Science.gov

Sample records for 6-phosphate fructose 6-phosphate

  1. FRUCTOSE-6-PHOSPHATE REDUCTASE FROM SALMONELLA GALLINARUM

    PubMed Central

    Zancan, Glaci T.; Bacila, Metry

    1964-01-01

    Zancan, Glaci T. (Universidade do Paraná, Curitiba, Paraná, Brazil), and Metry Bacila. Fructose-6-phosphate reductase from Salmonella gallinarum. J. Bacteriol. 87:614–618. 1964.—A fructose-6-phosphate reductase present in cell-free extracts of Salmonella gallinarum was purified approximately 42 times. The optimal pH for this enzyme is 8.0. The enzyme is specific for fructose-6-phosphate and reduced nicotinamide adenine dinucleotide (NADH). The dissociation constants are 1.78 × 10−4m for fructose-6-phosphate and 8.3 × 10−5m for NADH. The Q10, reaction order, and equilibrium constant were determined. The enzyme is sensitive to p-chloromercuribenzoic acid, but not to o-iodosobenzoic acid nor to N-ethylmaleimide. PMID:14127579

  2. Characterization of a Mannose-6-Phosphate Isomerase from Bacillus amyloliquefaciens and Its Application in Fructose-6-Phosphate Production

    PubMed Central

    Sigdel, Sujan; Singh, Ranjitha; Kim, Tae-Su; Li, Jinglin; Kim, Sang-Yong; Kim, In-Won; Jung, Woo-Suk; Pan, Cheol-Ho; Kang, Yun Chan; Lee, Jung-Kul

    2015-01-01

    The BaM6PI gene encoding a mannose-6-phosphate isomerase (M6PI, EC 5.3.1.8) was cloned from Bacillus amyloliquefaciens DSM7 and overexpressed in Escherichia coli. The enzyme activity of BaM6PI was optimal at pH and temperature of 7.5 and 70°C, respectively, with a kcat/Km of 13,900 s-1 mM-1 for mannose-6-phosphate (M6P). The purified BaM6PI demonstrated the highest catalytic efficiency of all characterized M6PIs. Although M6PIs have been characterized from several other sources, BaM6PI is distinguished from other M6PIs by its wide pH range and high catalytic efficiency for M6P. The binding orientation of the substrate M6P in the active site of BaM6PI shed light on the molecular basis of its unusually high activity. BaM6PI showed 97% substrate conversion from M6P to fructose-6-phosphate demonstrating the potential for using BaM6PI in industrial applications. PMID:26171785

  3. Glucose-6-phosphate dehydrogenase

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003671.htm Glucose-6-phosphate dehydrogenase test To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) is a protein that ...

  4. Characterisation of glutamine fructose-6-phosphate amidotransferase (EC 2.6.1.16) and N-acetylglucosamine metabolism in Bifidobacterium.

    PubMed

    Foley, Sophie; Stolarczyk, Emilie; Mouni, Fadoua; Brassart, Colette; Vidal, Olivier; Aïssi, Eliane; Bouquelet, Stéphane; Krzewinski, Frédéric

    2008-02-01

    Bifidobacterium bifidum, in contrast to other bifidobacterial species, is auxotrophic for N-acetylglucosamine. Growth experiments revealed assimilation of radiolabelled N-acetylglucosamine in bacterial cell walls and in acetate, an end-product of central metabolism via the bifidobacterial D: -fructose-6-phosphate shunt. While supplementation with fructose led to reduced N-acetylglucosamine assimilation via the D: -fructose-6-phosphate shunt, no significant difference was observed in levels of radiolabelled N-acetylglucosamine incorporated into cell walls. Considering the central role played by glutamine fructose-6-phosphate transaminase (GlmS) in linking the biosynthetic pathway for N-acetylglucosamine to hexose metabolism, the GlmS of Bifidobacterium was characterized. The genes encoding the putative GlmS of B. longum DSM20219 and B. bifidum DSM20082 were cloned and sequenced. Bioinformatic analyses of the predicted proteins revealed 43% amino acid identity with the Escherichia coli GlmS, with conservation of key amino acids in the catalytic domain. The B. longum GlmS was over-produced as a histidine-tagged fusion protein. The purified C-terminal His-tagged GlmS possessed glutamine fructose-6-phosphate amidotransferase activity as demonstrated by synthesis of glucosamine-6-phosphate from fructose-6-phosphate and glutamine. It also possesses an independent glutaminase activity, converting glutamine to glutamate in the absence of fructose-6-phosphate. This is of interest considering the apparently reduced coding potential in bifidobacteria for enzymes associated with glutamine metabolism.

  5. Crystal Structure Analysis of Human Glutamine : Fructose 6-Phosphate Amidotransferase, a Key Regulator in Type 2 Diabetes

    NASA Astrophysics Data System (ADS)

    Nakaishi, Yuichiro; Bando, Masahiko

    Glutamine : fructose 6-phosphate amidotransferase (GFAT) is a rate-limiting enzyme in the hexoamine biosythetic pathway and plays an important role in type 2 diabetes. We now report the first structures of the isomerase domain of the human GFAT in the presence of cyclic glucose 6-phosphate and linear glucosamine 6-phosphate. The C-terminal tail including the active site displays a rigid conformation, similar to the corresponding Escherichia coli enzyme. The diversity of the CF helix near the active site suggests the helix is a major target for drug design. Our study provides insights into the development of therapeutic drugs for type 2 diabetes.

  6. Allosteric Regulation of Lactobacillus plantarum Xylulose 5-Phosphate/Fructose 6-Phosphate Phosphoketolase (Xfp)

    PubMed Central

    Glenn, Katie

    2015-01-01

    ABSTRACT Xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp), which catalyzes the conversion of xylulose 5-phosphate (X5P) or fructose 6-phosphate (F6P) to acetyl phosphate, plays a key role in carbohydrate metabolism in a number of bacteria. Recently, we demonstrated that the fungal Cryptococcus neoformans Xfp2 exhibits both substrate cooperativity for all substrates (X5P, F6P, and Pi) and allosteric regulation in the forms of inhibition by phosphoenolpyruvate (PEP), oxaloacetic acid (OAA), and ATP and activation by AMP (K. Glenn, C. Ingram-Smith, and K. S. Smith. Eukaryot Cell 13:657–663, 2014). Allosteric regulation has not been reported previously for the characterized bacterial Xfps. Here, we report the discovery of substrate cooperativity and allosteric regulation among bacterial Xfps, specifically the Lactobacillus plantarum Xfp. L. plantarum Xfp is an allosteric enzyme inhibited by PEP, OAA, and glyoxylate but unaffected by the presence of ATP or AMP. Glyoxylate is an additional inhibitor to those previously reported for C. neoformans Xfp2. As with C. neoformans Xfp2, PEP and OAA share the same or possess overlapping sites on L. plantarum Xfp. Glyoxylate, which had the lowest half-maximal inhibitory concentration of the three inhibitors, binds at a separate site. This study demonstrates that substrate cooperativity and allosteric regulation may be common properties among bacterial and eukaryotic Xfp enzymes, yet important differences exist between the enzymes in these two domains. IMPORTANCE Xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp) plays a key role in carbohydrate metabolism in a number of bacteria. Although we recently demonstrated that the fungal Cryptococcus Xfp is subject to substrate cooperativity and allosteric regulation, neither phenomenon has been reported for a bacterial Xfp. Here, we report that the Lactobacillus plantarum Xfp displays substrate cooperativity and is allosterically inhibited by

  7. Aggregation of banana pyrophosphate fructose 6-phosphate 1-phosphotransferase by glycerol.

    PubMed

    Surendranathan, K K; Kanulkar, S U; Nair, P M

    1996-12-01

    Addition of glycerol during purification of banana (Musaceae, Musa cavendishii) pyrophosphate fructose 6-phosphate 1-phosphotransferase [(PFP), EC 2.7.1.90] initiated molecular aggregation of the enzyme. The aggregation process was dependent on the glycerol concentration. The native enzyme (66 kDa molecular mass) showed enhanced activity at 3% (V/V) or less of glycerol concentration. Glycerol concentration between 4 and 5% (V/V) affected a gradual and sequential aggregation of native form of the enzyme. These aggregated forms had molecular masses of 135, 200 and 270 kDa. The 135 and 200 kDa forms were stable for about 72 hrs and prolonged storage over 2 weeks resulted in the formation of the 270 kDa form. Concentration over 5% could reduce the time required for aggregation. Fru2.6 bis P activated the enzyme over ten fold, but did not help in the aggregation process. Studies on the role of glycerol on PFP specific activity suggested a difference in the activation process compared to that by Fru2.6bis P. Replacement of Hepes buffer by Tris increased the Fru2.6 bis P requirement for maximum activation by around 10 fold. Removal of glycerol from the buffer media resulted in almost complete inactivation of the enzyme.

  8. D-Fructose-6-phosphate aldolase-catalyzed one-pot synthesis of iminocyclitols.

    PubMed

    Sugiyama, Masakazu; Hong, Zhangyong; Liang, Pi-Hui; Dean, Stephen M; Whalen, Lisa J; Greenberg, William A; Wong, Chi-Huey

    2007-11-28

    A one-pot chemoenzymatic method for the synthesis of a variety of new iminocyclitols from readily available, non-phosphorylated donor substrates has been developed. The method utilizes the recently discovered fructose-6-phosphate aldolase (FSA), which is functionally distinct from known aldolases in its tolerance of different donor substrates as well as acceptor substrates. Kinetic studies were performed with dihydroxyacetone (DHA), the presumed endogenous substrate for FSA, as well as hydroxy acetone (HA) and 1-hydroxy-2-butanone (HB) as donor substrates, in each case using glyceraldehyde-3-phosphate as acceptor substrate. Remarkably, FSA used the three donor substrates with equal efficiency, with kcat/KMvalues of 33, 75, and 20 M-1 s-1, respectively. This level of donor substrate tolerance is unprecedented for an aldolase. Furthermore, DHA, HA, and HB were accepted as donors in FSA-catalyzed aldol reactions with a variety of azido- and Cbz-amino aldehyde acceptors. The broad substrate tolerance of FSA and the ability to circumvent the need for phosphorylated substrates allowed for one-pot synthesis of a number of known and novel iminocyclitols in good yields, and in a very concise fashion. New iminocyclitols were assayed as inhibitors against a panel of glycosidases. Compounds 15 and 16 were specific alpha-mannosidase inhibitors, and 24 and 26 were potent and selective inhibitors of beta-N-acetylglucosaminidases in the submicromolar range. Facile access to these compounds makes them attractive core structures for further inhibitor optimization.

  9. Hexose phosphate binding sites of fructose-6-phosphate,2-kinase:fructose-2,6-bisphosphatase

    SciTech Connect

    Sakakibara, R.; Kitajima, S.; Hartman, F.C.; Uyeda, K.

    1984-11-25

    The hexose phosphate binding sites of a bifunctional enzyme, fructose-6-P,2-kinase:fructose-2,6-bisphosphatase were studied. N-Bromoacetylethanolamine phosphate is a competitive inhibitor with respect to fructose-6-P and a noncompetitive inhibitor with ATP (K/sub i/ = 0.8 mM). The reagent inactivates fructose-6-P,2-kinase but not fructose-2,6-bisphosphatase, and the inactivation is prevented by fructose-6-P. The inactivation reaction follows pseudo first-order kinetics to completion and with increasing concentrations of N-bromoacetylethanolamine phosphate a rate saturation effect is observed. The concentration of the reagent giving the half-maximum inactivation is 2.2 mM and the apparent first order rate constant is 0.0046 s/sup -1/. The enzyme alkylated by N-bromoacetylethanolamine-P has lost over 90% of the kinase activity, retains nearly full activity of fructose-2,6-bisphosphatase, and its inhibition by fructose-6-P is not altered. 3-Bromo-1,4-dihydroxy-2-butanone 1,4-bisphosphate is also a competitive inhibitor of fructose-6-P,2-kinase with respect to fructose-6-P in the forward reaction and fructose-2,6-P/sub 2/ in the reverse direction. This reagent inhibits 93% of fructose-6-P,2-kinase but activated fructose-2,6-bisphosphatase 3.7-fold. 3-Bromo-1,4-dihydroxy-2-butanone 1,4-bisphosphate alters the fructose-2,6-P/sub 2/ saturation kinetic curve from negative cooperativity to normal Michaelis-Menten kinetics with K/sub 0.5/ of 0.8 ..mu..M. The reagent, however, has no effect on the fructose-6-P inhibition of phosphatase. These results strongly suggest that hexose phosphate binding sites of fructose-6-P,2-kinase and fructose-2,6-bisphosphatase are distinct and located in different regions of this bifunctional enzyme. 19 references, 9 figures, 1 table.

  10. Characterization of the d-Xylulose 5-Phosphate/d-Fructose 6-Phosphate Phosphoketolase Gene (xfp) from Bifidobacterium lactis

    PubMed Central

    Meile, Leo; Rohr, Lukas M.; Geissmann, Thomas A.; Herensperger, Monique; Teuber, Michael

    2001-01-01

    A d-xylulose 5-phosphate/d-fructose 6-phosphate phosphoketolase (Xfp) from the probiotic Bifidobacterium lactis was purified to homogeneity. The specific activity of the purified enzyme with d-fructose 6-phosphate as a substrate is 4.28 Units per mg of enzyme. Km values for d-xylulose 5-phosphate and d-fructose 6-phosphate are 45 and 10 mM, respectively. The native enzyme has a molecular mass of 550,000 Da. The subunit size upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (90,000 Da) corresponds with the size (92,529 Da) calculated from the amino acid sequence of the isolated gene (named xfp) encoding 825 amino acids. The xfp gene was identified on the chromosome of B. lactis with the help of degenerated nucleotide probes deduced from the common N-terminal amino acid sequence of both the native and denatured enzyme. Comparison of the deduced amino acid sequence of the cloned gene with sequences in public databases revealed high homologies with hypothetical proteins (26 to 55% identity) in 20 microbial genomes. The amino acid sequence derived from the xfp gene contains typical thiamine diphosphate (ThDP) binding sites reported for other ThDP-dependent enzymes. Two truncated putative genes, pta and guaA, were localized adjacent to xfp on the B. lactis chromosome coding for a phosphotransacetylase and a guanosine monophosphate synthetase homologous to products of genes in Mycobacterium tuberculosis. However, xfp is transcribed in B. lactis as a monocistronic operon. It is the first reported and sequenced gene of a phosphoketolase. PMID:11292814

  11. Breaking the dogma of aldolase specificity: Simple aliphatic ketones and aldehyde are nucleophiles for fructose-6-phosphate aldolase.

    PubMed

    Roldán, Raquel; Sanchez-Moreno, Israel; Scheidt, Thomas; Hélaine, Virgil; Lemaire, Marielle; Parella, Teodor; Clapés, Pere; Fessner, Wolf-Dieter; Guérard-Hélaine, Christine

    2017-03-07

    D-Fructose-6-phosphate aldolase (FSA) was probed for extended nucleophile promiscuity by using a series of fluorogenic substrates to reveal retro-aldol activity. Four nucleophiles ethanal, propanone, butanone and cyclopentanone were subsequently confirmed to be non-natural substrates in the synthesis direction using the wild type enzyme and its D6H variant. This exceptional widening of the nucleophile substrate scope offers a rapid entry, in good yields and high stereoselectivity, to less oxygenated alkyl ketones and aldehydes, which was hitherto impossible.

