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:2.3.3.1 (citrate synthase)
4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This paper presents a study of the metabolic and contractile types of 34 samples from 30 muscles in five crossbred Pietrain-Large White pigs 6 to 7 months old. The activity of the following enzymes was measured: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase using high (LDH-h) or low (LDH-b) pyruvate concentrations in the reaction medium, citrate synthase (CS), and myofibrillar Ca-Mg activated ATPase. Haeminic iron and ultimate pH (pHu) were measured on the same samples. The results showed a negative, rather linear relationship between GAPDH, LDH and ATPase activities on the one hand and CS and haeminic iron on the other. Rather high correlations (r = 0.7 to 0.8) were observed between metabolic and contractile criteria and pHu; the red (slow) muscles had the highest pHu.
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PMID:[Enzyme metabolic and contractile activities of 30 pig muscles. Relation with the final ph attained after death]. 293 86

To determine whether respiratory muscles undergo alterations in enzyme activities of energy metabolism as a result of increased mechanical activity, adult male Wistar rats were subjected to a prolonged endurance training program. Analysis off maximal enzyme activity patterns in the diaphragm following 15 weeks of extreme training (final running duration: 210 min per day, 27 m.min-1 at 15 degrees grade, indicated significant reductions in the marker enzymes of the citric acid cycle (citrate synthase), glycolysis (pyruvate kinase, PK; lactate dehydrogenase, LDH), ketone body utilization (3-keto acid: CoA transferase) and transamination (glutamate pyruvate transaminase, GPT). No changes were found for the enzymes of glycogenolysis (phosphorylase, PHOSPH), glycolysis (glyceraldehyde phosphate dehydrogenase, GAPDH), glucose phosphorylation (hexokinase, HK) and beta-oxidation (3-hydroxyacyl: CoA dehydrogenase, HAD) following training. In contrast, in the external intercostal muscle, increases in the range of 57-77% were noted for the enzymes CS and HAD, whereas in the internal intercostal muscles no training induced alteration was evident for these enzymes. For both the intercostal muscles, a consistent trend was noted towards a reduction in all of the glycolytic enzymes investigated, however, significantly lower values were recorded for only PK and LDH in the internal intercostals. GPT was increased in the internal intercostal muscles. These findings indicate that the response pattern observed in the enzyme activities studied following training are to some degree specific to the respiratory muscle investigated.
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PMID:Differential response of enzyme activities in rat diaphragm and intercostal muscles to exercise training. 337 43

Thirty-six biopsy specimens of human biceps and vastus lateralis muscles were examined by histometric analysis and determination of enzyme activities (phosphorylase, triosephosphate dehydrogenase, 3-hydroxacyl-CoA-dehydrogenase, lactate dehydrogenase, hexose isomerase, citrate synthetase, 6-phosphogluconate dehydrogenase). The series included 13 specimens from patients suffering from a benign form of muscular dystrophy (limb girdle and Becker type of muscular dystrophy) and 12 specimens from patients with an acute (n = 5) or chronic (n = 7) form of myositis. Muscle fibres were atrophic in myositis and hypertrophic (with an increased variation of fibre diameters) in muscular dystrophies, as has been shown previously. When myositis samples were compared with either normal or dystrophic muscles, a highly significant lowering of glycolytic enzyme activity was found in chronic myositis, while the activity of 6-phosphogluconate dehydrogenase was elevated to highly significant levels. Measurements of the latter enzyme's activity might be of additional value in differentiating chronic forms of myositis from benign muscular dystrophies.
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PMID:Additional biochemical criteria in the differential diagnosis of myositis. 343 Jan 87

