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)

In vitro incubation of key glycolytic enzymes in supernatant fluids from rabbit kidney medulla with increasing concentrations of sodium laurate resulted in progressive inhibition of hexokinase, phosphofructokinase and pyruvate kinase. A corresponding reduction in the production of lactate from glucose was also observed. The possible effects of these enzyme inhibitions on the naturesis observed during fasting are discussed.
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PMID:Inhibition of key glycolytic enzymes from rabbit kidney medulla by free fatty acids in vitro. 14 34

Three control point enzymes of the Embden-Meyerhof pathway, hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK), have been measured in individual hypothalamic nuclei during the 5-day estrous cycle of adult rats by quantitative histochemical methods. PK levels, low during proestrus, rise to maximum activity during estrus; this rise is significantly greater than on all other days of the cycle in the lateral preoptic area (LP), ventromedial pars medialis (VMM) and pars lateralis (VML) and posterior hypothalamic (Post) nuclei. HK activity also rises from low proestrous levels during the cycle but, in contrast to PK, reaches maximum activity during diestrus-1 (D-1) or diestrus-2 (D-2). PFK showed variable changes during the estrous cycle with peaks occurring during estrus in some nuclei and during diestrus in others, but these changes were not significantly different. These metabolic changes occur in specific hypothalamic nuclei which have been shown by electrical stimulation, lesion production, stereotaxic hormone implantation and localization of luteinizing hormone-releasing factor experiments to have an important role in reproductive physiology and sexual behavior.
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PMID:Quantitative histochemical studies of the hypothalamus. Control point enzymes during the estrous cycle. 14 24

Hexokinase, glucokinase, and phosphofructokinase activity in supernatant hepatic fluid obtained by centrifugation of the homogenate at 20,000 g for 20 minutes was studied during the development of experimental necrosis of the heart muscle. The activity of these enzymes was lowest in the 12th and 24th hour following arterial occlusion. Phosphofructokinase and glucokinase activity returned to the initial level on the 6th and 9th days, respectively; hexokinase activity was still diminished after the 12th day.
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PMID:[Activity of key enzymes of glycolysis in the rat liver during the development of experimental myocardial necrosis]. 14 17

Extensor digitorum longus muscles of rats were removed and injected with a solution of Marcaine plus hyaluronidase. After incubation in Marcaine solution for 10 min, the muscles were grafted into their original beds. The grafts and the contralateral control muscles were removed from the rats at 0, 1-5, 7, 11, 36, and 69 days postoperatively. The muscles were then frozen in dry ice and isopentane and subsequently homogenized and centrifuged. The supernatant was analyzed for a number of enzymes, the regenerative patterns of which can be classified into 3 groups: (1) early increase in activity: hexokinase, glucose-6-phosphate dehydrogenase; (2) early decrease in activity with failure to recover to control levels: phosphorylase, phosphofructokinase, alpha-glycerophosphate dehydrogenase; and (3) early decrease followed by return to control levels: lactate dehydrogenase, pyruvate kinase, creatine phosphokinase, adenylate kinase. These patterns are not identical to those reported for embryogenesis of muscle. The data are discussed with regard to correlative histological studies of muscle regeneration.
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PMID:Developmental patterns of glycolytic enzymes in regenerating skeletal muscle after autogenous free grafting. 14 74

An extension of a previous model [2] is proposed of the glycolysis of erythrocytes which includes realistic rat laws for the hexokinase-phosphofructokinase system and for the 2,3-P2G phosphatase. Whereas most conclusions previously drawn are reinforced, the mechanism of ATP regulation is different in the present model. The ATP concentration is mainly regulated by the inhibitory action of ATP and the activating effect of AMP on the phosphofructokinase. The role of the 2,3-P2G bypass as a buffer of changes in the ATP demand is of lesser significance than previously thought. Besides the feedback action of the adenine nucleotides on the hexokinase-phosphofructokinase system in the quasisteady state the role of 2,3-P2G as an energy source is important since it can yield ATP for a certain period of time. The present version of the model describes qualitatively the experimental data on the modulation of Na+-K+-ATPase.
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PMID:An extended model of the glycolysis in erythrocytes. 14 74

