Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Rabbit red blood cell hexokinase (EC 2.7.1.1.) has been purified 300,000-fold by a combination of ion exchange chromatography, affinity chromatography, and preparative polyacrylamide gel electrophoresis. The hexokinase activity has been isolated in 35% yield as a protein that is homogeneous by polyacrylamide and sodium dodecyl sulfate gel electrophoresis. The highest specific activity obtained was 145 units/mg of proteins. The native protein has a molecular weight of 110,000 by gel filtration on Ultrogel AcA 44 and 112,000 by sedimentation velocity on sucrose density gradients. Sodium dodecyl sulfate-polyacrylamide gels gave a molecular weight of 110,000 indicating that hexokinase is a monomer. The enzyme had a pI of 6.20 to 6.30 pH units by isoelectric focusing. The enzyme was specific for Mg . ATP and Mg . ITP as the nucleotide substrates. Several hexokinase with different affinities.
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PMID:Rabbit red blood cell hexokinase. Purification and properties. 735 51

Endosulfan-induced changes in blood glucose, plasma electrolytes, and blood and brain ascorbic acid, hexokinase and glutathione have been investigated following acute and subacute administration in 12 h fasted male rats. After a single oral dose of endosulfan (40 mg/kg) a significant increase in blood glucose, blood ascorbic acid, and blood and brain glutathione was observed. The maximum increase in blood was observed at 2 h (36%). Increase in blood and brain glutathione was highly significant at 4 h (50 and 43%, respectively). The blood ascorbic acid slowly increased by 19% over control during the treatment period. No significant change in brain hexokinase was observed. Repeated oral administration of endosulfan (0.625 to 20 mg/kg) for 7 weeks had no effect on plasma sodium and potassium. At the highest dose (20 mg/kg), blood glucose was slightly increased (16%). Plasma Ca was significantly decreased, the maximum fall (35%) being observed at 4 h.
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PMID:Endosulfan intoxication: Blood glucose, electrolytes, Ca levels, ascsorbic acid and glutathione in rats. 746 37

This study determined how selected functional, metabolic, and contractile properties were impacted by sodium pivalate, a compound which creates a secondary carnitine deficiency. Young male rats received either sodium pivalate (20 mM, PIV) or sodium bicarbonate (20 mM, CONTR) in their drinking water. After 11-12 weeks cardiac function and glucose oxidation rates were measured in isolated, perfused working heart preparations. Hearts were also analyzed for carnitine content, activities of hexokinase (HK), citrate synthase (CS), and B-hydroxyacyl CoA dehydrogenase (HOAD), and myosin isoenzyme distribution. Sodium pivalate treatment significantly reduced cardiac carnitine content and increased glucose oxidation but did not alter cardiac functional capacity. HK activity was increased in the PIV group (p < 0.05), and HOAD activity decreased (p < 0.05). CS activity and myosin isoform distribution (VI > 85%) remained unchanged. These results demonstrate that pivalate treatment of this duration and the accompanying carnitine deficiency shift cardiac substrate utilization without compromising cardiac functional capacity.
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PMID:Sodium pivalate reduces cardiac carnitine content and increases glucose oxidation without affecting cardiac functional capacity. 747 77

Mouse sperm contain a major phosphotyrosine-containing protein of M(r) 95,000 (nonreducing conditions) which has been implicated as a sperm membrane receptor for the egg zona pellucida glycoprotein, ZP3 (Leyton, L., and Saling, P. (1989) Cell 57, 1123-1130; Leyton, L., LeGuen, P., Bunch, D., and Saling, P. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 11692-11695). This protein was purified and subjected to limited tryptic digestion and subsequent amino acid analysis. Three sequenced peptides revealed 100% amino acid identity to a mouse hepatoma hexokinase (Arora, K. K., Fanciulli, M., and Pederson, P. L. (1990) J. Biol. Chem. 265, 6481-6488). The purified protein, which migrated at M(r) 116,000 under reducing conditions (p95/116), reacted with an antiserum to the purified rat brain hexokinase, type 1, and comigrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with the purified rat brain enzyme under both nonreducing and reducing conditions. Unlike p95/116, the rat brain enzyme was not a phosphotyrosine-containing protein. The p95/116 protein could be immunoprecipitated with the hexokinase antiserum or an O-phosphotyrosine antibody. Limited tryptic digestion of the purified p95/116 and the rat brain enzyme generated subsets of identical peptides which reacted with the hexokinase antiserum. However, p95/116 also contained phosphotyrosine-containing peptides that were not present in the rat brain hexokinase. When different mouse tissues were probed with the hexokinase antiserum all tissues, with the exception of liver, contained immunoreactive protein. In contrast, only sperm and testis possessed a phosphotyrosine-containing form of hexokinase. These data suggest that the germ cell component of the testis possesses a unique tyrosine-phosphorylated form of hexokinase.
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PMID:p95, the major phosphotyrosine-containing protein in mouse spermatozoa, is a hexokinase with unique properties. 750 20

