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)

Representative enzyme activities of energy supplying metabolism were measured in muscle specimens of brachial biceps, deltoid or anterior tibial muscle of patients with affections of the peripheral nerves. Simultaneously performed measurements of the same enzyme activities in the contralateral normal muscles served as a control. 5 patients suffered from a lesion of the brachial plexus, 7 patients had a paralysis of the axillary nerve, and 8 patients had a peroneal paralysis. In all denervated muscles no electrophysiological signs of reinnervation were present. The activities of glycogen phosphorylase, triosephosphate dehydrogenase, lactate dehydrogenase and alpha-glycerophosphate dehydrogenase were found to be highest in the normal brachial biceps muscle. Lower activities were measured in the normal deltoid and anterior tibial muscle. The oxidative enzymes, 3-hydroxyacyl-CoA dehydrogenase and citrate synthase as well as hexokinase, showed no significant difference from the levels of the control. It is suggested that a probable factor determining the differences of the enzyme activities of glycogenolysis, glycolysis and alpha-glycerophosphate oxidation between brachial biceps, deltoid and anterior tibial muscle, might be the pattern of impulse activity in the motor nerves of these muscles. The enzyme activities of glycogen phosphorylase, triosephosphate dehydrogenase, lactate dehydrogenase and alpha-glycerophosphate dehydrogenase, decreased rapidly during the first 2 months after denervation in the brachial biceps, deltoid and anterior tibial muscle, whereas the decrease was slight during the following months. The activities of the oxidative enzymes (3-hydroxyacyl-CoA dehydrogenase and citrate synthase) showed no significant change after denervation. The metabolic difference of glycogenolysis, glycolysis and alpha-glycerophosphate oxidation between the three muscles was no longer maintained. The possible causes of the deeply decreased enzyme activities of glycogenolysis, glycolysis and alpha-glycerophosphate oxidation, as well as the causes of the unchanged oxidative enzyme activities and of the increased hexokinase activity after denervation in the human brachial biceps, deltoid and anterior tibial muscle, are discussed.
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PMID:[Representative enzymes of energy supplying metabolism in the normal and denervated human brachial biceps, deltoid and anterior tibial muscles (author's transl)]. 5 9

Male 13-lined ground squirrels induced to emerge from hibernation resumed feeding and gained weight. The weight gain was supported by increases in the levels of glucose 6-phosphate dehydrogenase, L-alanine aminotransferase and carnitine acetyltransferase in the liver. Maturation of the testis occurred in a period of about 16 days spanning the time of induced arousal. The testes of hibernating males were characterized by higher levels of L-alanine aminotransferase, glucose 6-phosphate dehydrogenase and 3-hydroxyacyl-CoA dehydrogenase than the testes of aroused males. Hexokinase, carnitine acetyltransferase and citrate synthase levels were similar in the testes of hibernating and aroused males. 3-Hydroxyacyl-CoA dehydrogenase was more active and L-alanine aminotransferase less active in ground squirrel sperm than in rat sperm.
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PMID:Changes in enzyme levels in the testis and liver of the 13-lined ground squirrel (spermophilus tridecemlineatus) at the time of arousal from hibernation. 7 Oct 81

Differences of metabolic qualities and capacities among organs and tissues of perinatal rabbits were investigated. A suitable alternative for the measurement of substrate utilization of single organs seems to be the total amount of certain key enzyme activities calculated for whole organs. The immediate perinatal period is the object of this study with adult animals serving as a reference. We have selected the phosphofructokinase activity to represent the upper segment of glycolytic reactions, 3-hydroxyacyl-CoA dehydrogenase as a key enzyme for beta-oxidation of fatty acids and citrate synthase activity to represent the Krebs cycle activity. In fetal, newborn, and adult rabbits we analyzed liver, kidneys, heart, lung, brain, brown and white adipose tissue, stomach and intestines, skin, a representative sample of skeletal muscles, and of bones. The organ weight distribution, total amount of protein, and DNA was determined for the same ten organs. The share each organ contributes to the total body key enzyme activity shows the importance of each metabolic capacity which is represented by the three enzymes. In perinatal adipose tissue the very high potential for energy production through utilization of Krebs cycle reactions is striking. The same tissue has a high capacity to oxidize fatty acids. The skeletal muscle represents the biggest capacity of glycolytic reactions in all age groups. After birth the metabolic profile of the whole organism shows a marked and steep increase of glycolytic capacity, whereas the capacity to oxidize fatty acids decreases slowly.
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PMID:Perinatal changes of interorgan differences in cell metabolism. 12 90

