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)

Enzymes of the Embden-Meyerhof-Parnas pathway and hexose monophosphate shunt were examined in cytoplasmic extracts of three serovars of Ureaplasma urealyticum. We found no glucose-6-phosphate or 6-phosphogluconate dehydrogenase, hexokinase, phosphoglucose isomerase, aldolase, or lactic dehydrogenase activities. We failed to find cytochrome pigments in extracts and found no significant production of 14CO2 from [U-14C]glucose, nor did we find oxygen-dependent reduced nicotinamide adenine dinucleotide oxidase activity. Lactic acid was found only at trace levels in spent culture fluids. Ureaplasmas are apparently nonfermentative and are unlike all other mollicutes in that they have no detectable oxygen-dependent reduced nicotinamide adenine dinucleotide oxidase activity.
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PMID:Metabolic distinctiveness of ureaplasmas. 379 29

The glycosomes of in vitro grown procyclic trypomastigote forms of Trypanosoma brucei were purified by three different procedures and the results compared by electron microscopy, enzyme assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Centrifugation on a self-forming Percoll gradient followed by a sucrose gradient centrifugation resulted in the least enriched glycosomal preparation. Centrifugation on a pre-formed Nycodenz gradient gave an improved preparation but the most homogeneous preparation of intact glycosomes was obtained after centrifugation on two successive sucrose gradients. Glycosomes purified by both the Nycodenz and double sucrose gradient procedures appeared larger than in situ glycosomes presumably due to an osmotic effect resulting from disruption of the granular matrix of the organelles. Nevertheless, there appears to be no loss of cisternal contents due to the swelling of the organelles. The glycosomes of the bloodstream form trypomastigotes purified by the same procedures show, however, no sign of swelling. A comparison of glycosomes purified from procyclic trypomastigotes and bloodstream form trypomastigotes prepared by the same double sucrose procedure demonstrated that in the glycosome of procyclic trypomastigotes: activities of hexokinase, phosphoglucose isomerase, phosphofructose kinase, aldolase and phosphoglycerate kinase and diminished by 80-100%; activities of glyceraldehyde-3-phosphate dehydrogenase, triose phosphate isomerase and glycerol-3-phosphate dehydrogenase remain unchanged or are only slightly reduced; there is an appearance of four major new proteins, among which could be phosphoenol pyruvate carboxykinase and malate dehydrogenase. These observations are in basic agreement with those by Hart et al. (Mol. Biochem. Parasitol. 12, 25-35, 1984).
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PMID:An improved purification of glycosomes from the procyclic trypomastigotes of Trypanosoma brucei. 380 43

Serum levels of phosphohexose isomerase (PHI), aldolase (ALD) and hexokinase (HK) activities have been determined in 76 patients of carcinoma cervix, in search of proper diagnostic and prognostic parameters. All the three glycolytic enzyme levels studied were found to be significantly elevated in all the groups of malignancy and showed a relation to the clinical stage and tumor. Serum PHI levels were of best diagnostic significance even at an early stage of the disease. The enzyme levels correlated well with the prognosis of the disease.
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PMID:Diagnostic and prognostic significance of serum phosphohexose isomerase, aldolase and hexokinase in carcinoma cervix. 381 45

Glucokinase (ATP:D-glucose 6-phosphotransferase, EC 2.7.1.1) plays a pivotal role in hepatic glucose metabolism and serves as the glucose sensor in pancreatic islet beta-cells. Biochemical studies of this enzyme are complicated by the cellular heterogeneity of the liver and the pancreas and because the presence of hexokinases (ATP:D-hexose 6-phosphotransferases, EC 2.7.1.1) seriously interferes with currently available analytical procedures. A radiometric assay was designed to deal with these problems. It is based on the liberation of 3H2O from D-[2-3H(N)]glucose 6-phosphate, the product of the glucokinase reaction, using exogenous phosphoglucose isomerase (D-glucose-6-phosphate ketol-isomerase, EC 5.3.1.9). Interference by hexokinases was largely eliminated by using glucose 6-phosphate as inhibitor and the sensitivity of the assay was greatly increased by using small volumes with the oil well procedure. The assay was sufficiently sensitive to detect about 1 pg of glucokinase. It thus allowed the application of quantitative histochemical procedures to the study of intralobular hepatic glucokinase profiles and the pancreatic beta-cell glucose sensor. The quantitative histochemical procedures were sufficiently sensitive and reliable for measuring important kinetic constants of glucokinase (i.e., the Km and the Hill number) in microscopic samples of tissue.
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PMID:Radiometric oil well assay for glucokinase in microscopic structures. 388 80