The concentrations of lactose, glucose, glucose 6-phosphate, glucose 1-phosphate, UDPglucose, UDPgalactose, UDP, UMP, inorganic phosphate, ADP and AMP (metabolites involved in the lactose synthesis pathway), and cAMP, galactose and sodium were measured in the mammary secretion from four or five mammary glands on each of six sows during the first 5 d post weaning. The concentrations of lactose, glucose and galactose were also measured in plasma during this time. Following weaning, the rapid increase in the concentrations of glucose 6-phosphate and UDPgalactose suggested that the rate of lactose synthesis was regulated by the inhibition of hexokinase and/or lactose synthase, while the decrease in glucose and AMP indicated a subsequent decline in glucose and ATP utilization. The rapid increase in glucose 6-phosphate which plays a pivotal role as a substrate for both lactose and de novo fatty acid synthesis, and the rapid decrease in AMP which reflects ATP utilization, were good markers of decreased metabolic activity. These rapid changes in the metabolic activity of the mammary glands were not observed in a second weaning study when two piglets were removed from selected mammary glands for periods up to 5 h during established lactation. Since concentrations of lactogenic hormones remain elevated following partial weaning, but fall following total weaning (Rojkittikhun et al. 1991), these differences in mammary gland metabolism indicate that endocrine rather than autocrine mechanisms are controlling lactose and fat synthesis during the initial stages of total weaning.
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PMID:Assessment of mammary gland metabolism in the sow. III. Cellular metabolites in the mammary secretion and plasma following weaning. 760 70

The effect of DL alpha-lipoic acid on the nephrotoxic potential of gentamicin was examined. Intraperitoneal injection of gentamicin (100 mg/kg/day) to rats resulted in decreased activity of the glycolytic enzymes-hexokinase, phosphoglucoisomerase, aldolase and lactate dehydrogenase. The two gluconeogenic enzymes--glucose-6-phosphatase and fructose-1,6-diphosphatase, the transmembrane enzymes namely the Na+, K(+)-ATPase, Ca(2+)-ATPase, Mg(2+)-ATPase and the brushborder enzyme alkaline phosphatase, also showed decreased activities. This decrease in the activities of ATPases and alkaline phosphatase suggests basolateral and brush border membrane damage. Decreased activity of the TCA cycle enzymes isocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH) and malate dehydrogenase (MDH), suggests a loss in mitochondrial integrity. These biochemical disturbances were effectively counteracted by lipoic acid administration. Lipoic acid administration by gastric intubation at two different concentrations (10 mg and 25 mg/kg/day) brought about an increase in the activity of the glycolytic enzymes, ATPases and the TCA cycle enzymes. The gluconeogenic enzymes however showed a further decrease in their activities at both the concentrations of lipoic acid administered. These observations shed light on the nephroprotective action of lipoic acid against experimental aminoglycoside toxicity and the protection afforded at 25 mg/kg/day of lipoic acid was noted to be higher than that at 10 mg level.
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PMID:Role of DL alpha-lipoic acid in gentamicin induced nephrotoxicity. 765 73

Hypoxia effect on the nuclear of the Scorpaena porcus (L.) in vivo was studied. It was shown, that existence of the fishes in environmental with low oxygen concentration-1.3-1.4 mg.1-1 (15% initial saturation) resulted in reducing in activities of Na+, K(+)-ATPase, hexokinase and glucose-6-phosphate dehydrogenase in the erythrocyte for 50.0 (p < 0.001), 26.5% (p < 0.01) and 53.7% (p < 0.05) accordingly. ATP concentration in cells and membrane gradient of Na+, K+ concentrations between blood serum and intracellular environment did not change. A conclusion was made about a decrease of cells membrane penetration and oppression of intracellular metabolism. These changes proceeded on a background of the blood serum dehydration and decrease of the mean volume of erythrocytes. The part of aldosteron and vasopressin in membrane penetration of nuclear erythrocytes is discussed.
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PMID:[Effect of hypoxia on biochemical parameters of Scorpaena erythrocytes]. 774 38

