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

We have shown different enzymatic activities responsible for the phosphorylation of glucose in pig erythrocytes. These activities were observed after partial purification from hemolyzed red cells. One of the enzymes involved is the hexokinase which is present in all tissues; the other is similar to hepatic glucokinase. We have determined the kinetic properties of these activities in hemolysates and in partially purified preparations. Their electrophoretic-migration characteristics were studied too.
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PMID:Glucokinase and hexokinase in pig erythrocytes. 2 45

The aluminum present as a contaminant in ATP preparations can cause strong inhibition of yeast hexokinase P-II activity at pH 7.0 or below but has little or no inhibitory effect at a pH of 7.5 or greater. The inhibition is reversed by citrate, 3-phosphoglycerate, malate, phosphate, and catecholamines, all of which have previously been described as activators of hexokinase at low pH. We suggest that these agents activate the enzyme only by virtue of their ability to coordinate with aluminum present in the assay system. The presence of aluminum is also responsible for the "negative cooperativity" observed at low pH with respect to Mg . ATP concentration--i.e., the inhibition by aluminum is uncompetitive at low Mg . ATP concentrations but becomes competitive at high Mg . ATP concentrations. The inhibition is thought to be due to formation of a complex of Al . ATP with the enzyme, with a dissociation constant (Ki) of 0.1 microM. Yeast hexokinase P-I is somewhat less sensitive to A1 than is hexokinase P-II, and yeast glucokinase is not detectably affected. The hexokinase in rat brain (type I) shows a pH-dependent inhibition by Al similar to that observed with the yeast hexokinases, whereas the rat muscle (type II) enzyme is less sensitive, suggesting a possible relationship to aluminum encephalopathy in man.
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PMID:Proton-dependent inhibition of yeast and brain hexokinases by aluminum in ATP preparations. 11 25

The regularities for changes were established in activity of hexokinase, glucokinase, glucosephosphate-isomerase, phosphofructokinase and glucose-6-phosphate dehydrogenaseduring the early development of loach (Misgurnus fossilis). It was found that a 30-minute incubation of fertilized loach eggs in the lactate or fumarate solutions decreases the glucokinase activity in the embryos of 3, 6, 9, 12, 15, 18 and 24 hours of their development, while the inhibitory effect of glucose on the enzyme activity is pronounced only after 18 and 24 hours of the development. A significant increase in the hexokinase and glucose-6-phosphate dehydrogenase activities under the above-mentioned conditions is observed only under the effect of glucose 9 and 6 and 9 hours, respectively, after fertilization. The glucose phosphate isomerase and phosphofructokinase activites under the effect of used compounds undergo no changes during the primary stages of embryogenesis.
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PMID:[Enzymes of glycolysis and pentosephosphate shunt during early embryogenesis of the loach and the effect of glucose, lactate and fumarate on fertilized oocytes]. 12 65

The activity of carbohydrate metabolism certain enzymes [hexokinase (EC 2.7.1.1.), glucokinase (EC 2.7.1.2), phosphofructokinase (EC 2.7.1.11.1), glucoso-6-phosphate-dehydrogenase (EC 1.1.1.49.)] was studied in the sheep skin when adding vitamin A, sodium sulphate and insulin to the basic ration. The activity of the studied enzymes in the skin was established to be rather high and depend to a considerable extent on feeding, seasonal and hormonal factors. In summer the activity of such enzymes as glucoso-6-phosphate-dehydrogenase and glucokinase decreases, and that of hexokinase, vice versa, increases. Vitamin A alone against a background of the basic ration almost has no effect on the activity of the enzymes, with the exception of phosphofructokinase in certain periods of the experiment. More noticeable shifts in the activity of the enzymes were observed in the case when vitamin A and sodium sulphate were added to the ration of sheep, and also with the injection of insulin. In such cases in the sheep skin there occurs first of all an increase in the activity of glucokinase and glucoso-6-phosphate-dehydrogenase.
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PMID:[Activity of some carbohydrate-metabolizing enzymes in sheep skin]. 13 Jul 4

