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)

1. Activities of 20 red cell enzymes were compared in 8 normal female Ovis Aries, in a serially bled ewe followed by 243 days, and in young and old red cell populations separated by density gradient centrifugation. 2. These comparisons indicate that the erythrocyte enzymes which show significant changes with cell age are glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, hexokinase, phosphoglucose isomerase, lactate dehydrogenase, glutathione reductase, enolase and phosphoglycerate kinase. 3. The usefulness of these data in interpretation of enzyme activities from fetal Ovis Aries is discussed.
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PMID:Erythrocyte enzymes in Ovis aries. Effect of cell age. 706 Mar 50

The S-methylated derivatives of adenosine 5'-O-(1-thiotriphosphate) (ATP alpha SCH3) have been prepared by the reaction of both diastereomers of adenosine 5'-O-(1-thiotriphosphate) (ATP alpha S) with methyl iodide. At physiological pH ATP alpha SCH3 was unstable, decomposing predominantly to adenosine 5'-O-(S-methyl thiophosphate) (AMPSCH3) and pyrophosphate. A minor degradation pathway also yielded ATP and methyl mercaptan. Greatly enhanced stability was observed at lower pH. The Sp diastereomer of ATP alpha SCH3 was a substrate for hexokinase and acetate kinase, and both diastereomers were active with fructose-6-phosphate kinase. The products of these reactions were the appropriate sugar or acyl phosphate, AMPSCH3, and inorganic phosphate, the latter two species arising from the breakdown of the transient intermediate 5'-O-(S-methyl 1-thiodiphosphate) (ADP alpha SCH3). No measurable substrate activities were observed with creatine and phosphoglycerate kinase. These results are interpreted as meaning that creatine and phosphoglycerate kinase require Mg2+ coordination to the alpha-phosphate group during the enzyme-catalyzed reaction whereas the other three enzymes do not. Attempts to prepare adenosine 5'-O-(S-methyl 2-thiotriphosphate) (ATP beta SCH3) and ADP-alpha SCH3 by similar methods were unsuccessful with adenosine 5'-O-(S-methyl 2-thiodiphosphate) (ADP beta S) and AMPSCH3 being respectively isolated as the major products.
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PMID:S-Methylated nucleoside phosphorothioates as probes of enzyme metal X nucleotide binding sites. 715 May 48

Red cell glycolytic intermediates and enzymes in term infants in the first year of life were correlated with the fetal hemoglobin concentration (%F), intra- and extracellular venous pH, plasma inorganic phosphorus (Pi) and pyruvate kinase (PK) activity. Changes in the non-age-dependent enzymes phosphoglycerate kinase, enolase, and phosphofructokinase correlated most significantly with the postnatal decline in %F (P less than 0.001), not the age of the red cell population, as reflected in PK activity. The age-dependent enzymes, hexokinase and glucose-6-phosphate dehydrogenase, however, correlated well with PK activity (P less than 0.001). The concentration of glucose-6-phosphate did not correlate significantly with the postnatal decline in %F (P greater than 0.05) or PK (P greater than 0.10), but correalted significantly with the plasma Pi concentration (P less than 0.001). "Total triose phosphate" and 2,3-diphosphoglycerate did not correlate with Pi. It appears from these studies that an extracellular factor, Pi alters the pattern of glycolytic intermediates in term infants and that the postnatal changes in phosphoglycerate kinase, enolase, and phosphofructokinase are unique to the "fetal" red cell and reflect passage from fetal to "adult" erythropoiesis.
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PMID:Red cell metabolic alterations in postnatal life in term infants: possible control mechanisms. 725 39