  12. Glucose-6-Phosphate Dehydrogenase Revisited

    PubMed Central

    O'Connell, Jerome T.; Henderson, Alfred R.

    1984-01-01

    Hemolytic diseases associated with drugs have been recognized since antiquity. Many of these anemias have been associated with oxidizing agents and deficiencies in the intraerythrocytic enzyme glucose-6-phosphate dehydrogenase. This paper outlines the discovery, prevalence, and variants of this enzyme. Methods of diagnosis of associated anemias are offered. PMID:6502728

  13. Physical mapping of the human glutamine:fructose-6-phosphate amidotransferase gene (GFPT) to chromosome 2p13

    SciTech Connect

    Whitmore, T.E.; Mudri, S.L.; McKnight, G.L.

    1995-03-20

    Diabetic hyperglycemia influences insulin resistance through a process termed glucose toxicity. Implicated as a source of the mediators of this toxicity is an increased intracellular glucose metabolism through the hexosamine pathway. The hexosamine pathway itself is controlled by the rate-limiting enzyme glutamine:fructose-6-phosphate amidotransferase (GFAT), which is the first enzyme of the pathway. It has been shown that there is a close correlation between the glucose-mediated reduction of GFAT activity and the onset of insulin desensitization of the glucose transport system, a condition associated with insulin-resistant states of non-insulin-dependent diabetes mellitus and obesity. To gain a better understanding of the molecular regulation of GFAT and its role in the induction of insulin resistance, we previously isolated and cloned the cDNA for the human form of this enzyme and expressed the functional protein in Escherichia coli. 9 refs., 1 fig.

  14. Characterization of ATP-Dependent Fructose 6-Phosphate 1-Phosphotransferase Isozymes from Leaf and Endosperm Tissues of Ricinus communis1

    PubMed Central

    Knowles, Vicki L.; Greyson, Maureen F.; Dennis, David T.

    1990-01-01

    Plastid and cytosolic isozymes of ATP:fructose 6-phosphate 1-phosphotransferase (PFKp and PFKc, respectively) have been isolated from leaves and developing endosperm tissues of the castor oil plant (Ricinus communis L). Endosperm PFKp has been purified to apparent homogeneity. Polyclonal antibodies raised against one of the four polypeptides associated with potato tuber PFK (molecular mass, 46 kilodaltons) immunoprecipitated developing endosperm and leaf PFKp, but not PFKc isozymes. Western blots, sodium dodecyl sulfate polyacrylamide gel electrophoresis, and analytical gel filtration show that PFKp from developing endosperm is a 220 kilodalton homotetramer composed of 57 kilodalton subunits. Kinetic studies of leaf PFKp and PFKc isozymes reveal both similarities and differences to the characteristics of the respective endosperm isozymes studied previously (WJ Garland, DT Dennis [1980] Arch Biochem Biophys 204: 302-317). The immunological and kinetic data suggest that leaf and developing endosperm PFKp are different but structurally related proteins. Images Figure 2 PMID:16667239

  15. Glucose-6-Phosphate Dehydrogenase Deficiency.

    PubMed

    Luzzatto, Lucio; Nannelli, Caterina; Notaro, Rosario

    2016-04-01

    G6PD is a housekeeping gene expressed in all cells. Glucose-6-phosphate dehydrogenase (G6PD) is part of the pentose phosphate pathway, and its main physiologic role is to provide NADPH. G6PD deficiency, one of the commonest inherited enzyme abnormalities in humans, arises through one of many possible mutations, most of which reduce the stability of the enzyme and its level as red cells age. G6PD-deficient persons are mostly asymptomatic, but they can develop severe jaundice during the neonatal period and acute hemolytic anemia when they ingest fava beans or when they are exposed to certain infections or drugs. G6PD deficiency is a global health issue.

  16. Mathematical model for aldol addition catalyzed by two D-fructose-6-phosphate aldolases variants overexpressed in E. coli.

    PubMed

    Sudar, Martina; Findrik, Zvjezdana; Vasić-Rački, Durđa; Clapés, Pere; Lozano, Carles

    2013-09-10

    Two D-fructose-6-phosphate aldolase variants namely, single variant FSA A129S and double variant FSA A129S/A165G, were used as catalysts in the aldol addition of dihydroxyacetone (DHA) to N-Cbz-3-aminopropanal. Mathematical model for reaction catalyzed by both enzymes, consisting of kinetic and mass balance equations, was developed. Kinetic parameters were estimated from the experimental data gathered by using the initial reaction rate method. The model was validated in the batch and continuously operated ultrafiltration membrane reactor (UFMR). The same type of kinetic model could be applied for both enzymes. The operational stability of the aldolases was assessed by measuring enzyme activity during the experiments. FSA A129S/A165G had better operational stability in the batch reactor (half-life time 26.7 h) in comparison to FSA A129S (half-life time 5.78 h). Both variants were unstable in the continuously operated UFMR in which half-life times were 1.99 and 3.64 h for FSA A129S and FSA A129S/A165G, respectively.

  17. Effects of glucose-6-phosphate dehydrogenase deficiency on the metabolic and cardiac responses to obesogenic or high-fructose diets.

    PubMed

    Hecker, Peter A; Mapanga, Rudo F; Kimar, Charlene P; Ribeiro, Rogerio F; Brown, Bethany H; O'Connell, Kelly A; Cox, James W; Shekar, Kadambari C; Asemu, Girma; Essop, M Faadiel; Stanley, William C

    2012-10-15

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common human enzymopathy that affects cellular redox status and may lower flux into nonoxidative pathways of glucose metabolism. Oxidative stress may worsen systemic glucose tolerance and cardiometabolic syndrome. We hypothesized that G6PD deficiency exacerbates diet-induced systemic metabolic dysfunction by increasing oxidative stress but in myocardium prevents diet-induced oxidative stress and pathology. WT and G6PD-deficient (G6PDX) mice received a standard high-starch diet, a high-fat/high-sucrose diet to induce obesity (DIO), or a high-fructose diet. After 31 wk, DIO increased adipose and body mass compared with the high-starch diet but to a greater extent in G6PDX than WT mice (24 and 20% lower, respectively). Serum free fatty acids were increased by 77% and triglycerides by 90% in G6PDX mice, but not in WT mice, by DIO and high-fructose intake. G6PD deficiency did not affect glucose tolerance or the increased insulin levels seen in WT mice. There was no diet-induced hypertension or cardiac dysfunction in either mouse strain. However, G6PD deficiency increased aconitase activity by 42% and blunted markers of nonoxidative glucose pathway activation in myocardium, including the hexosamine biosynthetic pathway activation and advanced glycation end product formation. These results reveal a complex interplay between diet-induced metabolic effects and G6PD deficiency, where G6PD deficiency decreases weight gain and hyperinsulinemia with DIO, but elevates serum free fatty acids, without affecting glucose tolerance. On the other hand, it modestly suppressed indexes of glucose flux into nonoxidative pathways in myocardium, suggesting potential protective effects.

  18. Glucosamine: fructose-6-phosphate amidotransferase in the white shrimp Litopenaeus vannamei: characterization and regulation under alkaline and cadmium stress.

    PubMed

    Liu, Y; Cai, D X; Wang, L; Li, J Z; Wang, W N

    2015-10-01

    Heavy metal residues and chemical contaminators considered as relevant sources of aquatic environmental pollutants have a generally immunosuppressive effect on aquatic organisms, depressing metabolic activities and immune response. Glutamine: fructose-6-phosphate aminotransferase (GFAT, EC2.6.1.16) is the first, and rate-limiting, enzyme in the hexosamine biosynthetic pathway, and is involved in the regulation of chitin biosynthesis and glycosylation of proteins. We have isolated and characterized GFAT from the white shrimp Litopenaeus vannamei. Amino acid sequence similarity of the Lv-GFAT (L.vannamei-GFAT) was highest to GFATs isolated from insects and mammals (83 % similarity to that of Haemaphysalis longicornis). The open-reading frame of the Lv-GFAT codes for a protein of 41.6 kDa with a calculated isoelectric point of 5.03. RT-PCR assays showed that endogenous Lv-GFAT mRNA is most strongly expressed in the intestine. Further analysis of Lv-GFAT gene expression in hepatopancreas by quantitative real-time PCR demonstrated that Lv-GFAT transcript levels increased when the shrimp were exposed to alkaline pH (9.3) and cadmium stress, but the time when its mRNA expression level peaked differed under these stresses. We also first expressed the recombinant protein of GFAT from shrimps in Escherichia coli. Western blot analyses confirmed that the Lv-GFAT protein was strongly expressed in the hepatopancreas after exposure to the LC-Cd stress. These results suggest that Lv-GFAT expression is stimulated by alkaline pH and cadmium stress and that it may play important roles in resistance of shrimp to environmental stresses.

  19. {open_quotes}The effects of diabetes on the activity of the enzyme glutamine: fructose-6-phosphate amindotransferase{close_quotes}

    SciTech Connect

    Nelson, S.P.

    1994-12-31

    Hexsoamine synthetic pathway (HexNSP) controls the supply of essential substrates for glycoprotein synthesis. In vitro studies suggest that increased flux of glucose via the hexsoamine synthetic pathway may play a role in glucose induced insulin resistance of glucose transport. Glutamine: fructose-6-phosphate amindotransferase (GFAT) controls flux into the hexsoamine synthetic pathway; the major products are UDPN-acetylhexosamines (UDP.HexNac=UDP.GlcNAc= UDP.GalNac). I examined whether diabetes ({approximately} 7 days post intravenous streptozotocin, and genetically linked) affects the activity of glutamine: fructose-6-phosphate in rat and mouse skeletal muscle in vivo. Nucleotide linked HexNAc were analyzed by high pressure liquid chromatography(HPLC) in deproteinized hind limb muscle extracts.

  20. Global N-linked Glycosylation is Not Significantly Impaired in Myoblasts in Congenital Myasthenic Syndromes Caused by Defective Glutamine-Fructose-6-Phosphate Transaminase 1 (GFPT1).

    PubMed

    Chen, Qiushi; Müller, Juliane S; Pang, Poh-Choo; Laval, Steve H; Haslam, Stuart M; Lochmüller, Hanns; Dell, Anne

    2015-10-16

    Glutamine-fructose-6-phosphate transaminase 1 (GFPT1) is the first enzyme of the hexosamine biosynthetic pathway. It transfers an amino group from glutamine to fructose-6-phosphate to yield glucosamine-6-phosphate, thus providing the precursor for uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) synthesis. UDP-GlcNAc is an essential substrate for all mammalian glycosylation biosynthetic pathways and N-glycan branching is especially sensitive to alterations in the concentration of this sugar nucleotide. It has been reported that GFPT1 mutations lead to a distinct sub-class of congenital myasthenic syndromes (CMS) termed "limb-girdle CMS with tubular aggregates". CMS are hereditary neuromuscular transmission disorders in which neuromuscular junctions are impaired. To investigate whether alterations in protein glycosylation at the neuromuscular junction might be involved in this impairment, we have employed mass spectrometric strategies to study the N-glycomes of myoblasts and myotubes derived from two healthy controls, three GFPT1 patients, and four patients with other muscular diseases, namely CMS caused by mutations in DOK7, myopathy caused by mutations in MTND5, limb girdle muscular dystrophy type 2A (LGMD2A), and Pompe disease. A comparison of the relative abundances of bi-, tri-, and tetra-antennary N-glycans in each of the cell preparations revealed that all samples exhibited broadly similar levels of branching. Moreover, although some differences were observed in the relative abundances of some of the N-glycan constituents, these variations were modest and were not confined to the GFPT1 samples. Therefore, GFPT1 mutations in CMS patients do not appear to compromise global N-glycosylation in muscle cells.

  1. Global N-linked Glycosylation is Not Significantly Impaired in Myoblasts in Congenital Myasthenic Syndromes Caused by Defective Glutamine-Fructose-6-Phosphate Transaminase 1 (GFPT1)

    PubMed Central

    Chen, Qiushi; Müller, Juliane S.; Pang, Poh-Choo; Laval, Steve H.; Haslam, Stuart M.; Lochmüller, Hanns; Dell, Anne

    2015-01-01

    Glutamine-fructose-6-phosphate transaminase 1 (GFPT1) is the first enzyme of the hexosamine biosynthetic pathway. It transfers an amino group from glutamine to fructose-6-phosphate to yield glucosamine-6-phosphate, thus providing the precursor for uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) synthesis. UDP-GlcNAc is an essential substrate for all mammalian glycosylation biosynthetic pathways and N-glycan branching is especially sensitive to alterations in the concentration of this sugar nucleotide. It has been reported that GFPT1 mutations lead to a distinct sub-class of congenital myasthenic syndromes (CMS) termed “limb-girdle CMS with tubular aggregates”. CMS are hereditary neuromuscular transmission disorders in which neuromuscular junctions are impaired. To investigate whether alterations in protein glycosylation at the neuromuscular junction might be involved in this impairment, we have employed mass spectrometric strategies to study the N-glycomes of myoblasts and myotubes derived from two healthy controls, three GFPT1 patients, and four patients with other muscular diseases, namely CMS caused by mutations in DOK7, myopathy caused by mutations in MTND5, limb girdle muscular dystrophy type 2A (LGMD2A), and Pompe disease. A comparison of the relative abundances of bi-, tri-, and tetra-antennary N-glycans in each of the cell preparations revealed that all samples exhibited broadly similar levels of branching. Moreover, although some differences were observed in the relative abundances of some of the N-glycan constituents, these variations were modest and were not confined to the GFPT1 samples. Therefore, GFPT1 mutations in CMS patients do not appear to compromise global N-glycosylation in muscle cells. PMID:26501342

  2. [Glucose-6-phosphate dehydrogenase deficiency in Japan].

    PubMed

    Kanno, Hitoshi; Ogura, Hiromi

    2015-07-01

    In the past 10 years, we have diagnosed congenital hemolytic anemia in 294 patients, approximately 33% of whom were found to have glucose-6-phosphate dehydrogenase (G6PD) deficiency. It is becoming more common for Japanese to marry people of other ethnic origins, such that G6PD deficiency is becoming more prevalent in Japan. Japanese G6PD deficiency tends to be diagnosed in the neonatal period due to severe jaundice, while G6PD-deficient patients with foreign ancestors tend to be diagnosed at the onset of an acute hemolytic crisis before the age of six. It is difficult to predict the clinical course of each patient by G6PD activity, reduced glutathione content, or the presence/absence of severe neonatal jaundice. We propose that both neonatal G6PD screening and systematic analyses of G6PD gene mutations may be useful for personalized management of patients with G6PD-deficient hemolytic anemia.

  3. Glucose-6-phosphate dehydrogenase deficiency in Chinese

    PubMed Central

    Lai, H. C.; Lai, Michael P. Y.; Leung, Kevin S. N.

