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:4.1.1.32 (phosphoenolpyruvate carboxykinase)
4,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Evidence is presented for the occurrence of glycosomes (organelles resembling peroxisomes) in four major species of Leishmania (viz. L. major, L.m. mexicana, L. b. braziliensis and L. donovani), based on latency as well as differential and isopycnic centrifugation studies. The enzymes involved in glycolysis; (hexokinase, phosphoglucose isomerase, phosphofructokinase, fructose-1,6-bisphosphate aldolase, triosephosphate isomerase, glyceraldehyde-phosphate dehydrogenase and phosphoglycerate kinase); glycerol metabolism (sn-glycerol-3-phosphate dehydrogenase and glycerol kinase); carbon dioxide fixation (phosphoenolpyruvate carboxykinase and possibly malate dehydrogenase); together with an enzyme involved in the beta-oxidation of fatty acids (3-beta-hydroxybutyryl coenzyme A dehydrogenase); a key enzyme in the synthesis of ether lipids (dihydroxyacetone phosphate acyltransferase) as well as the ADP utilising enzyme adenylate kinase, were all found associated, at least in part, with a subcellular organelle which had a buoyant density in sucrose gradients of 1.21 to 1.24 g cm-3. Little variance in enzyme composition was found between the different species of Leishmania or in comparison with other members of the Trypanosomatidae, supporting the unifying principle that glycosomes are a unique characteristic of this family. The occurrence of important catabolic, anabolic and anaplerotic pathways in the glycosomes of Leishmania renders them prime targets for chemotherapy.
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PMID:The occurrence of glycosomes (microbodies) in the promastigote stage of four major Leishmania species. 644 18

Highly purified glycosomes were isolated from Trypanosoma brucei bloodstream forms and cultured procyclic trypomastigotes. A comparison of the specific activities of glycosomal enzymes revealed that glycosomes from insect stages had decreased levels of hexokinase, phosphoglucose isomerase, phospho-fructokinase, fructose-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase and phosphoglycerate kinase, but contained increased levels of adenylate kinase, malate dehydrogenase and phosphoenolpyruvate carboxykinase. Glycosomes from bloodstream forms were almost totally devoid of the latter two activities. Comparison of the two types of glycosomes by sodium dodecylsulphate-polyacrylamide gel electrophoresis revealed that bloodstream form glycosomes contained 3 prominent polypeptides (64, 46 and 40 kDa) which were hardly detectable in insect stage glycosomes, whereas the latter contained 3 insect stage specific bands with molecular weight of 34 000, 61 000 and 77 000 and 4 additional bands with molecular weights between 94 000 and 110 000. Both types of glycosome contained the phospholipids phosphatidylcholine and phosphatidylethanolamine. Insect stage glycosomes contained in addition also phosphatidylinositol and some phosphatidylserine.
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PMID:A comparison of the glycosomes (microbodies) isolated from Trypanosoma brucei bloodstream form and cultured procyclic trypomastigotes. 674 87

Recently, it has been reported that paromomycin sulfate has marked anthelmintic efficacy against tapeworm infections in man. In the present study this drug was used in the treatment of 14 cases of diphyllobothriasis latum and 1 case of taeniasis saginata. Also, the actions of paromomycin sulfate on Diphyllobothrium ditremum and D. erinacei were examined pharmacologically using Magnus apparatus and biochemical methods. The results obtained were as follows. For the treatment, a total of 50 mg/kg of paromomycin sulfate divided into 2 doses was given orally at intervals of 30 minutes. Two hours after medication, 20 g of magnesium sulfate dissolved in 200--300 ml of water was given as purgative. One or 2 worms were found in the stools of 11 cases with D. latum and 1 case with T. saginata within 24 hours after medication, but scolex was found in only 2 of them. All cases were negative for the eggs or segments in stool examinations at 1 and 3 months after treatment. Except 1 case complained mild and transient vomiting no side effects were noticed. All cases showed no abnormality in blood examination, liver function test and urinalysis. Both of the proglottids of D. ditremum and D. erinacei showed muscle relaxation in Tyrode solution containing 10(-4) g/ml of paromomycin sulfate. In D. ditremum the recovery of muscle tonus was observed within 10--15 minutes after affection of this drug, while the persistence of muscle relaxation was seen in D. erinacei. The activity of phosphoglucose isomerase was slightly inhibited by 10(-3) M paromomycin sulfate while those of hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase were not inhibited. In phosphoenolpyruvate-succinate pathway, the activity of fumarate reductase was slightly inhibited 10(-3) M paromomycin sulfate while those of phosphoenolpyruvate carboxykinase and malate dehydrogenase were not inhibited.
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PMID:[Efficacy of paromomycin sulfate against human cestodiasis and its pharmacological action on tapeworm in vitro]. 687 66

