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)

A trial has been performed of a new sweetening agent saccharol, glycosides complex, on energy metabolism in rats with experimental alloxan diabetes. Elevated glucose level observed in rats with insulin insufficiency was associated with hexokinase activity inhibition and changes in the activity of the enzymes involved in glucose-6-phosphate transformation: enhanced activity of glucose-6-phosphatase and glucose-6-phosphate dehydrogenase against inhibition of phosphoglucomutase activity. Introduction of saccharose aggravated the above shifts in the rat liver, whereas saccharol possesses a protective action on hexokinase hepatic reaction and enzymes of glucose-6-phosphate conversion, reduced blood glucose. Positive changes induced by saccharol on energy metabolism in animals with insulin insufficiency can be attributed to the effect of saccharol glycosides.
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PMID:[Effect of saccharol glycosides on energy metabolism in animals with abnormal carbohydrate tolerance]. 797 8

Glucose-repressed growth of Saccharomyces cerevisiae was analysed in a nitrogen-limited continuous culture at different dilution rates (D). The glucose consumption of the yeast decreased from 3.4 g g-1 h-1 to 3.0 g g-1 h-1 when D was decreased from 0.3 h-1 to 0.15 h-1. No transcripts of the SUC2 and HXK1 genes, encoding, respectively, invertase and hexokinase isoenzyme 1, could be detected. Because both genes are regulated by glucose repression at the transcriptional level, this confirmed that the culture was glucose repressed at every D. During the decrease in D, no change in the activities or mRNA levels of key enzymes in carbon metabolism was observed, except for alcohol dehydrogenases I and II and phosphoglucomutase. These enzymes increased in activity and/or mRNA level when D was decreased, which was also observed in glucose- and galactose-limited continuous cultures. This demonstrates that the expression levels of alcohol dehydrogenases I and II, and also phosphoglucomutase, are coupled to the growth rate of the organism. A comparison between the alcohol dehydrogenase II activity in glucose- and nitrogen-limited continuous cultures demonstrated that the growth rate contributes as much to repression of alcohol dehydrogenase II activity as does glucose. Both the glucose consumption and the activity of the glycolytic enzymes were relatively constant when D was decreased and, as a consequence, the concentrations of intracellular metabolites remained constant. A slight decrease in the glucose 6-phosphate concentration was observed, which could be caused by the slight decrease in glucose consumption at low D values.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A nitrogen-limited, glucose-repressed, continuous culture of Saccharomyces cerevisiae. 801 81

When different strains of Saccharomyces cerevisiae grown at 23 degrees C were transferred to 36 degrees C, trehalose and glycogen were accumulated. Glycogen accumulation was less extensive and its synthesis started at least 15 min after initiation of trehalose synthesis. The steady-state intracellular concentration of trehalose increased simultaneously with the activities of the enzymes trehalose-6P synthase, UDPG-pyrophosphorylase, phosphoglucomutase and trehalase. A small but significant change was observed in hexokinase activity. Our results directly implicate isoform PII of hexokinase and the minor isoform of phosphoglucomutase in the pathway of trehalose formation during heat-shock. We also showed that the major isoform of phosphoglucomutase increased in activity but was not essential for trehalose accumulation. Studies with the glucose uptake system indicated that trehalose accumulation could be primarily determined by intracellular availability of substrates due to the increase in the rate of glucose uptake. The increased uptake appears to have two components: a kinetic effect of temperature upon glucose transporters and an increase in the numbers of molecules of the transporters, probably mediated by synthesis de novo.
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PMID:Trehalose metabolism in Saccharomyces cerevisiae during heat-shock. 803 33

With the advent of new techniques of human in vitro fertilization (IVF), identifying parameters of oocyte quality to allow selection of those most likely to fertilize becomes crucial. Morphology of oocytes, which correlates positively with biological performance, is the currently utilized classification criterion. However, biological links between form and function are tenuous, and underlying mechanisms remain elusive. We investigated whether biochemical activation is quantitatively associated with the stages of maturation in ova obtained from patients undergoing gynecologic surgery during unstimulated cycles and women undergoing IVF after exogenous gonadotropin stimulation. Changes in selected enzymes from protein, lipid, and carbohydrate metabolism (hexokinase, phosphoglucomutase, glycogen synthetase, uridine diphosphoglucose pyrophosphorylase, glucose-6-phosphate dehydrogenase, cytosolic thiolase, beta-hydroxyacyl-CoA dehydrogenase, alanine aminotransferase, and aspartate aminotransferase) were determined simultaneously, in individual oocytes, utilizing a highly sensitive biochemical methodology. Several enzyme activities paralleled maturation grade and were higher in stimulated oocytes after correction for grade. These biochemical findings quantify metabolic and functional changes that increase as ova mature, possibly contributing to their reproductive performance.
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PMID:Enzyme activities and maturation in unstimulated and exogenous gonadotropin-stimulated human oocytes. 809 73

