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)

Administration of 60,000 i.e. of vitamin A into rats within three weeks caused an increase in amount of reticulocytes, in the rate of glucose utilization and in formation of lactic acid by erythrocytes. The activity of glycolytic enzymes was intensified. The activity of hexokinase was increased by 84.6%, activities of aldolase and phosphohexoisomerase were increased by 34%. But in the erythrocytes content of AMP, ADP and ATP was unaltered, probably due to activation of total and Na+, K+-dependent ATPase. The harmful effect of an excess of the vitamin A was manifested in an increased content of Na+ in erythrocytes and also in decreased stability of the cells to acid hemolytics.
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PMID:[Intensity of glycolysis and energy metabolism in erythrocytes in experimental hypervitaminosis A]. 13 57

A long-term administration of retinol in a dose exceeding 15-fold the diurnal requirement to rats weighing 170-200 g provoked a diminution of the erythrocytes resistance to an acid hemolytic, an intensified uptake of glucose, and increased activity of glycolytic enzymes (hexokinase, aldolase, phosphohexoisomerase), accumulation of lactate, along with changes in the redox enzymes activity, suppression of the catalase and intensification of peroxidase activity. The content of microergic nucleotides and electrolites (Na+ and K+) remained unchanged.
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PMID:[Effect of long-term vitamin A administration on the acid fastness and biochemical properties of erythrocytes]. 96 79

In extracts of rabbit bone marrow cells was studied effect of erythropoietine on the activity of some enzymes (hexokinase, phosphoglucomutase, phosphohexoisomerase, lactate dehydrogenase, glucoso-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADP-reductase). The NADP-reductase activity was increased under the effect of erythropoietine; the activities of other enzymes studied was not altered.
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PMID:[Study of the mechanism of erythropoietin effect on energy metabolism in the bone marrow]. 103 Aug 78

The dynamics of glycolysis and glycogenolysis in the postnatal period, determined from the accumulation of lactate in the homogenate of the heart muscle, indicates that the glycolytic activity begins to subside right after the birth and becomes constant after a lapse of 15-20 days. The activity of the phosphorylase, phosphohexoisomerase, enolase and pyruvate-kinase in the heart muscle extract was found to remain virtually unchanged. Some decline is noted in the activity of the aldolase and hexokinase, while that of the phosphofructokinase and lactate-dehydrogenase rises by 50-60 per cent. These data suggest that in the early ontogenesis the increasing capacity of the mitochondrial system in the heart muscle is paralled by an adjustable conditioned inhibition of the glycolytic phosphorylation, with concurrently rising activity of the phosphofructokinas and, consequently, also of the potential capacity of glycolysis and glycogenolysis.
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PMID:[Dynamics of carbohydrate metabolism in the heart muscle in early ontogenesis]. 116 19

Selected enzymes of energy metabolism were measured in random individual fibers of soleus and tibialis anterior (TA) muscles from rats exposed for 2 wk to spaceflight (F) aboard COSMOS 2044 or tail suspension (T) and from synchronous controls. Average size of soleus fibers (dry weight per unit length) was reduced 37% in F and T fibers; there was little change in TA fibers. Enzyme changes were more pronounced in soleus than in TA fibers. Three enzymes characteristic of fast-twitch muscles, pyruvate kinase, glycerol-3-phosphate dehydrogenase, and 1-phosphofructokinase, were elevated in F and T soleus fibers, but changes in phosphofructokinase were not statistically significant. 3-Ketoacid-CoA transferase, characteristic of slow-twitch muscles, did not change significantly in either F or T fibers. Hexokinase, usually moderately higher in slow- than in fast-twitch muscles, increased markedly in both F and T fibers. In TA fibers analyzed for hexokinase, malate dehydrogenase, phosphohexoisomerase, and pyruvate kinase, only hexokinase and malate dehydrogenase showed significant changes. Hexokinase increased 83% in one of two T muscles. Enzyme data for TA fibers typed by myosin adenosinetriphosphatase were more informative: phosphofructokinase, phosphorylase, and glycerol-3-phosphate dehydrogenase were increased in type IIb fibers of either F or T muscles or both. Malate dehydrogenase was not changed in fibers of any type in either F or T muscle.
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PMID:Effects of microgravity and tail suspension on enzymes of individual soleus and tibialis anterior fibers. 138 50