The longitudinal localization of nine enzymes of the carbohydrate metabolism was studied in rats fed standard or high fructose diets, two months after a reciprocal jejuno-ileal transposition. In the ileal segment transposed to jejunal location, an adaptive increase of mucosal mass was observed, but the functional characteristics of enterocytes remained the same in the case of triokinase, aldolase, triose phosphate isomerase, glucose-6-phosphate isomerase and glucose-6-phosphatase activities. In the case of ketohexokinase and hexokinase activities, the functional properties of cells tended to resemble that of jejunum, as revealed by a significant increase in the specific enzyme activity. In the jejunum transposed to the place of the ileum, the fundamental properties of enterocytes and the functional capacity of the gut were maintained except in the case of fructose-1.6-bis phosphatase and of glucose-6-phosphatase. The high fructose diet did not facilitate the re-establishment of the gradient in its normal, aboral, direction. Indeed except for glucose-6-phosphatase, the enzymes of the jejunum transposed to the place of the ileum kept a high sensitivity and the enzymes of transposed ileum a low sensitivity to dietary fructose. Our conclusion is that the response to the diet depends more on the original position of the intestinal segment than on the local nutritional conditions and therefore that the basal activity of the majority of the intracellular enzymes implicated in carbohydrate metabolism and also their regulatory systems, are an intrinsic characteristic of the intestinal cells.
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PMID:[Intestinal adaptation and enzymatic changes following reciprocal jejunoileal transposition in rats. Effects of a high-fructose diet]. 397 35

The enzyme activities of cultured early erythroid progenitor cells (burst-forming unit erythroid, BFU-E) were measured and were compared with the activities of mature erythrocytes. The enzyme activity of acetylcholinesterase was not detectable in the erythroblasts. The ratios of phosphofructokinase and glutathione peroxidase were low due to low enzyme activities in both the erythroblasts and erythrocytes. The ratios of triose phosphate isomerase, phosphoglycerate kinase, and adenylate kinase were low due to high enzyme activities in both the erythroblasts and erythrocytes. The ratios of hexokinase, glucose phosphate isomerase, monophosphoglyceromutase, pyruvate kinase, and adenosine deaminase were high due to high enzyme activities in the erythroblasts. The isozyme of erythroblast hexokinase was of the prototype isozyme I, while pyruvate kinase was predominantly of the prototype M2, with two hybrid isozymes to the anodal side by electrophoresis. These facts suggest that there is a greatly different metabolic pattern during the maturation of the erythroid cells.
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PMID:Enzyme activities of cultured erythroblasts. 403 55

The serum phosphohexose isomerase (PHI), aldolase and hexokinase activities have been determined in 36 patients of carcinoma ovary with different clinical stages and in 25 healthy normal female subjects. The serum PHI and hexokinase levels were significantly elevated (P less than .001) in all the stages of malignancy while serum aldolase was significantly elevated only in stages III and IV of malignancy. The enzyme levels showed statistically significant response to therapy in stage II patients. The mean values in patients with progression of the disease were not significantly different.
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PMID:Significance of serum phosphohexose isomerase, hexokinase and aldolase in carcinoma ovary. 405 17