Isoenzymes of phosphoglucomutase and hexokinase were repeatedly evaluated using starch gel electrophoresis in polyxenic cultures of Entamoeba histolytica. In two out of 18 strains spontaneous changes of isoenzyme patterns were recorded. While originally they were categorized into virulent group of zymodemes, following isoenzyme analysis classified them as non-virulent. The relation between virulence and isoenzyme pattern is questionable.
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PMID:Change of isoenzyme pattern during long-term polyxenic cultivation of Entamoeba histolytica. 821 12

In the presence of glycogen, ADP, phosphoglucomutase and hexokinase, the glycogen phosphorylase b activity associated to sarcoplasmic reticulum (SR) membranes stimulates Ca2+ uptake by SR membrane fragments in the absence of added ATP. Phosphoglucomutase and hexokinase lead to the formation of glucose 6-phosphate which in turn is used as an ATP regenerating system by the Ca2+ pump. It is proposed that a raise of cytosolic AMP and ADP concentrations after muscle contraction can activate an alternative metabolic route which would be used to ensure the maintenance of a low cytosolic Ca2+ concentration and avoid unnecessary metabolic energy depletion in muscle cells.
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PMID:Glycogen phosphorolysis can form a metabolic shuttle to support Ca2+ uptake by sarcoplasmic reticulum membranes in skeletal muscle. 825 Aug 71

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

The zymodemes, electrophoretic patterns of hexokinase, phosphoglucomutase and glucose phosphate isomerase isoenzymes, have been widely used to determine the pathogenicity of Entamoeba histolytica isolates. Although pathogenic and nonpathogenic forms of E. histolytica differ clearly in sequences of many homologous genes, a conversion between pathogenic and nonpathogenic zymodemes has been reported by several laboratories. To approach the question what might be the basis for the observed conversion, we examined the molecular biology of the hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) isoenzymes in pathogenic E. histolytica. We isolated two different cDNAs pHXK1 and pHXK2 coding for polypeptides with significant sequence similarity to hexokinases and deduced molecular masses of 49.8 kDa and 49.4 kDa. The two hexokinase sequences differed by 11% on the amino acid and by 8% on the nucleotide level. Expression of the cDNAs in Escherichia coli as nonfusion proteins gave two polypeptides with hexokinase activity. The recombinant Hxk1 and Hxk2 polypeptides comigrated with the more basic and more acidic isoforms of pathogenic amoebae in starch gel electrophoresis, as well as in low and high resolution isoelectric focussing gels. This identified the observed hexokinase isoenzymes of pathogenic E. histolytica as the products of two genes, hxk1 and hxk2.
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PMID:Molecular analysis of two hexokinase isoenzymes from Entamoeba histolytica. 857 26

The glycogenolytic-sarcoplasmic reticulum complex from rat skeletal muscle accumulates Ca2+ upon stimulation of glycogen phosphorolysis in the absence of added ATP. It is shown that an efficient Ca2+ uptake involves the sequential action of glycogen phosphorylase, phosphoglucomutase and hexokinase, which generate low concentrations of ATP (approximately 1-2 microM) compartmentalized in the immediate vicinity of the sarcoplasmic reticulum Ca2+, Mg(2+)-ATPase (the Ca2+ pump). The Ca2+ uptake supported by glycogenolysis in this subcellular structure is strongly stimulated by micromolar concentrations of AMP, showing that the glycogen phosphorylase associated with this complex is in the dephosphorylated b form. The results point out that the flux through this compartmentalized metabolic pathway should be enhanced in physiological conditions leading to increased AMP concentrations in the sarcoplasm, such as long-lasting contractions and in ischemic muscle.
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PMID:Ca2+ uptake coupled to glycogen phosphorolysis in the glycogenolytic-sarcoplasmic reticulum complex from rat skeletal muscle. 881 99

Samples of two Phlebotomus sergenti natural populations from San Juan (Tenerife), representing the western edge of the distribution area of this species, and Axos (Crete) were collected. The morphological comparison showed marked differences in the lengths of parts of the male genitalia, female pharynx, and spermathecae. The isoenzyme study revealed characteristic monomorphic phenotypes for glucose phosphate isomerase, hexokinase, and phosphoglucomutase in the Canarian specimens as compared with the Cretan population. These results confirm the heterogeneity of P. sergenti and indicate the utility of a systematic double approach for a revision of this taxon.
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PMID:Phlebotomus sergenti parrot, 1917: morphological and isoenzymatic comparisons of two natural populations from Tenerife (Canary Islands, Spain) and Crete (Greece). 882 45


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