Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidative capacity of muscles correlates with capillary density and with microcirculation, which in turn depend on various regulatory factors, including NO generated by endothelial nitric oxide synthase (eNOS). To determine the role of eNOS in patterns of regulation of energy metabolism in various muscles, we studied mitochondrial respiration in situ in saponin-permeabilized fibres as well as the energy metabolism enzyme profile in the cardiac, soleus (oxidative) and gastrocnemius (glycolytic) muscles isolated from mice lacking eNOS (eNOS(-/-)). In soleus muscle, the absence of eNOS induced a marked decrease in both basal mitochondrial respiration without ADP (-32%; P <0.05) and maximal respiration in the presence of ADP (-29%; P <0.05). Furthermore, the eNOS(-/-) soleus muscle showed a decrease in total creatine kinase (-29%; P <0.05), citrate synthase (-31%; P <0.01), adenylate kinase (-27%; P <0.05), glyceraldehyde-3-phosphate dehydrogenase (-43%; P <0.01) and pyruvate kinase (-26%; P <0.05) activities. The percentage of myosin heavy chains I (slow isoform) was significantly increased from 24.3+/-1.5% in control to 30.1+/-1.1% in eNOS(-/-) soleus muscle ( P <0.05) at the expense of a slight non-significant decrease in the three other (fast) isoforms. Besides, eNOS(-/-) soleus showed a 28% loss of weight. Interestingly, we did not find differences in any parameters in cardiac and gastrocnemius muscles compared with respective controls. These results show that eNOS knockout has an important effect on muscle oxidative capacity as well on the activities of energy metabolism enzymes in oxidative (soleus) muscle. The absence of such effects in cardiac and glycolytic (gastrocnemius) muscle suggests a specific role for eNOS-produced NO in oxidative skeletal muscle.
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PMID:Endothelial nitric oxide synthase (NOS) deficiency affects energy metabolism pattern in murine oxidative skeletal muscle. 1212 18

Nia30(145) transformants with very low nitrate reductase activity provide an in vivo screen to identify processes that are regulated by nitrate. Nia30(145) resembles nitrate-limited wild-type plants with respect to growth rate and protein and amino acid content but accumulates large amounts of nitrate when it is grown on high nitrate. The transcripts for nitrate reductase (NR), nitrite reductase, cytosolic glutamine synthetase, and glutamate synthase increased; NR and nitrite reductase activity increased in leaves and roots; and glutamine synthetase activity increased in roots. The transcripts for phosphoenolpyruvate carboxylase, cytosolic pyruvate kinase, citrate synthase, and NADP-isocitrate dehydrogenase increased; phosphoenolpyruvate carboxylase activity increased; and malate, citrate, isocitrate, and [alpha]-oxoglutarate accumulated in leaves and roots. There was a decrease of the ADP-glucose pyrophosphorylase transcript and activity, and starch decreased in the leaves and roots. After adding 12 mM nitrate to nitrate-limited Nia30(145), the transcripts for NR and phosphoenolpyruvate carboxylase increased, and the transcripts for ADP-glucose pyrophosphorylase decreased within 2 and 4 hr, respectively. Starch was remobilized at almost the same rate as in wild-type plants, even though growth was not stimulated in Nia30(145). It is proposed that nitrate acts as a signal to initiate coordinated changes in carbon and nitrogen metabolism.
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PMID:Nitrate Acts as a Signal to Induce Organic Acid Metabolism and Repress Starch Metabolism in Tobacco. 1223 66

We present a prototype of a new database tool, GeneCensus, which focuses on comparing genomes globally, in terms of the collective properties of many genes, rather than in terms of the attributes of a single gene (e.g. sequence similarity for a particular ortholog). The comparisons are presented in a visual fashion over the web at GeneCensus.org. The system concentrates on two types of comparisons: (i) trees based on the sharing of generalized protein families between genomes, and (ii) whole pathway analysis in terms of activity levels. For the trees, we have developed a module (TreeViewer) that clusters genomes in terms of the folds, superfamilies or orthologs--all can be considered as generalized 'families' or 'protein parts'--they share, and compares the resulting trees side-by-side with those built from sequence similarity of individual genes (e.g. a traditional tree built on ribosomal similarity). We also include comparisons to trees built on whole-genome dinucleotide or codon composition. For pathway comparisons, we have implemented a module (PathwayPainter) that graphically depicts, in selected metabolic pathways, the fluxes or expression levels of the associated enzymes (i.e. generalized 'activities'). One can, consequently, compare organisms (and organism states) in terms of representations of these systemic quantities. Develop ment of this module involved compiling, calculating and standardizing flux and expression information from many different sources. We illustrate pathway analysis for enzymes involved in central metabolism. We are able to show that, to some degree, flux and expression fluctuations have characteristic values in different sections of the central metabolism and that control points in this system (e.g. hexokinase, pyruvate kinase, phosphofructokinase, isocitrate dehydrogenase and citric synthase) tend to be especially variable in flux and expression. Both the TreeViewer and PathwayPainter modules connect to other information sources related to individual-gene or organism properties (e.g. a single-gene structural annotation viewer).
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PMID:GeneCensus: genome comparisons in terms of metabolic pathway activity and protein family sharing. 1238 5

