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

---

Query: EC:2.7.1.1 (hexokinase)
5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In soluble fraction of rat liver studies have been made on the activity of glycolytic enzymes and dehydrogenases of the pentose phosphate pathway 3 and 20 hours after the electrical stimulation of the medial (HVM) and lateral (AHL) structures of the medial hypothalamus via chronically implanted electrodes. Electrical stimulation of the HVM within 3 hours decreased total hexokinase, glucose-6-phosphate dehydrogenase, and lactate dehydrogenase activities, and to a lower extent -- the activity of glucokinase. This effect was not prevented by the adrenalectomy. During stimulation of the AHL, the decrease of LDH activity was the same, whereas the activity of hexokinase, glucose-6-phosphate dehydrogenase and glucokinase decreased to a lower extent. Electrical stimulation of the medial hypothalamus within 20 hours decreased the response, this effect being presumably associated with the decrease in the content of endogenous noradrenalin in the liver of animals. The role of the hypothalamus and sympathetic nervous system in regulation of the investigated enzymes of energy metabolism in the liver is discussed.
...
PMID:[Participation of the hypothalamus in regulating the activity of rat liver energy metabolism enzymes]. 98 65

Partial sympathectomy of rat liver, carried out by bilateral section of celiac nerves, caused a distinct increase in the activity of hexokinase and glucose-6-phosphate dehydrogenase and (less distinctly) of 6-phosphogluconate dehydrogenase and lactate dehydrogenase in liver tissue. The alterations in glucokinase activity were not statistically significant. Noradrenaline disappeared completely from rat liver after the celiac nerves section. Activities of the above-mentioned enzymes were altered to the same degree in sympathectomized liver of adrenalectomized animals. The increase in the hexokinase and glucose-6-phosphate dehydrogenase activity was prevented by administration of actinomycin D immediately after the section of celiac nerves. The data obtained suggest that after section of liver celiac nerves the alterations in the enzymatic activities are determined by the increase of their biosynthesis and occur as a result of impairment of liver sympathetic innervation.
...
PMID:[Nature of changes in the activity of certain enzymes of energy metabolism in the liver after partial sympathectomy]. 102 52

1. The effects of dietary energy level and dietary energy source on protein utilization by plaice (Pleuronectes platessa) were examined by giving diets containing 400 g crude protein/kg to nine groups of fish. Five of these diets contained only lipid as a source of energy (in addition to protein) and their energy contents were varied by increasing the lipid level in a step-wise manner from 56 to 176 g/kg. The remaining four diets contained both lipid and carbohydrate (glucose plus dextrin) together as energy sources: two levels of carbohydrate (100 and 200 g/kg) being used at each of two (56 and 86 g/kg) lipid levels. 2. Weight gains of plaice given the diets containing only lipid as an energy source did not differ significantly from each other. Weight gains of plaice given diets containing carbohydrate as well as protein and lipid were superior to those given diets lacking carbohydrate. 3. Values obtained for protein efficiency ratio (PER) and net protein utilization (NPU) increased with increasing dietary energy level in both those fish given the diets containing carbohydrate and those given diets lacking it. Both PER and NPU values were greater for plaice given diets containing carbohydrate than for fish diets without carbohydrate even when the total energy content of the diets was approximately the same. 4. Liver glycogen levels were significantly higher in plaice given diets containing 200 g carbohydrate/kg than in plaice given diets without carbohydrate. Blood glucose levels and hepatic hexokinase (EC 2-7-1-1) levels were not significantly different in plaice given these diets. No glucokinase (EC 2-7-2-2) was detected in plaice given either diet. 5. The metabolic fate of glucose carbon in plaice was investigated by injecting the fish intraperitoneally with [U-14C] glucose and examining, 18 h afterwards the distribution of radioactivity in different biochemical fractions from the fish. 6. Glucose was respired much less rapidly in the carnivorous plaice, irrespective of dietary treatment, than in omnivorous mammals (mouse and rat). The rate of production of 14CO2 from (U-14C) glucose by plaice given diets containing carbohydrate was not significantly greater than that by plaice given diets lacking carbohydrate. 7. More glucose was incorporated into liver glycogen when plaice were given carbohydrate in their food than when it was absent. Otherwise no differences were apparent in the fate of glucose C by plaice which could be related to the diets used. 8. No mortalities occurred nor was any histopathology observed in the plaice as a consequence of the inclusion of carbohydrate in the food.
...
PMID:Studies on the nutrition of marine flatfish. The metabolism of glucose by plaice (Pleuronectes platessa) and the effect of dietary energy source on protein utilization in plaice. 111 61

