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 metabolism of 2-deoxy-D-galactose has been studied in AS-30D rat ascites hepatoma cells in suspension. Using 2-deoxy-D-(1-14C)galactose and an alkaline ethanol deproteinization procedure, the quantitatively identified metabolites included 2-deoxy-D-galactose 1-phosphate comprising 99.3%, and UDP-2-deoxy-D-galactose and UDP-2-deoxy-D-glucose, together amounting to 0.4% of the total metabolites. After incubation for 5 h in the presence of 2-deoxy-D-galactose (1 mmo1/1), the content of 2-deoxy-D-galactose 1-phosphate reached 35 mmo1x(kg cells)-1. The rate of phosphorylation of 2-deoxy-D-galactose was rapid during the first 30 min and decreased to approximately 20% of this rate during the subsequent hours. The rapid trapping of Pi in the form of 2-deoxy-D-galactose 1-phosphate resulted in a depression of free intracellular Pi in spite of a concomitant increase in net 32Pi uptake from the medium and a decrease of ATP and other 5'-nucleotides. The rates of glucose utilization and lactate production were depressed by more than 80% in the presence of 2-deoxy-D-galactose (1 mmo1/1). Interruption of Pi trapping by removal of 2-deoxy-D-galactose from the medium reversed the depressions of Pi and ATP and resulted in a rapid but incomplete relief of glycolysis inhibition. Crossover analysis of glycolytic intermediates indicated an inhibition at the 6-phosphofructokinase step. The depression of glucose utilization may be mediated by the increased level of glucose 6-phosphate, a potent inhibitor of hexokinase. An additional inhibitory effect of a metabolite of 2-deoxy-D-galactose at the 6-phosphofructokinase step was indicated by crossover analysis after reversal of Pi and ATP depressions in the presence of a high intracellular content of 2-deoxy-D-glactose 1-phosphate. The quantitative analysis of the metabolites of 2-deoxy-D-galactose demonstrated the predominance of the monophosphate and the negligible formation of UPD derivatives of this sugar analog in AS-30D hepatoma cells. This provides a system for the investigation of a galactose analog as a phosphate-trapping agent in the virtual absence of uridylate trapping.
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PMID:2-Deoxy-D-galactose metabolism in ascites hepatoma cells results in phosphate trapping and glycolysis inhibition. 19 12

The action of free fatty acids on glycolytic enzymes was compared in normal and neoplastic tissues. Preincubation of tissue supernatant fractions with octanoate or laurate caused an inhibition of the activities of hexokinase and phosphofructokinase. An inhibition was also observed of lactate production with either glucose or glucose 6-phosphate as substrate. A similar degree of inhibition was observed for actions on normal liver and kidney, on the 7800 and 3924-A hepatomas and on the MK-3 renal cortical tumor. The possible relationship between the inhibition of glycolytic enzymes by fatty acids and anti-tumor activity previously observed with these compounds was noted.
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PMID:Inhibition of glycolytic enzymes of rat liver and hepatomas by free fatty acids. 19 94

The activities of hexokinase, glucokinase, phosphofructokinase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, and fructose-1,6-diphosphatase were determined in loach embryos developed in solutions of insulin, hydrocortisone, estrone and thyroxin at different stages of embryogenesis. Glucokinase and fructose-1,6-diphosphatase activties are shown not to change markedly under the influence of the above-mentioned hormones. During some periods of early development the hexokinase activity is inhibited by insulin, estrone and thyroxin. The glucose-6-phosphate dehydrogenase activity is suppressed by each of the used hormones at all the stages of early embryogenesis while the glocose-6-phosphatase activity decreased only under the influence of insulin at the cleavage, blastula and gastrula stages. Insulin increased the activity of phosphofructokinase at the cleavage, blastula and early gastrula stages and hydrocortisone, estrone and thyroxine during certain periods of these stages. From middle gastrula two last hormones decreased the phosphofructokinase activity in the loach embryos.
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PMID:[Activity of carbohydrate metabolism enzymes in loach embryos under the influence of hormones]. 19 80

