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)

The activities of jejunal carbohydrate-metabolizing enzymes show adaptive drugs, and sex hormones. To learn whether insulin, tolbutamide, and glucagon had effects on these enzymes, we performed serial peroral jejunal biopsies in normal young men and in obese patients, before and after treatment with these agents. Jejunal mucosa was assayed for glycolytic enzyme activities, pyruvate kinase (PK), hexokinase (HK), and fructose-1,6-diphosphate aldolase (FDPA), and the nonglycolytic enzyme activity, fructose diphosphatase (FDPase). Insulin significantly increased the activity of jejunal PK (+48% change from control) and HK (+6%), decreased the activity of FDPase (-36%),and had no effect on FDPA. Glucagon had opposite effects; the activity of PK was decreased (-33%) and FDPase was increased (+50%). Tolbutamide significantly increased the activities of PK (+47%), HK (+14%), and FDPA (+7%), and decreased the activities of FDPase (-36%). The results of tolbutamide on glycolytic enzyme activities were independent of endogenous insulin. The data support the concept that jejunal carbohydrate-metabolizing enzymes in man respond to hormones and drugs similar to responses observed in rat liver. This is important because it now gives us a means of studying the actions of these hormones directly in human tissue.
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PMID:Effects of insulin, tolbutamide, and glucagon on activities of jejunal carbohydrate-metabolizing enzymes in humans. 16 65

Established epithelial cell lines derived from livers of 7-day (B, B-R, B-3-4-7, J-C-1, J-C-13, J-5-2-1, E-C-4 and E-C-7) and adult (AL-2, AL-3, AL-4, AL-5 and AL-6) rats were analyzed for hexokinase (HK), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glucose 6-phosphatase (G6Pase) and fructose 1,6-diphosphatase (FDPase). None of the cell lines showed appreciable activities of adult type liver enzymes (HK Type IVs (glucokinase), PK Type L, G6Pase and FDPase). On the contrary, the activities of fetal type liver enzymes (HK Types I and II, PK Type M2 and G6PD) increased markedly as compared with dispersed cells or tissues of adult liver. 6PGD gave minimum changes in activity, and the 6PGD/G6PD ratio decreased consistently. HK Type III was found only in J-C-13, AL-5 and AL-6, while HK Type IVf (high Km) was present in all the cell lines examined. Possible explanations for the undifferentiated patterns of carbohydrate-metabolizing enzymes in the established cell lines, which have several evidence of hepatocyte origin, are presented.
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PMID:Undifferentiated patterns of key glycolytic and gluconeogenic enzymes in epithelial cell lines derived from rat liver. 16 73

1. The ratio of the combined activities of hexokinase (EC 2.7.1.1) and glucokinase (EC 2.7.1.2) to the activity of glucose-6-phosphatase (EC 3.1.3.9) changed in favour of the glycolytic enzymes during pregnancy and at peak lactation. 2. There were no important changes in the ratio of the activity of phosphofructokinase (EC 2.7.1.11) to that of fructose diphosphatase (EC 3.1.3.11). 3. The ratio of the activity of pyruvate kinase (EC 2.7.1.40) to the combined activities of phosphoenolpyruvate carboxylase (EE 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1) changed in favour of the glycolytic enzyme during pregnancy and at peak lactation, but changed in favour of the gluconeogenic enzymes immediately after parturition. 4. These changes are considered in relation to the changes in food intake and hormonal status that occur during pregnancy and lactation.
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PMID:The effects of pregnancy and lactation on the activities in rat liver of some enzymes associated with glucose metabolism. 17 Sep 98