A new approach for the analysis of hepatic metabolism after burn injury is introduced. Relative anaplerotic, pyruvate recycling and gluconeogenic fluxes were measured by 13C NMR isotopomer analysis of blood glucose from rats with 40% body surface area injury, and from rats exposed to sham injury. A short chain fatty acid, [U-13C] propionate which is avidly extracted by the liver, was infused intravenously to deliver 13C into the citric acid cycle. There was no difference in the multiplets detected in the glucose carbon-2 (C-2) anomer from blood or liver after 45 or 60 min of infusion of propionate, indicating that steady-state isotopic conditions were achieved. Gluconeogenesis relative to citric acid cycle flux was not altered by burn injury; in both sham and burn groups the rate of glucose production was about equal to flux through citrate synthase. In the sham group of animals the rate of entry of carbon skeletons into the citric acid cycle was about four times citric acid cycle flux in animals after thermal injury. Similarly, flux through pyruvate kinase (again relative to citrate synthase) was significantly increased in burn injury.
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PMID:Effect of thermal injury on relative anaplerosis and gluconeogenesis in the rat during infusion of [U-13C] propionate. 1241 55

Trisomy 21 (Down's syndrome) is the most common genetic cause of human mental retardation. In Down's syndrome (DS) patients, deteriorated glucose, lipid, purine, folate and methionine/homocysteine metabolism has been reported. In our study, we used a proteomic approach to evaluate protein expression of enzyme proteins of intermediary metabolism in the brain of Down's syndrome fetuses. In fetal DS brain, we detected increased protein levels of mitochondrial aconitase as well as NADP-linked isocitrate dehydrogenase, decreased protein expression of citrate synthase and cytosolic aspartate aminotransferase. From two spots that corresponded to either pyruvate kinase M1 or M2 isozymes, significant elevation was observed only in one, while the second spot as well as the sum of the spots showed no differences between DS and controls. These results suggest derangement of intermediary metabolism during prenatal development of DS individuals.
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PMID:Proteomic evaluation of intermediary metabolism enzyme proteins in fetal Down's syndrome cerebral cortex. 1244 54

This study evaluated the link between swimming endurance and condition of Atlantic cod Gadus morhua that had been fed or starved during the 16 weeks preceding the tests, and assessed whether muscle metabolic capacities explain such links. The condition factor [(somatic mass x fork length(-3))x100] of starved cod was 0.54+/-0.1 whereas that of fed cod was 0.81+/-0.1. In white and red muscle, we measured four glycolytic enzymes: phosphofructokinase (PFK), pyruvate kinase (PK), creatine kinase (CK) and lactate dehydrogenase (LDH), two mitochondrial enzymes: cytochrome c oxidase (CCO) and citrate synthase (CS), a biosynthetic enzyme, nucleoside diphosphate kinase (NDPK), glycogen and protein levels and water content. Muscle samples were taken at three positions along the length of the fish; starvation affected the metabolic capacities of white muscle more than those of red muscle. The levels of glycolytic enzymes and glycogen changed more in white than red muscle during starvation. Both in fed and starved cod, muscle metabolic capacities varied with position along the fish; starvation reduced this longitudinal variation more in white than red muscle. In white muscle of fed cod, the glycolytic enzyme levels increased from head to tail, while in starved cod this longitudinal variation disappeared. In red muscle mitochondrial enzyme levels were highest in the caudal sample, but fewer differences were found for glycolytic enzymes. Swimming endurance was markedly affected by fish condition, with starved fish swimming only 30% of the time (and distance) of fed fish. This endurance was closely linked with the number of burst-coast movements during the test and the activity of CCO and LDH in white muscle. The number of burst-coast movements was significantly linked with condition factor and PFK activity in caudal red muscle and gill arch mass. Our data indicated that cod use both glycolytic and oxidative capacities to support endurance swimming. Furthermore, swimming endurance is linked with the metabolic capacities of red and white muscle.
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PMID:Condition, prolonged swimming performance and muscle metabolic capacities of cod Gadus morhua. 1250 71

