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 glucose flow in Xanthomonas campestris was investigated with radio-labelled glucose and by enzymological studies. Only 7% of the radioactivity was incorporated into the cell material, but 41% was oxidized to carbon dioxide and 28% transformed to xanthan. Up to 16% of cell dry weight consisted of the polysaccharide glycogen. In the presence of 2.7 mM methionine, which is an inhibitor of xanthan formation, increased carbon dioxide formation (51%) occurred. This increase was in accordance with a twofold increase in the NAD-dependent isocitrate dehydrogenase activity. The other carbon dioxide liberating enzyme, 6-P-gluconate dehydrogenase, was not influenced by methionine, but its occurrence indicates the presence of an active pentose phosphate pathway in X. campestris. Among the other enzymes detected in X. campestris was glucose dehydrogenase. The presence of this enzyme together with hexokinase indicates the operation of two different glucose metabolizing steps: one oxidative, the other phosphorylative. Only the latter directly provides phosphorylated glucose as a precursor for the activated sugars required for xanthan synthesis.
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PMID:Glucose metabolism in Xanthomonas campestris and influence of methionine on the carbon flow. 314 63

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

Adriamycin is used for the treatment of leukemia and other neoplastic processes. Unfortunately the drug has a toxic effect on some tissues. Cardiotoxicity in particular limits the use of the drug. Several hypotheses have been given to explain adriamycin heart toxicity. The authors have studied the effect of the drug on the enzymes isocitrate dehydrogenase-NADP, malic enzyme, 6-P-gluconate dehydrogenase, malic dehydrogenase-NAD+, hexokinase, and phosphofructokinase. They observed that adriamycin inhibits the NADP-dependent enzymes, and that the sulfhydryl group of the enzymes may be involved in the inhibitory action of adriamycin.
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PMID:[Study of the inhibition produced by adriamycin against specific enzymes in the rat heart]. 610 Apr 65

The effect of dissolved oxygen concentration on the metabolism of glucose in Pseudomonas aeruginosa was studied with chemostat cultures using both single-step and gradual transitions from either ammonium or glucose limitation to oxygen limitation and studying transient and steady states. The pathway of glucose metabolism was regulated by the availability of oxygen. The organism responded to oxygen limitation by adjusting its metabolism of glucose from the extracellular direct oxidative pathway, which produces gluconate and 2-oxogluconate, to the intracellular phosphorylative route. This change was a consequence of decreased activities of glucose dehydrogenase and gluconate dehydrogenase and of the transport systems for gluconate and 2-oxogluconate, and an increased activity of glucose transport, while relatively high activities of hexokinase and glucose-6-phosphate dehydrogenase were maintained. Citrate synthase, isocitrate dehydrogenase and malate dehydrogenase activities responded to changes in dissolved oxygen concentration rather than to changes in the glucose or ammonium concentrations. The effect of oxygen limitation on the oxo-acid dehydrogenases and aconitase was probably due, wholly or in part, to repression by glucose consequent upon the increase in residual glucose concentration. Succinate dehydrogenase was repressed by an increase in ammonium concentration under an oxygen limitation.
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PMID:The role of oxygen in the regulation of glucose metabolism, transport and the tricarboxylic acid cycle in Pseudomonas aeruginosa. 708 92

Tissue distribution and activity of enzymes involved in sucrose and hexose metabolism were examined in kernels of two inbreds of maize (Zea mays L.) at progressive stages of development. Levels of sugars and starch were also quantitated throughout development. Enzyme activities studied were: ATP-linked fructokinase, UTP-linked fructokinase, ATP-linked glucokinase, sucrose synthase, UDP-Glc pyrophosphorylase, UDP-Glc dehydrogenase, PPi-linked phosphofructokinase, ATP-linked phosphofructokinase, NAD-dependent sorbitol dehydrogenase, NADP-dependent 6-P-gluconate dehydrogenase, NADP-dependent Glc-6-P dehydrogenase, aldolase, phosphoglucoisomerase, and phosphoglucomutase. Distribution of invertase activity was examined histochemically. Hexokinase and ATP-linked phosphofructokinase activities were the lowest among these enzymes and it is likely that these enzymes may regulate the utilization of sucrose in developing maize kernels. Most of the hexokinase activity was found in the endosperm, but the embryo had high activity on a dry weight basis. The endosperm, which stores primarily starch, contained high PPi-linked phosphofructokinase and low ATP-linked phosphofructokinase activities, whereas the embryo, which stores primarily lipids, had much higher ATP-linked phosphofructokinase activity than did the endosperm. It is suggested that PPi required by UDP-Glc pyrophosphorylase and PPi-linked phosphofructokinase in the endosperm may be supplied by starch synthesis. Sorbitol dehydrogenase activity was largely restricted to the endosperm, whereas 6-P-gluconate and Glc-6-P dehydrogenase activities were highest in the base and pericarp. A possible metabolic pathway by which sucrose is converted into starch is proposed.
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PMID:Enzymes of sucrose and hexose metabolism in developing kernels of two inbreds of maize. 1666 24

Erythritol is an important sugar alcohol industrially produced only by fermentation. The highly osmophilic yeast-like fungi, Trichosporonoides megachiliensis SN-G42, enables commercial production of erythritol with a high conversion from glucose to erythritol of more than 47%. However, the microbial production pathway of erythritol remains unclear. In the present study, the activities of enzymes in the pentose phosphate pathway of Trichosporonoides megachiliensis SN-G42 used for industrial erythritol production were measured under various culture conditions to examine the production mechanism and the key-enzymes. As a result, the various enzyme activities of this organism are revealed in the pentose phosphate pathway, i.e., those of hexokinase, glucose-6-phosphate dehydrogenase, gluconate dehydrogenase, transketolase, transaldolase, and erythrose reductase. In the cultures in which erythritol was produced after completion of cell growth, the enzyme activities of the pentose phosphate pathway were higher than those of the TCA cycle. In particular, transketolase activity was correlated with erythritol productivity under various production cultures with different agitation speeds and thiamine concentrations. These results suggest that erythritol may be produced mainly through the pentose phosphate pathway. In addition, the high activity of transketolase is required to produce abundant intermediates, which results in high erythritol productivity. As such, transketolase appears to be a key-enzyme for erythritol production in the organism studied.
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PMID:Key role for transketolase activity in erythritol production by Trichosporonoides megachiliensis SN-G42. 1980 61