Men with regular physical training habits voluntarily increased their dietary fat intake from 43 to 54% of energy (E%) for four weeks. This was followed by a low-fat (29 E%), high-carbohydrate diet for another four weeks. During the high-fat diet period, the muscle lipoprotein lipase activity (LPLA) increased from 59 +/- 8 to 106 +/- 12 mU/g (mean +/- SE) (P less than 0.05). After the high-carbohydrate diet, LPLA was 57 +/- 16 mU/g, and unchanged relative to the pre-trial value. The triglyceride content in m. vastus lateralis increased from 30 +/- 4 to 47 +/- 9 mmol/kg d.w. (P less than 0.05; mean +/- SE) following the high-fat diet and to 41 +/- 8 following the high-carbohydrate diet. Neither of the diets affected the serum triglyceride and insulin concentrations, nor glucose, glycerol, beta-hydroxybutyrate, citrate and lactate levels in the blood. Nor did they alter enzyme activities in muscle used as markers for the oxidative (citrate synthase, beta-hydroxy-acyl CoA dehydrogenase) and glycolytic (glyceraldehyde phosphate dehydrogenase, lactate dehydrogenase) capacity. It is concluded that one month's adaptation to a high-fat diet results in increased muscle-LPL activity indicating a higher capacity for uptake of fatty acids from circulating serum triglycerides into the muscle cell in association with a greater capacity for triglyceride storage in the muscle. Under these conditions serum triglycerides were not decreased despite the increased muscle LPLA, and serum insulin variations could not explain the change in muscle LPLA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipoprotein lipase activity and intramuscular triglyceride stores after long-term high-fat and high-carbohydrate diets in physically trained men. 354 51

We determined representative enzyme activities of glycogenolysis (glycogen phosphorylase) glycolysis (d-glyceraldehyde-3-phosphate dehydrogenase, GAPDH), beta oxidation of free fatty acids (1-3-hydroxyacyl CoA dehydrogenase, HADH), citric acid cycle (citrate synthase, CS), lactate fermentation (lactate dehydrogenase LDH), and creatine phosphate metabolism (creatine kinase, CK) in left ventricular samples of 36 patients to investigate if the metabolic capacities of the energy-supplying pathways are differently affected in different heart diseases. There were 17 patients with mitral valve diseases (MVD), 8 patients with aortic valve diseases (AVD), and 11 patients who suffered from dilative cardiomyopathies (DCM). The main metabolic characteristic on the level of enzymatic organization in patients with DCM was an increased ratio of GAPDH/HADH activities and a decreased ratio of HADH/CS activities compared to the valve-diseased patients. This result indicates that the capacity of glucose oxidation is enhanced at the expense of fatty acid metabolism in patients with DCM. Furthermore, we determined significantly lower myocardial CK activities in this group of patients, most probably reflecting a diminished content of myofibrils. Citrate synthase activity was lowest in patients with AVD. Although we cannot rule out that the impaired left ventricular function is in part responsible for the shift of the capacities of the energy-supplying metabolism in patients with DCM, we favor the assumption that it is a specific feature of this myocardial disease.
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PMID:Comparative analysis of myocardial enzyme activities of the energy-supplying metabolism in patients with dilative cardiomyopathies and valve diseases. 370 46

Muscle fiber distribution and muscle enzyme activity (m. vastus lat.) were investigated in 10 elite sprint cyclists and 12 nonathletes. The ratio of fast to slow muscle fibers was 2:3 in cyclists and 3:2 in nonathletes. The mean diameter of each muscle fiber type was significantly higher in the athletes. The mean enzyme activity values in mu kat X g-1 w.w. for cyclists and nonathletes, respectively, were as follows: triosephosphate dehydrogenase (TPDH), 6.2 and 3.78; lactate dehydrogenase (LDH), 4.4 and 4.59; citrate synthase (CS), 0.154 and 0.13; hydroxyacyl-CoA dehydrogenase (HAD), 0.041 and 0.07. The mean difference between groups in TPDH and in (TPDH + LDH)/(CS + HAD) ratio were statistically significant. Maximum voluntary isometric strength (knee extension) was about 17% greater in cyclists than the mean value for Czechoslovakian men of the same age. A strong positive correlation (r = 0.72) between the percent of fast glycolytic fibers (type II B) and isometric strength was observed in the cyclists. Furthermore, mean weight-compensated maximal oxygen consumption (VO2 max, ml X kg-1 X min-1) for all subjects (n = 22) was significantly related to percent of slow oxidative fibers (type I) (r = 0.75) and to the mean diameter of type II B (r = 0.58), fast oxidative-glycolytic fibers (type II A) (r = 0.68) and type I fibers (r = 0.59).
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PMID:Skeletal muscle characteristics of sprint cyclists and nonathletes. 379 40