    1968-01-01

    In a Chinese population 1,000 full-term male neonates and a further 117 jaundiced neonates of both sexes were studied in an investigation of the frequency of deficiency of erythrocyte glucose-6-phosphate dehydrogenase (G6PD). This enzyme was found to be deficient in 3·6% of male neonates. Correlation of the results with the birthplace of the 602 mothers who were known to come from Kwangtung province showed no significant differences in the frequency of the deficiency between certain parts of the province. The deficiency of G6PD in hemizygous males is profound but it is not associated with erythrocyte acid monophosphoesterase deficiency in Chinese in Hong Kong. The G6PD deficiency accounts for 15·4% of all the 117 cases of neonatal jaundice. The relative importance of G6PD deficiency as a cause of neonatal jaundice does not differ materially in male and female mutants. Neonatal jaundice can occur in all genotypes of G6PD mutation in Chinese. PMID:5697334

  4. Producing Glucose 6-Phosphate from Cellulosic Biomass

    PubMed Central

    Bacik, John-Paul; Klesmith, Justin R.; Whitehead, Timothy A.; Jarboe, Laura R.; Unkefer, Clifford J.; Mark, Brian L.; Michalczyk, Ryszard

    2015-01-01

    The most abundant carbohydrate product of cellulosic biomass pyrolysis is the anhydrosugar levoglucosan (1,6-anhydro-β-d-glucopyranose), which can be converted to glucose 6-phosphate by levoglucosan kinase (LGK). In addition to the canonical kinase phosphotransfer reaction, the conversion requires cleavage of the 1,6-anhydro ring to allow ATP-dependent phosphorylation of the sugar O6 atom. Using x-ray crystallography, we show that LGK binds two magnesium ions in the active site that are additionally coordinated with the nucleotide and water molecules to result in ideal octahedral coordination. To further verify the metal binding sites, we co-crystallized LGK in the presence of manganese instead of magnesium and solved the structure de novo using the anomalous signal from four manganese atoms in the dimeric structure. The first metal is required for catalysis, whereas our work suggests that the second is either required or significantly promotes the catalytic rate. Although the enzyme binds its sugar substrate in a similar orientation to the structurally related 1,6-anhydro-N-acetylmuramic acid kinase (AnmK), it forms markedly fewer bonding interactions with the substrate. In this orientation, the sugar is in an optimal position to couple phosphorylation with ring cleavage. We also observed a second alternate binding orientation for levoglucosan, and in these structures, ADP was found to bind with lower affinity. These combined observations provide an explanation for the high Km of LGK for levoglucosan. Greater knowledge of the factors that contribute to the catalytic efficiency of LGK can be used to improve applications of this enzyme for levoglucosan-derived biofuel production. PMID:26354439

  5. A new synthesis of sucrose 6'-phosphate.

    PubMed

    Kim, K B; Behrman, E J

    1995-04-18

    Sucrose 6'-phosphate (3) is the key intermediate for sucrose (1) synthesis in plants [1]. It has recently become commercially available at ca. $1500/g (Sigma). The only chemical synthesis is that of Buchanan et al. [2]. This six-step procedure, while unambiguous, gives an overall yield of only ca. 6%. We describe here a simplified route (2 steps) with an unoptimized yield of ca. 15%. Our strategy was to use a phosphorylation reagent selective for primary hydroxyl groups and thus to avoid the necessity for blocking all of the secondary ones. Sowa and Ouchi [3] described a suitable system which they used very effectively for the synthesis of 5'-nucleotides from unprotected nucleosides. We applied this reagent to 2,1':4,6-di-O-isopropylidenesucrose (2) [4] in which the only unprotected primary hydroxyl group is that at the 6'-position (Scheme 1). The identity of the product was established by comparison of its rotation with the literature value and by the correspondence of its 1H and 13C NMR spectra with those of an authentic sample synthesized by Buchanan's method (Sigma) 1H assignments were made with the help of the assignments of du Penhoat et al. [5] for sucrose and the results of a one-bond H-C COSY experiment (Fig. 1). The 13C spectrum showed that all of the resonances were shifted downfield by ca. 0.5 ppm as compared with sucrose [6] except for the C-5' doublet which was shifted upfield by 0.5 ppm and the C-6' doublet which was shifted downfield by 2.2 ppm (Table 1).

  6. Streptococcus mutans serotype c tagatose 6-phosphate pathway gene cluster.

    PubMed Central

    Jagusztyn-Krynicka, E K; Hansen, J B; Crow, V L; Thomas, T D; Honeyman, A L; Curtiss, R

    1992-01-01

    DNA cloned into Escherichia coli K-12 from a serotype c strain of Streptococcus mutans encodes three enzyme activities for galactose utilization via the tagatose 6-phosphate pathway: galactose 6-phosphate isomerase, tagatose 6-phosphate kinase, and tagatose-1,6-bisphosphate aldolase. The genes coding for the tagatose 6-phosphate pathway were located on a 3.28-kb HindIII DNA fragment. Analysis of the tagatose proteins expressed by recombinant plasmids in minicells was used to determine the sizes of the various gene products. Mutagenesis of these plasmids with transposon Tn5 was used to determine the order of the tagatose genes. Tagatose 6-phosphate isomerase appears to be composed of 14- and 19-kDa subunits. The sizes of the kinase and aldolase were found to be 34 and 36 kDa, respectively. These values correspond to those reported previously for the tagatose pathway enzymes in Staphylococcus aureus and Lactococcus lactis. Images PMID:1328153

  7. Inhibition of hexose transport by glucose in a glucose-6-phosphate isomerase mutant of Saccharomyces cerevisiae.

    PubMed

    Alonso, A; Pascual, C; Romay, C; Herrera, L; Kotyk, A

    1989-01-01

    The rate of hexose transport was approximately 60% lower for both the high- and the low-affinity components of hexose uptake when a glucose-6-phosphate isomerase mutant of Saccharomyces cerevisiae was preincubated with glucose, as compared with preincubation with water. Similarly the Jmax value of the high-affinity system of the mutant was 25-35% of the corresponding Jmax value for normal cells incubated with glucose. Accumulation of glucose 6-phosphate or of some other metabolite, such as fructose 6-phosphate or trehalose, may be responsible for this striking inhibition.

  8. Priapism and glucose-6-phosphate dehydrogenase deficiency: An underestimated correlation?

    PubMed

    De Rose, Aldo Franco; Mantica, Guglielmo; Tosi, Mattia; Bovio, Giulio; Terrone, Carlo

    2016-10-05

    Priapism is a rare clinical condition characterized by a persistent erection unrelated to sexual excitement. Often the etiology is idiopathic. Three cases of priapism in glucose-6-phosphate dehydrogenase (G6PD) deficiency patients have been described in literature. We present the case of a 39-year-old man with glucose- 6-phosphate dehydrogenase deficiency, who reached out to our department for the arising of a non-ischemic priapism without arteriolacunar fistula. We suggest that the glucose-6-phosphate dehydrogenase deficiency could be an underestimated risk factor for priapism.

  9. N-Acetylation of Glucosamine-6-Phosphate in Leuconostoc mesenteroides

    PubMed Central

    DeMoss, R. D.; Moser, K.

    1969-01-01

    A partially purified enzyme (120-fold) from Leuconostoc mesenteroides catalyzed the reversible N-acetylation of d-glucosamine-6-phosphate. Coenzyme A was not required and inhibited the reaction rate. Neither d-glucosamine nor N-acetyl-d-glucosamine served as a substrate for the reversible reaction. The enzyme preparation retained 50% of its original activity after 5 min at 100 C. The Km for acetate was 7.7 × 10−2m in the presence of 2 × 10−2md-glucosamine-6-phosphate. The Km for d-glucosamine-6-phosphate was 5.0 × 10−3m in the presence of 0.64 m acetate. The product of the reaction was characterized by comparison with N-acetyl-d-glucosamine-6-phosphate prepared by enzymatic phosphorylation of N-acetyl-d-glusamine. The characterization tests were: chromatographic migration, acid hydrolysis, enzymatic dephosphorylation, sodium borohydride reduction, and periodate oxidation. The equilibrium constant for the reaction was about 7.5 m for the expression K = (d-glucosamine-6-phosphate)(acetate)/N-acetyl-d-glucosamine-6-phosphate. The standard free energy of the reaction was approximately 1,200 cal per mole. PMID:5781575

  10. Some Properties of Potato Tuber UDPGd-fructose-2-glucosyltransferase (E.C. 2.4.1.14) and UDPGd-fructose-6-phosphate-2-glucosyltransferase (E.C. 2.4.1.13) 1

    PubMed Central

    Slabnik, Estanislava; Frydman, Rosalia B.; Cardini, Carlos E.

    1968-01-01

    Sucrose and sucrose 6-phosphate synthetase were isolated from potato tubers, partially purified and their properties studied. The sucrose synthetase showed optimum activity at 45° and was inhibited competitively by ADP and some phenolic glucosides. The Ki′s for these inhibitors were determined. Mg2+ was found to activate this enzyme. Activity toward UDP-glucose or ADP-glucose formation was measured. The optimum conditions for sucrose and UDP-glucose formation were found to differ. The specificity for the glucosyl donor and acceptor were determined. The optimum conditions for sucrose 6-phosphate synthetase activity were studied. This enzyme was not inhibited by either ADP or phenolic glucosides; UDP-glucose was the only glucosyl donor for sucrose 6-phosphate formation. PMID:16656883

  11. Structural basis for glucose-6-phosphate activation of glycogen synthase

    SciTech Connect

    Baskaran, Sulochanadevi; Roach, Peter J.; DePaoli-Roach, Anna A.; Hurley, Thomas D.

    2010-11-22

    Regulation of the storage of glycogen, one of the major energy reserves, is of utmost metabolic importance. In eukaryotes, this regulation is accomplished through glucose-6-phosphate levels and protein phosphorylation. Glycogen synthase homologs in bacteria and archaea lack regulation, while the eukaryotic enzymes are inhibited by protein kinase mediated phosphorylation and activated by protein phosphatases and glucose-6-phosphate binding. We determined the crystal structures corresponding to the basal activity state and glucose-6-phosphate activated state of yeast glycogen synthase-2. The enzyme is assembled into an unusual tetramer by an insertion unique to the eukaryotic enzymes, and this subunit interface is rearranged by the binding of glucose-6-phosphate, which frees the active site cleft and facilitates catalysis. Using both mutagenesis and intein-mediated phospho-peptide ligation experiments, we demonstrate that the enzyme's response to glucose-6-phosphate is controlled by Arg583 and Arg587, while four additional arginine residues present within the same regulatory helix regulate the response to phosphorylation.

  12. Purification and Structural and Kinetic Characterization of the Pyrophosphate:Fructose-6-Phosphate 1-Phosphotransferase from the Crassulacean Acid Metabolism Plant, Pineapple.

    PubMed Central

    Tripodi, KEJ.; Podesta, F. E.

    1997-01-01

    Pyrphosphate-dependent phosphofructokinase (PFP) was purified to electrophoretic homogeneity from illuminated pineapple (Ananas comosus) leaves. The purified enzyme consists of a single subunit of 61.5 kD that is immunologically related to the potato tuber PFP [beta] subunit. The native form of PFP likely consists of a homodimer of 97.2 kD, as determined by gel filtration. PFP's glycolytic activity was strongly dependent on pH, displaying a maximum at pH 7.7 to 7.9. Gluconeogenic activity was relatively constant between pH 6.7 and 8.7. Activation by Fru-2,6-bisphosphate (Fru-2,6-P2) was dependent on assay pH. In the glycolytic direction, it activated about 10-fold at pH 6.7, but only 2-fold at pH 7.7. The gluconeogenic reaction was only weakly affected by Fru-2,6-P2. The true substrates for the PFP forward and reverse reactions were Fru-6-phosphate and Mg-pyrophosphate, and Fru-1,6-P2, orthophosphate, and Mg2+, respectively. The results suggest that pineapple PFP displays regulatory properties consistent with a pH-based regulation of its glycolytic activity, in which a decrease in cytosolic pH caused by nocturnal acidification during Crassulacean acid metabolism, which could curtail its activity, is compensated by a parallel increase in its sensitivity to Fru-2,6-P2. It is also evident that the [beta] subunit alone is sufficient to confer PFP with a high catalytic rate and the regulatory properties associated with activation by Fru-2,6-P2. PMID:12223643

  13. Trehalose-6-phosphate-potent anti-onchocerciatic agent.

    PubMed

    Oke, J M; Watt, R A

    1998-01-01

    Onchocerciasis is a disease that engages the attention of most researchers. Presently, there is not an ideal onchocerciatic agent, hence the search must continues. Consequently alpha, alpha-trehalose-6-phosphate was synthesised and assessed for onchocerciatic activity against O. volvulus; using diethylcarbamizine citrate as the control drug. Results from this study showed that alpha, alpha-trehalose-6-phosphate is a glucose analogue with effective micro and macro-filaricidal agent, better than that of the control drug. The inhibitory action of this compound on enzyme trehalase is a postulate for the mechanism of action of trehalose-6-phosphate. The structure-activity relationship of this new compound is fully discussed. This study postulates that this compound could be used to eradicate onchocerciasis both in man and animals.

  14. Red Algal Bromophenols as Glucose 6-Phosphate Dehydrogenase Inhibitors

    PubMed Central

    Mikami, Daisuke; Kurihara, Hideyuki; Kim, Sang Moo; Takahashi, Koretaro

    2013-01-01

    Five bromophenols isolated from three Rhodomelaceae algae (Laurencia nipponica, Polysiphonia morrowii, Odonthalia corymbifera) showed inhibitory effects against glucose 6-phosphate dehydrogenase (G6PD). Among them, the symmetric bromophenol dimer (5) showed the highest inhibitory activity against G6PD. PMID:24152564

  15. Glucose-6-phosphate dehydrogenase deficiency: not exclusively in males.

    PubMed

    van den Broek, Leonie; Heylen, Evelien; van den Akker, Machiel

    2016-12-01

    Glucose-6-phosphate (G6PD) deficiency is the most common human enzyme defect, often presenting with neonatal jaundice and/or acute hemolytic anemia, triggered by oxidizing agents. G6PD deficiency is an X-linked, hereditary disease, mainly affecting men, but should also be considered in females with an oxidative hemolysis.

