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

---

Query: EC:2.7.1.1 (hexokinase)
5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
...
PMID:Energy metabolism of the contagious equine metritis bacterium. 708 71

A method for the determination of glucose is described. H2O2, produced by the action of glucose oxidase, is measured from the change in absorbance due to oxidation of NAD(P)H in the presence of catalase, aldehyde dehydrogenase and a high concentration of ethanol. The quality data of the method are equivalent to those of the hexokinase-glucose-6-phosphate dehydrogenase method used as reference.
...
PMID:A new enzymatic method for the determination of glucose. 728 78

From poly(vinyl alcohol) precursors, various reactive carriers for the immobilization of enzymes were synthesized. As insoluble starting polymers, the following products were used: poly(vinyl alcohol), gels crosslinked with terephthalaldehyde, hydrolyzed beads of crosslinked poly(vinyl acetate), poly(vinyl acetate-co- ethylene) tubes coated with poly(vinyl alcohol), and poly(vinyl alcohol)-containing synthetic pulp. Reactive groups introduced into these carriers or methods for their activation included the diazonium- and isothiocyanato group, and the glutardialdehyde-, BrCN, 2, 4, 6-trichloro-s-triazien, and p-benzoquinone methods. Furthermore, SH-specific reactive groups such as N-substituted maleimide groups or activated mixed disulfides with 2-thiopyridyl groups could be introduced into PVA-polymers. Enzymes like hydrolases (e.g. papain, trypsin, chymotrypsin, urease), oxidoreductases (e.g. glucose oxydase, catalase, glucose-6-phosphate dehydrogenase) as well as the example of transferase hexokinase coimmobilized with glucose-6-phosphate dehydrogenase, were immobilized by reactive poly(vinyl alcohol) carriers. The properties of the immobilized enzymes were investigated.
...
PMID:Some new reactive polymers for the immobilization of enzymes. 741 95

Beagle serum proteins were separated by polyacrylamide gel electrophoresis (PAGE) and the electrophoretograms were examined by one- and two-dimensional analyses with a laser densitometer. In order from the anodic side of the PAGE pattern, pre-albumin, hexokinase, tyrosinase, alkaline phosphatase, urease, and aldehyde dehydrogenase were assumed to be present based on Rf and Mw. Serum albumin, lactate dehydrogenase, and catalase appeared to be present based on a comparison of their electrophoretic mobility with that of protein standards of known Mw. Verification of beagle serum protein fractions by immunofixation electrophoresis and western blotting electrophoresis, with rabbit anti-human serum, indicated alpha 1-antitrypsin, albumin, haptoglobin, ceruloplasmin, C3c complement, IgG, and IgA. Serum protein fraction values (%) obtained by one- and two-dimensional analyses were similar.
...
PMID:Analysis of a polyacrylamide gel electrophoretogram of beagle serum protein by laser densitometer. 765 Sep 2

Sudden episodes of massive hemolysis have become the most common cause of death among captive black rhinoceroses, and there is evidence that they occur in the wild as well. We have observed radically unique enzyme and metabolite profiles in normal rhinoceros erythrocytes compared to humans and other mammals, including marked deficiencies of intracellular adenosine triphosphate (ATP), catalase, adenosine deaminase, and other enzymes involved in glycolysis, glutathione cycling, and nucleotide metabolism. Minimal concentrations of ATP appear to impair effective acceleration of hexosemonophosphate shunt activity in response to oxidants by restricting substrate generation at the hexokinase step. Antioxidant defenses are further compromised by catalase deficiency, which may be a general characteristic of rhinoceros erythrocytes, perhaps related to the common occurrence of severe mucocutaneous ulcerative disease. It is proposed that erythrocyte ATP deficiency in rhinoceroses may be an evolutionary adaptation conferring selective advantage against common hemic parasites, comparable to the role of human glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in falciparum malaria.
...
PMID:Acute episodic hemolysis in the African black rhinoceros as an analogue of human glucose-6-phosphate dehydrogenase deficiency. 841 95

The purpose of this research was to evaluate the effect of age on protective antioxidant enzyme activity of normal fresh cadaver human retina of the macula and periphery. Antioxidant enzymes were assayed in tissue extracts generated from 5 mm trephined punches of retina obtained centered over the macula and the superior midperiphery of normal fresh human cadaver retina. Cadaver tissue was obtained from donors of a wide age range (age 7 to 85 years). The assays were performed within 6 h of enucleation and within 24 h of donor death. Antioxidant enzymes assayed included superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase. Hexokinase and glucose-6-phosphate dehydrogenase, enzymes not directly involved in protection against oxidative damage, were assayed for comparison. Enzyme specific activities were calculated for the macula and periphery using protein concentration of the extract as the denominator. Using linear regression analysis, over the age range of 25 to 75 years, superoxide dismutase activity of the periphery but not the macula tended to decline with age (p = 0.04, R2 = 0.21). Interindividual variability was high, and variability increased with age. The difference between the macular and peripheral enzyme activities for glutathione peroxidase tended to decline with increasing donor age (p = 0.025, R2 = 0.33). There was no effect of age on the specific activities of catalase, glucose-6-phosphate dehydrogenase, and glutathione reductase. The specific activity of hexokinase from the macula declined with increasing donor age (p = 0.022, R2 = 0.43). Time from death to enucleation or beginning of experiment was not a significant factor. In summary, age does not have an effect on the activity of major antioxidant enzymes of the macula in normal human retina. There is a tendency for an effect of age on peripheral superoxide dismutase activity and the difference between macular and peripheral glutathione peroxidase activity. High interindividual variability of antioxidant enzyme activity exists in humans.
...
PMID:Antioxidant enzymes of the human retina: effect of age on enzyme activity of macula and periphery. 865 7