Hexokinase (ATP:D-glucose 6-phosphotransferase EC 2.7.1.2) and pyruvate kinase (ATP:pyruvate 2-0-phosphotransferase EC 2.7.1.40) were co-immobilized within semipermeable collodion microcapsules. The resulting microcapsules displayed excellent hexokinase and pyruvate kinase activities, with the measured pyruvate kinase activity considerably greater than that measured for hexokinase. The co-immobilized enzymes, when used sequentially were capable of recycling both ATP and ADP when exposed to the appropriate conditions. Furthermore, when exposed to limiting amounts of coenzyme, the cycles were capable of reusing the total amount of coenzyme supplied at least three times in 90 min. The use of microencapsulation to produce partially "self sufficient" enzyme systems is discussed.
...
PMID:Epnzymatric recycling of coenzymes by a multi-enzyme system immobilized within semipermeable collodion microcapsules. 114 55

D-Glucosamine was found to be phosphorylated by a rat liver extract in the presence of a high concentration of glucose, which was formerly believed to be a strong competitive inhibitor of this reaction. Results suggested that glucosamine may be phosphorylated by high Km hexokinase, i.e. glucokinase [EC 2.7.1.2]. The enzyme involved was separated from specific N-acetyl-D-glucosamine kinase [EC 2.7.1.59]. The phosphorylation was not inhibited by a physiological level of glucose or glucose 6-phosphate, which strongly inhibited low Km hexokinase. The apparent Km of glucokinase for glucosamine was estimated as 8 mM, which is ten times that of low Km hexokinase.
...
PMID:Phosphorylation of D-glucosamine by rat liver glucokinase. 115 56

The realtionship between growth rate and the metabolic activity of certain liver enzymes was studied using two strains of White Plymouth Rock chickens which had been selected in divergent directions for eight-week body weight. The activities of hexokinase, glucokinase, phosphofructokinase, glucose-6-phosphate dehydrogenase, citrate synthase, glycogen synthetase, glutamate dehydrogenase and aspartate transaminase were measured at 4, 8 and 20 weeks of age. The mean percentage rate of growth of the birds selected for high eight-week body weight exceeded that of the birds selected for low eight-week body weight only during the early growth period. Thereafter, and until sexual maturity, the low-line birds grew at a faster rate, relative to body size. The mature body weight of the high-line birds exceeded that of the low-line birds by a factor of approximately 1.5. A close similarity was noted between the metabolic activity of certain liver enzymes and the growth rate (relative to body size) of the birds studied. At four and eight weeks of age, the faster-growing birds (whether high- or low-line) generally exhibited a greater capacity for glucose phosphorylation and glycolysis, but a poorer capacity for glycogen synthesis, than the slower-growing birds. At twenty weeks, growth rate and metabolic activity were similar in both strains.
...
PMID:Activity of certain liver enzymes in fast- and slow-growing lines of chickens. 118 17

A new improved procedure for the purification of rat hepatic glucokinase (ATP-d-glucose 6-phosphotransferase, EC 2.7.1.2) is given. A key step is affinity chromatography on Sepharose-N-(6-aminohexanoyl)-2-amino-2-deoxy-d-glucopyranose. A homogeneous enzyme, specific activity 150 units/mg of protein, is obtained in about 40% yield. The molecular weight of the pure enzyme was determined by several procedures. In particular, sedimentation-equilibrium studies under a variety of conditions indicate a molecular weight of 48000 and no evidence for dimerization; reports in the literature of other values are discussed in the light of this evidence on the pure enzyme. The amino acid composition suggests that hepatic glucokinase is closely related to rat brain hexokinase and also the wheat "light" hexokinases.
...
PMID:The purification in high yield and characterization of rat hepatic glucokinase. 127 94