  16. Evidence that adrenal hexose-6-phosphate dehydrogenase can effect microsomal P450 cytochrome steroidogenic enzymes.

    PubMed

    Foster, Christy A; Mick, Gail J; Wang, Xudong; McCormick, Kenneth

    2013-09-01

    The role of adrenal hexose-6-phosphate dehydrogenase in providing reducing equivalents to P450 cytochrome steroidogenic enzymes in the endoplasmic reticulum is uncertain. Hexose-6-phosphate dehydrogenase resides in the endoplasmic reticulum lumen and co-localizes with the bidirectional enzyme 11β-hydroxysteroid dehydrogenase 1. Hexose-6-phosphate dehydrogenase likely provides 11β-hydroxysteroid dehydrogenase 1 with NADPH electrons via channeling. Intracellularly, two compartmentalized reactions generate NADPH upon oxidation of glucose-6-phosphate: cytosolic glucose-6-phosphate dehydrogenase and microsomal hexose-6-phosphate dehydrogenase. Because some endoplasmic reticulum enzymes require an electron donor (NADPH), it is conceivable that hexose-6-phosphate dehydrogenase serves in this capacity for these pathways. Besides 11β-hydroxysteroid dehydrogenase 1, we examined whether hexose-6-phosphate dehydrogenase generates reduced pyridine nucleotide for pivotal adrenal microsomal P450 enzymes. 21-hydroxylase activity was increased with glucose-6-phosphate and, also, glucose and glucosamine-6-phosphate. The latter two substrates are only metabolized by hexose-6-phosphate dehydrogenase, indicating that requisite NADPH for 21-hydroxylase activity was not via glucose-6-phosphate dehydrogenase. Moreover, dihydroepiandrostenedione, a non-competitive inhibitor of glucose-6-phosphate dehydrogenase, but not hexose-6-phosphate dehydrogenase, did not curtail activation by glucose-6-phosphate. Finally, the most compelling observation was that the microsomal glucose-6-phosphate transport inhibitor, chlorogenic acid, blunted the activation by glucose-6-phosphate of both 21-hydroxylase and 17-hydroxylase indicating that luminal hexose-6-phosphate dehydrogenase can supply NADPH for these enzymes. Analogous kinetic observations were found with microsomal 17-hydroxylase. These findings indicate that hexose-6-phosphate dehydrogenase can be a source, but not exclusively so, of NADPH

  17. The glucose-6-phosphate transport is not mediated by a glucose-6-phosphate/phosphate exchange in liver microsomes.

    PubMed

    Marcolongo, Paola; Fulceri, Rosella; Giunti, Roberta; Margittai, Eva; Banhegyi, Gabor; Benedetti, Angelo

    2012-09-21

    A phosphate-linked antiporter activity of the glucose-6-phosphate transporter (G6PT) has been recently described in liposomes including the reconstituded transporter protein. We directly investigated the mechanism of glucose-6-phosphate (G6P) transport in rat liver microsomal vesicles. Pre-loading with inorganic phosphate (Pi) did not stimulate G6P or Pi microsomal inward transport. Pi efflux from pre-loaded microsomes could not be enhanced by G6P or Pi addition. Rapid G6P or Pi influx was registered by light-scattering in microsomes not containing G6P or Pi. The G6PT inhibitor, S3483, blocked G6P transport irrespectively of experimental conditions. We conclude that hepatic G6PT functions as an uniporter.

  18. Overproduction of Trehalose: Heterologous Expression of Escherichia coli Trehalose-6-Phosphate Synthase and Trehalose-6-Phosphate Phosphatase in Corynebacterium glutamicum

    PubMed Central

    Padilla, Leandro; Krämer, Reinhard; Stephanopoulos, Gregory; Agosin, Eduardo

    2004-01-01

    Trehalose is a disaccharide with potential applications in the biotechnology and food industries. We propose a method for industrial production of trehalose, based on improved strains of Corynebacterium glutamicum. This paper describes the heterologous expression of Escherichia coli trehalose-synthesizing enzymes trehalose-6-phosphate synthase (OtsA) and trehalose-6-phosphate phosphatase (OtsB) in C. glutamicum, as well as its impact on the trehalose biosynthetic rate and metabolic-flux distributions, during growth in a defined culture medium. The new recombinant strain showed a five- to sixfold increase in the activity of OtsAB pathway enzymes, compared to a control strain, as well as an almost fourfold increase in the trehalose excretion rate during the exponential growth phase and a twofold increase in the final titer of trehalose. The heterologous expression described resulted in a reduced specific glucose uptake rate and Krebs cycle flux, as well as reduced pentose pathway flux, a consequence of downregulated glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. The results proved the suitability of using the heterologous expression of Ots proteins in C. glutamicum to increase the trehalose biosynthetic rate and yield and suggest critical points for further improvement of trehalose overproduction in C. glutamicum. PMID:14711665

  19. ScrB (Cg2927) is a sucrose-6-phosphate hydrolase essential for sucrose utilization by Corynebacterium glutamicum.

    PubMed

    Engels, Verena; Georgi, Tobias; Wendisch, Volker F

    2008-12-01

    Corynebacterium glutamicum can grow on a variety of carbohydrates from which glucose, fructose and sucrose are taken up and phosphorylated by the phosphoenolpyruvate-dependent phosphotransferase system (PTS). Here, we show that cg2927 (scrB) encodes sucrose-6-phosphate hydrolase. The purified His-tagged protein hydrolyzed sucrose-6-phosphate and sucrose, but not sucrose-6'-phosphate. The Km value for sucrose was 190 mM while the Km for sucrose-6-phosphate was much lower, 0.04 mM. Sucrose-6-phosphate hydrolase activity was stimulated by MgSO4 and fructose-6-phosphate and was inhibited by MnCl2, CaCl2, CuSO4 and ZnSO4. A scrB deletion mutant could not grow on sucrose as the sole carbon source. In addition, growth in the absence of scrB was severely decreased when sucrose was present in addition to glucose, fructose or acetate, suggesting that higher intracellular concentrations of sucrose-6-phosphate are toxic. Transcriptional start sites in the cg2929-cg2928-scrB-ptsS locus could be revealed upstream of cg2929 and upstream of the sucrose-specific PTS gene ptsS. Of these, only ptsS showed increased expression when grown in the presence of sucrose, which was due to control by the transcriptional regulator SugR. The sucrose-6-phosphate hydrolase activity, however, was increased two- to threefold during growth in fructose- or sucrose-containing media, regardless of the presence or absence of SugR.

  20. Malaria, favism and glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Huheey, J E; Martin, D L

    1975-10-15

    Although glucose-6-phosphate dehydrogenase deficient individuals may suffer (sometimes fatally) from favism, a high incidence of this trait occurs in many Mediterranean populations. This apparent paradox is explained on the basis of a synergistic interaction between favism and G-6-PD deficiency that provides increased protection against malaria compared to that of the G-6-PD deficiency alone. This relationship is analogous to that between various hemoglobins and malaria in that there is selection for a more severe trait if it provides more protection against malaria.

  1. Drug-induced haemolysis in glucose-6-phosphate dehydrogenase deficiency.

    PubMed Central

    Chan, T K; Todd, D; Tso, S C

    1976-01-01

    People with the variants of glucose-6-phosphate dehydrogenase (GPD) deficiency common in the southern Chinese (Canton, B(-)Chinese, and Hong Kong-Pokfulam) have a moderate shortening of red-cell survival but no anaemia when they are in the steady state. With a cross-transfusion technique, primaquine, nitrofurantoin, and large doses of aspirin were found to aggravate the haemolysis while sulphamethoxazole did so only in some people. Individual differences in drug metabolism may be the reason for this. Many commonly used drugs reported to accentuate haemolysis in GPD deficiency did not shorten red-cell survival. PMID:990860

  2. 21 CFR 864.7360 - Erythrocytic glucose-6-phosphate dehydrogenase assay.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Erythrocytic glucose-6-phosphate dehydrogenase... § 864.7360 Erythrocytic glucose-6-phosphate dehydrogenase assay. (a) Identification. An erythrocytic glucose-6-phosphate dehydrogenase assay is a device used to measure the activity of the enzyme glucose-6...

  3. 21 CFR 864.7360 - Erythrocytic glucose-6-phosphate dehydrogenase assay.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Erythrocytic glucose-6-phosphate dehydrogenase... § 864.7360 Erythrocytic glucose-6-phosphate dehydrogenase assay. (a) Identification. An erythrocytic glucose-6-phosphate dehydrogenase assay is a device used to measure the activity of the enzyme glucose-6...

  4. 21 CFR 864.7360 - Erythrocytic glucose-6-phosphate dehydrogenase assay.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Erythrocytic glucose-6-phosphate dehydrogenase... § 864.7360 Erythrocytic glucose-6-phosphate dehydrogenase assay. (a) Identification. An erythrocytic glucose-6-phosphate dehydrogenase assay is a device used to measure the activity of the enzyme glucose-6...

  5. 21 CFR 864.7360 - Erythrocytic glucose-6-phosphate dehydrogenase assay.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Erythrocytic glucose-6-phosphate dehydrogenase... § 864.7360 Erythrocytic glucose-6-phosphate dehydrogenase assay. (a) Identification. An erythrocytic glucose-6-phosphate dehydrogenase assay is a device used to measure the activity of the enzyme glucose-6...

  6. 21 CFR 864.7360 - Erythrocytic glucose-6-phosphate dehydrogenase assay.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Erythrocytic glucose-6-phosphate dehydrogenase... § 864.7360 Erythrocytic glucose-6-phosphate dehydrogenase assay. (a) Identification. An erythrocytic glucose-6-phosphate dehydrogenase assay is a device used to measure the activity of the enzyme glucose-6...

  7. Structural Basis for Morpheein-type Allosteric Regulation of Escherichia coli Glucosamine-6-phosphate Synthase

    PubMed Central

    Mouilleron, Stéphane; Badet-Denisot, Marie-Ange; Pecqueur, Ludovic; Madiona, Karine; Assrir, Nadine; Badet, Bernard; Golinelli-Pimpaneau, Béatrice

    2012-01-01

    The amino-terminal cysteine of glucosamine-6-phosphate synthase (GlmS) acts as a nucleophile to release and transfer ammonia from glutamine to fructose 6-phosphate through a channel. The crystal structure of the C1A mutant of Escherichia coli GlmS, solved at 2.5 Å resolution, is organized as a hexamer, where the glutaminase domains adopt an inactive conformation. Although the wild-type enzyme is active as a dimer, size exclusion chromatography, dynamic and quasi-elastic light scattering, native polyacrylamide gel electrophoresis, and ultracentrifugation data show that the dimer is in equilibrium with a hexameric state, in vitro and in cellulo. The previously determined structures of the wild-type enzyme, alone or in complex with glucosamine 6-phosphate, are also consistent with a hexameric assembly that is catalytically inactive because the ammonia channel is not formed. The shift of the equilibrium toward the hexameric form in the presence of cyclic glucosamine 6-phosphate, together with the decrease of the specific activity with increasing enzyme concentration, strongly supports product inhibition through hexamer stabilization. Altogether, our data allow us to propose a morpheein model, in which the active dimer can rearrange into a transiently stable form, which has the propensity to form an inactive hexamer. This would account for a physiologically relevant allosteric regulation of E. coli GlmS. Finally, in addition to cyclic glucose 6-phosphate bound at the active site, the hexameric organization of E. coli GlmS enables the binding of another linear sugar molecule. Targeting this sugar-binding site to stabilize the inactive hexameric state is therefore suggested for the development of specific antibacterial inhibitors. PMID:22851174

  8. [Sorbitol-6-Phosphate Dehydrogenase Gene Polymorhism in Malus Mill. (Rosaceae)].

    PubMed

    Boris, K V; Kudryavtsev, A M; Kochieva, E Z

    2015-11-01

    The sorbitol-6-phosphate dehydrogenase gene (S6PDH) sequences of six representatives of the genus Malus, which belong to five different taxonomic sections, were examined for the first time. The exon-intron structure and polymorphism of the nucleotide and amino acid sequences of these genes was characterized. The intraspecific polymorphism of the S6PDH gene was assessed for the first time in 40 Russian and foreign apple (Malus domestica) cultivars. It was demonstrated that the interspecific polymorphism level of the S6PDH coding sequences in the studied. representatives of the genus Malus was 4%, and the intraspecific polymorphism level of M. domestica cultivars was very low, constituting 0.96%.

  9. Hemolytic anemia caused by glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Olivares, N; Medina, C; Sánchez-Corona, J; Rivas, F; Rivera, H; Hernández, A; Delgado, J L; Ibarra, B; Cantú, J M; Vaca, G; Martínez, C

    1979-01-01

    Results are reported concerning quantitation of glucose -6- phosphate dehydrogenase (G6PD) enzyme activity where in one of the members of a family a clinical diagnosis of acute hemolytic anemia due to G6PD deficiency had been established. In the propositus, G6PD levels were found to be less than 10 per cent thus confirming diagnosis; the same enzymatic deficiency was identified in one of the siblings without a history of hematologic pathology and in a maternal cousin with a history of neonatal jaundice as well as two obliged carriers. Electrophoretical enzyme phenotype was similar to A variant in three affected males. Advantages of prevention and medical care possible with early diagnosis of G6PD deficiency are discussed.

  10. Conjugated bilirubin in neonates with glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Kaplan, M; Rubaltelli, F F; Hammerman, C; Vilei, M T; Leiter, C; Abramov, A; Muraca, M

    1996-05-01

    We used a system capable of measuring conjugated bilirubin and its monoconjugated and diconjugated fractions in serum to assess bilirubin conjugation in 29 glucose-6-phosphate dehydrogenase (G6PD)-deficient, term, male newborn infants and 35 control subjects; all had serum bilirubin levels > or = 256 mumol/L (15 mg/dI). The median value for diconjugated bilirubin was lower in the G6PD-deficient neonates than in control subjects (0.06 (range 0.00 to 1.84) vs 0.21 (range 0.00 to 1.02) mumol/L, p = 0.006). Diglucuronide was undetectable in 11 (38.9%) of the G6PD-deficient infants versus 3 (8.6%) of the control subjects (p = 0.015). These findings imply a partial defect of bilirubin conjugation not previously demonstrated in G6PD-deficient newborn infants.

  11. Trehalose biosynthesis in Thermus thermophilus RQ-1: biochemical properties of the trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase.

    PubMed

    Silva, Zélia; Alarico, Susana; da Costa, Milton S

    2005-02-01

    The genes for trehalose synthesis in Thermus thermophilus RQ-1, namely otsA [trehalose-phosphate synthase (TPS)], otsB [trehalose-phosphate phosphatase (TPP)], and treS [trehalose synthase (maltose converting) (TreS)] genes are structurally linked. The TPS/TPP pathway plays a role in osmoadaptation, since mutants unable to synthesize trehalose via this pathway were less osmotolerant, in trehalose-deprived medium, than the wild-type strain. The otsA and otsB genes have now been individually cloned and overexpressed in Escherichia coli and the corresponding recombinant enzymes purified. The apparent molecular masses of TPS and TPP were 52 and 26 kDa, respectively. The recombinant TPS utilized UDP-glucose, TDP-glucose, ADP-glucose, or GDP-glucose, in this order as glucosyl donors, and glucose-6-phosphate as the glucosyl acceptor to produce trehalose-6-phosphate (T6P). The recombinant TPP catalyzed the dephosphorylation of T6P to trehalose. This enzyme also dephosphorylated G6P, and this activity was enhanced by NDP-glucose. TPS had an optimal activity at about 98 degrees C and pH near 6.0; TPP had a maximal activity near 70 degrees C and at pH 7.0. The enzymes were extremely thermostable: at 100 degrees C, TPS had a half-life of 31 min, and TPP had a half-life of 40 min. The enzymes did not require the presence of divalent cations for activity; however, the presence of Co2+ and Mg2+ stimulates both TPS and TPP. This is the first report of the characterization of TPS and TPP from a thermophilic organism.

