Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Comparison of the activities of hexokinase, phosphorylase and phosphofructokinase in muscles from marine invertebrates indicates that they can be divided into three groups. First, the activities of the three enzymes are low in coelenterate muscles, catch muscles of molluscs and muscles of echinoderms; this indicates a low rate of carbohydrate (and energy) utilization by these muscles. Secondly, high activities of phosphorylase and phosphofructokinase relative to those of hexokinase are found in, for example, lobster abdominal and scallop snap muscles; this indicates that these muscles depend largely on anaerobic degradation of glycogen for energy production. Thirdly, high activities of hexokinase are found in the radular muscles of prosobranch molluscs and the fin muscles of squids; this indicates a high capacity for glucose utilization, which is consistent with the high activities of enzymes of the tricarboxylic acid cycle in these muscles [Alp, Newsholme & Zammit (1976) Biochem. J. 154, 689-700]. 2. The activities of lactate dehydrogenase, octopine dehydrogenase, phosphoenolpyruvate carboxykinase, cytosolic and mitochondrial glycerol 3-phosphate dehydrogenase and glutamate-oxaloacetate transaminase were measured in order to provide a qualitative indication of the importance of different processes for oxidation of glycolytically formed NADH. The muscles are divided into four groups: those that have a high activity of lactate dehydrogenase relative to the activities of phosphofructokinase (e.g. crustacean muscles); those that have high activities of octopine dehydrogenase but low activities of lactate dehydrogenase (e.g. scallop snap muscle); those that have moderate activities of both lactate dehydrogenase and octopine dehydrogenase (radular muscles of prosobranchs), and those that have low activities of both lactate dehydrogenase and octopine dehydrogenase, but which possess activities of phosphoenolpyruvate carboxykinase (oyster adductor muscles). It is suggested that, under anaerobic conditions, muscles of marine invertebrates form lactate and/or octopine or succinate (or similar end product) according to the activities of the enzymes present in the muscles (see above). The muscles investigated possess low activities of cytosolic glycerol 3-phosphate dehydrogenase, which indicates that glycerol phosphate formation is quantitatively unimportant under anaerobic conditions, and low activities of mitochondrial glycerol phosphate dehydrogenase, which indicates that the glycerol phosphate cycle is unimportant in the re-oxidation of glycolytically produced NADH in these muscles under aerobic conditions. Conversely, high activities of glutamate-oxaloacetate transaminase are present in some muscles, which indicates that the malate-aspartate cycle may be important in oxidation of glycolytically produced NADH under aerobic conditions. 3. High activities of nucleoside diphosphate kinase were found in muscles that function for prolonged periods under anaerobic conditions (e.g...
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PMID:The maximum activities of hexokinase, phosphorylase, phosphofructokinase, glycerol phosphate dehydrogenases, lactate dehydrogenase, octopine dehydrogenase, phosphoenolpyruvate carboxykinase, nucleoside diphosphatekinase, glutamate-oxaloacetate transaminase and arginine kinase in relation to carbohydrate utilization in muscles from marine invertebrates. 1 83

1) In intact Ehrlich ascites tumour cells the anaerobic glycolytic flux rate and pattern of intermediates have been investigated at different pH values of the extracellular medium. 2) As predicted from the dependence of the lactic acid dehydrogenase equilibrium on pH a strong negative correlation between log ([lactate]/[pyruvate]) and pH has been found. 3) The steady state fluxes of glycolysis at pH 8.0 and 7.4 are rather equal, despite significant differences in the intracellular concentrations of glycolytic intermediates. At pH 8.0 the concentrations of ATP, glucose 6-phosphate, and fructose 6-phosphate are lower, and the concentrations of ADP, AMP, fructose 1,6-bisphosphate, triose phosphates, phosphoglycerates, and phosphoenolpyruvate are higher than at pH 7.4. 4) From the analysis of the pH dependent changes of metabolites it follows that different mechanisms are responsible for maintaining equal actual activities of hexokinase, phosphofructokinase and pyruvate kinase at pH 7.4 and 8.0. 5) From an application of the linear theory of enzymatic chains and a calculation of the control strength of the regulatory important enzymes results that hexokinase is evidently rate-limiting for glycolysis, and phosphofructokinase is also significantly influencing the glycolytic flux. Pyruvate kinase and glyceraldehyde phosphate dehydrogenase, on the other hand, do not significantly affect the rate of the overall glycolytic flux in ascites.
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PMID:Regulation of anaerobic glycolysis in Ehrlich ascites tumour cells. 2 29

