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)

1. In vitro glucose uptake and glycogen utilization by Hymenolepis microstoma decreased under high oxygen concentrations. 2. 5-Hydroxytryptamine did not stimulate in vitro glucose uptake but did increase glycogen utilizations by H. microstoma. 3. The reduced glucose uptake under high oxygen concentrations (21 and 95%) resulted in a reduction in excretory products. 4. 14CO2-incorporation studies confirmed that, under both 95% O2:5% CO2 and air-minus-CO2 (identical to 21% O2). CO2-fixation by phosphoenolpyruvate carboxykinase (EC 4.1.1.32) was inhibited. 5. The specific activity of hexokinase (EC 2.7.1.1), phosphofructokinase (EC 2.7.1.11) and pyruvate kinase (EC 2.7.1.40) was not stimulated by 5-HT. 6. The concentration of ATP required for optimal stimulation of phosphofructokinase activity was 0.67 mM. Activity was further significantly increased by the addition of cAMP and even greater by AMP.
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PMID:5-hydroxytryptamine, glucose uptake, glycogen utilization and carbon dioxide fixation in Hymenolepis microstoma (Cestoda). 681 65

Recently, it has been reported that paromomycin sulfate has marked anthelmintic efficacy against tapeworm infections in man. In the present study this drug was used in the treatment of 14 cases of diphyllobothriasis latum and 1 case of taeniasis saginata. Also, the actions of paromomycin sulfate on Diphyllobothrium ditremum and D. erinacei were examined pharmacologically using Magnus apparatus and biochemical methods. The results obtained were as follows. For the treatment, a total of 50 mg/kg of paromomycin sulfate divided into 2 doses was given orally at intervals of 30 minutes. Two hours after medication, 20 g of magnesium sulfate dissolved in 200--300 ml of water was given as purgative. One or 2 worms were found in the stools of 11 cases with D. latum and 1 case with T. saginata within 24 hours after medication, but scolex was found in only 2 of them. All cases were negative for the eggs or segments in stool examinations at 1 and 3 months after treatment. Except 1 case complained mild and transient vomiting no side effects were noticed. All cases showed no abnormality in blood examination, liver function test and urinalysis. Both of the proglottids of D. ditremum and D. erinacei showed muscle relaxation in Tyrode solution containing 10(-4) g/ml of paromomycin sulfate. In D. ditremum the recovery of muscle tonus was observed within 10--15 minutes after affection of this drug, while the persistence of muscle relaxation was seen in D. erinacei. The activity of phosphoglucose isomerase was slightly inhibited by 10(-3) M paromomycin sulfate while those of hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase were not inhibited. In phosphoenolpyruvate-succinate pathway, the activity of fumarate reductase was slightly inhibited 10(-3) M paromomycin sulfate while those of phosphoenolpyruvate carboxykinase and malate dehydrogenase were not inhibited.
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PMID:[Efficacy of paromomycin sulfate against human cestodiasis and its pharmacological action on tapeworm in vitro]. 687 66

The effects of a high fat diet (30% (w/w) corn oil) on chronic streptozotocin-diabetic rats were investigated at the whole body level and at the enzyme level. The diet caused significant decreases in the extent of polydipsia (66% decrease), polyphagia (49%), polyuria (67%) and glycosuria (70%). The activities of selected hepatic enzymes from the glycolytic, gluconeogenic, ureogenic and lipogenic clusters were determined. The fat diet caused significant decreases (range: 47 to 54%) in the activity of the ureogenic enzymes carbamyl phosphate synthetase, ornithine transcarbamylase and arginase; had no effect on the glycolytic enzymes glucokinase, hexokinase and pyruvate kinase; partially decreased the diabetes-induced elevated activities of the gluconeogenic enzymes phosphoenolpyruvate carboxykinase (63% decrease), serine dehydratase (90%), alanine aminotransferase (31%) and aspartate aminotransferase (65%), and partially reversed the activity of one lipogenic enzyme, ATP citrate lyase.
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PMID:The effects of a high fat diet on chronic streptozotocin-diabetic rats. 692 68