The activity of glucokinase, hexokinase and glucose-6- phosphoric dehydrogenase of the liver and myocardium of rabbits was tested at different stages of pyrogenal fever with the aid of spectrophotometry. A marked decrease in the activity of the enzymes under study was observed in fever. After the subsidence of fever the activity of the enzymes became normal.
...
PMID:[Hepatic and myocardial glucokinase, hexokinase and glucose-6-phosphate dehydrogenase activity in rabbits with pyrogenal fever]. 127 11

Addition of glucose-related fermentable sugars or protonophores to derepressed cells of the yeast Saccharomyces cerevisiae causes a 3- to 4-fold activation of the plasma membrane H(+)-ATPase within a few minutes. These conditions are known to cause rapid increases in the cAMP level. In yeast strains carrying temperature-sensitive mutations in genes required for cAMP synthesis, incubation at the restrictive temperature reduced the extent of H(+)-ATPase activation. Incubation of non-temperature-sensitive strains, however, at such temperatures also caused reduction of H(+)-ATPase activation. Yeast strains which are specifically deficient in the glucose-induced cAMP increase (and not in basal cAMP synthesis) still showed plasma membrane H(+)-ATPase activation. Yeast mutants with widely divergent activity levels of cAMP-dependent protein kinase displayed very similar levels of activation of the plasma membrane H(+)-ATPase. This was also true for a yeast mutant carrying a deletion in the CDC25 gene. These results show that the cAMP-protein kinase A signaling pathway is not required for glucose activation of the H(+)-ATPase. They also contradict the specific requirement of the CDC25 gene product. Experiments with yeast strains carrying point or deletion mutations in the genes coding for the sugar phosphorylating enzymes hexokinase PI and PII and glucokinase showed that activation of the H(+)-ATPase with glucose or fructose was completely dependent on the presence of a kinase able to phosphorylate the sugar. These and other data concerning the role of initial sugar metabolism in triggering activation are consistent with the idea that the glucose-induced activation pathways of cAMP-synthesis and H(+)-ATPase have a common initiation point.
...
PMID:Glucose-induced activation of plasma membrane H(+)-ATPase in mutants of the yeast Saccharomyces cerevisiae affected in cAMP metabolism, cAMP-dependent protein phosphorylation and the initiation of glycolysis. 132 8

The gene encoding human glucokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1), a major component of glucose sensing in pancreatic islet beta-cells, was isolated and characterized. The gene was shown by Southern blotting to exist as a single copy in the genome which mapped to chromosome 7p. It contained 12 exons including two tissue-specific first exons, one active in islet beta-cells (1B), and the other active in liver (1H), and one optional cassette exon which was expressed as a minor form in the liver. Thus the three previously reported isoforms of glucokinase mRNA were the result of tissue-specific activation of separate liver and islet promoters and subsequent alternative splicing events. Eleven exons, including 1H and the optional cassette exon 2A, were scattered over 16 kilobase (kb) in the genome, while exon 1B was separated from the rest by at least 20 kb. Although the islet promoter was found to lack a TATA box, a major transcript from the islet promoter was mapped 486 nucleotides upstream of the translation initiation site. The presence in the islet glucokinase promoter of the potential control element GCCACCAG, a homology of the regulatory element present in both human insulin (GCCACCGG) and rat insulin (GCCATCTG) genes, implied a possible tissue-specific regulatory role of this element. The liver promoter was found to contain a TATA box-like sequence, and transcription was initiated predominantly at 168 nucleotides upstream of the translation initiation site of the major isoform. A new highly polymorphic microsatellite, composed of a compound imperfect dinucleotide repeat [GT]15[GA]8CA[GA]7CA[GA]3AA[GA]2, was mapped 6 kb upstream of islet exon 1. A polymerase chain reaction-based assay was developed, and seven different sized alleles were identified in American Blacks. The sequence information reported here, along with the new polymorphic marker, will make it possible to clarify the molecular basis of potential glucokinase defects in noninsulin-dependent diabetes mellitus patients and may further elucidate the nature of genetic susceptibility to the development of this common metabolic disease.
...
PMID:Human glucokinase gene: isolation, structural characterization, and identification of a microsatellite repeat polymorphism. 135 40


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---