Metabolic potential and muscle development were investigated relative to habitat and phylogeny in seven species of New Zealand triplefin fishes. Activity was measured in three principal glycolytic enzymes (lactate dehydrogenase, pyruvate kinase and phosphofructokinase) and two oxidative enzymes (citrate synthase and L3-hydroxyacyl CoA:NAD(+) oxidoreductase). The non-bicarbonate buffering capacity of caudal muscle was also estimated. Phylogenetic independent contrast analyses were used to reduce the effects of phylogenetic history in analyses. A positive relationship between metabolic potential and the effective water velocity at respective habitat depths was found only after the exclusion from analyses of the semi-pelagic species Obliquichthys maryannae. O. maryannae showed high glycolytic enzyme activities, and displayed double the activity of both oxidative enzymes relative to the six benthic species. Histochemically stained sections taken immediately posterior to the vent showed that adult O. maryannae and larval Forsterygion lapillum had significantly more red muscle, and smaller cross-sectional areas of white and red muscle fibres, than adults of benthic species. The distribution of red muscle in adult O. maryannae resembled that of larval F. lapillum, and differed from the typical teleost pattern seen in adults of the six benthic species. Both adult O. maryannae and larval F. lapillum have an expansive lateralis superficialis muscle, typical of larval fish, which encompasses much of the caudal trunk. Results suggest that anaerobic potential in New Zealand triplefins: (a) increases with the locomotory requirements of different habitats, and (b) displays a negative relationship with depth-dependent water velocities in benthic species. O. maryannae appears to have increased aerobic potential for sustained swimming by paedomorphic retention of larval muscle architecture.
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PMID:Key metabolic enzymes and muscle structure in triplefin fishes (Tripterygiidae): a phylogenetic comparison. 1262 49

Activities of several metabolic enzymes show distinct patterns of zonation along the intestinal tract of tilapia (Oreochromis niloticus), rainbow trout (Oncorhynchus mykiss) and copper rockfish (Sebastes caurinus). Zonation is species and enzyme specific, with different metabolic activities concentrated in specific areas, and few generalizations can be made. The rockfish show the smallest degree of zonation, with highest activities in the third quarter of the intestine, and shallow gradients to either side, and a general upswing in activity towards the distal end. In the trout, mitochondrial enzyme activities (citrate synthase, glutamate dehydrogenase, malate dehydrogenase) are highest in the pyloric caeca and decrease along the length of the small intestine. This pattern is accentuated for malic enzyme and glucose 6-phosphate dehydrogenase. These enzymes drop precipitously in activity after the first few sections of the small intestine, while other NADP-linked dehydrogenases (isocitrate dehydrogenase, and 6-phosphogluconate dehydrogenase) show moderate activity in pyloric caeca and peak toward the distal section of the small intestine. In tilapia, glutamate dehydrogenase shows a similar decrease as in trout, but citrate synthase peaks towards the distal sections. NADP-dependent dehydrogenases reveal distinct patterns, peaking in different sections of the intestine-malic enzyme in the proximal midsection, glucose 6-phosphate dehydrogenase in the distal mid-section, and isocitrate dehydrogenase in the anal section. Enzyme activities in the stomach of trout and tilapia also show zonation, with the midsection generally displaying the highest activities. A 5-day treatment of tilapia with an intraperitoneal cortisol deposit (25 mg kg(-1) wet mass) drastically alters metabolic performance along the gut in enzyme specific patterns, generally increasing enzyme activities in site-specific arrangements. Cortisol treatment also leads to the expected increases in activities of phosphoenolpyruvate carboxykinase, pyruvate kinase and aspartate aminotransferase in liver, but not in kidney. Aspartate aminotransferase is the only enzyme in brain significantly increased by cortisol treatment. Short-term food deprivation changes enzyme patterns, often resembling those observed after cortisol administration. We conclude that brain, liver and intestinal amino acid metabolism is an important target for cortisol action in fish and that metabolic zonation is a key factor to be reckoned with when analyzing physiological phenomena in the fish intestine.
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PMID:Metabolic zonation in teleost gastrointestinal tract. Effects of fasting and cortisol in tilapia. 1278 63

