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)

The pathway of glucose metabolism in Pseudomonas aeruginosa was regulated by the availability of glucose and related compounds. On changing from an ammonium limitation to a glucose limitation, the organism responded by adjusting its metabolism substantially from the extracellular direct oxidative pathway to the intracellular phosphorylative route. This change was achieved by repression of the transport systems for gluconate and 2-oxogluconate and of the associated enzymes for 2-oxogluconate metabolism and gluconate kinase, while increasing the levels of glucose transport, hexokinase and glucose 6-phosphate dehydrogenase. The role of gluconate, produced by the action of glucose dehydrogenase, as a major inhibitory factor for glucose transport, and the possible significance of these regulatory mechanisms to the organism in its natural environment, are discussed.
J Gen Microbiol 1976 Feb
PMID:The role of glucose limitation in the regulation of the transport of glucose, gluconate and 2-oxogluconate, and of glucose metabolism in Pseudomonas aeruginosa. 17 10

Mutants with defective carbon catabolite repression have been isolated in the yeast Saccharomyces cerevisiae using a selective procedure. This was based on the fact that invertase is a glucose repressible cell wall enzyme which slowly hydrolyses raffinose to yield fructose and that the inhibitory effects of 2-deoxyglucose can be counteracted by fructose. Repressed cells were plated on a raffinose--2-doexyglucose medium and the resistant cells growing up into colonies were tested for glucose non-repressible invertase and maltase. The yield of regulatory mutants was very high. All were equally derepressed for invertase and maltase, no mutants were obtained with only non-repressible invertase synthesis which was the selected function. A total of 61 mutants isolated in different strains were allele tested and could be attributed to three genes. They were all recessive. Mutants in one gene had reduced hexokinase activities, the other class, located in a centromere linked gene, had elevated hexokinase levels and was inhibited by maltose. Mutants in a third gene were isolated on a 2-deoxyglucose galactose medium and had normal hexokinase levels. A partial derepression was observed for malate dehydrogenase in all mutants. Isocitrate lyase, however, was still fully repressible.
Mol Gen Genet 1977 Jul 07
PMID:Mutants of Saccharomyces cerevisiae resistant to carbon catabolite repression. 19 90

When strains of Saccharomyces cerevisiae carrying a single glucose-phosphorylating enzyme such as hexokinase Pl or hexokinase P2 or glucokinase, are subjected to the selection pressure against the toxic sugar 2-deoxyglucose, the majority of survivors are mutants lacking the respective enzymes. All the 2-deoxyglucose-resistant segregants recovered from backcrosses of these mutants to a wild type strain are glucose-negative and all the sensitive ones are glucose-positive. The hexokinase mutations are located in the same complementation groups as defined by the structural genes of hexokinase P1 and hexokinase P2. No interallelic complementation has been observed either in hexokinase P1 or in hexokinase P2 amongst a total of 4 X 64, and 5 X 60 different combinations of independent mutants at the hxk1 and hxk2 loci respectively. There appears to be neither a common genetic regulator controlling two or more of these glucose-phosphorylating enzymes nor a sugar carrier that can be dispensed with.
Mol Gen Genet 1977 Dec 09
PMID:Resistance to 2-deoxyglucose in yeast: a direct selection of mutants lacking glucose-phosphorylating enzymes. 34 Sep 26

The levels of glucose-6-phosphate and 6-phosphogluconate dehydrogenase in wildtype cells of Aspergillus nidulans varied with the carbon and nitrogen source. In general, hexokinase activity did not vary with carbon or nitrogen source. The ammonium derepressed mutant amrA1 had only 50% of the wildtype level of hexokinase. Phosphoglucomutase activity was low in wildtype cells grown with nitrate, but high in cells grown with ammonium when glucose was the carbon source. A non-inducible mutant, nirA-1, in the regulatory gene for nitrate reductase, had high phosphoglucomutase activity when grown with nitrate or ammonium. A constitutive mutant nirAc1, in the regulatory gene for nitrate reductase had low phosphoglucomutase activity when grown with nitrate or ammonium. The mutants nir-1 and nirAc1 are recessive and semi-dominant respectively for abnormal phosphoglucomutase activity.
Mol Gen Genet 1979 Mar 09
PMID:The regulation of hexokinase and phosphoglucomutase activity in Aspergillus nidulans. 37 22

