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)

The effect of tris-(2-chloroethyl)-amine (HN-3) on RNA and DNA was investigated spectrophotometrically. The shift in the absorbance spectrum caused by the addition of HN-3 was used to test a variety of compounds for their ability to inhibit RNA alkylation. The effect of HN-3 on the activity of several enzymes was also investigated. The activities of ribonuclease A, desoxyribonuclease I, acetylcholinesterase, diaphorase, glutathione reductase, adenosine desaminase, glyoxalase I, 3-hydroxyacyl-CoA-dehydrogenase, xanthine oxidase, glucose-6-phosphate dehydrogenase, hexokinase and the microsomal N-oxygenation of aniline were not changed by HN-3, whereas the activity of cytochrome-c-reductase exhibited a dose dependent diminution in the presence HN-3. Of 105 compounds tested only 14, namely, sodium thiosulfate, dithioxanthine, thiosalicylic acid, 1,2,4-triazole-5-thiol, 2-thiocytosine, 2-thiohistadine, 2,3-dithiosuccinic acid, thioglycolic acid, 3-mercapto-D-valine,6-amino-2-thiouracil, thionicotine amide, dithiothreitol, sodium sulfite, and ergothioneine prevented the alkylation of RNA. All of them also reacted with HN-3 in absence of RNA. No correlation was found between the reaction constant of the reaction compound:HN-3 in the absence of RNA and the concentration of the compound which inhibited RNA alkylation by 50%. The compounds which were effective in vitro were also tested in mice for their ability to reduce HN-3 toxicity in vivo. Only sodium thiosulfate, d-penicillamine, and dithiosuccinic acid were effective. A 3.9fold increase in the LD50 of HN-3 was achieved in mice treated with sodium thiosulfate 3330 mg/kg i.p., a 1.7fold with 2125 mg dithiosuccinic acid/kg, and a 2fold increase with 2500 mg/kg d-penicillamine. The compound tested was injected i.p. 0.5 to 1 min after the s.c. injection of HN-3.
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PMID:Effect of various compounds on the reaction of tris-(2-chloroethyl)amine with ribonucleic acid in vitro and on its toxicity in mice. 617 33

A sharp and strong suppression of protein synthesis by cycloheximide in liver cells of starving rats is paralleled with activation of RNA synthesis and glucose-6-phosphate dehydrogenase production. Subsequent reconstitution and stimulation of protein synthesis (6-12 hrs after cycloheximide injection) result in activation of hexokinase. Upon stimulation of DNA synthesis (48-60 hrs after cycloheximide injection) the activity of both enzymes is very low. Since glucose-6-phosphate dehydrogenase appears to be the limiting step of glucose decay via the pentose phosphate pathway, and hexokinase is the limiting step of glycolysis, it was assumed that RNA synthesis predominantly occurs via the pentose phosphate pathway, while that of proteins via glycolysis.
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PMID:[Correlation between the rate of protein and nucleic acid synthesis and the intensity of various glucose metabolic pathways in rat liver cells]. 620 Nov 97

Analysis of 71 strains of Neisseriaceae by starch-gel electrophoresis of hexokinase, phosphoglucomutase, glucose phosphate isomerase, and L-malate-nicotinamide adenine dinucleotide phosphate oxidoreductase showed that all gonococci and all memingococci have a characteristic hexokinase isoenzyme that is specific for each species and clearly distinguishes meningococci and gonococci from each other and from other species of Neisseriaceae. Strains of gonococci that were transformed into maltose utilizers by DNA from Neisseria lactamica and Neisseria meningitidis showed no change in the isoenzymes so that they could still be differentiated from meningococci and other Neisseriaceae by isoenzyme electrophoresis. In view of the limited sensitivity and specificity of conventional tests for the identification of gonococci and the possibility that gonococci may be transformed into maltose utilizers by DNA from normal throat flora, electrophoresis of hexokinase isoenzymes should be useful for the precise laboratory identification of the pathogenic neisseriae, especially those from atypical sites and those giving indeterminate reactions.
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PMID:Differentiation of neisseriaceae by isoenzyme electrophoresis. 621 68

Activities of key enzymes in hepatic glucose utilization were compared between obese (C57BL/6J ob/ob) mice, their lean controls and outbred Swiss albino mice in the fed condition and during fasting. As liver hyperplasia and hepatocyte hypertrophy were present in the ob/ob mice at 4-5 months of age and changes in hepatic cellularity did occur with fasting, enzyme activity was expressed on the basis of protein, DNA, and wet weight. In the fed state, activities of glucokinase + hexokinase (glucose phosphorylating capability), phosphofructokinase and pyruvate kinase were significantly greater in livers of ob/ob mice when compared to those of the lean control. Glucokinase + hexokinase activities in livers of ob/ob mice remained significantly higher throughout the 48 h fast yet the activities of hepatic phosphofructokinase and pyruvate kinase, when expressed per g wet wt or mg protein, decreased so that a statistical difference from the fasted lean control was no longer detected. When expressed per 100 g body weight, hepatic glucokinase + hexokinase as well as phosphofructokinase and pyruvate kinase activities in obese mice were higher both in the fed and fasted states when compared to lean controls in the comparable nutritional condition. This increased capacity of key enzyme activities in hepatic glucose utilization can be attributed to liver hyperplasia found in ob/ob mice in both the fed and fasted condition. While higher hepatic glucose phosphorylating capability was maintained during fasting, the elevated specific activities of hepatic phosphofructokinase and pyruvate kinase in the obese mouse in the fed state decreased with starvation to values found in the lean control.
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PMID:Enzyme activities of hepatic glucose utilization in the fed and fasting genetically obese mouse at 4-5 months of age. 624 16

