Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 effect of cooling and subsequent rewarming on the tissue respiration of canine hearts was studied during polycomponent ether-oxygen anaesthesia. The tests included the determinations of the activity of the dehydrogenases of the cytrate cycle, the content and activity of chromoproteids, the respiration rate of the mitochondrias on succinate, glutamate and ketoglutarate, the content of glycogen, the activity of the phosphorylases, hexokinase, lactate dehydrogenase, the content of lactate, pyruvate, adenyl nucleotides and creatine phosphate. Significant changes were noted in the content and activity of the above substances, acceleration of mitochondrial respiration, reduced energy regulation of respiration, and decreased amount of the adenyl components. It is suggested that under artificial hypothermia the processes of chromoproteids biosynthesis are enhanced, which results in an increased power of terminal respiration, and conformational rearaangements of the enzymes connected with the membranes occur.
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PMID:[Characteristics of energy metabolism in the myocardium under artificial hypothermia]. 19 79

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

In liver tissue of mice, administered with diethyl nitrosamine (2.5 mg/kg of body weight) within 2-8 months, activities of hexokinase and glucoso-6-phosphate dehydrogenase were increased and the activity of glucose-6-phosphatase was decreased . Termination of the administration of diethyl nitrosamine, which was carried out during 1-2 months, caused the temporary normalization of the enzymatic activity, but later on the alterations typical for carcinogensis were developed. After more prolonged administration of diethyl nitrosamine the period of normalization gradually disappeared. The distinct alterations in the enzymatic activity, after termination of diethyl-nitrosamine administration, were closely related to development of tumors in liver tissue.
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PMID:[Enzymatic activity of glucose-6-phosphate metabolism in the liver during the administration of a hepatic carcinogen]. 19 15

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

Reaction of ADP with hexamethylene diisocyanate in hexamethylphosphoramide followed by treatment in an acidic medium afforded three new adenine nucleotide analogues, N6-[N-(6-aminohexyl)carbamoyl]-ADP, N6-[N-(6-aminohexyl)carbamoyl]-ATP, and N6-[N-(6-aminohexyl)carbamoyl]-AMP in yields of 13%, 12% and 17%, respectively. The occurrence of the ATP analogue may be interpreted in terms of the equilibrium, 2ADP = ATP + AMP. Coenzymic activities of the ADP analogue against acetate kinase and pyruvate kinase were 82% and 20%, respectively, relative to ADP and those of the ATP analogue against hexokinase and glycerokinase were 63% and 87%, respectively, relative to ATP. These analogues were bound to CNBr-activated soluble dextran through their terminal amino group to give an immobilized ADP and an immobilized ATP, each of which was recycled in a system comprising acetate kinase and hexokinase, and when placed in a membrane reactor together with the enzymes, functioned as an immobilized coenzyme continuously yielding glucose 6-phosphate. A series of chemically defined affinity adsorbents were obtained by coupling these analogues to CNBr-activated Sepharose, and were used to separate the enzymes in a mixture of hexokinase, pyruvate kinase, phosphoglycerate kinase, lactate dehydrogenase, and alcohol dehydrogenase.
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PMID:Preparation of N6-[N-(6-aminohexyl) carbamoyl]-adenine nucleotides and their application to coenzymically active immobilized ADP and ATP, and affinity adsorbents. 19 56

A tumorigenic anchorage-dependent cell line (H-91) was established in culture from an azo-dye-induced rat ascites hepatoma. When grown in a glucose-containing medium the cells exhibit high rates of lactic acid production characteristic of rapidly growing tumor cells. However, when glucose is replaced with galactose the cells grow equally well but exhibit only moderately elevated rates of lactic acid production. The molecular basis for this observation cannot be attributed to differences in permeability because initial rates of glucose and galactose entry into hepatoma cells are identical. Rather, the activity of hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) is found to be high in hepatoma cells, about 20-fold higher than that of control and regenerating rat liver. Moreover, tumor hexokinase activity is not inhibited by low concentrations (<0.6 mM) of the reaction product glucose 6-phosphate. Additionally, 50% of the hexokinase activity of hepatoma cells is found associated with the mitochondrial fraction. This fraction is 3-fold enriched in hexokinase activity relative to the homogenate and 4-fold enriched relative to the nuclear and postmitochondrial fractions. Tumor mitochondrial hexokinase appears to be coupled directly to oxidative phosphorylation, because addition of glucose to respiring hepatoma mitochondria (after a burst of ATP synthesis) results in stimulation of respiration. In contrast, glucose has no effect on the respiration of mitochondria from control and regenerating liver. These results suggest that the high glycolytic capacity of H-91 hepatoma cells is due, at least in part, to an elevated form of hexokinase concentrated in the mitochondrial fraction of the cell.
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PMID:High aerobic glycolysis of rat hepatoma cells in culture: role of mitochondrial hexokinase. 19 1