N-Acetyl-D-[2-3H]glucosamine was synthesized from N-acetyl-D-mannosamine by alkaline 2-epimerization in pyridine containing 3H2O and nickelous acetate. The reaction involves reversible formation of an enol intermediate and therefore also resulted in incorporation of tritium into N-acetylmannosamine. After completed reaction, the two N-acetylhexosamines were separated from other radioactive products and Morgan-Elson chromogens by chromatography on a column of Sephadex G-10, which was eluted with 10% ethanol, and were then separated from each other by chromatography on Sephadex G-15 in 0.27 M sodium borate (pH 7.8). The location of the incorporated tritium was established by treatment of the N-acetylhexosamines with borate under the conditions of the Morgan-Elson reaction, which converts the sugars to Kuhn's chromogen I with concomitant loss of the C-2 hydrogen. As expected, this treatment resulted in the formation of 3H2O, indicating that the tritium was located at C-2. [2-3H]Glucosamine was prepared by acid hydrolysis of the labelled N-acetylglucosamine and was converted to [2-3H]glucosamine 6-phosphate by incubation with hexokinase and ATP. The sugar phosphate was used as a substrate for glucosamine 6-phosphate deaminase (isomerase, EC 5.3.1.10) in a simple 3H2O release assay.
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PMID:Tritium labelling of amino sugars at C-2 by alkaline epimerization in tritiated water. 778 Jan 91

A variety of stressful conditions, such as heat shock, ethanol, osmotic shock, glucose deprivation, and oxidative stress, are known to induce the synthesis of specific proteins. Here, we report the induction in Escherichia coli of a protein elicited in response to a hitherto unidentified stress condition, i.e., the overexpression of foreign proteins. The induced protein identified as glucokinase (EC 2.7.1.2) is produced at a level > or = 20-fold higher than the level in wild-type E. coli when foreign proteins are expressed under the control of the alkaline phosphatase (phoA) promoter. The bacterial glucokinase is shown to have a mass of approximately 47 kDa determined by a "renaturation activity stain assay" in situ following sodium dodecyl sulfate-poly-acrylamide gel electrophoresis and exhibits a high specificity for the phosphorylation of glucose. The apparent Km values for glucose and ATP for the enzyme are 0.15 and 0.50 mM, respectively, indicating that the E. coli enzyme is a low Km glucose hexokinase. The enzyme cross-reacts with rabbit antisera raised against hexokinase from higher eukaryotes, implicating some sequence similarity with mammalian hexokinases. Under normal conditions, E. coli glucokinase plays a minor role in glucose metabolism. However, under anabolic stress conditions, this glycolytic enzyme may be required to supplement levels of glucose 6-phosphate. Alternatively, glucokinase, which is predicted in analogy to other hexose-utilizing kinases to have structural folds characteristic of hsp 70, may itself, or in combination with other E. coli proteins, function in the stabilization of newly synthesized proteins.
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PMID:Glucokinase of Escherichia coli: induction in response to the stress of overexpressing foreign proteins. 778 44

Sodium butyrate is widely used to differentiate insulinoma cell lines. However, sodium has been shown to decrease glucose phosphorylation in the liver and heart and decrease the expression of glucose transporter. Since these mechanisms are essential for glucose-induced insulin secretion, the ultimate function of the pancreatic beta-cell, we investigated the effect of sodium butyrate on both glucose-phosphorylating enzymes as well as glucose transport in the pancreatic cell line RIN-m5F. Treatment of RIN-m5F cells with 2.5 mM sodium butyrate for 72 h increased by twofold both hexokinase and glucokinase (GK) activities, as well as the gene expression of GK. Sodium butyrate treatment had no effect on GLUT-1 mRNA levels but increased the GLUT-2 mRNA 3.7-fold. Kinetic analysis of 2-deoxyglucose transport displayed a single curve with Km = 1.2 mM and Vmax = 10.9 pmol/micrograms protein/min in the untreated cells, values similar to the low Km glucose transport reported in the pancreatic beta-cells. This low Km transport component markedly decreased with sodium butyrate treatment, and interestingly a second component with a higher Km appeared, consistent with the increase in GLUT-2 mRNA. We conclude that the differentiating action of sodium butyrate involves increases in GK and GLUT-2 gene expression, which characterizes the differentiated state of the pancreatic beta-cell. However, the inhibitory effect of sodium butyrate on low Km glucose transport needs to be considered in the use of this compound to promote differentiation.
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PMID:Effect of sodium butyrate on glucose transport and glucose-phosphorylating enzymes in RIN-m5F cells. 830 95


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