The concentrations of ten or 12 enzymes involved in the metabolism of DNA, collagen, amino acids, or glucose have been determined in variants of human intestinal and pulmonary tissues. In comparison to nonneoplastic adult colon, normal fetal colon had elevated concentrations of thymidine kinase, peptidyl proline hydroxylase, phosphoserine phosphatase, ornithine transcarbamylase, gamma-glutamyl transpeptidase, and ornithine aminotransferase. Raised activities of the first five of these enzymes, and of hexokinase, glucose-6-phosphate dehydrogenase, and pyrroline-5-carboxylate reductase distinguishes neoplastic from nonneoplastic sections of adult colon. Study of a wide range of pulmonary specimens permitted comparisons of different types of tumors, and revealed some subtle differences between lungs of noncancer patients and nonneoplastic portions of host lungs. The concentrations of eight previously identified enzymic indicators were less in moderately or well differentiated than in poorly differentiated pulmonary adenocarcinomas. The latter differed from epidermoid carcinomas (also poorly differentiated) by containing lower concentrations of thymidine kinase (both soluble and particulate) and hexokinase.
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PMID:Enzyme activities in human fetal and neoplastic tissues. 625 48

The natures and roles of ligand-induced conformational changes are described in terms of the influence of the ligand on the equilibrium distribution of the protein structure among various conformational states. A very commonly observed conformational change is produced by a ligand binding into a cleft that lies between two domains and then closing the cleft through a hinge-like motion. Such a change in hexokinase serves to bring potential catalytic groups into the active site and to provide a binding site for the three phosphates of ATP. Flexibility in gene regulatory proteins such as the Escherichia coli catabolite activator protein and lac repressor may be important in the dual requirement for rapid diffusion of the proteins along the DNA as well as specific recognition of base sequences. A second role for flexibility in this class of proteins is to reduce their affinity for affinity for DNA, without reducing their capacity to discriminate among sequences.
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PMID:Ligand-induced conformational changes in proteins. 630 81

Carbon catabolite repression in yeast depends on catalytic active hexokinase isoenzyme PII ( Entian 1980a ). A yeast strain lacking hexokinase isoenzymes PI and PII was transformed, using a recombinant pool with inserts of yeast nuclear DNA up to 10 kbp in length. One hundred transformants for hexokinase were obtained. All selected plasmids coded for hexokinase isoenzyme PII, none for hexokinase isoenzyme PI, and carbon catabolite repression was restored in the transformants. Thirty-five independently isolated stable plasmids were investigated further. Analysis with the restriction enzyme EcoRI showed that these plasmids fell into two classes with different restriction behaviour. One representative of each class was amplified in Escherichia coli and transferred back into the yeast hexokinase-deficient strain with concomitant complementation of the nuclear mutation. The two types of insert were analysed in detail with 16 restriction enzymes, having 0-3 cleavage sites on transformant vector YRp7 . The plasmids differed from each other by the orientation of the yeast insert in the vector. After yeast transformation with fragments of one plasmid the hexokinase PII gene was localised within a region of 1.65 kbp.
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PMID:Cloning and restriction analysis of the hexokinase PII gene of the yeast Saccharomyces cerevisiae. 632 10

Genes complementing the glucose-negative fructose-negative Saccharomyces cerevisiae triple mutant strain (hxkl hxk2 glk1), which lacks hexokinase PI, hexokinase PII, and glucokinase, were obtained from a pool of yeast DNA in the multicopy plasmid YEp13.
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PMID:Cloning of genes that complement yeast hexokinase and glucokinase mutants. 634 51

Enzymatic glycogen regulation in mouse splenocytes cultured in vitro with and without LPS, was studied from 0-72 h. Increased [3H]glucose uptake and hexokinase activity demonstrated the activation of cells treated with LPS. There was a greater time-dependent increase of cellular glycogen content in LPS-stimulated cells as compared to control. Glycogen synthetase I in LPS-stimulated cells increased about 200% above control cells to a plateau at 48 h, while in unstimulated cells there was little increase throughout. Glycogen synthetase D increased continually to 72 h in both groups. In the stimulated cells, phosphorylase increased only 90% above control cells up to 48 h. It was concluded that the increased glycogen content of LPS-stimulated cells seen at 48 h may result from an increase in both glycogen synthetase I and D activity compared to lesser increase in hydrolysis. However, between 48 and 72 h, the period of RNA and DNA increased synthesis, the glycogen content of stimulated cells did not increase further, consistent with the observation that synthetase I activity remained constant and synthetase D decreased. Thus, following mitogenic stimulation, the net effect of the enzymatic regulation is to increase cellular glycogen, as an energy source for subsequent events.
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PMID:Glycogen regulation in LPS-stimulated murine splenocytes. 642 95

The radiobiological consequences of chronic exposure to 3H at a dose level of 37 kBq/ml or 1 muCi/ml is reported. An inbred strain of Swiss albino mice was exposed up to 5 generations. Metabolic disorders were recorded by monitoring quantitative and qualitative changes in hexokinase and its isozymes from brain, liver and spleen from both sexes. The delivered dose ranged from approximately 41 mGy to 98 mGy. Nonetheless, the changes in enzyme activities as well as electrophoretic mobilities were significant. Deviations from normal levels were recorded in both sexes. The evidence indicates that direct effects of beta-irradiation can cause conformational changes in enzyme molecules. However, damage to DNA and membranes as being causal factors for variations in the enzyme levels cannot be ruled out. These disorders culminated in a gradual reduction in litter size. The implications of exposure to this dose of tritiated water is discussed in the light of NCRP recommendations and relevant literature.
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PMID:Effects of tritiated water ingestion on mice: III. Hexokinase isozymes in brain, liver and spleen up to five generations. 661 23


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