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. Activities of 20 red cell enzymes were compared in 8 normal female Ovis Aries, in a serially bled ewe followed by 243 days, and in young and old red cell populations separated by density gradient centrifugation. 2. These comparisons indicate that the erythrocyte enzymes which show significant changes with cell age are glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, hexokinase, phosphoglucose isomerase, lactate dehydrogenase, glutathione reductase, enolase and phosphoglycerate kinase. 3. The usefulness of these data in interpretation of enzyme activities from fetal Ovis Aries is discussed.
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PMID:Erythrocyte enzymes in Ovis aries. Effect of cell age. 706 Mar 50

Current cell disruption and fractionation techniques are time consuming and unsuitable for metabolic studies. We have developed a rapid method for platelets in which separation of cytosol and particle fraction is obtained within 50 s. Isolated platelet suspensions were incubated with low concentrations of digitonin followed by separation of soluble and particle fraction by centrifugation through a phthalate layer. Cell disruption was 90.1+/-4.2% (mean+/-SD, n=18; lactate dehydrogenase leakage). Contamination of granules: acid hydrolase vesicles 16.2+/-3.6% (n=18, beta-N-acetylglucosaminidase), dense granules 7--9% (n=3, 14C-serotonin), mitochondrial matrix 0.6+/-0.1% (n=18, glutamate dehydrogenase). Low concentrations of digitonin did not affect sialic acid content, nucleoside diphosphate kinase and phosphodiesterase activity in isolated membranes. The method showed that most enzymes of glycolysis and hexose monophosphate shunt were localized in the cytosol except for hexokinase (96% particle bound), phosphoglucose isomerase (10% bound) and glutathion reductase (26% bound). About half the total ATP+ADP and most glycolytic intermediates were found partly particle bound, especially fructose 1,6-diphosphate (40% bound). The data suggest that in platelets glycolysis occurs in different cell compartments.
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PMID:Rapid separation of cytosol and particle fraction of human platelets by digitonin-induced cell damage. 737 1

Several glycolytic enzymes exist in muscle as free and structure-bound forms. A fraction of hexokinase (HK) is associated with the outer mitochondrial membrane. Phosphofructokinase (PFK) and aldolase (ALD) bind to F-actin, and AMP deaminase (AMPase) interacts with myosin. Using low-frequency stimulation (10 Hz, 24 h/d), we studied in rat fast-twitch muscle effects of contractile activity on soluble and structure-bound forms of these enzymes. Phosphoglucose isomerase (PGI), a soluble enzyme, was also examined. Fractional extraction was applied to study the intracellular distribution of soluble and bound enzyme activities 5 min, 1 h, 3 h, 1 d, and 7 d after the onset of stimulation. Confirming previous findings, total HK activity increased 7-fold in 7-d-stimulated muscles, whereas PFK, ALD, and PGI were reduced, ranging between 55% and 80% of their normal activities. AMPase activity was unaltered. At the time points studied, no changes were found in the extraction behavior of PGI and AMPase. The fraction of bound ALD increased slightly (12%). However, the distribution of HK and PFK was markedly altered. Bound PFK increased from 50% in the control to 85% in 7-d-stimulated muscles. Bound HK rose from 52% to 83% during the same time period. The increase in PFK binding was steep and occurred mainly within the first minutes and hours. The increase in HK binding occurred with some delay, but was significant in muscles stimulated for more than 1 h. In view of the altered kinetic properties of F-actin-bound PFK (alleviated allosteric inhibition by ATP) and bound HK (elevated catalytic activity), these changes are interpreted as early responses to match the metabolic demands during maximal contractile activity imposed on a muscle not programmed for sustained activity: Enhanced binding of PFK serves to accelerate glycolytic flux immediately after the onset of stimulation, whereas mitochondrial binding of HK facilitates the phosphorylation of exogenous glucose when glycogen stores have been depleted.
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PMID:Effects of low-frequency stimulation on soluble and structure-bound activities of hexokinase and phosphofructokinase in rat fast-twitch muscle. 766 4

