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)

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

This study examined variations in resting oxygen consumption rate (ROCR), post-exercise oxygen consumption rate, relative scope for activity (RSA), liver and muscle aerobic and anaerobic capacities (using citrate synthase (CS) and lactate dehydrogenase, respectively, as indicators), and tissue biosynthetic capacities (using nucleoside diphosphate kinase (NDPK) as an indicator), in wild yellow perch from four lakes varying in copper (Cu) and cadmium (Cd) contamination. Liver Cu and Cd concentrations largely reflected environmental contamination and were positively correlated with liver protein concentrations and NDPK activities. Our results suggest that metal contamination leads to an upregulation of liver protein metabolism, presumably at least in part for the purpose of metal detoxification. In contrast, muscle NDPK activities decreased with increasing liver Cd concentrations and NDPK activities. There was a 25% decrease in ROCR for a doubling of liver Cu concentrations and a 42% decrease in RSA for a doubling of liver Cd concentrations in the range studied. Cu contamination was also associated with lower muscle CS activities. Our results support previous findings of impaired aerobic capacities in the muscle of metal-contaminated fish, and demonstrate that this impairment is also reflected in aerobic capacities of whole fish. The evidence presented suggests that mitochondria may be primary targets for inhibition by Cu, and that Cd may reduce gill respiratory capacity. Muscle aerobic and anaerobic capacities were inversely related. This work indicates that metal exposure of wild yellow perch leads to a wide range of disturbances in metabolic capacities.
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PMID:Impairment of metabolic capacities in copper and calcium contaminated wild yellow perch (Perca flavescens). 1282 Jun 29

Activity-body size relationships for eight enzymes (citrate synthase, CS; lactate dehydrogenase, LDH; pyruvate kinase, PK; alanine aminotransferase, ala AT; aspartate aminotransferase, asp AT; glutamate dehydrogenase, GDH; glucose-6-phosphate dehydrogenase, G6Pdh; and nucleoside diphosphate kinase, NDPK) were examined in the brine shrimp, Artemia franciscana. The animals were fed on the alga Dunaliella salina, which was provided in three concentrations representing a 25-fold range. Enzyme activities per animal (Y) were regressed against body size (M, expressed as dry mass or protein) in the form of the allometric equation, log Y = log a + b log M, where a and b are fitted constants. For all enzymes considered, the value of the scaling exponent (b) was significantly higher when dry mass was used, as a body size index, than when protein mass was used. Therefore, the index of body size chosen can influence the exponent obtained in allometric studies. Although specific growth rates of different cultures varied greatly, no significant differences in scaling relationships were found between cultures for any enzyme. For many enzymes, growth rate may not be a source of variation in scaling relationships. Unlike the other enzymes examined, the log-transformed NDPK activity versus log-transformed mass was not linear; NDPK activity reached a plateau. Variation in NDPK scaling relationships with growth may provide a means to predict growth rate in Artemia.
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PMID:Relationship Between Body Size, Growth Rate, and Maximal Enzyme Activities in the Brine Shrimp, Artemia franciscana. 2931 70