Relationships between functional anaerobic indicators and the character of cellular muscle energy metabolism were studied. Twelve untrained male students were tested by a specific anaerobic test on the treadmill. The mean values of the anaerobic test were as follows: blood lactate 10.69 mmol . 1(-1), running speed 16.08 km . h-1 and duration 92.67 s. The average distribution of muscle fibres (m. vastus lateralis) was: type I 52.2%, type II A 29.0% and type II B 18.8%. The mean enzyme activity values were: triosephosphate dehydrogenase (TPDH) 4.67 mu kat . g-1 w.w., lactate dehydrogenase (LDH) 5.76 mu kat . g-1 w.w, citrate synthase (CS) 0.21 mu kat . g-1 w.w. and hydroxyacyl-CoA dehydrogenase (HAD) 0.12 mu kat . g-1 w.w. Significant negative correlations were found between delta LA and CS (r = 0.64) and % of fibre type II B and CS (r = 0.78) and positive correlations between % of fibre type I and CS and/or HAD (r = 0.60 and r = 0.62, respectively).
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PMID:The relationship between anaerobic performance and muscle metabolic capacity and fibre distribution. 406 28

Crude extracts of both vegetative cells and glycerol-induced microcysts of Myxococcus xanthus contained the following enzyme activities: phosphofructokinase, phosphoglucoisomerase, fructose-1,6-diphosphatase, fructosediphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate carboxylase, citrate synthase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphoglucomutase, and uridine diphosphate glucose pyrophosphorylase. With the exception of isocitrate dehydrogenase, which was present at a fivefold higher concentration in microcysts, all activities in extracts from both types of cells were essentially equal. Hexokinase and pyruvate kinase could not be detected in extracts from either type of cell. Microcysts metabolized acetate at a lower rate than did vegetative cells. Most of this decrease was reflected in a substantial decrease in ability of microcysts to oxidize acetate to CO(2). In addition, microcysts and vegetative cells showed a different distribution of (14)C-label from incorporated acetate.
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PMID:Comparative intermediary metabolism of vegetative cells and microcysts of Myxococcus xanthus. 430 96

The effect of 5 days' complete fasting on the activity of 7 enzymes of energy supplying metabolism was studied in the vastus lateralis muscles of 9 healthy male volunteers. There was a significant decrease of lactate dehydrogenase (by 66%), triosephosphate dehydrogenase (by 61%), malate:NAD dehydrogenase (by 48%), hexokinase (by 40%), 3-hydroxyacyl-CoA-dehydrogenase (by 40%), triosephosphate dehydrogenase/3-hydroxyacyl-CoA-dehydrogenase (by 35%), citrate synthase (by 33%). Glycerolphosphate:NAD dehydrogenase activity did not decrease significantly. These findings suggest a) that utilization of the major energy substrates decreases; b) that the decrease mainly concerns the catabolism of carbohydrates, that of fatty acids to a lesser extent; c) that the decreased capacity of carbohydrate catabolism is partly compensated for by the predominance of the more economic aerobic-oxidative pathway; d) that the reducing equivalents formed in the cytosol may be transported via the glycerolphosphate shuttle into the respiratory chain to a greater extent, so that a greater portion is not lost by the reduction of pyruvate to lactate.
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PMID:Activities of muscle energy supplying enzymes after 5 days complete fasting in young men. 621 60

Fibre characteristics and enzyme activities were determined for the gluteus, semitendinosus, vastus lateralis and triceps brachii muscles of 55 Standardbred trotters of different ages. Four fibre types (I, IIA, IIB, IIC) were demonstrated by histochemical staining of myofibrillar adenosine triphosphatase after preincubation at different pH values. Type II fibres predominated in all the muscles and the type IIA/IIB ratio was higher in horses over 5 years than in younger horses, except in the vastus in which the IIA/IIB ratio did not change with age. The vastus had the highest proportion of type IIA fibres and the semitendinosus the highest proportion of type IIB fibres. Histochemical demonstration of NADH dehydrogenase disclosed that almost 100 per cent of the type IIA and many of the type I and IIB fibres were medium-stained; the remaining type I fibres were darkly stained and the type IIB fibres lightly stained. In older horses more fibres were stained for NADH dehydrogenase. The activity of triosephosphate dehydrogenase decreased that that of 3-hydroxy-acyl-coA dehydrogenase and citrate synthase increased in all the muscles except the vastus with increasing age. The greatest increase in oxidative capacity occurred in the gluteus and triceps. Training, rather than age, was regarded as the factor inducing these changes. The results emphasise that histochemical data are only semiquantitative, and there are apparent discrepancies in the intensities of histochemical staining and the biochemical evaluation of various enzymes.
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PMID:Histochemical properties of muscle fibres types and enzyme activities in skeletal muscles of Standardbred trotters of different ages. 644 65


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