This collaborative study on the determination of glucose and fructose in wine was performed by 18 laboratories on 4 matched pairs of commercial wine. The method uses the enzymes hexokinase, glucose-6-phosphate dehydrogenase, and phosphoglucose isomerase and the coenzyme nicotinamide-adenine dinucleotide phosphate. Both glucose and fructose can be determined in the same sample without separation. The method is simple but care is necessary to ensure precise transfer of small volumes. Repeatability and reproducibility standard deviations for glucose ranged from 2.6 to 14.6 mg/L and 4.7 to 16.5 mg/L, respectively. Repeatability and reproducibility values for fructose ranged from 2.4 to 16.1 mg/L and 6.0 to 21.3 mg/L, respectively. The method has been adopted official first action.
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PMID:Enzymatic-ultraviolet determination of glucose and fructose in wine: collaborative study. 405 18

1. Intracellular concentrations of intermediates and cofactors of glycolysis were measured in guinea-pig cerebral cortex slices incubated under varying conditions. 2. Comparison of mass-action ratios with apparent equilibrium constants for the reactions of glycolysis showed that hexokinase, phosphofructokinase and pyruvate kinase catalyse reactions generally far from equilibrium, whereas phosphoglucose isomerase, aldolase, phosphoglycerate kinase, phosphoglycerate mutase, enolase, adenlyate kinase and creatine phosphokinase are generally close to equilibrium. The possibility that glyceraldehyde 3-phosphate dehydrogenase may catalyse a ;non-equilibrium' reaction is discussed. 3. Correlation of changes in concentrations of substrates for enzymes catalysing ;non-equilibrium' reactions with changes in rates of glycolysis caused by alteration of the conditions of incubation showed that hexokinase, phosphofructokinase, pyruvate kinase and possibly glyceraldehyde 3-phosphate dehydrogenase are subject to metabolic control in cerebral cortex slices. 4. It is suggested that the glycolysis is controlled by two regulatory systems, the hexokinase-phosphofructokinase system and the glyceraldehyde 3-phosphate dehydrogenase-pyruvate kinase system. These are discussed. 5. It is concluded that the rate of glycolysis in guinea-pig cerebral cortex slices is limited either by the rate of glucose entry into the slices or by the hexokinase-phosphofructokinase system. 6. It is concluded that addition of 0.1mm-ouabain to guinea-pig cerebral cortex slices causes inhibition of either glyceraldehyde 3-phosphate dehydrogenase or phosphoglycerate kinase or both, in a manner independent of the known action of ouabain on the sodium- and potassium-activated adenosine triphosphatase.
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PMID:Control of glycolysis in cerebral cortex slices. 422 84

1. Methods of homogenizing suspensions of washed mammalian spermatozoa were studied. The most useful methods were those using sonication and those using a French press. 2. Hexokinase, phosphofructokinase, glucose phosphate isomerase and adenosine triphosphatase activities in ram, bull and boar spermatozoa were investigated by using these two homogenization methods. Glucose phosphate isomerase, representative of soluble cytoplasmic material, was very readily extracted and remained entirely in the supernatant after centrifugation at 145000g for 60min. In contrast, the other three activities were less easily extracted and were sedimented in various proportions under the described conditions of centrifugation. 3. Attempts to obtain subcellular fractions from sperm homogenates by ;classical' methods failed, owing apparently to the inhomogeneity of subcellular particles in the homogenates. It is concluded that, after removal of sperm heads, the only meaningful fractionation is a separation of spermatozoal material which sediments at 145000g during 60min from that which does not. 4. The stabilities of hexokinase and phosphofructokinase activities in bull, boar and ram sperm homogenates were investigated. Hexokinases showed very little dependence on the various environments tested, whereas the optimum conditions for phosphofructokinase stability were: a minimum of sonication, the presence of phosphate ions and of a thiol-group protectant, and a pH7.5. Activities of hexokinase, phosphofructokinase and glucose phosphate isomerase per sperm cell were compared with published data on rates of fructolysis by spermatozoa; the potential catalytic activities were shown to be considerably in excess of these rates. However, phosphofructokinase may be the rate-limiting enzyme of glycolysis in vivo in bull and ram spermatozoa.
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PMID:Glycolytic enzymes in mammalian spermatozoa. Activities and stabilities of hexokinase and phosphofructokinase in various fractions from sperm homogenates. 425 94


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