It is established that in embryos incubated until the early blastula stage in the solution of insulin with addition of cycloheximide or puromycin, there is neither a decrease in the hexokinase and glucose-61 phosphate dehydrogenase activities nor an increase in the phosphofructokinase activity, as it is shown under the influence of insulin only. Puromycin removes an inhibitory effect of insulin on the glucose-6-phosphatase activity, and actinomycin D removes this influence with respect to glucose-6-phosphate dehydrogenase and glucose-6-phosphatase activities. The addition of antibiotics removes inhibition of the hexokinase, glucose-6-phosphate dehydrogenase and glucose-6-phosphatase activities by the hormone in the unfertilized eggs as well. Actinomycin D alone inhibits the hexokinase and activates the phosphofructokinase activities in the embryos and eggs, puromycin decreases their hexokinase activity and cycloheximide has the same effect on the glucose-6-phosphatase activity in the embryos only.
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PMID:[Effect of insulin on activity of carbohydrate metabolism enzymes in loach embryos in early development]. 19 74

Starch gel electrophoretic patterns of 26 enzymes (corresponding to 36 gene loci) were examined in hemolysates of erythrocytes from 11 first-trimester and mid-trimester human fetuses (65-138 gestation days). The zymograms of 16 enzymes were identical in fetal and control adult red cells. Six enzymes (enolase, guanylate kinase, lactate dehydrogenase, nucleoside phosphorylase, phosphofructokinase, hexokinase) showed differences in the staining intensity of certain isozyme zones as compared with the controls. Also, the fetal red cell zymograms, in contrast to those of adults, contained the mitochondrial forms of isocitric dehydrogenase and glutamic oxaloacetic transaminase as well as more definite zones of phosphoglucomutase-3. Finally, some of the isozymes of uridine diphosphate kinase in the fetal cells had slightly retarded mobility. These observed differences between fetal and adult red cells could reflect the expression of a different program of protein synthesis in red cells of the fetuses or the epigenetic modifications of isozymes in immature red cells.
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PMID:Isozyme patterns in erythrocytes from human fetuses. 20 89

The activity of hexokinase, glycose-6-phosphatase, phosphofructokinase, fructose diphosphate aldolase and ketose-1-phosphate aldolase was studied in kidneys, blood serum and urine or rats, the proximal and distal areas of their nephron being affected with the chemical substances. A pronounced decrease in the activity of the mentioned enzymes in the renal tissue was greater with afection of the nephron proximal area. The activity of the mentioned enzymes in urine, vice versa, increases sharply and in blood serum it was almost unchanges (exception for keto-1-phosphate aldolase). The pronounced enzyme uria may reflect the deep changes in epithelium cells of canals, especially of proximal ones where the enzymes under study are mainly localized.
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PMID:[Activity of glycolysis enzymes in kidneys, blood serum and urine with toxicity of certain segments of the nephron]. 20 89

An ultramicrochemical technique has been adapted to the evolution of enzyme profiles within individual human mammary tumors. Tandem observation of adjacent stained and lyophilized sections permitted dissection of microgram quantities of freeze-dried material within confirmed regions of malignancy. Enzymes frequently monitored to examine glycolytic, respiratory, and metastatic capacity were microanalyzed successfully: lactic dehydrogenase (LDH), phosphoglucose isomerase (PGI), malate dehydrogenase (MDH), acid phosphatase (AP), aldolase (ALD), glucose-6-phosphate dehydrogenase (G6PDH), pyruvate kinase (PK), alpha-glycerophosphate dehydrogenase (alpha-GOPDH), hexokinase (HK), and phosphofructokinase (PRK). All enzyme activities were higher in infiltrating ductal carcinomas than in fibroadenomas. Extracts of tumor cells mixed in varying proportions with brain or muscle extracts of rat evidenced no modification of expected activity. The technical adaptation described provided a sensitive methodology to resolve problems of relication, profile analysis, sample quantity, and selectivity within heterogeneous tissues.
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PMID:Application of a microchemical technique to the elucidation of enzyme activity profiles within single human mammary tumors. 20 41