The metabolism of D-[U-14C]glucose, D-[1-14C]glucose, D-[6-14C]glucose, D-[1-3H]glucose, D-[2-3H]glucose, D-[3-3H]glucose, D-[3,4-3H]glucose, D-[5-3H]glucose, and D-[6-3H]glucose was examined in rat erythrocytes. There was a fair agreement between the rate of 3HOH production from either D-[3-3H]glucose and D-[5-3H]glucose, the decrease in the 2,3-diphosphoglycerate pool, its fractional turnover rate, the production of 14C-labeled lactate from D-[U-14C]glucose, and the total lactate output. The generation of both 3HOH and tritiated acidic metabolites from D-[3,4-3H]glucose indicated incomplete detritiation of the C4 during interconversion of fructose-1,6-bisphosphate and triose phosphates. Erythrocytes unexpectedly generated 3HOH from D-[6-3H]glucose, a phenomenon possibly attributable to the detritiation of [3-3H]pyruvate in the reaction catalyzed by glutamate pyruvate transaminase. The production of 3HOH from D-[2-3H]glucose was lower than that from D-[5-3H]glucose, suggesting enzyme-to-enzyme tunneling of glycolytic intermediates in the hexokinase/phosphoglucoisomerase/phosphofructokinase sequence. The production of 3HOH from D-[1-3H]glucose largely exceeded that of 14CO2 from D-[1-14C]glucose, a situation tentatively ascribed to the generation of 3HOH in the phosphomannoisomerase reaction. It is further speculated that the adjustment in specific radioactivity of D-[1-3H]glucose-6-phosphate cannot simultaneously match the vastly different degrees of isotopic discrimination in velocity at the levels of the reactions catalyzed by either glucose-6-phosphate dehydrogenase or phosphoglucoisomerase. The interpretation of the present findings thus raises a number of questions, which are proposed as a scope for further investigations.
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PMID:Metabolism of tritiated D-glucose in rat erythrocytes. 189 64

In Chaberia ovina species an electrophoretic study of 15 loci of the following enzymes has been conducted: glucose phosphate isomerase, mannose phosphate isomerase, glucose-6-phosphate dehydrogenase, glutamate-oxaloacetate transaminase, superoxide dismutase, isocitrate dehydrogenase, hexokinase, adenylate kinase, malate dehydrogenase, malic enzyme, carbonic anhydrase and 6-phosphogluconate dehydrogenase. The genetic variability has been relatively high, with 40% polymorphism values noted, an 0.10 mean heterozygosity observed and an 0.17 mean heterozygosity expected. The greater part of the allele frequencies were not in Hardy-Weinberg equilibrium.
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PMID:Electrophoretic analysis of gene-enzyme systems in Chabertia ovina. 233 99

Mannose in animal cells is phosphorylated by hexokinase (HK) and later isomerised by mannose phosphate isomerase (MPI) to fructose-6-P, which is incorporated in the glycolysis pathway. In this paper we report a significant decrease of MPI activity in splenic lymphoid cells from AKR/J old mice with lymphocytic leukaemia in comparison to that found in splenic lymphocytes from AKR/J non-leukaemic young mice and BALB/c young and old control mice. However, HK with mannose as substrate presents a normal activity in AKR/J leukaemic mice. This marked shortage of MPI explains the in vitro mannose toxicity found by us here in splenic lymphoid cells from AKR/J leukaemic mice. MPI activity was also decreased in peripheral blood lymphocytes from 4 out of the 6 patients studied with chronic lymphocytic leukaemia in relation to the activity found in the lymphocytes from healthy donors. The utility of analysing MPI activity in leukaemia patients and the use of mannose as an innocuous chemotherapic supporting agent in patients with decreased MPI activity is proposed.
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PMID:Enzymes of mannose metabolism in murine and human lymphocytic leukaemia. 321 65