During the first 72 h after 67% partial hepatectomy of female Wistar rats (160 g) the specific activities [mumol X min-1 X (g liver)-1] of the glucogenic glucose-6-phosphatase and fructose-bisphosphatase and of the glycolytic hexokinase and 6-phosphofructokinase remained essentially constant. However, the activity of the glycolytic pyruvate kinase (L- plus M2-type) was decreased slightly and that of glucokinase was decreased markedly to below 30%, while the glucogenic phosphoenolpyruvate carboxykinase was increased to over 200%. Between 10 and 40 h after partial hepatectomy, when the proliferation started in the periportal area, a shift of the glucogenic glucose-6-phosphatase-rich zone from its normal periportal to an intermediate or even perivenous position was observed histochemically. After 48 h, when the proliferation was no longer restricted to the periportal zone, the normal glucose-6-phosphatase zonation (as before partial hepatectomy) was restored. Glycogen was degraded rapidly during the first 4 h after operation; it was later repeatedly resynthesized and degraded in correlation with the feeding rhythm of the animals. The zonation of glycogen metabolism was in accord with the observed zonation of glucose-6-phosphatase.
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PMID:Increase of the gluconeogenic and decrease of the glycolytic capacity of rat liver with a change of the metabolic zonation after partial hepatectomy. 21 1

Yeast mutants blocked at different steps of the glycolytic pathways have been used to study the inactivation of several gluconeogenic enzymes upon addition of sugars. While phosphorylation of the sugars appears a requisite for the inactivation of fructose 1,6-bisphosphatase and phosphoenol-pyruvate carboxykinase, malate dehydrogenase is inactivated by fructose in mutants lacking hexokinase. The normal inactivation elicited by glucose in a mutant lacking phosphofructokinase indicates that the process does not require metabolism of the sugar beyond hexose monophosphates. A possible role for ATP in the inactivation process is suggested.
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PMID:Inactivation of gluconeogenic enzymes in glycolytic mutants of Saccharomyces cerevisiae. 23 32

The hepatocyte and haematopoietic cell contents of the liver of the foetal guinea pig were measured over the latter half of gestation. Hepatocytes represented about 30% of liver volume at mid-gestation and this increased to 70-80% by term; cell volume remained fairly constant until 5-7 days before term, then more than doubled. Haematopoietic cells represented about 5% of liver volume at mid-gestation and this progressively fell to <1% by term. At 75% of gestation hepatocytes and haematopoietic cells were prepared from perfused foetal livers by collagenase digestion. Enzyme activity of the hepatocyte was, without exception, similar to that of the whole liver. In general, enzyme activity in the haematopoietic cells was similar to that in erythrocytes, with relatively low values for aldolase, glycerol 3-phosphate dehydrogenase, phosphoglycerate mutase, enolase, lactate dehydrogenase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, isocitrate dehydrogenase, ;malic' enzyme, glutamate dehydrogenase and aspartate aminotransferase. The haematopoietic cell contribution to total enzyme activity in the foetal liver was usually much less than 10% and could thus not account for the major changes in hepatic enzyme activity over the latter half of gestation. Hepatocytes contained hexokinase isoenzymes I and III, aldolase isoenzymes A and B and pyruvate kinase isoenzymes 1, 2 and 4. The haematopoietic cells contained hexokinase isoenzyme I and two additional bands of activity with slightly greater mobility, aldolase isoenzyme A and pyruvate kinase isoenzymes 2 and 4.
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PMID:The distribution of enzyme and isoenzyme activities between parenchymal and haematopoietic cells in the liver of the foetal guinea pig. 43 88

It is shown in experiments is vivo that development of experimental metabolic alkalosis in rats is followed by changes in redox processes in the eye retina and tunic. For the first two months of the experiment the number of sulphydryl group decreases, while that of disulphide ones of water-soluble proteins and low-molecular compounds increases. The amount of oxidized metabolites of glycolysis and of a cycle of tricarboxylic acids (pyruvate, oxaloacetate, alpha-ketoglutarate) increases relative to the reduced ones (lactate, isocitrate, malate), as well as activities of hexokinase, pyruvate kinase, NAD-dependent malate dehydrogenase, while activities of fructose diphosphatase, glucoso-6-phosphate dehydrogenase, glutathione peroxidase and glutathione reductase fall. The content of malonic dialdehyde increases. 90 days later disorders of certain compensatory mechanisms of the metabolic system of alkalosis regulation probably occurred in the eye retina and tunic tissues: hexokinase and pyruvate kinase activity fell to the control values, while that of NAD-dependent malate dehydrogenase--below the control level; the content of lactate increased. Activity of glutathione-dependent enzymes remained low and the amount of malonic dialdehyde grew much more than in the previous terms.
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PMID:[Redox processes in the retina and tunic tissues of the rat eye in experimental alkalosis]. 144 Sep 68

