP and SP isomers of guanosine 5'-O-(1-thiodiphosphate) (GDP alpha S) were substrates with low turnover, and a small preference for the RP isomer was observed. Neither the enzyme-metal nor the nucleotide-metal complex elicited any substantial change in the selectivity. Guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) exhibited no substrate activity for the enzyme, regardless of the cations. This nucleotide was a competitive inhibitor against GDP, however. Both RP and SP diastereomers of guanosine 5'-O-(1-thiotriphosphate) (GTP alpha S) were good substrates for phosphoenolpyruvate carboxykinase; in several cases, depending upon the cation, kcat and/or Vm/Km for the RP isomer is greater than for the substrate GTP. The enzyme-metal complex but not the nucleotide-metal complex affects the relative Km and the Vmax values. In contrast, guanosine 5'-O-(2-thiotriphosphate) (GTP beta S) (SP) is a much better substrate (greater than 50 times) than is GTP beta S (RP). The metal ions have little effect on the selectivity. These results suggest a specific interaction of the beta-phosphate of the nucleotide with the protein. The analogue guanosine 5'-O-(3-thiotriphosphate) (GPT gamma S) serves as a substrate to yield GDP and thiophosphoenolpyruvate. The latter was detected by 31P NMR and was shown to slowly hydrolyze to form phosphoenolpyruvate.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Guanosine thiophosphate derivatives as substrate analogues for phosphoenolpyruvate carboxykinase. 391 4

Muscle branched-chain amino acid metabolism is coupled to alanine formation via branched-chain amino acid aminotransferase and alanine aminotransferase, but the subcellular distributions of these and other associated enzymes are uncertain. Recovery of branched-chain aminotransferase in the cytosol fraction after differential centrifugation was shown to be accompanied by leakage of mitochondrial-matrix marker enzymes. By using a differential fractional extraction procedure, most of the branched-chain aminotransferase activity in rat muscle was located in the mitochondrial compartment, whereas alanine aminotransferase was predominantly in the cytosolic compartment. Phosphoenolpyruvate carboxykinase, like aspartate aminotransferase, was approximately equally distributed between these subcellular compartments. This arrangement necessitates a transfer of branched-chain amino nitrogen and carbon from the mitochondria to the cytosol for alanine synthesis de novo to occur. In incubations of hemidiaphragms from 48 h-starved rats with 3mM-valine or 3mM-glutamate, the stimulation of alanine release was inhibited by 69% by 1 mM-aminomethoxybut-3-enoate, a selective inhibitor of aspartate aminotransferase. Leucine-stimulated alanine release was unaffected. These data implicate aspartate aminotransferase in the transfer of amino acid carbon and nitrogen from the mitochondria to the cytosol, and suggest that oxaloacetate, via phosphoenolpyruvate carboxykinase, can serve as an intermediate on the route of pyruvate formation for muscle alanine synthesis.
...
PMID:Branched-chain amino acid metabolism and alanine formation in rat muscles in vitro. Mitochondrial-cytosolic interrelationships. 397 57

A delayed wasting syndrome similar to that induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was observed in male Sprague-Dawley rats exposed to 3,3', 4,4'-tetrachloroazoxybenzene (TCAOB) and 3,3',4,4'-tetrachloroazobenzene (TCAB). After a slow growth period, all treatment animals (25 mg/kg, i.p., 2 doses per week) exhibited a starvation-like syndrome characterized by reduced food intake, dramatic loss of body weight and subsequent death. Although the growth of all major organs in the treatment animals was affected, the thymus appeared severely atrophied. The growth kinetics during the earlier phase were further analyzed using serially-killed rats receiving TCAOB. In addition, TCAOB was found to markedly depress the specific activity (mumol/min/g wet liver) of glucose-6-phosphatase, fructose-1,6-bisphosphatase, phosphoenolpyruvate carboxykinase, and pyruvate kinase in the liver. Significant changes in the levels of cytochrome P-450, glutamic-pyruvic transaminase and malic enzyme in the liver were also observed.
...
PMID:Delayed wasting syndrome and alterations of liver gluconeogenic enzymes in rats exposed to the TCDD congener 3,3', 4,4'-tetrachloroazoxybenzene. 401 2

Aspartate aminotransferase (AAT), alanine aminotransferase (ALAT), malic enzyme (ME), malate dehydrogenase (MDH), pyruvate kinase (PK), and phosphoenolpyruvate carboxykinase (PEPCK) activities in cytosolic and mitochondrial fractions of gill tissue from Modiolus demissus (ribbed mussel), Mytilus edulis (sea mussel), Crassostrea virginica (oyster) and Mercenaria mercenaria (quahog) were determined using enzyme assay and starch gel electrophoresis combined with subcellular fractionation. AAT showed distinct mitochondrial and cytosolic isozymes in gills of all these animals. Although ALAT showed distinct mitochondrial and cytosolic isozymes in the gills of oysters, sea mussels and quahogs, only the mitochondrial ALAT was evident in ribbed mussel gill tissue. PK and PEPCK were cytosolic in all these preparations. ME was found only in the mitochondrial fraction of ribbed mussel and quahog gill tissue whereas sea mussel gills showed distinct cytosolic and mitochondrial ME isozymes. With oyster gills, the "cytosolic ME" was electrophoretically identical to the mitochondrial ME indicating that in vivo, the ME is probably mitochondrial. MDH showed distinct cytosolic and mitochondrial isozymes in all bivalve gills tested.
...
PMID:Subcellular distribution of aminotransferases, and pyruvate branch point enzymes in gill tissue from four bivalves. 405 67

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.
...
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.
...
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


<< Previous 1 2 3 4 5 6 7 8 9 Next >>

---