A smooth muscle plasma membrane vesicular fraction (PMV) purified for the (Ca2+/Mg2+)-ATPase has endogenous glycolytic enzyme activity. In the presence of glycolytic substrate (fructose 1,6-diphosphate) and cofactors, PMV produced ATP and lactate and supported calcium uptake. The endogenous glycolytic cascade supports calcium uptake independent of bath [ATP]. A 10-fold dilution of PMV, with the resultant 10-fold dilution of glycolytically produced bath [ATP] did not change glycolytically fueled calcium uptake (nanomoles per milligram protein). Furthermore, the calcium uptake fueled by the endogenous glycolytic cascade persisted in the presence of a hexokinase-based ATP trap which eliminated calcium uptake fueled by exogenously added ATP. Thus, it appears that the endogenous glycolytic cascade fuels calcium uptake in PMV via a membrane-associated pool of ATP and not via an exchange of ATP with the bulk solution. To determine whether ATP produced endogenously was utilized preferentially by the calcium pump, the ATP production rates of the endogenous creatine kinase and pyruvate kinase were matched to that of glycolysis and the calcium uptake fueled by the endogenous sources was compared with that fueled by exogenous ATP added at the same rate. The rate of calcium uptake fueled by endogenous sources of ATP was approximately twice that supported by exogenously added ATP, indicating that the calcium pump preferentially utilizes ATP produced by membrane-bound enzymes.
J Gen Physiol 1992 Jan
PMID:Comparison of endogenous and exogenous sources of ATP in fueling Ca2+ uptake in smooth muscle plasma membrane vesicles. 131 Oct 20

mRNA steady-state levels and activities of enzymes of intermediary carbon metabolism (hexokinase, phosphoglucoisomerase, phosphofructokinase, glucose-6-phosphate dehydrogenase, phosphoglucomutase) and glucose-regulated enzymes (pyruvate decarboxylase, pyruvate dehydrogenase, invertase, alcohol dehydrogenase) were determined in glucose-limited continuous cultures of an industrial strain of Saccharomyces cerevisiae at different dilution rates (D) ranging from 0.05 to 0.315 h-1. The activity of most enzymes measured remained constant over this range except for alcohol dehydrogenase I/II which decreased proportionally with increasing dilution rate. A decrease in phosphoglucomutase activity occurred with increasing dilution rate but reached a minimum at D 0.2 h-1 and from thereon remained constant. A decrease in pyruvate decarboxylase activity and a slight decrease in phosphoglucoisomerase activity was observed. At D 0.29/0.315 h-1, at the onset of the Crabtree effect, most glycolytic enzymes remained constant except for pyruvate decarboxylase and glucose-6-phosphate dehydrogenase which increased at D 0.315 h-1 and alcohol dehydrogenase I/II which decreased. The ADHI/II and PDC1 mRNA levels obtained at the different dilution rates were in accordance with the activity measurements. The mRNA level of HXK1 decreased with increasing dilution rates, whereas the transcription of HXK2 increased. Pyruvate dehydrogenase (PDA1) and PGI1 mRNA fluctuated but no significant change could be detected. These results indicate that there is no transcriptional or translational regulation of glycolytic flux between D 0.05 h-1 and 0.315 h-1 except at the branch point between oxidative and fermentative metabolism (pyruvate decarboxylase/pyruvate dehydrogenase) at D 0.315 h-1. Surprisingly regulation of the Crabtree effect does not seem to involve transcriptional regulation of PDA1.(ABSTRACT TRUNCATED AT 250 WORDS)
J Gen Microbiol 1992 Dec
PMID:Analysis of transcription and translation of glycolytic enzymes in glucose-limited continuous cultures of Saccharomyces cerevisiae. 148 26