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

The author reports a modification of the UV method UltraZyme Plus alpha-Amyl Harleco and the adaptation to the Eppendorf Enzymautomat 5010. alpha-amylase acts on an oligosaccharide mixture yielding maltose, which is hydrolysed by alpha-glucosidase. The liberated glucose is determined specifically by the hexokinase/glucose-6-phosphate dehydrogenase (NAD+-dependent) method+ by addition of pyruvate, lactate dehydrogenase and ATP. Thereafter the lactate dehydrogenase reaction is stopped by addition of oxamate and the alpha-amylase activity is measured.
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PMID:[Kinetic determination of alpha-amylase in serum and urine with an oligosaccharide as substrate--modification for a fully mechanized enzyme measuring device (author's transl)]. 9 28

The metabolic effects on rat cardiac and skeletal muscle of a strenous program of swimming, of cold acclimation and of isoprenaline treatment (0.3 mg/kg daily for 5 five-day weeks) were compared. Exercised and cold-exposed rats gained less body weight than did controls or isoprenaline-treated rats. In all treated groups the heart and the intercapular brown adipose tissue hypertrophied. The size of the adrenals increased only in isoprenaline-treated animals. Cold-acclimation and physical training increased and isoprenaline treatment reduced or did not affect the activities of succinate dehydrogenase, malate dehydrogenase and citrate synthase of cardiac muscle. In the skeletal muscle all treatments resulted in increased activities of these enzymes. Of the anaerobic enzymes analysed, only the activity of hexokinase increased in response to the treatements used. This increase was the same in cardiac as in skeletal muscle, but it was significantly greater with isoprenaline-treatment than with training or with cold-acclimation. The activities of lactate dehydrogenase and phosphofructokinase did not differ significantly. All treatments improved cold resistance, but only swimming exercise and cold acclimation significantly increased tolerance to exercise. It is concluded that prolonged stimulation of adrenergic beta-receptors by catecholamines is responsible for the metabolic changes observed.
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PMID:Comparison of the effects of physical exercise, cold acclimation and repeated injections of isoprenaline on rat muscle enzymes. 12 87

Specimens of human adipose tissue were cultured for one week with or without the addition of insulin. The basal as well as the noradenaline-stimulated lipolysis were enhanced in the explants cultured with insulin, showing that the long-term effect of the hormone is lipolytic. However, an acute antilipolytic effect of insulin could be demonstrated in these explants in the subsequent short-term incubations. The basal rate of glucose incorporation into the lipids was enhanced in the explants cultured with insulin. When insulin was added in the short-term incubations these explants did not further respond to the hormone while this was the case with the explants cultured without insulin. Thus, it seems that prolonged exposure to insulin leads to a diminished acute effect of the hormone on glucose metabolism. However, the same explants responded to the antilipolytic effect showing that insulin was able to bind itself to the membrane. The activities of hexokinase (HK), glucose-6-phosphage dehydrogenase (G6PDH), pyruvate kinase (PK) and lactate dehydrogenase (LDH) were increased in large fat cells both in freshly excised tissue and in cultured explants. However, the activity of phosphofructokinase (PFK) did not correlate with the cell size. The presence of insulin during the culture period enhanced the activities of G7PDH, PK, and LDH, while this was not found for HK or PFK. The data thus suggest that the metabolic capacity of human fat cells is enhanced by long-term exposure to insulin. Although enzyme induction could be shown for G6PDH, PK and LDH it seems unlikely that this is of importance for the increased rates of glucose metabolism in these explants since the rate-limiting enzymes, HK and PGK, were not increased. Most probably, then, this stimulating effect of insulin is exerted on the membrane and the rate of glucose transport.
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PMID:Human adipose tissue in culture V. Studies on the metabolic effects of insulin. 13 27