The physiological and metabolic responses to gnd knockout in Escherichia coli K-12 was quantitatively investigated by using the (13)C tracer experiment (GC-MS/NMR) together with the enzyme activity analysis. It was shown that the general response to the gene knockout was the local flux rerouting via Entner-Doudoroff pathway and the direction reversing via non-oxidative pentose phosphate pathway (PPP). The mutant was found to direct higher flux to phosphoglucose isomerase reaction as compared to the wild-type, but the respiratory metabolism was comparable in both strains. The anaplerotic pathway catalyzed by malic enzyme was identified in the mutant, which was accompanied with an up-regulation of phosphoenolpyruvate carboxylase and down-regulation of phosphoenolpyruvate carboxykinase. The presented results provide first evidence that compensatory mechanism existed in PPP and anaplerotic pathway in response to the gnd deletion.
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PMID:Analysis of metabolic and physiological responses to gnd knockout in Escherichia coli by using C-13 tracer experiment and enzyme activity measurement. 1267 Jun 95

An integrated study on cell growth, enzyme activities and carbon flux redistribution was made to investigate how the central metabolism of Escherichia coli changes with the knockout of genes in the oxidative pentose phosphate pathway (PPP). Mutants deficient in glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were constructed by disrupting the zwf and gnd genes and were grown in minimal media with two different carbon sources, such as glucose or pyruvate. It was shown that the knockout of either gnd or zwf gene did not affect the cell growth rate significantly, but the cellular metabolism was changed. While the specific substrate uptake rate and the specific carbon dioxide evolution rate for either mutant grown on glucose were higher than those obtained for the parent strain, these two rates were markedly decreased in mutants grown on pyruvate. The measurement of enzyme activities implied a significant change in metabolism, when alternative pathways such as the Entner-Doudoroff pathway (EDP) and the malic enzyme pathway were activated in the gnd mutant grown on glucose. As compared with the parent strain, the activities of phosphoglucose isomerase were increased in mutants grown on glucose but decreased in mutants grown on pyruvate. The metabolic flux redistribution obtained based on 13C-labeling experiments further indicated that the direction of the flux through the non-oxidative PPP was reversed in response to the gene knockout. Moreover, the knockout of genes caused an increased flux through the tricarboxlic acid cycle in mutants grown on glucose but caused a decrease in the case of using pyruvate. There was also a negative correlation between the fluxes through malic enzyme and isocitrate dehydrogenase in the mutants; and a positive correlation was found between the fluxes through malic enzyme and phosphoenolpyruvate carboxylase.
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PMID:Global metabolic response of Escherichia coli to gnd or zwf gene-knockout, based on 13C-labeling experiments and the measurement of enzyme activities. 1466 Nov 15

Mesembryanthemum crystallinum, a halophilic, inducible Crassulacean acid metabolism (CAM) species, was grown at NaCl concentrations of 20 and 400 millimolar in the rooting medium. Plants from the low salinity treatment showed exclusively C(3)-photosynthetic net CO(2) fixation, whereas plants exposed to the high salinity level exhibited net CO(2) dark fixation involving CAM. Mesophyll protoplasts, isolated from both tissues, were gently ruptured, and the intracellular localization of enzymes was studied following differential centrifugation and Percoll density gradient centrifugation of protoplast extracts. Both centrifugation techniques resulted in the separation of intact chloroplasts, with up to 90% yield, from other organelles and the nonparticulate fraction of cells. Enzymes were identified by determination of activity and by sodium dodecyl sulfate gel electrophoresis of enzyme protein.Experiments established the extraorganellar (cytoplasmic) location of phosphoenolpyruvate carboxylase, enolase, phosphoglyceromutase, and NADP-malic enzyme; the mitochondrial location of NAD-malic enzyme; and the chloroplastic location of pyruvate, Pi dikinase. NAD-glyceraldehyde-3-phosphate dehydrogenase, phosphohexose isomerase, and phosphoglycerate kinase were associated with both cytoplasm and chloroplasts. NADP-dependent malate dehydrogenase activity was found in both the chloroplastic and extrachloroplastic fractions; the activity in the chloroplast showed an optimum at pH 8.0 and was dependent upon preincubation of enzyme with dithiothreitol. The extrachloroplastic activity showed an optimum at pH 6.5 and was independent of pretreatment with dithiothreitol. Protoplast extracts of M. crystallinum performing CAM exhibited higher activities (expressed per mg chlorophyll per min) of phosphoenolpyruvate carboxylase, pyruvate, Pi dikinase, NADP-malic enzyme, NAD-malic enzyme, NADP-malate dehydrogenase, enolase, phosphoglyceromutase, NAD-glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, and phosphohexose isomerase than protoplast extracts from M. crystallinum not exhibiting CAM. The increase in total activity of the latter three enzymes following exposure of plants to 400 millimolar NaCl and the development of CAM was due to specific increases in the levels of activity in the cytoplasm.
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PMID:Intracellular Localization of Enzymes of Carbon Metabolism in Mesembryanthemum crystallinum Exhibiting C(3) Photosynthetic Characteristics or Performing Crassulacean Acid Metabolism. 1666 97