  12. Inhibition of Recombinant Aldose-6-Phosphate Reductase from Peach Leaves by Hexose-Phosphates, Inorganic Phosphate and Oxidants.

    PubMed

    Hartman, Matías D; Figueroa, Carlos M; Arias, Diego G; Iglesias, Alberto A

    2017-01-01

    Glucitol, also known as sorbitol, is a major photosynthetic product in plants from the Rosaceae family. This sugar alcohol is synthesized from glucose-6-phosphate by the combined activities of aldose-6-phosphate reductase (Ald6PRase) and glucitol-6-phosphatase. In this work we show the purification and characterization of recombinant Ald6PRase from peach leaves. The recombinant enzyme was inhibited by glucose-1-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate and orthophosphate. Oxidizing agents irreversibly inhibited the enzyme and produced protein precipitation. Enzyme thiolation with oxidized glutathione protected the enzyme from insolubilization caused by diamide, while incubation with NADP+ (one of the substrates) completely prevented enzyme precipitation. Our results suggest that Ald6PRase is finely regulated to control carbon partitioning in peach leaves. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  13. Lactose metabolism by Staphylococcus aureus: characterization of lacABCD, the structural genes of the tagatose 6-phosphate pathway.

    PubMed Central

    Rosey, E L; Oskouian, B; Stewart, G C

    1991-01-01

    The nucleotide and deduced amino acid sequences of the lacA and lacB genes of the Staphylococcus aureus lactose operon (lacABCDFEG) are presented. The primary translation products are polypeptides of 142 (Mr = 15,425) and 171 (Mr = 18,953) amino acids, respectively. The lacABCD loci were shown to encode enzymes of the tagatose 6-phosphate pathway through both in vitro studies and complementation analysis in Escherichia coli. A serum aldolase assay, modified to allow detection of the tagatose 6-phosphate pathway enzymes utilizing galactose 6-phosphate or fructose phosphate analogs as substrate, is described. Expression of both lacA and lacB was required for galactose 6-phosphate isomerase activity. LacC (34 kDa) demonstrated tagatose 6-phosphate kinase activity and was found to share significant homology with LacC from Lactococcus lactis and with both the minor 6-phosphofructokinase (PfkB) and 1-phosphofructokinase (FruK) from E. coli. Detection of tagatose 1,6-bisphosphate aldolase activity was dependent on expression of the 36-kDa protein specified by lacD. The LacD protein is highly homologous with LacD of L. lactis. Thus, the lacABCD genes comprise the tagatose 6-phosphate pathway and are cotranscribed with genes lacFEG, which specify proteins for transport and cleavage of lactose in S. aureus. PMID:1655695

  14. Psychotic mania in glucose-6-phosphate-dehydrogenase-deficient subjects

    PubMed Central

    Bocchetta, Alberto

    2003-01-01

    Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency has been associated with acute psychosis, catatonic schizophrenia, and bipolar disorders by previous inconclusive reports. A particularly disproportionate rate of enzyme deficiency was found in manic schizoaffective patients from 662 lithium patients surveyed in Sardinia. The purpose of this study was to describe clinical characteristics which may be potentially associated with G6PD deficiency. Methods Characteristics of episodes, course of illness, family pattern of illness, laboratory tests, and treatment response of 29 G6PD-deficient subjects with a Research Diagnostic Criteria diagnosis of manic schizoaffective disorder were abstracted from available records. Results The most peculiar pattern was that of acute recurrent psychotic manic episodes, mostly characterized by loosening of associations, agitation, catatonic symptoms, and/or transient confusion, concurrent hyperbilirubinemia, positive psychiatric family history, and partial response to long-term lithium treatment. Conclusions A relationship between psychiatric disorder and G6PD deficiency is to be searched in the bipolar spectrum, particularly among patients with a history of acute episodes with psychotic and/or catatonic symptoms or with transient confusion. PMID:12844366

  15. Glucose-6-phosphate dehydrogenase deficiency: the added value of cytology.

    PubMed

    Roelens, Marie; Dossier, Claire; Fenneteau, Odile; Couque, Nathalie; Da Costa, Lydie

    2016-06-01

    We report the case of a 2 year-old boy hospitalized into the emergency room for influenza pneumonia infection. The evolution was marked by a respiratory distress syndrome, a severe hemolytic anemia, associated with thrombocytopenia and kidney failure. First, a diagnosis of hemolytic uremic syndrome (HUS) has been judiciously suggested due to the classical triad: kidney failure, hemolytic anemia and thrombocytopenia. But, strikingly, blood smears do not exhibit schizocytes, but instead ghosts and hemighosts, some characteristic features of a glucose-6-phosphate dehydrogenase deficiency. Our hypothesis has been confirmed by enzymatic dosage and molecular biology. The unusual initial aplastic feature of this anemia could be the result of a transient erythroblastopenia due to the viral agent, at the origin of the G6PD crisis on a background of a major erythrocyte anti-oxydant enzyme defect. This case of G6PD defect points out the continuously importance of the cytology, which was able to redirect the diagnosis by the hemighost and ghost detection.

  16. Inactivation of Bakers' yeast glucose-6-phosphate dehydrogenase by aluminum

    SciTech Connect

    Cho, Sungwoo; Joshi, J.G. )

    1989-04-18

    Preincubation of yeast glucose-6-phosphate dehydrogenase (G6PD) with Al(III) produced an inactive enzyme containing 1 mol of Al(III)/mol of enzyme subunit. None of the enzyme-bound Al(III) was dissociated by dialysis against 10 mM Tris-HCl, pH 7.0, containing 0.2 mM EDTA at 4{degree}C for 24 h. Citrate, NADP{sup +}, EDTA, or NaF protected the enzyme against the Al(III) inactivation. The Al(III)-inactivated enzyme, however, was completely reactivated only by citrate and NaF. The dissociation constant for the enzyme-aluminum complex was calculated to be 4 {times} 10{sup {minus}6} M with NaF, a known reversible chelator for aluminum. Modification of histidine and lysine residues of the enzyme with diethyl pyrocarbonate and acetylsalicylic acid, respectively, inactivated the enzyme. However, the modified enzyme still bound 1 mol of Al(III)/mol of enzyme subunit. Circular dichroism studies showed that the binding of Al(III) to the enzyme induced a decrease in {alpha}-helix and {beta}-sheet and an increase in random coil. Therefore, it is suggested that inactivation of G6PD by Al(III) is due to the conformational change induced by Al(III) binding.

  17. Silencing trehalose-6-phosphate synthase incapacitates adult mosquitoes by interfering with the biosynthetic pathway for flight fuel

    USDA-ARS?s Scientific Manuscript database

    Trehalose is a disaccharide comprised of two glucose molecules. It is the main blood sugar of insects and is essential for flight. Trehalose is synthesized by two enzymes: trehalose-6-phosphate synthase (T6PS) converts glucose-6-phosphate to trehalose-6-phosphate, and trehalose-6-phosphate phosphata...

  18. Diagnostic value of glucose-6-phosphate isomerase in rheumatoid arthritis.

    PubMed

    Fan, Lie Ying; Zong, Ming; Wang, Qiang; Yang, Lin; Sun, Li Shan; Ye, Qin; Ding, Yuan Yuan; Ma, Jian Wei

    2010-12-14

    Although glucose-6-phosphate isomerase (G6PI), anti-G6PI antibodies and G6PI-containing immune complexes (G6PI-CIC) have proved high expression in patients with rheumatoid arthritis (RA), comprehensive evaluation of the G6PI-derived markers, G6PI antigen, anti-G6PI Abs, G6PI-CIC and G6PI mRNA, in the diagnosis of RA remains necessary. We measured G6PI antigen, anti-G6PI Abs, C1q/G6PI-CIC as well as anti-cyclic citrullinated peptide antibodies (anti-CCP Abs) in serum and concomitantly synovial fluid (SF) by ELISA in RA, other rheumatic diseases and healthy controls. The G6PI mRNA expression in peripheral blood mononuclear cells (PBMCs) was assessed with real-time PCR. As compared with non-RA patients, RA patients had increased levels of G6PI antigen, anti-G6PI Abs, C1q/G6PI-CIC and G6PI mRNA expression in sera or PBMCs, and increased levels of G6PI and C1q/G6PI-CIC in SF. The serum G6PI levels in RA patients positively correlated with anti-G6PI Abs, C1q/G6PI-CIC, G6PI mRNA, anti-CCP Abs, RF, CRP and ESR, respectively. The area under curve analyses demonstrated that serum G6PI had the best discriminating power for RA and active RA followed by C1q/G6PI-CIC, anti-G6PI Abs and G6PI mRNA. The simultaneous use of serum G6PI and anti-CCP Abs assays in the form of either of them tested positive gave improved sensitivities of 88.1% for RA and 95.8% for active RA. Despite the elevated expression of all G6PI-derived markers in RA, the serum G6PI has the best discriminating power among the four G6PI-derived markers. The serum G6PI determination either alone or in combination with anti-CCP Abs improves the diagnosis of RA. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Glucose-6-phosphate dehydrogenase deficiency in Nigerian children.

    PubMed

    Williams, Olatundun; Gbadero, Daniel; Edowhorhu, Grace; Brearley, Ann; Slusher, Tina; Lund, Troy C

    2013-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy and in Sub-Saharan Africa, is a significant cause of infection- and drug-induced hemolysis and neonatal jaundice. Our goals were to determine the prevalence of G6PD deficiency among Nigerian children of different ethnic backgrounds and to identify predictors of G6PD deficiency by analyzing vital signs and hematocrit and by asking screening questions about symptoms of hemolysis. We studied 1,122 children (561 males and 561 females) aged 1 month to 15 years. The mean age was 7.4 ± 3.2 years. Children of Yoruba ethnicity made up the largest group (77.5%) followed by those Igbo descent (10.6%) and those of Igede (10.2%) and Tiv (1.8%) ethnicity. G6PD status was determined using the fluorescent spot method. We found that the overall prevalence of G6PD deficiency was 15.3% (24.1% in males, 6.6% in females). Yoruba children had a higher prevalence (16.9%) than Igede (10.5%), Igbo (10.1%) and Tiv (5.0%) children. The odds of G6PD deficiency were 0.38 times as high in Igbo children compared to Yoruba children (p=0.0500). The odds for Igede and Tiv children were not significantly different from Yoruba children (p=0.7528 and 0.9789 respectively). Mean oxygen saturation, heart rate and hematocrit were not significantly different in G6PD deficient and G6PD sufficient children. The odds of being G6PD deficient were 2.1 times higher in children with scleral icterus than those without (p=0.0351). In conclusion, we determined the prevalence of G6PD deficiency in Nigerian sub-populations. The odds of G6PD deficiency were decreased in Igbo children compared to Yoruba children. There was no association between vital parameters or hematocrit and G6PD deficiency. We found that a history of scleral icterus may increase the odds of G6PD deficiency, but we did not exclude other common causes of icterus such as sickle cell disease or malarial infection.

  20. Astrocytic glucose-6-phosphatase and the permeability of brain microsomes to glucose 6-phosphate.

    PubMed Central

    Forsyth, R J; Bartlett, K; Burchell, A; Scott, H M; Eyre, J A

    1993-01-01

    Cells from primary rat astrocyte cultures express a 36.5 kDa protein that cross-reacts with polyclonal antibodies to the catalytic subunit of rat hepatic glucose-6-phosphatase on Western blotting. Glucose-6-phosphate-hydrolysing activity of the order of 10 nmol/min per mg of total cellular protein can be demonstrated in cell homogenates. This activity shows latency, and is localized to the microsomal fraction. Kinetic analysis shows a Km of 15 mM and a Vmax. of 30 nmol/min per mg of microsomal protein in disrupted microsomes. Approx. 40% of the total phosphohydrolase activity is specific glucose-6-phosphatase, as judged by sensitivity to exposure to pH 5 at 37 degrees C. Previous reports that the brain microsomal glucose-6-phosphatase system does not distinguish glucose 6-phosphate and mannose 6-phosphate are confirmed in astrocyte microsomes. However, we demonstrate significant phosphomannose isomerase activity in brain microsomes, allowing for ready interconversion between mannose 6-phosphate and glucose 6-phosphate (Vmax. 15 nmol/min per mg of microsomal protein; apparent Km < 1 mM; pH optimum 5-6 for the two-step conversion). This finding invalidates the past inference from the failure of brain microsomes to distinguish mannose 6-phosphate and glucose 6-phosphate that the cerebral glucose-6-phosphatase system lacks a 'glucose 6-phosphate translocase' [Fishman and Karnovsky (1986) J. Neurochem. 46, 371-378]. Furthermore, light-scattering experiments confirm that a proportion of whole brain microsomes is readily permeable to glucose 6-phosphate. Images Figure 1 PMID:8395816

  1. Cloning, expression, purification, crystallization and preliminary X-ray crystallographic analysis of the mannose 6-phosphate isomerase from Salmonella typhimurium

    SciTech Connect

    Gowda, Giri; Sagurthi, Someswar Rao; Savithri, H. S.; Murthy, M. R. N.

    2008-02-01

    The cloning, expression, purification, crystallization and preliminary X-ray crystallographic studies of mannose 6-phosphate isomerase from S. typhimurium are reported. Mannose 6-phosphate isomerase (MPI; EC 5.3.1.8) catalyzes the reversible isomerization of d-mannose 6-phosphate (M6P) and d-fructose 6-phosphate (F6P). In the eukaryotes and prokaryotes investigated to date, the enzyme has been reported to play a crucial role in d-mannose metabolism and supply of the activated mannose donor guanosine diphosphate d-mannose (GDP-d-mannose). In the present study, MPI was cloned from Salmonella typhimurium, overexpressed in Escherichia coli and purified using Ni–NTA affinity column chromatography. Purified MPI crystallized in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 36.03, b = 92.2, c = 111.01 Å. A data set extending to 1.66 Å resolution was collected with 98.8% completeness using an image-plate detector system mounted on a rotating-anode X-ray generator. The asymmetric unit of the crystal cell was compatible with the presence of a monomer of MPI. A preliminary structure solution of the enzyme has been obtained by molecular replacement using Candida albicans MPI as the phasing model and the program Phaser. Further refinement and model building are in progress.

  2. On the functional role of Arg172 in substrate binding and allosteric transition in Escherichia coli glucosamine-6-phosphate deaminase.

    PubMed

    Lucumí-Moreno, Armando; Calcagno, Mario L

    2005-10-01

    Glucosamine-6-phosphate deaminase from Escherichia coli (EC 3.5.99.6) is an allosteric enzyme, activated by N-acetylglucosamine 6-phosphate, which converts glucosamine-6-phosphate into fructose 6-phosphate and ammonia. X-ray crystallographic structural models have showed that Arg172 and Lys208, together with the segment 41-44 of the main chain backbone, are involved in binding the substrate phospho group when the enzyme is in the R activated state. A set of mutants of the enzyme involving the targeted residues were constructed to analyze the role of Arg172 and Lys208 in deaminase allosteric function. The mutant enzymes were characterized by kinetic, chemical, and spectrometric methods, revealing conspicuous changes in their allosteric properties. The study of these mutants indicated that Arg172 which is located in the highly flexible motif 158-187 forming the active site lid has a specific role in binding the substrate to the enzyme in the T state. The possible role of this interaction in the conformational coupling of the active and the allosteric sites is discussed.