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

Carbamyl phosphate synthetase from Escherichia coli has been shown to use only the A isomer of adenosine-5'-[2-thiotriphosphate] in both the ATPase reaction (MgATP HCO3- leads to MgADP + Pi) and the carbamyl phosphate synthesis reaction (2MgATP + HCO3- + L-glutamine leads to 2MgADP + Pi + carbamyl-P + L-glutamate). The B isomer was less than 5% as reactive. In the reverse reaction, only the A isomer of adenosine-5'-[2-thiotriphosphate] is synthesized from adenosine-5'-[2-thiodiphosphate] and carbamyl-P as determined by 31P NMR and a coupled enzymatic assay with Cd2+- hexokinase. It is therefore proposed that carbamyl phosphate synthetase uses the same diastereomer of MgATP at both ATP sites.
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PMID:Carbamyl phosphate synthetase of Escherichia coli uses the same diastereomer of adenosine-5'-[2-thiotriphosphate] at both ATP sites. 21 Nov 24

The conversion of glucose into glucose 6-phosphate in an extract of isolated rat hepatocytes incubated in the presence of MgATP was studied spectrophotometrically at 340nm and also by a radiochemical procedure based on the release of (3)H from [2-(3)H]glucose. Both methods gave similar results. The glucose-saturation curve was sigmoidal and the shape of this curve was not influenced by the ionic composition of the incubation medium. The activity at 0.5mm-glucose was only 1-2% of V(max.), indicating a virtual absence of low-K(m) hexokinase in the preparation. The radiochemical method was also used for the determination of glucose phosphorylation by intact hepatocytes. The glucose-saturation curve was also markedly sigmoidal, but the s(0.5) (substrate concentration at half-maximal velocity) and the Hill coefficient were larger than in extracts of hepatocytes. These two parameters became smaller when cells were incubated in a medium in which Na(+) ions were replaced by K(+) ions. The increased rate of phosphorylation at low glucose concentration in a K(+) medium was accompanied by an increased rate of metabolite recycling between glucose and glucose 6-phosphate and also by an increased uptake of glucose. In both media phosphorylation of glucose was inhibited co-operatively by N-acetylglucosamine. Calculations indicate that this inhibition would reach 100% at saturation of the inhibitor, although at lower concentrations of N-acetylglucosamine it was smaller than expected from the known K(i) of N-acetylglucosamine for glucokinase. The rate of phosphorylation of glucose was proportional to the amount of glucokinase in hepatocytes from newborn rats and in conditions such as starvation and diabetes in which the total amount of glucokinase in the liver is decreased. In the same conditions, glucose 6-phosphatase activity was either normal or increased. It is concluded that the phosphorylation of glucose in isolated hepatocytes follows sigmoidal kinetics, which can be explained by the activity of glucokinase alone with no participation of low-K(m) hexokinase or of glucose 6-phosphatase.
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PMID:Phosphorylation of glucose in isolated rat hepatocytes. Sigmoidal kinetics explained by the activity of glucokinase alone. 21 56

A procedure is described to prepare uniformly labelled D-[14C]ribulose 1,5-bisphosphate enzymically from uniformly labelled D-[14C]glucose through the coupled reactions catalysed by hexokinase (EC 2.7.1.1), glucose 6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44) and 5-phosphoribulokinase (EC 2.7.1.19). All reagents utilized in the method are commercially available. The procedure is a reliable preparative-scale method for synthesizing the dibarium salt of D-[14C]ribulose 1,5-biphosphate with a specific radioactivity up to 7 mCi/mmol and a purity near 90%. The final product was free of other 14C-labelled sugars, sugar phosphate esters, Pi and nucleotides.
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PMID:Preparative-scale enzymic synthesis of D-[14C]ribulose 1,5-bisphosphate. 21 56


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