The plasma levels of corticosterone, insulin and glucagon, and the concomitant changes in the levels of several liver enzymes and metabolites were measured in intact rats in the basal state during 24 hours and under conditions of food deprivation and hypoxia. The levels of the following enzymes and metabolites were examined: phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, pyruvate kinase, phosphofructokinase, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, glucose, glucose-6-phosphate, glycogen, fructose-6-phosphate, hexokinase, tyrosine amino-transferase and tryptophan oxygenase. During food deprivation, the increased gluconeogenesis is possibly a result of glucagon activity. In contrast, however, during hypoxia the increase in gluconeogenesis seems to be a result of the higher plasma level of corticosterone. During starvation, the insulin concentration dropped steadily and came close to zero.
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PMID:Plasma concentrations of glucose, corticosterone, glucagon and insulin and liver content of metabolic substrates and enzymes during starvation and additional hypoxia in the rat. 703 Aug 99

With few exceptions, the specific activities of the glycolytic enzymes and the steady-state content of glycolytic and associated intermediates in protoscoleces of the horse (E.g.H) and sheep (E.g.S) strains of Echinococcus granulosus and the closely related E. multilocularis (E.m.) are very similar. Phosphorylase, hexokinase, phosphofructokinase and pyruvate kinase catalyse non-equilibrium reactions and the patterns of activity for pyruvate kinase, phosphoenolypyruvate carboxykinase and malic enzyme are similar in the three organisms. The levels of tricarboxylic acid cycle intermediates in E.g.H., E.g.S. and E.m. are of the same order as those reported in tissues with an active cycle. Each has a complete sequence of cycle enzymes but there are substantial differences between the three parasites with regard to the activity of individual enzymes. The activities of NAD and NADP-linked isocitrate dehydrogenases are significantly lower in E.g.H. than in E.g.S. and particularly in E.m. which suggests that the tricarboxylic acid cycle may play a more important role in carbohydrate metabolism and energy production in the latter parasites. Nevertheless, the three organisms utilize fermentative pathways for alternative energy production, fix carbon dioxide via phosphoenolpyruvate carboxykinase and have a partial reversed tricarboxylic acid cycle. It is speculated that in vivo more carbon will be channelled towards oxaloacetate than pyruvate at the phosphonenolpyruvate branch point. The steady state content of ATP and the ATP/AMP ratios are low in the three organisms, suggesting a low rate of ATP utilization in each.
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PMID:Intermediary carbohydrate metabolism in protoscoleces of Echinococcus granulosus (horse and sheep strains) and E. multilocularis. 707 Aug 45

The energy metabolism of the English E-CMO strain of contagious equine metritis bacterium was studied in whole cells and cell extracts. This bacterium appears to have an active Krebs cycle and probably obtains energy by oxidative phosphorylation since glycolysis and the hexose monophosphate pathways appear to be absent. These conclusions are based on the findings that [U-14C]glucose incorporation by this bacterium is below the level of detection, and that respiration is stimulated by Krebs cycle intermediates (i.e., malate, citrate, and succinate), but not by glucose, fructose, maltose, or sucrose. Furthermore, support comes from the fact that enzymes generally associated with the Krebs cycle and electron transport (i.e., malate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, fumarate hydratase, malate dehydrogenase [decarboxylating], cytochrome oxidase, superoxide dismutase, NADH dehydrogenase, and catalase) were detected. Those enzymes normally associated with glycolysis and the hexose monophosphate pathways (i.e., hexokinase, glucose 6-phosphate dehydrogenase, fructose biphosphate aldolase, glycerol 3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, pyruvate kinase, phosphate acetyl transferase, acetate kinase, alcohol dehydrogenase, and lactate dehydrogenase) were below the level of detection.
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PMID:Energy metabolism of the contagious equine metritis bacterium. 708 71

Radiochemical microprocedures were developed for the determination of hexokinase and phosphoenolpyruvate carboxykinase (PEPCK) activity in single microdissected segments of the mature rabbit nephron dissected from fresh tissue after collagenase treatment. All results were related to tubular length and tubular protein content. Hexokinase activity was found to be lowest in the proximal convoluted tubule and to increase along the following nephron segments, with highest activity in the connecting tubule. The gluconeogenic enzyme PEPCK, on the other hand, was exclusively found in the proximal tubule. Early and late portions of the convoluted segment exhibited the same specific activity, but only 50% was found in the pars recta. All other renal structures exhibited only insignificant activity of PEPCK. The results show that renal glucose metabolism and gluconeogenesis are clearly separated. As previously shown for the cytosolic rat enzyme, rabbit mitochondrial PEPCK is also exclusively a proximal tubular enzyme, thus confirming the dominant role of this segment in mammalian renal gluconeogenesis. The high activity of hexokinase in the segments of the distal tubule points to the role of glucose as metabolic fuel, glycogen precursor, and other glucose-6-phosphate-using pathways in these structures.
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PMID:Distribution of hexokinase and phosphoenolpyruvate carboxykinase along the rabbit nephron. 724 39