The intracellular location of pyruvate carboxylase (EC 6.4.1.1), citrate synthase (EC 4.1.3.7) and 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) in rat mammary gland was investigated by using a fractional-extraction technique. The results indicate a mitochondrial location for all three enzymes.
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PMID:The intracellular location of pyruvate carboxylase, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase in lactating rat mammary gland. 64 21

In biopsy samples of the lateral part of the quadriceps femoris muscle of 6 obese diabetic male patients and of 11 obese males with a normal glucose tolerance, the activities of 7 enzymes of energy metabolism were estimated: hexokinase, cytoplasmic glycerol-3-phosphate: NAD dehydrogenase, triosephosphate dehydrogenase, lactate dehydrogenase, citrate synthase, malate dehydrogenase and 3-hydroxyacyl-CoA dehydrogenase. The obese diabetic male patients exhibited decreased activities of enzymes of carbohydrate breakdown and cytoplasmic NAD regeneration. Enzymes connected functionally with aerobic metabolism were less affected. The unchanged activity of 3-hydroxyacyl-CoA dehydrogenase points to an increased role of fatty acid catabolism in the muscle.
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PMID:Enzyme activities in quadriceps femoris muscle of obese diabetic male patients. 90 76

1. In 3 groups of men, differing as to the amount and intensity of physical training loads, increasing in the order "sedentary": "sporting": "athletic", enzyme activities were estimated in biopsy samples of m. quadriceps femoris (vastus lateralis). The enzymes were: Hexokinase (HK), NAD: glycerol-3-phosphate dehydrogenase (GPDH), triosephosphate dehydrogenase (TPDH), lactate dehydrogenase (LDH), citrate synthase (CS), NAD: malate dehydrogenase (MDH), and 3-hydroxyacyl-CoA dehydrogenase (HOADH). Indicators of laboratory performance and whole-body metabolic capacities (maximal oxygen consumption etc.) were estimated in the "sporting" and "athletic" groups. 2. In the 2 latter groups, distinguished by greater physical activity, the atypical enzyme activity pattern, remarkable by a low activity of LDH and high relative activities of GPDH and HK, as reported earlier in a sedentary group (Bass et al., 1975a), disappeared. The possibility of the atypical low LDH enzyme activity pattern as resulting from lack of bodily exertion is discussed. 3. The moderately trained "sporting" group distinguishes itself from the "sedentary" one mainly by a higher activity of LDH and by lower activities of GPDH and MDH. In the intensively trained "athletic" group, enzymes connected to aerobic oxidation (MDH, CS, HOADH) and GPDH also show higher activities than in the "sporting" group. The difference between the two more active groups is further borne out by a higher maximum oxygen uptake and carbon dioxide release of the well-trained "athletic" group. This difference of enzyme activity pattern may not be confined to the quadriceps femoris muscle.
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PMID:Enzyme activity patterns of energy supplying metabolism in the quadriceps femoris muscle (vastus lateralis): sedentary men and physically active men of different performance levels. 94 91

We examined the oxidative and antioxidant enzyme activities in respiratory and locomotor muscles in response to endurance training in young and aging rats. Young adult (4-mo-old) and old (24-mo-old) female Fischer 344 rats were divided into four groups: 1) young trained (n = 12), 2) young untrained (n = 12), 3) old trained (n = 10), and 4) old untrained (n = 6). Both young and old endurance-trained animals performed the same training protocol during 10 wk of continuous treadmill exercise (60 min/day, 5 days/wk). Compared with young untrained animals, the young trained group had significantly elevated (P less than 0.05) activities of 3-hydroxyacyl-CoA dehydrogenase (HADH), glutathione peroxidase (GPX), and citrate synthase (CS) in both the costal diaphragm and the plantaris muscle. In contrast, training had no influence (P greater than 0.05) on the activity of lactate dehydrogenase within the costal diaphragm in young animals. In the aging animals, training did not alter (P greater than 0.05) activities of CS, HADH, GPX, or lactate dehydrogenase in the costal diaphragm but significantly (P less than 0.05) increased CS, HADH, and GPX activities in the plantaris muscle. Furthermore, training resulted in higher activities of CS and HADH in the intercostal muscles in the old trained than in the old untrained animals. Finally, activities of CS, HADH, and GPX were significantly (P less than 0.05) lower in the plantaris in the old untrained than in the young untrained animals; however, CS, HADH, and GPX activities were greater (P less than 0.05) in the costal diaphragm in the old sedentary than in the young untrained animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Aging and respiratory muscle metabolic plasticity: effects of endurance training. 156 62