For biological oceanography it is important to understand the coupling between physical and biological processes in pelagic systems. The calanoid copepod Calanus finmarchicus dominates the zoo-plankton biomass and is an important link between primary producers and higher trophic levels in the northern Atlantic. Thus understanding how the physical environment affects gene expression or population genetics in this species is important. However, very few nuclear genes have been characterized from this species, making it difficult to perform these types of studies. Four cDNAs encoding actin, hexokinase, phosphoglucose isomerase, and phosphofructokinase, as well as a hexokinase genomic DNA, have been isolated and characterized. These sequences constitute important molecular tools for biological oceanographers.
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PMID:Nuclear genes from the copepod Calanus finmarchicus. 767 Jun

Yeast hexokinase (EC 2.7.1.1) catalyzes the phosphorylation of D-glucal and methyl alpha- and beta-D-glucopyranosides at 1-5% of the rates of phosphorylation of D-glucose and 2-deoxy-D-glucose. Maltose, cellobiose, D-galactal and tetrahydropyran-2-methanol are not substrates of hexokinase. Enzymatically synthesized D-glucal-6-phosphate inhibits rabbit muscle phosphoglucose isomerase competitively (KI = 1.94 mM) and phosphoglucomutase noncompetitively (KI = 0.122 mM).
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PMID:Selective inhibition of metabolic enzymes by enzymatically synthesized D-glucal-6-phosphate. 785 68

The present paper evaluates the contributions of glucose and its metabolites to the post-translational regulation of hexose transport and GLUT-1 content in murine fibroblasts. The effects of 3-O-methylglucose, a nearly non-metabolizable glucose analogue, on 2-deoxyglucose-uptake, cell-surface expression and content of GLUT-1, glucose 6-phosphate levels, and phosphoglucose isomerase (PGI) and hexokinase activities of murine fibroblasts were compared with those of glucose and fructose. Glucose (EC50 approximately 6 mM) or 3-O-methylglucose (EC50 approximately 12 mM), which are substrates of GLUT-1, but not fructose, which is not transported by GLUT-1, are able to prevent the glucose-deprivation-induced increases in both hexose transport and cell-surface expression of GLUT-1. In contrast, glucose (EC50 approximately 6 mM), but not 3-O-methylglucose or fructose, prevents the glucose-deprivation-induced accumulation of total GLUT-1 polypeptides. Glucose (> or = 5 mM), but not fructose or 3-O-methylglucose, leads to significant glucose 6-phosphate accumulation. Although 3-O-methylglucose is weakly phosphorylated by fibroblasts, accumulation of phosphorylated product does not correlate with hexose-transport regulation. The activities of hexokinase and PGI are not altered by glucose, fructose or 3-O-methylglucose. We suggest that, in murine fibroblasts: (i) hexose transport and GLUT-1 content are differentially regulated; (ii) substrates of GLUT-1 and/or their immediate metabolites regulate the cell-surface expression of functional GLUT-1; and (iii) glucose metabolism is required for the regulation of GLUT-1 content.
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PMID:Differential control of the functional cell surface expression and content of hexose transporter GLUT-1 by glucose and glucose metabolism in murine fibroblasts. 821 41