Glucokinase and phosphoenolpyruvate carboxykinase are key enzymes of glucose metabolism in the rat liver. The former is considered to be instrumental in regulating glucose hepatic release/uptake according to the glycaemia level, and cytosolic phosphoenolpyruvate carboxykinase is a major flux-generating enzyme for gluconeogenesis. The level of expression of both enzymes and the regulation of their mRNAs in the human liver cell were investigated. Surgical biopsies of liver from patients undergoing partial hepatectomies and parenchymal hepatocytes derived from the biopsies were used to assay glucokinase, hexokinase and phosphoenolpyruvate carboxykinase activities. Hepatocytes were placed in culture and the actions of insulin, glucagon and cAMP on glucokinase and phosphoenolpyruvate carboxykinase mRNAs were studied. The main results are: (a) glucokinase accounts for 95% of the glucose phosphorylation activity of human hepatocytes, although this fact is masked in assays of total liver tissue; (b) glucokinase activity is set at a lower level in human hepatocytes than in rat hepatocytes, and vice-versa for the gluconeogenic enzyme phosphoenolpyruvate carboxykinase; and (c) as previously shown in rat liver, glucokinase and phosphoenolpyruvate carboxykinase mRNAs are regulated in a reciprocal fashion in human hepatocytes, insulin inducing the first enzyme and repressing the latter, whereas glucagon has opposite effects. These data have interesting implications with respect to metabolic regulation and intracellular hormone signaling in the human liver.
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PMID:Glucokinase and cytosolic phosphoenolpyruvate carboxykinase (GTP) in the human liver. Regulation of gene expression in cultured hepatocytes. 773 62

The elasticities for the different steps of carbohydrate catabolism in the tapeworm Hymenolepis diminuta were estimated from perturbation experiments. These data were then used to calculate flux and metabolite control coefficients. Enzyme elasticities were also calculated from the rate equations and an independent estimate of the flux control coefficients for phosphoenolpyruvate carboxykinase was made by inhibitor titration. The values obtained for the flux control coefficients for carbohydrate breakdown in H. diminuta are consistent with how the pathway is thought to be controlled in vivo. A sensitivity analysis of the flux control coefficients of the important regulatory enzymes in the pathway shows that for hexokinase, phosphofructokinase, pyruvate kinase, and phosphoenolpyruvate carboxykinase there are three or four key elasticities which have a significant effect on the coefficient. For glycogen synthase, the major factor in determining the magnitude of the flux control coefficient is the relative flux through the branch.
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PMID:Quantification of the control of carbohydrate catabolism in the tapeworm Hymenolepis diminuta. 812 48

Rabbit proximal tubule cells in primary culture revert from gluconeogenesis to glycolysis. To determine whether glucose and insulin deprivation of the culture medium could prevent this metabolic conversion without a loss of differentiation, rabbit proximal tubule cells were cultured in hormonally defined medium free of glucose and insulin and compared to rabbit proximal tubule cells cultured in medium supplemented with 17.5 mM glucose and 5 micrograms/ml insulin. In the two culture conditions, RPT cells grew at a similar rate and reached confluency within 4-5 days. Patterns of enzyme activity, including brush-border hydrolases, N-acetyl-beta-D-glucosaminidase and glutathione-S-transferases as a function of culture time were comparable in the two media. During the growth phase in glucose- and insulin-free medium, cells showed higher sodium-dependent glucose uptake. Scanning electron microscopy revealed a high density of microvilli at confluency regardless of the culture conditions. In both the presence and absence of glucose and insulin, the activities of gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase, as well as basal and pyruvate-stimulated glucose production fell markedly as a function of time. By contrast, glucose and insulin deprivation greatly reduced both the lactate production rate and the activities of glycolytic enzymes, pyruvate kinase, hexokinase and lactate dehydrogenase.
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PMID:Effect of glucose and insulin deprivation on differentiation and carbohydrate metabolism of rabbit proximal tubular cells in primary culture. 838 35


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