The behaviour of glycolytic flux and glycolytic metabolic concentrations was studied under conditions of magnesium deficiency. The Mg-deficiency was produced in whole animals (rats) by feeding a diet almost completely free of Mg and in hemolysates of men by the addition of a chelating agent. The results show that the decrease of the free Mg-level is diminished by partial destruction of ATP and 2,3-DPG. The analysis of the control strength of the overall flux leads to the conclusion that the decrease of the glycolytic rate is caused by an inhibition of the hexokinase-phosphofructokinase-control system. The decrease of the MgATP-Complex and free Mg++-level explains the diminished phosphorylation of glucose by the hexokinase. The ATP-inhibition of the phosphofructokinase is amplified by a small increase of free ATP-concentration and a simultaneous decrease of the Fru-6P-level. The increase of the PEP-level is caused by the diminished free Mg++ and MgATP-complex and does not demonstrate a larger control strength of the pyruvate kinase.
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PMID:[Control of glycolysis in magnesium deficiency: studies on intact red cells and hemolysates]. 14 77

Mutants have been isolated in S. cerevisiae with the phenotype of growth on pyruvate but not on glucose, or growth on rich medium with pyruvate but inhibition by glucose. Screening of mutagenized cultures was either without an enrichment step, or after enrichment using the antibiotic netropsin (Young et al. 1976) or inositol starvation (Henry, Donahue and Culbertson 1975). One class of mutants lacked pyruvate kinase (pyk), another class had all the enzymes of glycolysis, and one mutant lacked phosphoglucose isomerase (pgi, Maitra 1971). Partial reversion of pyruvate kinase mutants on rich medium containing glucose gave double mutants now also lacking hexokinase (hxk), phosphofructokinase (fk), or several enzymes of glycolysis (gcr). In diploids the mutations were recessive. pyk, pgi, pfk, and gcr segregated 2:2 from their wild-type alleles. PYK hxk, PYK pfk, and PYK gcr segregrants grew on glucose.
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PMID:Glycolysis mutants in Saccharomyces cerevisiae. 14 95

A study of post-mortem changes in human central nervous tissue has shown that within 100 h of death, no significant change occurs in the amount of nerve cell DNA and nucleolar RNA nor in some membrane-associated enzymes such as succinate dehydrogenase, NADH and NADPH diaphorase, and cytochrome oxidase. Low molecular weight RNA species, probably transfer and messenger RNA are quickly lost, but there is little alteration in ribosomal RNA content. Cytoplasmic enzymes show variable changes; phosphofructokinase activity is rapidly decreased; hexokinase is unaltered but lactate dehydrogenase, pyruvate kinase and glucose-6-phosphate dehydrogenase initially show increases in activity which subsequently decline. Oxygen uptake diminishes quickly. These findings indicate that mechanical alterations in cell structure, following death, render organelles physiologically ineffective long before any significant changes in certain constituent biochemicals are detected. This report emphasizes the great importance necessary in the selection of appropriately time matched post-mortem tissues if accurate comparative studies of many of the cells constituents are to be made.
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PMID:Post-mortem changes in human central nervous tissue and the effects on quantitation of nucleic acids and enzymes. 14 55

Three control point enzymes of the Embden-Meyerhof pathway, hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK) were measured by quantitative histochemical methods in individual hypothalamic nuclei of adult neonatally androgenized female rats. HK activity was significantly increased in anterior hypothalamic nuclei: medial preoptic, lateral preoptic, and suprachiasmatic. PK was significantly elevated in the lateral preoptic and suprachiasmatic nuclei of the anterior hypothalamus and also in the medial mamillary nucleus and median eminence. No significant changes occurred in PFK activity.
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PMID:Quantitative histochemical studies of the hypothalamus. Control point enzymes following androgen sterilization. 14 10

Vitamin A toxicity, caused by oral administration of 30,000 IU of vitamin A (retinyl palmitate) to young rats (70 to 90 g) once daily for 2 days, increased the levels of lipids, glycogen, and citrate in the liver. Furthermore, hypervitaminosis A decreased the activities of two key hepatic glycolytic enzymes, phosphofructokinase, and pyruvate kinase, without affecting those of hexokinase and glucokinase. It is suggested, therefore, that in addition to the increased activities of key gluconeogenic enzymes, reported earlier, a marked decrease in the activities of phosphofructokinase and pyruvate kinase and elevated level of citrate in the liver could account for the enhanced gluconeogenesis in hypervitaminosis A.
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PMID:Early effects of vitamin A toxicity on hepatic glycolysis in rat. 15 4


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