1. Cataract formation in streptozotocin-induced diabetes in rats was reduced by approximately 85% when a diet rich in maize oil (300 g/kg diet) (fat diet) was given, thus confirming results of earlier studies. However, the concentration of sorbitol in the lens of diabetic animals remained high, the values for diabetic rats given the standard diet and the fat died being 65 and 40 mumol/g protein respectively. 2. With the standard diet, the fatty acid profile of the triglycerides of the epididymal fat pads was characterized by a greater relative proportion of saturated fatty acids for the diabetic animals compared to that for the normal animals. The fat diet moderated the tendency towards saturation in the diabetic animals. 3. The fat diet had other effects on the diabetic animals; these included a reduced mortality rate, increased body-weight, a decrease in the daily water intake, and in the daily urinary excretion of glucose and urea. 4. In the diabetic animals the fat diet had no effect on the specific activities in the liver of hexokinase (EC 2.7.1.1), glucokinase (EC 2.7.1.2), phosphofructokinase (EC 2.7.1.11) and pyruvate kinase (EC 2.7.1.40). However, the specific activity of glucose-6-phosphatase (EC 3.1.3.9) was reduced, while that of malate dehydrogenase (decarboxylating) (NADP) (EC 1.1.1.40) was increased. The NAD+:NADH ratio, as calculated from liver pyruvate and lactate concentrations, tended to increase. 5. The results suggested that the fat diet moderated the long-term metabolic effects of diabetes.
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PMID:The effect of an unsaturated-fat diet on cataract formation in streptozotocin-induced diabetic rats. 13 11

The characteristics of the glycolytic pathway and the plasma membrane of Lactobacillus and Bifidobacterium were studied. The enzyme system of glycolysis (hexokinase, glucokinase and pyruvate kinase) which is the main source of energy in the anaerobic condition was localized in the cell soluble fraction (cytoplasma) of all species examined. Neither electron transfer chain components nor oxidase activities were found in anaerobically cultured Lactobacillus and Bifidobacterium. Adenosine triphosphatase (ATPase) activities were mainly localized in the plasma membrane, suggesting that membrane ATPase is playing a key role in membrane transport and ATP synthesis of anaerobic bacilla. SDS-polyacrylamide gel electrophoresis of membranes showed remarkable differences between the polypeptides patterns of B. adolescentis and B. bifidum. Such peculiarities in polypeptide patterns among the same genus may be useful in the identification of species.
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PMID:Characterization of the glycolysis pathway and the plasma membrane of Lactobacillus and Bifidobacterium strains. 13 31

The influence of clofibrate on the glycolytic pathway in liver was studied. The changes in the activity of glucokinase and hexokinase were not significant. A reduction of phosphofructokinase (p less than 0.05) and pyruvate kinase activity was found (p less than 0.0005) during clofibrate feeding. An in vitro inhibition of these enzymes could not be demonstrated by clofibrate up to a concentration of 2.5 mM. Crossover plots of glycolytic intermediates indicate that the reduced pyruvate kinase activity may influence the glycolytic pathway in vivo. Clofibrate feeding induces a lower ATP:ADP ratio, a lower adenylate energy charge and elevates AMP levels in rat liver. This may possibly stimulate the hepatic glycogenolysis and the glucose utilisation by this organ.
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PMID:Alterations of the glycolytic pathway and adenine nucleotide state in livers of clofibrate treated rats. 14 Aug 42

Hexokinase, glucokinase, and phosphofructokinase activity in supernatant hepatic fluid obtained by centrifugation of the homogenate at 20,000 g for 20 minutes was studied during the development of experimental necrosis of the heart muscle. The activity of these enzymes was lowest in the 12th and 24th hour following arterial occlusion. Phosphofructokinase and glucokinase activity returned to the initial level on the 6th and 9th days, respectively; hexokinase activity was still diminished after the 12th day.
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PMID:[Activity of key enzymes of glycolysis in the rat liver during the development of experimental myocardial necrosis]. 14 17

Vitamin A toxicity, caused by oral administration of 30,000 IU of vitamin A (retinyl palmitate) to young rats (70 to 90 g) once daily for 2 days, increased the levels of lipids, glycogen, and citrate in the liver. Furthermore, hypervitaminosis A decreased the activities of two key hepatic glycolytic enzymes, phosphofructokinase, and pyruvate kinase, without affecting those of hexokinase and glucokinase. It is suggested, therefore, that in addition to the increased activities of key gluconeogenic enzymes, reported earlier, a marked decrease in the activities of phosphofructokinase and pyruvate kinase and elevated level of citrate in the liver could account for the enhanced gluconeogenesis in hypervitaminosis A.
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PMID:Early effects of vitamin A toxicity on hepatic glycolysis in rat. 15 4

Activities of hexokinase isozymes in carbon tetrachloride (CCl(4))-injured rat liver were determined quantitatively by DEAE-cellulose column chromatography and compared with those of regenerating liver, fetal liver and ascites hepatoma cells (AH 130). The CCl(4)-injured liver revealed an isozyme distribution with predominant Types I, II and III (3.2, 8.8 and 6.8 times higher than the control values, respectively) and with undetectable activity of Type IV hexokinase (glucokinase). Although the isozyme pattern generally resembled that of fetal liver or hepatoma cells, the relatively high activity of hexokinase Type III in CCl(4) treatment characterizes the pattern of hexokinase isozyme in acue liver damage.
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PMID:Hexokinase isozyme pattern in CCl(4)-injured rat liver. 16 18


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