The activities of several glycolytic enzymes (hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase) as well as glycerol-1-phosphate dehydrogenase and (Mg2+)ATPase in normal cerebrospinal fluid (CSF) and blood plasma samples, from 12 healthy infants, aged 2-18 months, and in supernatants from brain tissue slices, taken during neurosurgical operations from infants of the same range of age were estimated. The values obtained confirm the high activity of the above enzymes found in animal brains, and indicate an independence of these activities in blood plasma and CSF. The origin of the activities of the investigated enzymes in CSF seems to be mainly, if not, exclusively, from brain tissue. This might be useful for detection of brain tissue damage as was earlier proven with LDH activity in CSF.
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PMID:Some glycolytic enzymes in normal cerebrospinal fluid, brain tissue and blood plasma of infants. 13 54

Enzyme activities were measured in homogenates of left and right ventricles of guinea pigs after 14 and 28 days' exposure to 400 mmHg barometric pressure. All animals developed anorexia and right ventricular hypertrophy. Two control groups of animals were used, one free fed and the other restricted to the amount of food chosen by the hypobaric group. The factorial design of the experiment allowed some distinction between the effects of anorexia, hypertrophy, and hypoxia. Dietary restriction was associated with a decrease in glycogen phosphorylase, hexokinase, and succinate dehydrogenase activity and an increase in the M-subunits of lactate dehydrogenase. Myocardial hypertrophy was associated with an increase in the activity of the enzymes of the glycolytic pathway down as far as phosphoglycerate kinase and an increase in the M-subunits of lactate dehydrogenase. Chronic hypoxia seemed specifically to be associated with an increase in the H-subunits of lactate dehydrogenase and possibly a slight transient increase in succinate dehydrogenase activity. Mixing studies indicated that changes in enzyme activities were likely to be due to changes in enzyme concentrations.
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PMID:Effects of chronic hypoxia and dietary restriction on myocardial enzyme activities. 13 6

Extensor digitorum longus muscles of rats were removed and injected with a solution of Marcaine plus hyaluronidase. After incubation in Marcaine solution for 10 min, the muscles were grafted into their original beds. The grafts and the contralateral control muscles were removed from the rats at 0, 1-5, 7, 11, 36, and 69 days postoperatively. The muscles were then frozen in dry ice and isopentane and subsequently homogenized and centrifuged. The supernatant was analyzed for a number of enzymes, the regenerative patterns of which can be classified into 3 groups: (1) early increase in activity: hexokinase, glucose-6-phosphate dehydrogenase; (2) early decrease in activity with failure to recover to control levels: phosphorylase, phosphofructokinase, alpha-glycerophosphate dehydrogenase; and (3) early decrease followed by return to control levels: lactate dehydrogenase, pyruvate kinase, creatine phosphokinase, adenylate kinase. These patterns are not identical to those reported for embryogenesis of muscle. The data are discussed with regard to correlative histological studies of muscle regeneration.
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PMID:Developmental patterns of glycolytic enzymes in regenerating skeletal muscle after autogenous free grafting. 14 74

A study of post-mortem changes in human central nervous tissue has shown that within 100 h of death, no significant change occurs in the amount of nerve cell DNA and nucleolar RNA nor in some membrane-associated enzymes such as succinate dehydrogenase, NADH and NADPH diaphorase, and cytochrome oxidase. Low molecular weight RNA species, probably transfer and messenger RNA are quickly lost, but there is little alteration in ribosomal RNA content. Cytoplasmic enzymes show variable changes; phosphofructokinase activity is rapidly decreased; hexokinase is unaltered but lactate dehydrogenase, pyruvate kinase and glucose-6-phosphate dehydrogenase initially show increases in activity which subsequently decline. Oxygen uptake diminishes quickly. These findings indicate that mechanical alterations in cell structure, following death, render organelles physiologically ineffective long before any significant changes in certain constituent biochemicals are detected. This report emphasizes the great importance necessary in the selection of appropriately time matched post-mortem tissues if accurate comparative studies of many of the cells constituents are to be made.
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PMID:Post-mortem changes in human central nervous tissue and the effects on quantitation of nucleic acids and enzymes. 14 55


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