THe level of enzyme activity, the enzyme thermostability profile, and the isozyme electrophoretic pattern were determined in young and old erythrocytes from newborn infants and adults and in samples from adult individuals with increased reticulocyte counts. Cord blood samples had higher levels of enzymatic activity for 12 of the 14 enzymes measured, adenylate kinase and phosphoglucomutase being the exceptions. The largest differences in activity between newborns and adults were for glutamic oxaloacetic transaminase, hexokinase, glucose 6-phosphate dehydrogenase, and glutathione reductase, while glutamic oxaloacetic transaminase and pyruvate kinase showed the largest differences between young and old cells. The levels of activity of glutathione reductase, adenylate kinase, phosphoglucomutase, lactate dehydrogenase, phosphoglycerokinase, and glucose phosphate isomerase in cord blood samples suggest the regulation of expression of these enzymes is different in fetal erythrocytes than in erythrocytes from an adult. Differences in the thermostability profile of enzymes from cells from different sources and/or of different ages were noted for 5 of 9 enzymes. No unique electrophoretically identifiable fetal isozymes were observed, although differences in isozyme distribution and staining intensity associated with cell source and/or cell age were noted for many of the 23 enzymes examined. Many of these differences in enzyme characteristics have the potential to be confused with genetic alterations in enzyme structure and function.
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PMID:Characteristics of enzymes of erythrocytes from newborn infants and adults: activity, thermostability, and electrophoretic profile as a function of cell age. 730 4

The reference strains Type A and Type B and two equine strains of Acholeplasma laidlawii were examined for a wide range of isoenzymes using thin-layer starch-gel electrophoresis; in addition two isoenzymes were examined in two strains of A. equifetale. The type strains A and B of A. laidlawii were differentiated by their lactate dehydrogenase, phosphoglucomutase and aspartate aminotransferase patterns and the two equine strains by their hexokinase, lactate dehydrogenase and phosphoglycerate kinase patterns. The two pairs of strains differed from one another with respect to hexokinase, phosphoglucomutase, adenylate kinase and glucose-6-phosphate dehydrogenase. The two strains of A. equifetale could be distinguished by their isoenzymes of hexokinase. The two species were differentiated by their hexokinase and phosphoglucomutase patterns.
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PMID:Isoenzymes in two species of Acholeplasma. 739 17

The presence of hexokinase, aldolase, glyceraldehyde-phosphate dehydrogenase, phosphoglycerate kinase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase has been detected in Y. enterocolitica, which indicates the glycolytic and pentosophosphate pathways of glucose catabolism. Y. enterocolitica can be classified as an opportunistic anaerobic microorganism on the basis of the whole complex of its characteristics (growth in both aerobic and anaerobic conditions, the reduction of nitrates into nitrites, the presence of higly active glycolytic enzymes).
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PMID:[Glucose metabolism in Yersinia enterocolitica cells]. 743 20

Infective (L3) larvae of Strongyloides ratti (homogonic strain) were freeze-clamped (-196 degrees C) and the steady-state content of the glycolytic, Krebs tricarboxylic acid (KTA)-cycle intermediates and adenine nucleotides analysed. Comparison of the mass-action ratios (MARs) of the glycolytic enzymes with their apparent equilibrium constants (K9eq) indicate that phosphoglucomutase, glucosephosphate isomerase, triosephosphate isomerase, phosphoglyceromutase and phosphopyruvate hydratase reactions were all at or near equilibrium, whilst hexokinase, phosphofructokinase and pyruvate kinase were displaced from equilibrium. The S. ratti aldolase and myokinase appear to be somewhat displaced from equilibrium and thus may have pseudoregulatory roles. The adenylate energy charge (AEC), ATP/ADP ratio and the available adenylate energy (AAE) indices were 0.9 +/- 0.04, 8.76 +/- 1.5 and 397 +/- 43, respectively. The free [NAD+]/[NADH+H+] ratio of the cytoplasmic compartment of S. ratti L3 larvae calculated employing the steady-state content of the oxidised and reduced substrates of lactate dehydrogenase (E.C. 1.1.1.27) and the combined glyceraldehyde 3-phosphate dehydrogenase (E.C. 1.2.1.12)/3-phosphoglycerate kinase (E.C. 2.7.2.3) system were ca. 523 and 1200, respectively. The free[NAD+]/[NADH+H+] ratio in the mitochondrial compartment of S. ratti L3 larvae calculated using the malate dehydrogenase (E.C. 1.1.1.37) equilibrium was found to be 1962:1. The data is discussed with respect to the predominantly aerobic nature of the energy metabolism of the L3 larvae.
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PMID:Steady-state content of glycolytic/tricarboxylic acid-cycle intermediates, adenine nucleotide pools and the cellular redox-status in the infective (L3) larvae of (homogonic) Strongyloides ratti. 762 25