Based on previous studies which have revealed that glucose 1,6-bisphosphate (Glc-1,6-P2) is a potent inhibitor of muscle hexokinase and an activator (deinhibitor) of phosphofructokinase and phosphoglucomutase, the effect of epinephrine on the levels of this regulator in rat diaphragm muscle was investigated. It was found that epinephrine caused an increase in diaphragm Glc-1,6-P2 levels, accompanied by a reduction in the activity of hexokinase and an activation (deinhibition) of phosphofructokinase and phosphoglucomutase. N6-2'-O-dibutyryl cyclic AMP was able to mimic all these effects of epinephrine. The concentration of glucose-6-phosphate was not changed by epinephrine, under conditions in which the hormone produced an increase in cyclic AMP and Glc-1,6-P2 levels and the concomitant decrease in hexokinase activity. It was also shown that Glc-1,6-P, in the concentration range found after epinephrine, inhibited the diaphragm hexokinase and deinhibited phosphoglucomutase. These results may suggest a mechanism of epinephrine action by which the activities of hexokinase, phosphoglucomutase and phosphofructokinase, through the action of Glc-1,6-P2, are synchronized with the cyclic AMP-mediated activation of glycogen phosphorylase, to achieve an increase in total glycogenolysis and glycolysis and a concomitant reduction in glucose utilization by the muscle.
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PMID:The effect of epinephrine and dibutyryl cyclic AMP on glucose 1,6-bisphosphate levels and the activities of hexokinase, phosphofructokinase and phosphoglucomutase in the isolated rat diaphragm. 20 4

Epinephrine, hydrocortisone, and dibutyril cAMP inhibited glycolysis and glucogenolysis. The inhibitory effect was also found when glucose-6-phosphate (G-6-P) was used as a glycolysis substrate, but not for fructose-1,6-diphosphate. This is the evidence of hexokinase activity inhibition by hormones and dibutyril cAMP, and presumably of phospholylase and phosphofructokinase as well. In the simulated cell-free system the hormones produced no effect, dibutyril cAMP inhibiting hexokinase alone. For the realization of hormones effect their interaction with the cell membrane is required. Inhibition of glycogen and G-6-P decomposition to lactic acid in the rat liver slices was not associated with the hormone action on phosphorylase and phosphofructokinase through cAMP and proteinkinase directly. The results obtained indicated the existence of a supplementary mechanism that modified cAMP effect on the activity of the said enzymes. Insulin was effective in any of the cases.
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PMID:[Effect of adrenaline, hydrocortisone, insulin and dibutyryl-cAMP on glycolysis and glycogenolysis in white rat liver slices]. 21 83

During the first 72 h after 67% partial hepatectomy of female Wistar rats (160 g) the specific activities [mumol X min-1 X (g liver)-1] of the glucogenic glucose-6-phosphatase and fructose-bisphosphatase and of the glycolytic hexokinase and 6-phosphofructokinase remained essentially constant. However, the activity of the glycolytic pyruvate kinase (L- plus M2-type) was decreased slightly and that of glucokinase was decreased markedly to below 30%, while the glucogenic phosphoenolpyruvate carboxykinase was increased to over 200%. Between 10 and 40 h after partial hepatectomy, when the proliferation started in the periportal area, a shift of the glucogenic glucose-6-phosphatase-rich zone from its normal periportal to an intermediate or even perivenous position was observed histochemically. After 48 h, when the proliferation was no longer restricted to the periportal zone, the normal glucose-6-phosphatase zonation (as before partial hepatectomy) was restored. Glycogen was degraded rapidly during the first 4 h after operation; it was later repeatedly resynthesized and degraded in correlation with the feeding rhythm of the animals. The zonation of glycogen metabolism was in accord with the observed zonation of glucose-6-phosphatase.
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PMID:Increase of the gluconeogenic and decrease of the glycolytic capacity of rat liver with a change of the metabolic zonation after partial hepatectomy. 21 1


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