We investigated age-related changes in antioxidant, glycolytic, beta-oxidation, and tricarboxylic acid cycle enzyme activity in the diaphragm and plantaris muscle of female Fischer 344 rats. Tissue samples from the costal and crural diaphragm and plantaris muscle were obtained from 30 animals in the following age groups: 1) 6 mo old (n = 10), 2) 26 mo old (n = 10), and 3) 30 mo old (n = 10). Aging had no effect (P greater than 0.05) on the activities of citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HADH) in the costal or crural diaphragm. Similarly, no age-related differences existed (P greater than 0.05) in the crural diaphragm in lactate dehydrogenase (LDH) or glutathione peroxidase (GPX) activity. In contrast, the activities of LDH and GPX were significantly (P less than 0.05) higher in the costal diaphragm in the 30- than in the 6-mo old animals. In addition, the ratio of LDH to CS activity increased (P less than 0.05) as a function of age in the costal diaphragm. Conversely, the ratio of CS to GPX activity in the costal diaphragm was lower (P less than 0.05) in the 30- than in the 6-mo old animals. No significant (P greater than 0.05) age-related differences existed in LDH-to-CS or CS-to-GPX activity ratios in the crural diaphragm. Finally, aging resulted in a significant decrease (P less than 0.05) in the activities of LDH, CS, and HADH in the plantaris muscle. These data demonstrate that, unlike many hindlimb locomotor muscles, the oxidative capacity of the Fischer 344 rat diaphragm does not decrease in old age.
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PMID:Alterations in diaphragmatic oxidative and antioxidant enzymes in the senescent Fischer 344 rat. 162 87

1. Activities of a glycolytic enzyme--lactate dehydrogenase, LDH, and two oxidative enzymes--citrate synthase (CS), a marker for TCA cycle entry, and 3-hydroxyacyl-CoA dehydrogenase (HAD), which indicates the capacity for beta-oxidation of endogenous lipids, were measured in fast (tibialis anterior, TA, and extensor digitorum longus, EDL) and slow (soleus, SOL) muscles of Sprague-Dawley rats with intact and limited blood supply, and following treatment with the xanthine derivative torbafylline (Hoechst, Werk Albert, Wiesbaden). 2. Limitation of blood supply by unilateral ligation of the common iliac artery increased activity of LDH in fast muscles, and activity of CS and HAD in soleus. 3. Torbafylline treatment caused an increased LDH activity in intact fast muscles and decreased it in soleus, although the relative capacity for anaerobic and aerobic metabolism (indicated by the ratio of LDH and CS activities) remained unchanged in all cases. 4. Whilst having little effect on oxidative enzyme activity of fast muscles, torbafylline decreased the activity of CS but increased activity of HAD in soleus, suggesting a greater reliance on lipid metabolism. 5. The effect of arterial ligation on enzyme activity was ameliorated by treatment with torbafylline, possibly due to its effect on the microcirculation.
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PMID:The effect of torbafylline on enzyme activities in fast and slow muscles with limited blood supply. 167 66

Maximal in vitro activities of key metabolic enzymes were measured in brain and eye heaters of five species of scombroid fishes. Istiophorid billfishes (blue marlin, striped marlin and Mediterranean spearfish), xiphiid billfishes (Pacific and Mediterranean stocks) and a scombrid fish (butterfly mackerel) were included in the analysis. Our main objectives were (1) to assess the maximum possible substrate flux in heater tissue, and (2) to determine what metabolic substrates could fuel heat production. Heater tissue of all scombroids examined showed extremely high oxidative capacity. Activities of citrate synthase, a commonly measured index of oxidative metabolism, included the highest value ever reported for vertebrate tissue. In most billfishes, citrate synthase activities were similar to or higher than those found for mammalian cardiac and avian flight muscle. Marker enzymes for aerobic carbohydrate metabolism (hexokinase) and fatty acid metabolism (carnitine palmitoyltransferase and 3-hydroxyacyl-CoA dehydrogenase) also displayed extraordinarily high activities. Activities of carnitine palmitoyltransferase measured in heater organs were among the highest reported for vertebrates. These results indicate that heat production could be fueled aerobically by either lipid or carbohydrate metabolism. Inter- and intraspecifically, heater organs of fishes from the colder Mediterranean waters had a higher aerobic capacity and, hence, a greater heat-generating potential, than fishes from the warmer waters of the Pacific. This difference may be attributed to different thermal environments or it may result from allometry, since fishes caught in the Mediterranean were considerably smaller than those caught in the Pacific.
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PMID:Activities of key metabolic enzymes in the heater organs of scombroid fishes. 175 72


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