D-Glyceraldehyde irreversibly inhibited rat liver glucokinase in a concentration-dependent manner. The inactivation of glucokinase by glyceraldehyde was blocked by the presence of its substrates such as glucose and mannose. Glucokinase was highly sensitive to glyceraldehyde compared with some other glycolytic enzymes (from animal tissues) including hexokinase, glucose-6-phosphate isomerase, 6-phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase. The amino acid analysis of untreated and glyceraldehyde-treated glucokinase suggested that glyceraldehyde-induced inactivation of glucokinase is caused by glycation of Lys residues of the enzyme by the triose. Treatment of pancreatic islets with 6 mM glyceraldehyde for 1 h at 37 degrees C caused both inactivation of glucokinase and inhibition of glucose-induced insulin secretion. Another glucose-phosphorylating enzyme (hexokinase) in pancreatic islets, however, was little affected by glyceraldehyde. In addition, glyceraldehyde did not affect the insulin secretory responses of islets to nonglucose secretagogues such as glyceraldehyde and Leu. When pancreatic islets were cultured with a lower concentration (1 mM) of glyceraldehyde for a longer time (17 h) in the presence of 10 mM glucose to mimic the in vivo conditions, both glucokinase activity and glucose-induced insulin secretion were again decreased. This study demonstrates that glucose-induced insulin secretion is impaired by glyceraldehyde through the inactivation of glucokinase. The implication of this finding in the pathophysiology of type II diabetes is discussed.
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PMID:Inhibition of glucose-induced insulin secretion through inactivation of glucokinase by glyceraldehyde. 851 67

The loci for three enzymes (hexokinase, phosphoglucomutase, and testicular esterase) and two eye-color mutants (brick and tan) are mapped on the X chromosome of Glossina palpalis palpalis. The loci occur in the order brick Hex (tan/Pgm) Est-t, with a recombination frequency of approximately 78% between the outer two loci. The locus for octanol dehydrogenase is located in linkage group II and the loci for malate dehydrogenase and phosphoglucose isomerase are separated by a recombination frequency of about 42.5% in linkage group III. Intrachromosomal recombination occurs at a much lower frequency in males than in females. The distribution of five biochemical marker genes in the linkage groups of G. p. palpalis is markedly different from that found in other higher flies.
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PMID:Genetics of Glossina palpalis palpalis: designation of linkage groups and the mapping of eight biochemical and visible marker genes. 853 97

It has been proposed that in mammalian systems the glucose analog 2-fluoro-2-deoxy-D-glucose (FDG) is phosphorylated and subsequently converted to the corresponding mannose derivative via the action of phosphoglucose isomerase. As is generally true in metabolic studies of fluorinated molecules, the fluorine spectrum alone is suggestive, without providing definitive structural evidence, while the use of 1H NMR techniques generally suffers from a lack of adequate selectivity. A 1H-19F version of the hetero-RELAY experiment has been applied to this problem. Formation of the corresponding C-6 phosphorylated 2-FDG analog with hexokinase, followed by treatment of the resulting phosphorylated products with phosphoglucose isomerase, resulted in the observation of additional 19F resonances consistent with the corresponding 2-fluoro-2-deoxy-D-mannose-6-phosphate metabolite. A more definitive product identification was obtained using the hetero-RELAY experiment, which provides a complete 19F-decoupled proton spectrum for each of the fluorinated species.
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PMID:Identification of 2-fluoro-2-deoxy-D-glucose metabolites by 19F(1H) hetero-RELAY. 854 95

We cloned and sequenced the pyruvate decarboxylase (PDC; EC 4.1.1.1) structural gene KIPDCA in the yeast Kluyveromyces lactis and found it to be allelic to the previously isolated rag6 mutation. The putative amino acid sequence of the KIPdcAp appeared to be highly homologous to those of the yeast Pdc proteins identified so far. The disruption of KIPDCA indicated that it is the only PDC structural gene in K. lactis, as evidenced by the lack of PDC activity and ethanol production in the pdcA delta strains and by the absence of growth on glucose in the presence of respiratory inhibitors. It was observed that expression of the KIPDCA gene is induced by glucose at the transcriptional level. Transcription of the gene was reduced in the rag1, rag2, rag5 and rag8 mutants, which are defective for the low-affinity glucose permease, phosphoglucose isomerase, hexokinase, and a positive regulator of RAG1 expression, respectively.
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PMID:The 'petite-negative' yeast Kluyveromyces lactis has a single gene expressing pyruvate decarboxylase activity. 882 34


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