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) The mitochondrial ATPase (EC 3.6.1.3) Ehrlich ascites cell mitochondria, was inhibited by D-glucose under physiological concentrations of ATP. The generation of ADP by the mitochondrial bound hexokinase, seems to be the reason for the D-glucose inhibitory effect. Reversal of the inhibitory effect of ADP on Ehrlich ascites cell mitochondria ATPase by an ATP-regenerating system was achieved. (2) Dissociation of mitochondrial bound hexokinase from the mitochondria eliminated the inhibitory effect of D-glucose. Rebinding of the hexokinase to the mitochondria regenerated the D-glucose inhibitory effect on Ehrlich ascites cell mitochondria ATPase. (3) Bioflavonoids such as quercetin inhibit the mitochondrial hexokinase activity, but do not change the mitochondrial ATPase activity of isolated Ehrlich ascites tumor cell mitochondria. (4) The inhibitory effect of bioflavonoids on mitochondrial bound hexokinase activity is shown to be dissociable from the ascites tumor cell mitochondria and seems to be associated with regulatory rather than catalitic sites of the enzyme.
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PMID:Bioflavonoid regulation of ATPase and hexokinase activity in Ehrlich ascites cell mitochondria. 1 95

Most chromosome aberrations in gliomas are numerical, resulting in either gains or deficiencies of whole chromosomes. In tumors of low malignancy, the karyotype is frequently normal or exhibits a loss of sex chromosome and a gain of chromosome 7. These two anomalies may not be directly related to malignancy. In the highly malignant cases, the two most frequent aberrations are the gain of chromosome 7 and the loss of chromosome 10, other anomalies such as losses or deletions of chromosomes, 9, 22, 6, 13 and 14 being detected at various frequencies. Several of these chromosomes carry important genes of adenine metabolism: AK1 and AK3 (adenylate kinase) and MTAP (methylthioadenosine phosphorylase) for chromosome 9; ADK (adenosine kinase) and mitochondrial ATPase for chromosome 10; ADSL (adenylosuccinate lyase) for chromosome 22, NP (nucleoside phosphorylase) for chromosome 14. We performed the corresponding assays of enzyme activity on both fresh tumors and tumors grafted on nude mice, which showed that these enzymes had a relatively low activity although the tumors were proliferating. However, chromosome losses do not seem to directly cause the metabolic alterations by gene dosage effect. Interestingly, chromosome 10, frequently deficient, also carries genes of importance for glycolysis (hexokinase) and glutamate metabolism (glutamate dehydrogenase and glutamate oxaloacetate transaminase). The deficiency for these genes could be taken into account for a better type of chemotherapy by antimetabolics.
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PMID:[Chromosome abnormalities and adenine metabolism in human glial tumors]. 144 60

Incubation of [gamma-32P]ATP with a molar excess of the membrane-bound form of mitochondrial ATPase (F1) results in binding of the bulk of the radioactive nucleotide in high affinity catalytic sites (Ka = 10(12) M-1). Subsequent initiation of respiration by addition of succinate or NADH is accompanied by a profound decrease in the affinity for ATP. About one-third of the bound radioactive ATP appears to dissociate, that is, the [gamma-32P]ATP becomes accessible to hexokinase. The NADH-stimulated dissociation of [gamma-32P]ATP is energy-dependent since the stimulation is inhibited by uncouplers of oxidative phosphorylation and is prevented by respiratory chain inhibitors. The rate of the energy-dependent dissociation of ATP that occurs in the presence of NADH, ADP, and Pi is commensurate with the measured initial rate of ATP synthesis in NADH-supported oxidative phosphorylation catalyzed by the same submitochondrial particles. Thus, the rate of dissociation of ATP from the high affinity catalytic site of submitochondrial particles meets the criterion of kinetic competency under the conditions of oxidative phosphorylation. These experiments provide evidence in support of the argument that energy conserved during the oxidation of substrates by the respiratory chain can be utilized to reduce the very tight binding of product ATP in high affinity catalytic sites and to promote dissociation of the nucleotide.
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PMID:Energy-dependent dissociation of ATP from high affinity catalytic sites of beef heart mitochondrial adenosine triphosphatase. 293 42

The effect of the local anesthetic bupivacaine on the energy metabolism of Ehrlich ascites tumor cells has been investigated. Even at low concentrations, bupivacaine decreased the oxygen uptake rate, but its effect was remarkably higher on the uncoupled respiration. Experiments on specific segments of the respiratory chain have shown that bupivacaine did not inhibit electron transport from Q to oxygen. Spectroscopic evidences demonstrated a NAD(P)H oxidation in bupivacaine-treated cells respiring on endogenous substrates, indicating that the inhibition of oxygen depended on a reduced electron transport from site 1-entering substrates to respiratory chain. The aerobic glycolysis was stimulated by low and inhibited by high bupivacaine concentrations. The increased lactate production rate was due to an activation of mitochondrial ATPase, whereas its decrease was related to an inhibition of the hexokinase activity.
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PMID:Effect of the local anesthetic bupivacaine on the energy metabolism of Ehrlich ascites tumor cells. 778 52