To investigate whether the energy derived from glycolysis is functionally coupled to Ca2+ active transport in sarcoplasmic reticulum (SR), we determined whether glycolytic enzymes were associated with SR membranes and whether metabolism through these enzymes was capable of supporting 45Ca transport. Sealed right-side-out SR vesicles were isolated by step sucrose gradient from rabbit skeletal and cardiac muscle. Intravesicular 45Ca transport was measured after the addition of glycolytic substrates and cofactors specific for each of the glycolytic reactions being studied or after the addition of exogenous ATP and was expressed as transport sensitive to the specific Ca(2+)-ATPase inhibitor thapsigargin. We found that the entire chain of glycolytic enzymes from aldolase onward, including aldolase, GAPDH, phosphoglycerate kinase (PGK), phosphoglyceromutase, enolase, and pyruvate kinase (PK), was associated with SR vesicles from both cardiac and skeletal muscle. Iodoacetic acid, an inhibitor of GAPDH, eliminated 45Ca transport supported by fructose-1,6-diphosphate, the substrate for aldolase, but transport was completely restored by phosphoenolpyruvate (the substrate for PK), indicating that both of the ATP-producing glycolytic enzymes, GAPDH/PGK and PK, were associated with the SR and functionally capable of providing ATP for the Ca2+ pump. Addition of a soluble hexokinase ATP trap eliminated 45Ca transport fueled by exogenous ATP but had markedly less effect on 45Ca transport supported by endogenously produced ATP (via glycolysis). Similarly, at very low concentrations of ATP and ADP (10 to 50 nmol/L), ATP that was produced endogenously from ADP and phosphoenolpyruvate supported 15-fold more 45Ca transport than ATP that was supplied exogenously at the same concentration. These results are consistent with functional coupling of glycolytic ATP to Ca2+ transport and support the hypothesis that ATP generated by SR-associated glycolytic enzymes may play an important role in cellular Ca2+ homeostasis by driving the SR Ca2+ pump.
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PMID:Functional coupling between glycolysis and sarcoplasmic reticulum Ca2+ transport. 778 86

Aqueous two-phase partition and temperature-induced phase separation using a non-ionic, random copolymer composed of 20% ethylene oxide, 80% propylene oxide (EO20 PO80) has been used for purification of glucose-6-phosphate dehydrogenase, hexokinase and 3-phosphoglycerate kinase from bakers' yeast. This EO20PO80 copolymer has a cloud point of 18 degrees C, at which temperature it phase separates from water. Enzymes were first partitioned at 4 degrees C in an initial EO20PO80-dextran T500 aqueous two-phase system. This system had an upper copolymer-rich phase and a lower dextran-rich phase. After phase separation had occurred the upper EO20PO80-rich phase was removed and placed at 24 degrees C. This resulted in formation of a new two-phase system with an upper water phase and a lower phase containing 98% copolymer and 2% water. Enzymes were recovered exclusively in upper water phase leaving a polymer-rich lower phase free of contamination. The phase diagram for the system EO20PO80 and dextran T500 at 4 degrees C has been determined.
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PMID:Application of temperature-induced phase partitioning at ambient temperature for enzyme purification. 812 71

Subcellular localization of hexokinase in the honeybee drone retina was examined following fractionation of cell homogenate using differential centrifugation. Nearly all hexokinase activity was found in the cytosolic fraction, following a similar distribution as the cytosolic enzymatic marker, phosphoglycerate kinase. The distribution of enzymatic markers of mitochondria (succinate dehydrogenase, rotenone-insensitive cytochrome c reductase, and adenylate kinase) indicated that the outer mitochondrial membrane was partly damaged, but their distributions were different from that of hexokinase. The activity of hexokinase in purified suspensions of cells was fivefold higher in glial cells than in photoreceptors. This result is consistent with the hypothesis based on quantitative 2-deoxy[3H]glucose autoradiography that only glial cells phosphorylate significant amounts of glucose to glucose-6-phosphate. The activities of alanine aminotransferase and to a lesser extent of glutamate dehydrogenase were higher in the cytosolic than in the mitochondrial fraction. This important cytosolic activity of glutamate dehydrogenase was consistent with the higher activity found in mitochondria-poor glial cells. In conclusion, this distribution of enzymes is consistent with the model of metabolic interactions between glial and photoreceptor cells in the intact bee retina.
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PMID:Cellular and subcellular localization of hexokinase, glutamate dehydrogenase, and alanine aminotransferase in the honeybee drone retina. 815 42


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