The effects of low concentrations of phosphate (low-P) on soluble protein content, the activities of 12 different enzymes, and the rates of photosynthesis and respiration on the basis of leaf area were investigated in maize (Zea mays L.) leaves 16 to 24 days after planting (DAP). With low-P treatment, a drastic decrease in the rate of photosynthesis to only 6% of the maximum rate in control plants was observed by 24 DAP. Low-P treatment had almost no effect on the rate of respiration until 21 DAP, but then the rate of respiration decreased progressively to about 55% of the maximum rate in control plants. The soluble protein content in low-P plants decreased to 56% of the maximum content in control plants. The changes in the activities of enzymes in low-P plants showed several different patterns. The activities of pyruvate, orthophosphate dikinase, 3-phosphoglycerate kinase, phosphoenolpyruvate carboxylase (PEPC), ribulose 1,5-bisphosphate carboxylase, fructose 1,6-bisphosphate aldolase, catalase, phosphohexose isomerase, chloroplastic fructose 1,6-bisphosphatase, and ADP-glucose-pyrophosphorylase decreased steadily from 85 to 100% of the maximum activity found in 18- to 21-day-old control plants (V(max)) to 30 to 70% of V(max). The activity of sucrose phosphate synthase remained virtually constant at approximately 85 to 100% of V(max). The activity of UDP-glucose-pyrophosphorylase remained almost constant up to 21 DAP and then decreased to 80% of V(max) by 24 DAP. The activity of cytochrome c oxidase increased slightly up to 21 DAP but then decreased to 50% of V(max) by 24 DAP. As indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of soluble proteins, the subunit of PEPC stained less intensely in 24-d-old low-P plants. The possibility is discussed that during low-P treatment there is selective degradation of PEPC without a concomitant degradation of sucrose phosphate synthase, both of which are known to be localized in the cytoplasmic compartment of mesophyll cells.
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PMID:Phosphate Deficiency in Maize : III. Changes in Enzyme Activities during the Course of Phosphate Deprivation. 1666 91

Temperature is a strong selective force on the evolution of proteins due to its effects on higher orders of protein structure and, thereby, on critical protein functions like ligand binding and catalysis. Comparisons among orthologous proteins from differently thermally adapted species show consistent patterns of adaptive variation in function, but few studies have examined functional adaptation among multiple structural families of proteins. Thus, with our present state of knowledge, it is difficult to predict what fraction of the proteome will exhibit adaptive variation in the face of temperature increases of a few to several degrees Celsius, that is, temperature increases of the magnitude predicted by models of global warming. Here, we compared orthologous enzymes of the warm-adapted Mediterranean mussel Mytilus galloprovincialis and the cold-adapted Mytilus trossulus, a native of the North Pacific Ocean, species whose physiologies exhibit significantly different responses to temperature. We measured the effects of temperature on the kinetics (Michaelis-Menten constant-K(m)) of five enzymes that are important for ATP generation and that represent distinct protein structural families. Among phosphoglucomutase (PGM), phosphoglucose isomerase (PGI), pyruvate kinase (PK), phosphoenolpyruvate carboxykinase (GTP) (PEPCK), and isocitrate dehydrogenase (NADP) (IDH), only IDH orthologs showed significantly different thermal responses of K(m) between the two species. The K(m) of isocitrate of M. galloprovincialis-IDH was intrinsically lower and more thermally stable than that of M. trossulus-IDH and thus had higher substrate affinity at high temperatures. Two amino acid substitutions account for the functional differences between IDH orthologs, one of which allows for more hydrogen bonds to form near the mobile region of the active site in M. galloprovincialis-IDH. Taken together, our findings cast light on the targets of adaptive evolution in the context of climate change; only a minority of proteins might adapt to small changes in temperature, and these adaptations may involve only small changes in sequence.
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PMID:Functional determinants of temperature adaptation in enzymes of cold- versus warm-adapted mussels (Genus Mytilus). 2249 Oct 35

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