Optimal concentrations of the essential components for analyzing the activity of each enzyme associated with glycolysis and gluconeogenesis in rabbit periodontal ligament were examined, and enzyme assay systems for 15 enzymes including 22 reactions were established using triethanolamine buffer. Specific activities of all the enzymes, except for the gluconeogenic reaction of phosphoglycerate kinase, were systematically evaluated using the optimum buffer for each enzyme, since the activity of each enzyme varied depending on the buffer used. For glycolysis, the activity levels of hexokinase and 6-phosphofructokinase were very low, and consequently these enzyme reactions were inferred to be the rate-limiting steps. For gluconeogenesis, fructose 1,6-bisphosphatase and aldolase activities were extremely low, and the activities of glucose 6-phosphatase, phosphoenolpyruvate carboxykinase and pyruvate carboxylase were undetectable. These results suggest that the periodontal ligament may have no gluconeogenesis capability. With a rise in pH, the activities of the key enzymes of glycolysis gradually increased, and a specific "crossover" point was found between the activities of glyceraldehyde-phosphate dehydrogenase and phosphoglyceromutase. In addition, the activity of fructose 1,6-bisphosphatase, one of the key enzymes of gluconeogenesis, was markedly increased with a rise in pH, although pH changes had no effect on aldolase activity. Consequently, alkaline pH appeared to result in overall stimulation of glycolysis.
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PMID:Enzymatic regulation of glycolysis and gluconeogenesis in rabbit periodontal ligament under various physiological pH conditions. 165 53

Treatment of rats with diazinon (40 mg/kg, i.p.) resulted in hyperglycaemia and depletion of glycogen from the brain and peripheral tissues two hours after administration. The activities of glycogen phosphorylase and phosphoglucomutase were significantly higher in the brain and liver; that of glucose-6-phosphatase was not altered. The activities of the glycolytic enzymes hexokinase and lactate dehydrogenase were increased only in the brain. The cholinesterase activity in the brain was reduced by treatment with diazinon. The activities of the hepatic gluconeogenic enzymes fructose 1,6-diphosphatase and phosphoenolpyruvate carboxykinase were significantly increased. The lactate level was increased in the brain and blood, whereas that of pyruvate was not changed. The activity of glucose-6-phosphate dehydrogenase was not changed to any major extent. Cholesterol and ascorbic acid contents of adrenals were depleted in diazinon-treated animals. The changes were pronounced after intraperitoneal administration of 40 mg/kg diazinon, they were slight but significant after 20 mg/kg, and absent after 10 mg/kg. Hyperglycaemia and changes in carbohydrate metabolism were abolished by adrenalectomy suggesting possible involvement of adrenals.
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PMID:The role of adrenals in diazinon-induced changes in carbohydrate metabolism in rats. 209 50

Treatment with diazinon (40 mg/kg, i.p.) resulted in hyperglycemia and depletion of glycogen from cerebral and peripheral tissues 2 hr after its administration in rats. The activities of the glycogenolytic enzymes glycogen phosphorylase and phosphoglucomutase were increased significantly in brain and liver, whereas that of glucose-6-phosphatase was not altered. The activities of the glycolytic enzymes hexokinase and lactate dehydrogenase were increased only in the brain. The cholinesterase activity of the brain was reduced by treatment with diazinon. The activities of the hepatic gluconeogenic enzymes fructose 1,6-diphosphatase and phosphoenolpyruvate carboxykinase were also increased significantly in diazinon-treated animals. The level of lactate was increased in brain and blood, whereas that of pyruvate was not changed. The activity of glucose-6-phosphate dehydrogenase was not changed significantly. The cholesterol and ascorbic acid contents of adrenals were depleted in diazinon-treated animals. The hyperglycemia and changes in carbohydrate metabolism were abolished by adrenalectomy, suggesting the possible involvement of the adrenals in the induced changes in diazinon-treated animals.
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PMID:Modification of diazinon-induced changes in carbohydrate metabolism by adrenalectomy in rats. 234 75


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