Energy metabolism in early life stages of the shrimp Farfantepenaeus paulensis subjected to temperature reduction (26 and 20 degrees C) was determined using the activities of citrate synthase (CS) and pyruvate kinase (PK). At both temperatures, weight-specific activity of CS decreased throughout the ontogenetic development from protozoea II (PZ II) to postlarva XII-XIV (PL XII-XIV). PK activity reached a pronounced peak in PL V-VI, followed by a further decrease in PL XII-XIV. Temperature reduction produced variation in oxygen consumption rates (QO(2)), ammonia-N excretion and in enzyme activities. Ammonia-N excretion was higher at 20 degrees C in mysis III (M III), PL V-VI and PL XII-XIV, resulting in substantially lower O:N ratios in these stages. QO(2) was increased in protozoea II (PZ II) and mysis I (M I) at 26 degrees C, while no difference in QO(2) was detected in the subsequent stages at either temperature. This fact coincided with higher CS and PK activities in M III, PL V-VI and PL XII-XIV at 20 degrees C compared with 26 degrees C. Regressions between individual enzyme activities and dry weight exhibited slope values of 0.85-0.92 for CS and 1.1-1.2 for PK and temperature reduction was reflected by higher slope values at 20 than at 26 degrees C for both enzymes. Weight-specific CS activity was positively correlated with QO(2) at 20 and 26 degrees C, and may thus be used as an indicator of aerobic metabolic rate throughout the early stages of F. paulensis. The variation in enzyme activities is discussed in relation to possible metabolic adaptations during specific ontogenetic events of the F. paulensis life cycle. Here, the catalytic efficiency of energy-metabolism enzymes was reflected in ontogenetic shifts in behaviour such as larval settlement and the adoption of a benthic existence in early postlarvae. In most cases, enhanced enzyme activities appeared to counteract negative effects of reduced temperature.
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PMID:Citrate synthase and pyruvate kinase activities during early life stages of the shrimp Farfantepenaeus paulensis (Crustacea, Decapoda, Penaeidae): effects of development and temperature. 1289 63

In this study, the phosphoproteome of Corynebacterium glutamicum, an industrially important soil bacterium of the Corynebacterium/Mycobacterium/Nocardia (CMN) group of Gram-positive bacteria, was investigated by two different detection methods: first, by in vivo radio-labeling using [(33)P]-phosphoric acid with subsequent autoradiography and second, by immunostaining with phosphoamino acid-specific monoclonal antibodies. After two-dimensional gel electrophoresis (2-DE), around 60 [(33)P]-labeled protein spots were visualized and around 90 antibody-decorated protein spots detected; 31 of the protein spots were detected with both methods. By peptide mass fingerprinting, 41 different proteins were identified, namely 5-enolpyruvylshikimate 3-phosphate synthase, aconitase, acyl-CoA carboxylase, acyl-CoA synthetase, ATP (synthase alpha- and beta-chain), carbamoyl-phosphate synthase, citrate synthase, cysteine synthase, DnaK, the elongation factors G, P, Ts and Tu, enolase, fructose bisphosphate aldolase, fumarase, Gap dehydrogenase, glutamine synthetase I, glycine hydroxymethyltransferase, GroEL2, GTPase, heat-inducible transcriptional repressor DnaJ2, inorganic pyrophosphatase, isocitrate dehydrogenase, ketol-acid reductoisomerase, lactate dehydrogenase, leucine-tRNA ligase, lipoamide dehydrogenase, methionine synthase, O-acetylhomoserine sulfhydrylase, pyruvate carboxylase, pyruvate kinase, pyruvate oxidase, ribosomal protein S1, RNA polymerase (beta-subunit), succinyl-CoA:CoA transferase, transketolase and UDP-N-acetylmuramoyl-L-alanine ligase, besides a hypothetical 35k protein and a hypothetical glucose kinase. Both detection techniques were used to create a phosphoproteome map. Additionally, the influence of nitrogen deprivation on the phosphoproteome of C. glutamicum was investigated.
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PMID:Towards a phosphoproteome map of Corynebacterium glutamicum. 1292 88


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