  3. Glucose-6-phosphate dehydrogenase deficiency presented with convulsion: a rare case.

    PubMed

    Merdin, Alparslan; Avci, Fatma; Guzelay, Nihal

    2014-01-29

    Red blood cells carry oxygen in the body and Glucose-6-Phosphate Dehydrogenase protects these cells from oxidative chemicals. If there is a lack of Glucose-6-Phosphate Dehydrogenase, red blood cells can go acute hemolysis. Convulsion is a rare presentation for acute hemolysis due to Glucose-6-Phosphate Dehydrogenase deficiency. Herein, we report a case report of a Glucose-6-Phosphate Dehydrogenase deficiency diagnosed patient after presentation with convulsion. A 70 year-old woman patient had been hospitalized because of convulsion and fatigue. She has not had similar symptoms before. She had ingested fava beans in the last two days. Her hypophyseal and brain magnetic resonance imaging were normal. Blood transfusion was performed and the patient recovered.

  4. Lactose metabolism by Streptococcus mutans: evidence for induction of the tagatose 6-phosphate pathway.

    PubMed Central

    Hamilton, I R; Lebtag, H

    1979-01-01

    Growth on lactose by strains of Streptococcus mutans resulted in the induction of the lactose-phosphoenolpyruvate-phosphotransferase system, phospho-beta-galactosidase, and the enzymes of the tagatose 6-phosphate pathway. PMID:230175

  5. Glycosidases Interact Selectively With Mannose-6-Phosphate Receptors of Bull Spermatozoa.

    PubMed

    Aguilera, Andrea C; Boschin, Verónica; Carvelli, Lorena; Cavicchia, Juan C; Sosa, Miguel A

    2016-11-01

    Glycosidases may play a role in sperm maturation during epididymal transit. In this work, we describe the interaction of these enzymes with bull spermatozoa. We found that β-galactosidase associated to spermatozoa can be released under low ionic strength conditions, whereas the interaction of N-acetyl-β-D-glucosaminidase and β-glucuronidase with spermatozoa appeared to be stronger. On the other hand, α-mannosidase and α-fucosidase cannot be removed from the gametes. In addition, part of N-acetyl-β-D-glucosaminidase, β-galactosidase, and β-glucuronidase can also be released by mannose-6-phosphate. Taking into account these data, we explored the presence of cation-independent- and cation-dependent-mannose-6-phosphate receptors in the spermatozoa and found that cation-independent mannose-6-phosphate receptor is highly expressed in bull spermatozoa and cation-dependent-mannose-6-phosphate receptor is expressed at a lesser extent. In addition, by immunofluorescence, we observed that cation-independent-mannose-6-phosphate receptor is mostly located at the acrosomal zone, whereas cation-dependent-mannose-6-phosphate receptor presents a different distribution pattern on spermatozoa during the epididymal transit. N-acetyl-β-D-glucosaminidase and β-glucuronidase isolated from epididymal fluid interacted mostly with cation-independent-mannose-6-phosphate receptor, while β-galactosidase was recognized by both receptors. We concluded that glycosidases might play different roles in bull spermatozoa and that mannos-6-phosphate receptors may act as recruiters of some enzymes. J. Cell. Biochem. 117: 2464-2472, 2016. © 2016 Wiley Periodicals, Inc.

  6. Biochemical characterization of rice trehalose-6-phosphate phosphatases supports distinctive functions of these plant enzymes.

    PubMed

    Shima, Shuhei; Matsui, Hirokazu; Tahara, Satoshi; Imai, Ryozo

    2007-03-01

    Substantial levels of trehalose accumulate in bacteria, fungi, and invertebrates, where it serves as a storage carbohydrate or as a protectant against environmental stresses. In higher plants, trehalose is detected at fairly low levels; therefore, a regulatory or signaling function has been proposed for this molecule. In many organisms, trehalose-6-phosphate phosphatase is the enzyme governing the final step of trehalose biosynthesis. Here we report that OsTPP1 and OsTPP2 are the two major trehalose-6-phosphate phosphatase genes expressed in vegetative tissues of rice. Similar to results obtained from our previous OsTPP1 study, complementation analysis of a yeast trehalose-6-phosphate phosphatase mutant and activity measurement of the recombinant protein demonstrated that OsTPP2 encodes a functional trehalose-6-phosphate phosphatase enzyme. OsTPP2 expression is transiently induced in response to chilling and other abiotic stresses. Enzymatic characterization of recombinant OsTPP1 and OsTPP2 revealed stringent substrate specificity for trehalose 6-phosphate and about 10 times lower K(m) values for trehalose 6-phosphate as compared with trehalose-6-phosphate phosphatase enzymes from microorganisms. OsTPP1 and OsTPP2 also clearly contrasted with microbial enzymes, in that they are generally unstable, almost completely losing activity when subjected to heat treatment at 50 degrees C for 4 min. These characteristics of rice trehalose-6-phosphate phosphatase enzymes are consistent with very low cellular substrate concentration and tightly regulated gene expression. These data also support a plant-specific function of trehalose biosynthesis in response to environmental stresses.

  7. Glucosamine-6-phosphate deaminase from beef kidney is an allosteric system of the V-type.

    PubMed

    Lara-Lemus, R; Calcagno, M L

    1998-10-14

    The enzyme glucosamine-6-phosphate deaminase from beef kidney has been purified to homogeneity by allosteric-site affinity chromatography. Its amino acid composition and the N-terminal sequence (1-42), were obtained. The amino acid sequence of this segment is essentially identical to the corresponding regions of the human and hamster glucosamine-6-phosphate deaminases. The beef enzyme is a hexamer of 32.5 kDa subunits; this is nearly 2.5 kDa higher than the molecular mass of the homologous enzyme from Escherichia coli. Beef kidney deaminase exhibits a notable difference from the bacterial enzyme in its allosteric activation by N-acetylglucosamine 6-phosphate This metabolite, which is also is the allosteric activator of the bacterial glucosamine-6-phosphate deaminase, activates the enzyme by increasing its kcat without any change in the Km values for glucosamine 6-phosphate, over a wide range of activator concentration. This observation places beef kidney deaminase in the class of V-type allosteric systems.

  8. Discovery of O-GlcNAc-6-phosphate Modified Proteins in Large-scale Phosphoproteomics Data*

    PubMed Central

    Hahne, Hannes; Kuster, Bernhard

    2012-01-01

    Phosphorylated O-GlcNAc is a novel post-translational modification that has so far only been found on the neuronal protein AP180 from the rat (Graham et al., J. Proteome Res. 2011, 10, 2725–2733). Upon collision induced dissociation, the modification generates a highly mass deficient fragment ion (m/z 284.0530) that can be used as a reporter for the identification of phosphorylated O-GlcNAc. Using a publically available mouse brain phosphoproteome data set, we employed our recently developed Oscore software to re-evaluate high resolution/high accuracy tandem mass spectra and discovered the modification on 23 peptides corresponding to 11 mouse proteins. The systematic analysis of 220 candidate phosphoGlcNAc tandem mass spectra as well as a synthetic standard enabled the dissection of the major phosphoGlcNAc fragmentation pathways, suggesting that the modification is O-GlcNAc-6-phosphate. We find that the classical O-GlcNAc modification often exists on the same peptides indicating that O-GlcNAc-6-phosphate may biosynthetically arise in two steps involving the O-GlcNAc transferase and a currently unknown kinase. Many of the identified proteins are involved in synaptic transmission and for Ca2+/calmodulin kinase IV, the O-GlcNAc-6-phosphate modification was found in the vicinity of two autophosphorylation sites required for full activation of the kinase suggesting a potential regulatory role for O-GlcNAc-6-phosphate. By re-analyzing mass spectrometric data from human embryonic and induced pluripotent stem cells, our study also identified Zinc finger protein 462 (ZNF462) as the first human O-GlcNAc-6-phosphate modified protein. Collectively, the data suggests that O-GlcNAc-6-phosphate is a general post-translation modification of mammalian proteins with a variety of possible cellular functions. PMID:22826440

  9. Trehalose 6-phosphate signal is closely related to sorbitol in apple (Malus domestica Borkh. cv. Gala)

    PubMed Central

    Zhang, Wen; Lunn, John E.; Feil, Regina; Wang, Yufei; Zhao, Jingjing; Tao, Hongxia; Zhao, Zhengyang

    2017-01-01

    ABSTRACT Trehalose-6-phosphate (Tre6P) is a precursor of trehalose, which is widespread in nature and greatly influences plant growth and development. Tre6P acts as a signal of carbon availability in many plants, but little is known about the function of Tre6P in rosaceous plants, which have specific sorbitol biosynthesis and transportation pathways. In the present study, Tre6P levels and Sorbitol:Tre6P ratios were analyzed in apple (Malus domestica, Borkh. cv. Gala). Tre6P levels were positively correlated with sorbitol content but negatively correlated with sucrose, glucose, and fructose content in developing fruit. However, under sorbitol-limited conditions, Tre6P levels were positively correlated with both sorbitol and sucrose. In the presence of different exogenous sugar supply, Tre6P levels increased corresponding with sorbitol, but this was not the case with sucrose. In addition, Tre6P content and sorbitol:Tre6P ratios were more highly correlated with ADP-glucose levels under sorbitol-limited conditions and fruit development stages, respectively. These results suggest that Tre6P is more closely related to sorbitol than other soluble sugars and has an important role in influencing carbon metabolism in apple. PMID:28069587

  10. Trehalose 6-phosphate signal is closely related to sorbitol in apple (Malus domestica Borkh. cv. Gala).

    PubMed

    Zhang, Wen; Lunn, John E; Feil, Regina; Wang, Yufei; Zhao, Jingjing; Tao, Hongxia; Guo, Yanping; Zhao, Zhengyang

    2017-02-15

    Trehalose-6-phosphate (Tre6P) is a precursor of trehalose, which is widespread in nature and greatly influences plant growth and development. Tre6P acts as a signal of carbon availability in many plants, but little is known about the function of Tre6P in rosaceous plants, which have specific sorbitol biosynthesis and transportation pathways. In the present study, Tre6P levels and Sorbitol:Tre6P ratios were analyzed in apple (Malus domestica, Borkh. cv. Gala). Tre6P levels were positively correlated with sorbitol content but negatively correlated with sucrose, glucose, and fructose content in developing fruit. However, under sorbitol-limited conditions, Tre6P levels were positively correlated with both sorbitol and sucrose. In the presence of different exogenous sugar supply, Tre6P levels increased corresponding with sorbitol, but this was not the case with sucrose. In addition, Tre6P content and sorbitol:Tre6P ratios were more highly correlated with ADP-glucose levels under sorbitol-limited conditions and fruit development stages, respectively. These results suggest that Tre6P is more closely related to sorbitol than other soluble sugars and has an important role in influencing carbon metabolism in apple.

  11. Regulation of a plant SNF1-related protein kinase by glucose-6-phosphate

    SciTech Connect

    Toroser, D.; Plaut, Z.; Huber, S.C.

    2000-05-01

    One of the major protein kinases (PK{sub III}) that phosphorylates serine-158 of spinach sucrose-phosphate synthase (SPS), which is responsible for light/dark modulation of activity, is known to be a member of the SNF1-related family of protein kinases. In the present study, the authors have developed a fluorescence-based continuous assay for measurement of PK{sub III} activity. Using the continuous assay, along with the fixed-time-point {sup 32}P-incorporation assay, they demonstrate that PK{sub III} activity is inhibited by glucose-6-phosphate (Glc-6-P). Relative inhibition by Glc-6-P was increased by decreasing pH from 8.5 to 5.5 and by reducing the concentration of Mg{sup 2+} in the assay from 10 to 2 nM. Under likely physiological conditions (PH 7.0 and 2 mM Mg{sup 2+}), 10 nM Glc-6-P inhibited kinase activity approximately 70%. Inhibition by Glc-6-P could not be ascribed to contaminants in the commercial preparations. Other metabolites inhibited PK{sub III} in the following order: Glc-6-P > mannose-6-P, fructose-1,6P{sub 2} > ribose-5-P, 3-PGA, fructose-6-P. Inorganic phosphate, Glc, and AMP were not inhibitory, and free Glc did not reverse the inhibition by Glc-6-P. Because SNF1-related protein kinases are thought to function broadly in the regulation of enzyme activity and gene expression, Glc-6-P inhibition of PK{sub III} activity potentially provides a mechanism for metabolic regulation of the reactions catalyzed by these important protein kinases.

  12. Glucose-6-phosphate dehydrogenase deficiency and sulfadimidin acetylation phenotypes in Egyptian oases.

    PubMed

    Hussein, L; Yamamah, G; Saleh, A

    1992-04-01

    Screening of 1315 males from two Egyptian oases for glucose-6-phosphate dehydrogenase deficiency (G-6PD) found an incidence of 5.9%. The rate of acetylation of sulfadimidin was also studied, and a bimodal distribution was found with 73% rapid acetylators. There is a correlation between high frequency of G-6PD deficiency and high frequency of slow acetylation rate.

  13. Glucose-6-phosphate dehydrogenase-derived NADPH fuels superoxide production in the failing heart

    USDA-ARS?s Scientific Manuscript database

    In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form superoxide. NADPH is supplied principally by the pentose phosphate pathway, whose rate-limiting enzyme is glucose 6-phosphate dehydrogenase (G6PD). Therefore, we hypothesized that cardiac G6PD activation dr...

  14. A trehalose-6-phosphate synthase gene from Saccharina japonica (Laminariales, Phaeophyceae).

    PubMed

    Deng, Yunyan; Wang, Xiuliang; Guo, Hui; Duan, Delin

    2014-01-01

    The full-length cDNA sequence of a trehalose-6-phosphate synthase gene from Saccharina japonica (designated as SjaTPS) (Accession: KC578568) was isolated based on homologous cloning and RACE-PCR. It was 4,127 bp, with 320 bp 5'-UTR, 21 bp 3'-UTR, and open reading frame (ORF) of 3,786 bp. The deduced 1,261 amino acids characterized with predicted molecular weight of 137.84 kDa and theoretical isoelectric point of 7.12. The SjaTPS had one N-terminal CBM20 (family 20 carbohydrate-binding module) domain, one TPS domain (trehalose-6-phosphate synthase) in the middle region and a single TPP (trehalose-6-phosphate phosphatase) domain near the C-terminus. Structural analysis suggested that the SjaTPS putatively functioned as trehalose-6-phosphate synthase, and might be related to laminaran metabolism in S. japonica. Homology analysis indicated that the SjaTPS shared 49-70 % similarities with the 13 known TPS sequences of other algae; only 55 % amino acid similarities were detected between SjaTPS and the previously reported TPS sequence of S. japonica (Accession: DQ666325). Phylogenetic analysis revealed close affinity between SjaTPS and TPS of brown alga Ectocarpus siliculosus (Accession: CBJ29609). Transcriptional analysis showed that desiccation greatly enhanced SjaTPS expression and the maximum appeared at 3 h, which was about 300-fold compared to that of the start, implied that SjaTPS was involved with drought adaption in kelp. In vitro expression of SjaTPS showed that one distinct band existed at ~115 kDa, and western blot detection proved that it was positive to the anti-His antibody with high specificity. Our results increased the knowledge of trehalose-6-phosphate synthase properties in S. japonica and also important for better understanding the role trehalose plays in kelp abiotic tolerance for adaption to the sublittoral habitats.