Experimentally induced diabetic rats were treated separately with insulin and vanadate. The activities of hexokinase (HK) and glucose-6-phosphate dehydrogenase (G-6PDH) were increased in reticulocyte hemolysate isolated from the diabetic rats and were restored to normal levels by insulin. The restoration was not detected in vanadate treated diabetic animals. The enzymes of glutathione metabolism namely glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-s-transferase (GST) exhibited increases in their activities with diabetes and were restored to almost control values by insulin treatment. Vanadate given to diabetic animals further increased GPx, and GST. The level of superoxide dismutase(SOD) decreased in the reticulocytes of diabetic rats and catalase (CAT) was unchanged. Both CAT and SOD had normal values when the diabetic rats were treated with insulin and vanadate. It is proposed that vanadate may cause an increase in the activity of GR which may stimulate glucose transporters and glucose metabolism.
...
PMID:Hexokinase, glucose-6-phosphate dehydrogenase and antioxidant enzymes in diabetic reticulocytes: effects of insulin and vanadate. 989 47

Whole cell lysates of pathogenic and nonpathogenic strains of Cryptobia salmositica were subjected to subcellular fractionation using differential and isopycnic centrifugation in sucrose. The glycolytic enzymes hexokinase, fructose-1,6-biphosphate aldolase, triosephosphate isomerase, glucosephosphate isomerase and glyceraldehyde-3-phosphate-dehydrogenase and the peroxisomal enzyme catalase were associated with a microbody that had a buoyant density in sucrose of 1.21 g cm-3. Lactate dehydrogenase was detected in whole cell lysates, but not in purified organelles. A microbody with a positive reaction for catalase was detected in electron microscope sections of the pathogenic and nonpathogenic strains. These catalase-containing microbodies fused with lipid bodies and vacuoles, arose by division from pre-existing microbodies and expelled their contents into the cytoplasm of the cell. Both strains also modified the catalase content in their microbodies. Under aerobic conditions, they metabolized glucose to pyruvate and lactate. We conclude that part of the glycolytic pathway in C. salmositica is compartmentalized in a microbody called the glycosome.
...
PMID:Identification of glycosomes and metabolic end products in pathogenic and nonpathogenic strains of Cryptobia salmositica (Kinetoplastida: Bodonidae). 1098 44

Two glucose-phosphorylating enzymes, a hexokinase phosphorylating both glucose and fructose, and a glucose-specific glucokinase were electrophoretically separated in the methylotrophic yeast Hansenula polymorpha. Hexokinase-negative, glucokinase-negative and double kinase-negative mutants were isolated in H. polymorpha by using mutagenesis, selection and genetic crosses. Regulation of synthesis of the sugar-repressed alcohol oxidase, catalase and maltase was studied in different hexose kinase mutants. In the wild type and in mutants possessing either hexokinase or glucokinase, glucose repressed the synthesis of maltase, alcohol oxidase and catalase. Glucose repression of alcohol oxidase and catalase was abolished in mutants lacking both glucose-phosphorylating enzymes (i.e. in double kinase-negative mutants). Thus, glucose repression in H. polymorpha cells requires a glucose-phosphorylating enzyme, either hexokinase or glucokinase. The presence of fructose-phosphorylating hexokinase in the cell was specifically needed for fructose repression of alcohol oxidase, catalase and maltase. Hence, glucose or fructose has to be phosphorylated in order to cause repression of the synthesis of these enzymes in H. polymorpha suggesting that sugar repression in this yeast therefore relies on the catalytic activity of hexose kinases.
...
PMID:Sugar repression in the methylotrophic yeast Hansenula polymorpha studied by using hexokinase-negative, glucokinase-negative and double kinase-negative mutants. 1150 18

We previously showed that, unlike other yeasts, Hansenula polymorpha possesses a glucokinase HPGLK1 that can mediate glucose repression in this yeast, although it cannot replace the regulatory function of hexokinase 2 in Saccharomyces cerevisiae. In the present study, the H. polymorpha hexokinase gene HPHXK1 was cloned by complementation of the glucose growth deficiency of the H. polymorpha double kinase-negative mutant A31-10 with a genomic library. The sequence of the 483-amino acid hexokinase protein deduced from the HPHXK1 gene showed the highest degree of identity (56%) with hexokinase from Schwanniomyces occidentalis, whereas the identity with hexokinase from Kluyveromyces lactis and both hexokinases from Sac. cerevisiae was 55%. The hexokinase protein was purified from crude extracts of H. polymorpha, using ion exchange chromatography and gel filtration. The K(m) values of the purified enzyme for glucose, fructose and ATP were 0.26 mM, 1.1 mM and 0.32 mM, respectively. H. polymorpha hexokinase was inhibited by trehalose-6-phosphate ( K(i)=12 microM) and ADP ( K(i)=1.6 mM), but not by glucose-6-phosphate. Transformation of a H. polymorpha hexokinase-negative mutant with a plasmid carrying the HPHXK1 gene restored the ability of the mutant to phosphorylate fructose and to repress the synthesis of alcohol oxidase and catalase by fructose. Therefore, hexokinase is specifically needed for the establishment of fructose repression in H. polymorpha.
...
PMID:Cloning and biochemical characterization of hexokinase from the methylotrophic yeast Hansenula polymorpha. 1453 Aug 68


<< Previous 1 2 3 4 5 6 Next >>

---