Activities of glycolytic enzymes were determined in elutriation fractionated cultures of Saccharomyces cerevisiae grown on different carbon sources. Almost pure fractions of single cells at the G1 state of cell division were obtained for some of the growth conditions tested, whereas other stages were enriched in particular fractions. Specific activities of glucose-6-phosphate dehydrogenase and alcohol dehydrogenase were found to be constant during the cell cycle, as reported by van Doorn et al. (1988a), Journal of Bacteriology 170, 4808-4815, and (1988b), Journal of General Microbiology 134, 785-790. In contrast to the earlier reports, the activities of hexokinase, phosphofructokinase, pyruvate kinase and trehalase were also constant in different states of the cell cycle. For hexokinase and phosphofructokinase it was shown that the apparent specific activity in a cell-free extract strongly diminished when extracts contained less that 0.5-1 mg protein ml-1. In the experiments of van Doorn et al. (1988a) the protein content of the outer fractions was up to 20 times lower than that of the central fractions, suggesting an alternative explanation for the observed changes in enzyme activities during the cell cycle. Therefore, we want to rectify the observations presented by van Doorn et al. (1988a), and conclude that the activities of the glycolytic enzymes do not vary greatly during the cell cycle of S. cervisiae.
J Gen Microbiol 1991 Apr
PMID:Changes in the activities of key enzymes of glycolysis during the cell cycle in yeast: a rectification. 185 83

The regulatory HEX2 gene plays an important role in glucose repression in the yeast Saccharomyces cerevisiae. The hex2 mutants have pleiotropic defects in the regulation of glucose-repressible enzymes, hexokinase PII synthesis and maltose uptake [Entian, K.-D. & Zimmermann, F.K. (1980) Mol. Gen. Genet. 177, 345-350]. The HEX2 gene encodes a protein of 114137 Da, deduced from its DNA sequence. There were no strong similarities to previously known genes. HEX2-lacZ fusions revealed a largely constitutive expression when repressing and non-repressing growth conditions were compared. Cellular fractionation studies indicated a nuclear localization of the Hex2 protein. The hex2 mutation was shown to be allelic to reg1, which releases galactose pathway enzymes from glucose repression [Matsumoto, K., Yoshimatsu, T. & Oshima, Y. (1983) J. Bacteriol. 153, 1405-1414]. Overexpression of HEX2 resulted in a 70% reduction of GAL1 expression under induced growth conditions. Our studies support the view that protein Hex2 is a negative regulatory element in glucose repression which may directly influence transcription, possibly by interaction with transcriptional factors. Deletion experiments identified a central core of Hex2, spanning only 492 out of 1026 amino acid residues, as mainly important for glucose repression. There are two strongly acidic regions within this part of the protein, their possible importance is discussed.
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PMID:Characterization of Hex2 protein, a negative regulatory element necessary for glucose repression in yeast. 188

The HXK2 gene product has an important role in controlling carbon catabolite repression in Saccharomyces cerevisiae. We have raised specific antibodies against the hexokinase PII protein and have demonstrated that it is a 58 kDa phosphoprotein with protein kinase activity. The predicted amino acid sequence of the HXK2 gene product has significant homology to the conserved catalytic domain of mammalian and yeast protein kinases. Protein kinase activity was located in a different domain of the protein from the hexose-phosphorylating activity. The hexokinase PII protein level remained unchanged in P2T22D mutant cells (hxk1 HXK2 glk1) growing in a complex medium with glucose. The protein kinase activity of hexokinase PII is regulated by the glucose concentration of the culture medium. Exit from the carbon catabolite repression phase and entry into derepression phase may be controlled, in part, by modulation of the 58 kDa protein kinase activity by changes in cyclic AMP concentration.
J Gen Microbiol 1989 May
PMID:The hexokinase isoenzyme PII of Saccharomyces cerevisiae ia a protein kinase. 255 46

1. Thioridazine and trifluoperazine, which have been previously found in this laboratory to be the most effective calmodulin antagonists in treatment of burns, are shown here to be also effective in the treatment of frostbite. 2. Electron microscopic studies have revealed a complete reversal of both the vascular and skin tissue damage induced by frostbite. 3. The reversal of the vascular damage was also demonstrated by the ability of these compounds to abolish the increase in hemoglobin content in the skin. 4. The reversal of the skin tissue damage was also revealed by the ability of these compounds to raise the decreased ATP level and the reduced activities of 6-phosphogluconate dehydrogenase and mitochondrial and soluble hexokinase in skin, induced by frostbite, to normal control levels.
Gen Pharmacol 1989
PMID:Treatment of frostbite with the calmodulin antagonists thioridazine and trifluoperazine. 260 33


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