  15. Crystal Structure and Substrate Specificity of D-Galactose-6-Phosphate Isomerase Complexed with Substrates

    PubMed Central

    Lee, Jung-Kul; Pan, Cheol-Ho

    2013-01-01

    D-Galactose-6-phosphate isomerase from Lactobacillus rhamnosus (LacAB; EC 5.3.1.26), which is encoded by the tagatose-6-phosphate pathway gene cluster (lacABCD), catalyzes the isomerization of D-galactose-6-phosphate to D-tagatose-6-phosphate during lactose catabolism and is used to produce rare sugars as low-calorie natural sweeteners. The crystal structures of LacAB and its complex with D-tagatose-6-phosphate revealed that LacAB is a homotetramer of LacA and LacB subunits, with a structure similar to that of ribose-5-phosphate isomerase (Rpi). Structurally, LacAB belongs to the RpiB/LacAB superfamily, having a Rossmann-like αβα sandwich fold as has been identified in pentose phosphate isomerase and hexose phosphate isomerase. In contrast to other family members, the LacB subunit also has a unique α7 helix in its C-terminus. One active site is distinctly located at the interface between LacA and LacB, whereas two active sites are present in RpiB. In the structure of the product complex, the phosphate group of D-tagatose-6-phosphate is bound to three arginine residues, including Arg-39, producing a different substrate orientation than that in RpiB, where the substrate binds at Asp-43. Due to the proximity of the Arg-134 residue and backbone Cα of the α6 helix in LacA to the last Asp-172 residue of LacB with a hydrogen bond, a six-carbon sugar-phosphate can bind in the larger pocket of LacAB, compared with RpiB. His-96 in the active site is important for ring opening and substrate orientation, and Cys-65 is essential for the isomerization activity of the enzyme. Two rare sugar substrates, D-psicose and D-ribulose, show optimal binding in the LacAB-substrate complex. These findings were supported by the results of LacA activity assays. PMID:24015281

  16. Patient with toxoplasmosis and glucose-6-phosphate dehydrogenase deficiency: a case report

    PubMed Central

    Nunes, Altacílio A

    2009-01-01

    Introduction Toxoplasmosis, a zoonotic protozoal disease caused by toxoplasma gondii, is prevalent throughout the world, affecting a large proportion of persons who usually have no symptoms. Glucose 6 phosphate dehydrogenase deficiency, an X-linked inherited disorder, is present in over 400 million people world wide. It is more common in tropical and subtropical countries and is one of the important causes of hemolytic anemia. Case presentation This case report relates the occurrence of the two diseases simultaneously in a child of five years old. Conclusion Patients with glucose-6-phosphate dehydrogenase deficiency are more susceptible to toxoplasmosis and this case report, reinforce the findings of this propensity and alert us for such possibility, what it is important, therefore, the treatment of toxoplasmosis can cause serious hemolysis in these patients. PMID:19918404

  17. Molecular Analysis of the Gene Encoding F420-Dependent Glucose-6-Phosphate Dehydrogenase from Mycobacterium smegmatis

    PubMed Central

    Purwantini, Endang; Daniels, Lacy

    1998-01-01

    The gene fgd, which codes for F420-dependent glucose-6-phosphate dehydrogenase (FGD), was cloned from Mycobacterium smegmatis, and its sequence was determined and analyzed. A homolog of FGD which has a very high similarity to the M. smegmatis FGD-derived amino acid sequence was identified in Mycobacterium tuberculosis. FGD showed significant homology with F420-dependent N5,N10-methylene-tetrahydromethanopterin reductase (MER) from methanogenic archaea and with several hypothetical proteins from M. tuberculosis and Archaeoglobus fulgidus, but FGD showed no significant homology with NADP-dependent glucose-6-phosphate dehydrogenases. Multiple alignment of FGD and MER proteins revealed four conserved consensus sequences. Multiple alignment of FGD with the hypothetical proteins also revealed portions of the same conserved sequences. Moderately high levels of FGD were expressed in Escherichia coli BL21(DE3) carrying fgd in pBluescript. PMID:9555906

  18. [Hemoglobin Woodville associated with double point mutation in the gene of glucose-6-phosphate dehydrogenase].

    PubMed

    Mansini, Adrián P; Fernández, Diego A; Aguirre, Fernando M; Pepe, Carolina; Milanesio, Berenice; Chaves, Alejandro; Eandi Eberle, Silvia; Feliú Torres, Aurora

    2015-01-01

    The co-inheritance of erythrocyte defects, hemoglobinopathies, enzymopathies, and membranopathies is not an unusual event. For the diagnosis, a laboratory strategy, including screening and confirmatory tests, additional to molecular characterization, was designed. As the result of this approach, a 24-year-old man carrying a hemoglobinopathy (Hemoglobin Woodville) and an enzymopathy (glucose-6-phosphate dehydrogenase deficiency) was identified. In the heterozygous state hemoglobin Woodville, is asymptomatic, and homozygous or double heterozygous individuals have not been reported thus far. On the other hand, previously described double point mutation in the gene for glucose-6-phosphate dehydrogenase c. [202G>A; 376A>G], p. [Val 68Met; Asn126Asp], causes hemolysis of varying severity after food or drug intake or infections. This case highlights the importance of the methodology carried out for the diagnosis, treatment, and proper genetic counseling.

  19. Mannose-6-phosphate receptor: a target for theranostics of prostate cancer.

    PubMed

    Vaillant, Ophélie; El Cheikh, Khaled; Warther, David; Brevet, David; Maynadier, Marie; Bouffard, Elise; Salgues, Frédéric; Jeanjean, Audrey; Puche, Pierre; Mazerolles, Catherine; Maillard, Philippe; Mongin, Olivier; Blanchard-Desce, Mireille; Raehm, Laurence; Rébillard, Xavier; Durand, Jean-Olivier; Gary-Bobo, Magali; Morère, Alain; Garcia, Marcel

    2015-05-11

    The development of personalized and non-invasive cancer therapies based on new targets combined with nanodevices is a major challenge in nanomedicine. In this work, the over-expression of a membrane lectin, the cation-independent mannose 6-phosphate receptor (M6PR), was specifically demonstrated in prostate cancer cell lines and tissues. To efficiently target this lectin a mannose-6-phosphate analogue was synthesized in six steps and grafted onto the surface of functionalized mesoporous silica nanoparticles (MSNs). These MSNs were used for in vitro and ex vivo photodynamic therapy to treat prostate cancer cell lines and primary cell cultures prepared from patient biopsies. The results demonstrated the efficiency of M6PR targeting for prostate cancer theranostic. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. The bovine mannose 6-phosphate/insulin-like growth factor II receptor. The role of arginine residues in mannose 6-phosphate binding.

    PubMed

    Dahms, N M; Rose, P A; Molkentin, J D; Zhang, Y; Brzycki, M A

    1993-03-15

    The extracytoplasmic region of the bovine cation-independent mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF-II receptor) consists of 15 homologous repeating domains, each of which is approximately 147 residues in length. The receptor contains two high affinity mannose 6-phosphate (Man-6-P) binding sites and our recent studies (Westlund, B., Dahms, N. M., and Kornfeld, S. (1991) J. Biol. Chem. 266, 23233-23239) have localized these two binding sites to domains 1-3 and 7-11. To further define the location of the Man-6-P binding sites and to determine the role of specific arginine residues in Man-6-P binding, site-directed mutagenesis was utilized to create truncated soluble forms of the M6P/IGF-II receptor in conjunction with either conservative (Lys) or nonconservative (Ala) replacement of arginine residues. These mutants were expressed transiently in COS-1 cells and assayed for their ability to bind phosphomannosyl residues by affinity chromatography. Analysis of the ligand binding activity of carboxyl-terminal truncated forms of the receptor's extracytoplasmic region demonstrated that the second Man-6-P binding site is contained within domains 7-9. Substitution of Arg435 in domain 3 of the amino-terminal binding site and Arg1334 in domain 9 of the second binding site results in a dramatic loss of ligand binding activity. However, substitutions at positions 435 and/or 1334 did not affect the secretion, glycosylation, or immunoreactivity of these truncated proteins. Taken together, these results indicate that Arg435 and Arg1334 are essential components of the M6P/IGF-II receptor's high affinity Man-6-P binding sites.

  1. Cloning and characterization of genes encoding trehalose-6-phosphate synthase (TPS1) and trehalose-6-phosphate phosphatase (TPS2) from Zygosaccharomyces rouxii.

    PubMed

    Kwon, Hawk-Bin; Yeo, Eun-Taeg; Hahn, Sang-Eun; Bae, Shin-Chul; Kim, Dool-Yi; Byun, Myung-Ok

    2003-06-01

    In many organisms, trehalose protects against several environmental stresses, such as heat, desiccation, and salt, probably by stabilizing protein structures and lipid membranes. Trehalose synthesis in yeast is mediated by a complex of trehalose-6-phosphate synthase (TPS1) and trehalose-6-phosphate phosphatase (TPS2). In this study, genes encoding TPS1 and TPS2 were isolated from Zygosaccharomyces rouxii (designated ZrTPS1 and ZrTPS2, respectively). They were functionally identified by their complementation of the tps1 and tps2 yeast deletion mutants, which are unable to grow on glucose medium and with heat, respectively. Full-length ZrTPS1 cDNA is composed of 1476 nucleotides encoding a protein of 492 amino acids with a molecular mass of 56 kDa. ZrTPS2 cDNA consists of 2843 nucleotides with an open reading frame of 2700 bp, which encodes a polypeptide of 900 amino acids with a molecular mass of 104 kDa. The amino acid sequence encoded by ZrTPS1 has relatively high homology with TPS1 of Saccharomyces cerevisiae and Schizosaccharomyces pombe, compared with TPS2. Western blot analysis showed that the antibody against S. cerevisiae TPS1 recognizes ZrTPS1. Under normal growth conditions, ZrTPS1 and ZrTPS2 were highly and constitutively expressed, unlike S. cerevisiae TPS1 and TPS2. Salt stress and heat stress reduced the expression of the ZrTPS1 and ZrTPS2 genes, respectively.

  2. Apparent role of dynein in glucose-6-phosphate dehydrogenase trafficking in neutrophils from pregnant women.

    PubMed

    Huang, Ji-Biao; Espinoza, Jimmy; Romero, Roberto; Petty, Howard R

    2006-03-01

    To better understand the mechanisms of metabolic microcompartmentalization associated with neutrophil hexose monophosphate shunt activity during pregnancy, we have studied the intracellular trafficking of glucose-6-phosphate dehydrogenase (G6PDase). Microtubule motor proteins colocalize with G6PDase. Dynein inhibitors block G6PDase accumulation at the microtubule-organizing center in pregnancy cells. On this basis, we conclude that microtubule motor proteins participate in hexose monophosphate shunt enzyme transport within leukocytes.

  3. Glucose-6-phosphate Reduces Calcium Accumulation in Rat Brain Endoplasmic Reticulum

    DTIC Science & Technology

    2012-04-01

    low millimolar range. Most Ca2+ is sequestered within organelles , including the endoplasmic reticulum (ER), Golgi, mitochondria , and nucleus (Carafoli...G6P and thapsigargin caused generalized reduction in Ca2+ accumulation in remarkably similar patterns with no apparent gray matter regional...with glucose-6-phosphate (10 mM) or thapsigargin (1 µM), revealed very similar pattern of generalized reduction in 45Ca2+ accumulation in gray and

  4. Aortic valve replacement for a patient with glucose-6-phosphate dehydrogenase deficiency and autoimmune hemolytic anemia.

    PubMed

    Tas, Serpil; Donmez, Arzu Antal; Kirali, Kaan; Alp, Mete H; Yakut, Cevat

    2005-01-01

    Autoimmune hemolytic anemia and deficiency of glucose-6-phosphate deyhdrogenase (G6PD) result in severe hemolysis with different mechanisms. In patients with both pathologies, the effects of cardiopulmonary bypass on red blood cells and thrombocytes demand special care before and after open heart surgery. We evaluated the preoperative management and postoperative care of a patient with severe aortic insufficiency associated with G6PD deficiency and autoimmune hemolytic anemia who underwent aortic valve replacement.

  5. Crystal structure of trehalose-6-phosphate phosphatase–related protein: Biochemical and biological implications

    PubMed Central

    Rao, Krishnamurthy N.; Kumaran, Desigan; Seetharaman, Jayaraman; Bonanno, Jeffrey B.; Burley, Stephen K.; Swaminathan, Subramanyam

    2006-01-01

    We report here the crystal structure of a trehalose-6-phosphate phosphatase–related protein (T6PP) from Thermoplasma acidophilum, TA1209, determined by the dual-wavelength anomalous diffraction (DAD) method. T6PP is a member of the haloacid dehalogenase (HAD) superfamily with significant sequence homology with trehalose-6-phosphate phosphatase, phosphoserine phosphatase, P-type ATPases and other members of the family. T6PP possesses a core domain of known α/β-hydrolase fold, characteristic of the HAD family, and a cap domain, with a tertiary fold consisting of a four-stranded β-sheet with two α-helices on one side of the sheet. An active-site magnesium ion and a glycerol molecule bound at the interface between the two domains provide insight into the mode of substrate binding by T6PP. A trehalose-6-phosphate molecule modeled into a cage formed by the two domains makes favorable interactions with the protein molecule. We have confirmed that T6PP is a trehalose phosphatase from amino acid sequence, three-dimensional structure, and biochemical assays. PMID:16815921

  6. Cloning, expression, purification and kinetics of trehalose-6-phosphate phosphatase of filarial parasite Brugia malayi.

    PubMed

    Kushwaha, Susheela; Singh, Prashant K; Rana, Ajay K; Misra-Bhattacharya, Shailja

    2011-08-01

    The pleiotropic functions of disaccharide trehalose in the biology of nematodes and its absence from mammalian cells suggest that its biosynthesis may provide a useful target for developing novel nematicidal drugs. The trehalose-6-phosphate phosphatase (TPP), one of the enzymes of trehalose metabolism has not been characterized so far in nematodes except the free living nematode Caenorhabditis elegans where it's silencing results into lethal outcomes. This prompted us to clone and characterize Brugia malayi TPP in order to discover novel antifilarial drug target. The recombinant protein (Bm-TPP) was purified with apparent homogeneity on a metal ion column and it was found to possess high phosphatase activity with robust specificity for the substrate trehalose-6-phosphate. Bm-TPP was found to be a member of the HAD-like hydrolase super family II based on the conserved motifs required for catalytic reaction. The K(m) for substrate trehalose-6-phosphate was around 0.42 mM with pH optimum ∼7.0 and the enzyme showed an almost absolute requirement for Mg(2+) as a metal ion. Bm-TPP was expressed in all the life-stages of B. malayi. In the absence of an effective macrofilaricidal agent and validated antifilarial drug target, Bm-TPP bodes well as a rational drug target against lymphatic filariasis.