The erythrocyte can phosphorylate a variety of hexoses. Since it can consume mannose and glucose equivalently in the hereditary deficiencies of hexokinase and phosphoglucose isomerase and since erythrocyte defense against oxidants is impaired in a variety of hereditary hemolytic anemias, we tested the hypothesis that mannose may be a significant alternative to glucose as a fuel for this defense system. Unexpectedly, mannose inhibited defense against oxidants as manifested by increased Heinz body formation when both normal and high-reticulocyte erythrocytes were incubated with acetylphenylhydrazine (APH). Using APH as the oxidant, mannose-incubated erythrocytes had decreased reduced glutathione stability and impaired hexose oxidation by the pentose shunt compared to glucose-incubated erythrocytes. After incubation with mannose and APH, normal erythrocytes showed a decrease in ATP content. Approximately 25% of the consumed mannose accumulated in the erythrocytes as mannose 6-phosphate. Erythrocytes incubated with mannose and APH displayed a significant loss of redox potential as manifested by decreased NADH/(NADH + NAD+) and NADPH/(NADPH + NADP+) ratios. Since phosphomannose isomerase is the rate-limiting step for mannose metabolism, our results suggest that mannose impairs erythrocyte defense against oxidants by causing ATP depletion and by impairing the regeneration of reduced pyridine nucleotides by the Embden-Meyerhof and pentose phosphate pathways.
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PMID:Inhibitory effect of mannose on erythrocyte defense against oxidants. 333 78

Human platelets were separated by desity-centrifugation into heavy and light populations. Heavy platelets have an average volume approximately twofold greater than light platelets, and have previously been shown to be young platelets. All 11 enzymes of the Embden-Meyerhof pathway plus the five related enzymes: phosphoglucomutase, glucose-6-P dehydrogenase, 6-P-gluconic dehydrogenase, alpha-glycerol-P dehydrogenase, and glutathione reductase (TPNH) were examined in cell lysates from total, heavy, and light platelet populations. Apparent Km for individual enzymes were measured in a total platelet population. Empirical V(max) of the individual enzymes were measured in total, heavy, and light platelet populations. The three apparent rate-limiting enzymes for glycolysis were hexokinase, phosphofructokinase, and glyceraldehyde-3-P dehydrogenase. Heavy platelets contained approximately twofold greater enzyme activity (per gram wet weight) than light platelets for 7 of the 16 enzymes measured: hexokinase, phosphohexoisomerase, phosphofructokinase, glyceraldehyde-3-P dehydrogenase, phosphoglycerokinase, lactic dehydrogenase, and phosphoglucomutase. Heavy platelets also contained 1.9-fold greater reduced glutathione (GSH), 1.7-fold greater DPNH, and 1.2-fold greater TPNH than light platelets. Heavy platelets contained 1.8-fold less lipid peroxidation products (malonyl aldehyde equivalents) than light platelets and were 2.4-fold more resistant to lipid peroxidation catalyzed by 0.1 mM FeCl(3). Sterile incubation of heavy platelets, in vitro for 17 hr, resulted in a significant loss of enzyme activity for the "elevated" seven enzymes when compared with the remainder. Reducing agents such as GSH (0.1 mM), ascorbic acid (0.1 mM), and dithiothreitol (0.01 mM), when added to the incubation mixture, significantly reduced the in vitro loss of activity. In vitro incubation was also associated with a significant loss of GSH and DPNH and a 1.8-fold increase in lipid peroxidation products.
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PMID:Heterogeneity of human platelets. V. Differences in glycolytic and related enzymes with possible relation to platelet age. 426 50


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