  7. Androgen-estrogen synergy in rat levator ani muscle Glucose-6-phosphate dehydrogenase

    NASA Technical Reports Server (NTRS)

    Max, S. R.

    1984-01-01

    The effects of castration and hormone administration on the activity of glucose-6-phosphate dehydrogenase in the rat levator ani muscle were studied. Castration caused a decrease in enzyme activity and in wet weight of the levator ani muscle. Chronic administration of testosterone propionate increased glucose-6-phosphate dehydrogenase activity in the levator ani muscle of castrated rats; the magnitude of the recovery of enzyme activity was related to the length of time of exposure to testosterone propionate after castration as well as to the length of time the animals were castrated. The longer the period of castration before exposure to testosterone propionate, the greater the effect. This result may be related to previously reported castration-mediated increases in androgen receptor binding in muscle. Dihydrotestosterone was less effective than testosterone propionate in enhancing glucose-6-phosphate dehydrogenase activity in the levator ani muscle from castrated rats; estradiol-17-beta alone was ineffective. Combined treatment with estradiol-17-beta and dihydrotestosterone, however, was as effective as testosterone alone. Thus, androgens and estrogens may exert synergistic effects on levator ani muscle.

  8. Bacillus licheniformis trehalose-6-phosphate hydrolase structures suggest keys to substrate specificity.

    PubMed

    Lin, Min Guan; Chi, Meng Chun; Naveen, Vankadari; Li, Yi Ching; Lin, Long Liu; Hsiao, Chwan Deng

    2016-01-01

    Trehalose-6-phosphate hydrolase (TreA) belongs to glycoside hydrolase family 13 (GH13) and catalyzes the hydrolysis of trehalose 6-phosphate (T6P) to yield glucose and glucose 6-phosphate. The products of this reaction can be further metabolized by the energy-generating glycolytic pathway. Here, crystal structures of Bacillus licheniformis TreA (BlTreA) and its R201Q mutant complexed with p-nitrophenyl-α-D-glucopyranoside (R201Q-pPNG) are presented at 2.0 and 2.05 Å resolution, respectively. The overall structure of BlTreA is similar to those of other GH13 family enzymes. However, detailed structural comparisons revealed that the catalytic site of BlTreA contains a long loop that adopts a different conformation from those of other GH13 family members. Unlike the homologous regions of Bacillus cereus oligo-1,6-glucosidase (BcOgl) and Erwinia rhapontici isomaltulose synthase (NX-5), the surface potential of the BlTreA active site exhibits a largely positive charge contributed by the four basic residues His281, His282, Lys284 and Lys292. Mutation of these residues resulted in significant decreases in the enzymatic activity of BlTreA. Strikingly, the (281)HHLK(284) motif and Lys292 play critical roles in substrate discrimination by BlTreA.

  9. Ischaemic Priapism and Glucose-6-Phosphate Dehydrogenase Deficiency: A Mechanism of Increased Oxidative Stress?

    PubMed

    Morrison, B F; Thompson, E B; Shah, S D; Wharfe, G H

    2014-07-03

    Ischaemic priapism is a devastating urological condition that has the potential to cause permanent erectile dysfunction. The disorder has been associated with numerous medical conditions and the use of pharmacotherapeutic agents. The aetiology is idiopathic in a number of cases. There are two prior case reports of the association of ischaemic priapism and glucose-6-phosphate dehydrogenase (G6PD) deficiency. We report on a third case of priapism associated with G6PD deficiency and review recently described molecular mechanisms of increased oxidative stress in the pathophysiology of ischaemic priapism. The case report of a 32-year old Afro-Caribbean male with his first episode of major ischaemic priapism is described. Screening for common causes of ischaemic priapism, including sickle cell disease was negative. Glucose-6-phosphate dehydrogenase deficiency was discovered on evaluation for priapism. Penile aspiration was performed and erectile function was good post treatment.Glucose-6-phosphate dehydrogenase deficiency is a cause for ischaemic priapism and should be a part of the screening process in idiopathic causes of the disorder. Increased oxidative stress occurs in G6PD deficiency and may lead to priapism.

  10. Effects of some drugs on human erythrocyte glucose 6-phosphate dehydrogenase: an in vitro study.

    PubMed

    Akkemik, Ebru; Budak, Harun; Ciftci, Mehmet

    2010-12-01

    Inhibitory effects of some drugs on glucose 6-phosphate dehydrogenase from the erythrocytes of human have been investigated. For this purpose, at the beginning, erythrocyte glucose 6-phosphate dehydrogenase was purified 2256 times in a yield of 44.22% by using ammonium sulphate precipitation and 2', 5'-ADP Sepharose 4B affinity gel. Temperature of +4°C was maintained during the purification process. Enzyme activity was determined with the Beutler method by using a spectrophotometer at 340 nm. This method was utilized for all kinetic studies. Ketotifen, dacarbazine, thiocolchicoside, meloxicam, methotrexate, furosemide, olanzapine, methylprednizolone acetate, paricalcitol, ritodrine hydrochloride, and gadobenate-dimeglumine were used as drugs. All the drugs indicated the inhibitory effects on the enzyme. Ki constants for glucose 6-phosphate dehydrogenase were found by means of Lineweaver-Burk graphs. While methylprednizolone acetate showed competitive inhibition, the others displayed non-competitive inhibition. In addition, IC(50) values of the drugs were determined by plotting Activity% vs [I].

  11. The quest for a thermostable sucrose phosphorylase reveals sucrose 6'-phosphate phosphorylase as a novel specificity.

    PubMed

    Verhaeghe, Tom; Aerts, Dirk; Diricks, Margo; Soetaert, Wim; Desmet, Tom

    2014-08-01

    Sucrose phosphorylase is a promising biocatalyst for the glycosylation of a wide range of compounds, but its industrial application has been hampered by the low thermostability of known representatives. Hence, in this study, the putative sucrose phosphorylase from the thermophile Thermoanaerobacterium thermosaccharolyticum was recombinantly expressed and fully characterised. The enzyme showed significant activity on sucrose (optimum at 55 °C), and with a melting temperature of 79 °C and a half-life of 60 h at the industrially relevant temperature of 60 °C, it is far more stable than known sucrose phosphorylases. Substrate screening and detailed kinetic characterisation revealed however a preference for sucrose 6'-phosphate over sucrose. The enzyme can thus be considered as a sucrose 6'-phosphate phosphorylase, a specificity not yet reported to date. Homology modelling and mutagenesis pointed out particular residues (Arg134 and His344) accounting for the difference in specificity. Moreover, phylogenetic and sequence analysis suggest that glycoside hydrolase 13 subfamily 18 might harbour even more specificities. In addition, the second gene residing in the same operon as sucrose 6'-phosphate phosphorylase was identified as well, and found to be a phosphofructokinase. The concerted action of both these enzymes implies a new pathway for the breakdown of sucrose, in which the reaction products end up at different stages of the glycolysis.

  12. Androgen-estrogen synergy in rat levator ani muscle Glucose-6-phosphate dehydrogenase

    NASA Technical Reports Server (NTRS)

    Max, S. R.

    1984-01-01

    The effects of castration and hormone administration on the activity of glucose-6-phosphate dehydrogenase in the rat levator ani muscle were studied. Castration caused a decrease in enzyme activity and in wet weight of the levator ani muscle. Chronic administration of testosterone propionate increased glucose-6-phosphate dehydrogenase activity in the levator ani muscle of castrated rats; the magnitude of the recovery of enzyme activity was related to the length of time of exposure to testosterone propionate after castration as well as to the length of time the animals were castrated. The longer the period of castration before exposure to testosterone propionate, the greater the effect. This result may be related to previously reported castration-mediated increases in androgen receptor binding in muscle. Dihydrotestosterone was less effective than testosterone propionate in enhancing glucose-6-phosphate dehydrogenase activity in the levator ani muscle from castrated rats; estradiol-17-beta alone was ineffective. Combined treatment with estradiol-17-beta and dihydrotestosterone, however, was as effective as testosterone alone. Thus, androgens and estrogens may exert synergistic effects on levator ani muscle.

  13. Novel mode of inhibition by D-tagatose 6-phosphate through a Heyns rearrangement in the active site of transaldolase B variants.

    PubMed

    Stellmacher, Lena; Sandalova, Tatyana; Schneider, Sarah; Schneider, Gunter; Sprenger, Georg A; Samland, Anne K

    2016-04-01

    Transaldolase B (TalB) and D-fructose-6-phosphate aldolase A (FSAA) from Escherichia coli are C-C bond-forming enzymes. Using kinetic inhibition studies and mass spectrometry, it is shown that enzyme variants of FSAA and TalB that exhibit D-fructose-6-phosphate aldolase activity are inhibited covalently and irreversibly by D-tagatose 6-phosphate (D-T6P), whereas no inhibition was observed for wild-type transaldolase B from E. coli. The crystal structure of the variant TalB(F178Y) with bound sugar phosphate was solved to a resolution of 1.46 Å and revealed a novel mode of covalent inhibition. The sugar is bound covalently via its C2 atom to the ℇ-NH2 group of the active-site residue Lys132. It is neither bound in the open-chain form nor as the closed-ring form of D-T6P, but has been converted to β-D-galactofuranose 6-phosphate (D-G6P), a five-membered ring structure. The furanose ring of the covalent adduct is formed via a Heyns rearrangement and subsequent hemiacetal formation. This reaction is facilitated by Tyr178, which is proposed to act as acid-base catalyst. The crystal structure of the inhibitor complex is compared with the structure of the Schiff-base intermediate of TalB(E96Q) formed with the substrate D-fructose 6-phosphate determined to a resolution of 2.20 Å. This comparison highlights the differences in stereochemistry at the C4 atom of the ligand as an essential determinant for the formation of the inhibitor adduct in the active site of the enzyme.

  14. Hypoglycaemic activity of Coccinia indica and Momordica charantia in diabetic rats: depression of the hepatic gluconeogenic enzymes glucose-6-phosphatase and fructose-1,6-bisphosphatase and elevation of both liver and red-cell shunt enzyme glucose-6-phosphate dehydrogenase.

    PubMed Central

    Shibib, B A; Khan, L A; Rahman, R

    1993-01-01

    Coccinia indica leaves were extracted with 60% ethanol, solvents were evaporated and the residue was suspended in water. This suspension was administered orally at a dose of 200 mg/kg body wt. after 18 h of fasting to normal fed and streptozotocin-induced male diabetic rats (180-250 g). After 90 min the rats were killed, and blood-glucose, hepatic glucose-6-phosphatase, fructose-1,6-bisphosphatase and glucose-6-phosphate dehydrogenase (G6PDH) and red-cell G6PDH were assayed. Blood sugar was depressed by 23% (P < 0.01) and 27% (P < 0.001) in the normal fed and streptozotocin-diabetic rats respectively compared with controls which were given distilled water. Hepatic glucose-6-phosphatase and fructose-1,6-bisphosphatase activities were depressed by 32% (P < 0.001) 30% (P < 0.05) respectively in the streptozotocin-diabetic rats, compared with 19% (P < 0.02) and 20% (P < 0.01) depression in the normal fed controls, whereas both the red-cell and hepatic G6PDH activities were found to be elevated by feeding the extract in the streptozotocin-diabetic and in the normal fed controls. Similar results were obtained with the 95%-ethanolic extract of Momordica charantia. Taken together, these results indicate that Coccinia indica and Momordica charantia extracts lowered blood glucose by depressing its synthesis, on the one hand through depression of the key gluconeogenic enzymes glucose-6-phosphatase and fructose-1,6-bisphosphatase and on the other by enhancing glucose oxidation by the shunt pathway through activation of its principal enzyme G6PDH. PMID:8389127

  15. Molecular Docking Studies of Catechin and Its Derivatives as Anti-bacterial Inhibitor for Glucosamine-6-Phosphate Synthase

    NASA Astrophysics Data System (ADS)

    Fikrika, H.; Ambarsari, L.; Sumaryada, T.

    2016-01-01

    Molecular docking simulation of catechin and its derivatives on Glucosamine-6- Phosphate Synthase (GlmS) has been performed in this research. GlmS inhibition by a particular ligand will suppress the production of bacterial cell wall and significantly reduce the population of invading bacteria. In this study, catechin derivatives i.e epicatechin, galloatechin and epigalloatechin were found to have stronger binding affinities as compared to natural ligand of GlmS, Fructose-6-Phosphate (F6P). Those three ligands were docked on the same pocket in GlmS target as F6P, with 70% binding sites similarity. Based on the docking results, gallocatechin turns out to be the most potent ligand for anti-bacterial agent with ΔG= -8.00 kcal/mol. The docking between GlmS and catechin derivatives are characterized by a constant present of a strong hydrogen bond between functional group O3 and Ser-349. This hydrogen bond most likely plays a significant role in the docking mechanism and binding modes selection. The surprising result is catechin itself exhibited a quite strong binding with GlmS (ΔG= -7.80 kcal.mol), but docked on a completely different pocket compared to other ligands. This results suggest that catechin might still have a curing effect but with a completely different pathway and mechanism as compared to its derivatives.

  16. Mutational Analyses of Glucose Dehydrogenase and Glucose-6-Phosphate Dehydrogenase Genes in Pseudomonas fluorescens Reveal Their Effects on Growth and Alginate Production.

    PubMed

    Maleki, Susan; Mærk, Mali; Valla, Svein; Ertesvåg, Helga

    2015-05-15

    The biosynthesis of alginate has been studied extensively due to the importance of this polymer in medicine and industry. Alginate is synthesized from fructose-6-phosphate and thus competes with the central carbon metabolism for this metabolite. The alginate-producing bacterium Pseudomonas fluorescens relies on the Entner-Doudoroff and pentose phosphate pathways for glucose metabolism, and these pathways are also important for the metabolism of fructose and glycerol. In the present study, the impact of key carbohydrate metabolism enzymes on growth and alginate synthesis was investigated in P. fluorescens. Mutants defective in glucose-6-phosphate dehydrogenase isoenzymes (Zwf-1 and Zwf-2) or glucose dehydrogenase (Gcd) were evaluated using media containing glucose, fructose, or glycerol. Zwf-1 was shown to be the most important glucose-6-phosphate dehydrogenase for catabolism. Both Zwf enzymes preferred NADP as a coenzyme, although NAD was also accepted. Only Zwf-2 was active in the presence of 3 mM ATP, and then only with NADP as a coenzyme, indicating an anabolic role for this isoenzyme. Disruption of zwf-1 resulted in increased alginate production when glycerol was used as the carbon source, possibly due to decreased flux through the Entner-Doudoroff pathway rendering more fructose-6-phosphate available for alginate biosynthesis. In alginate-producing cells grown on glucose, disruption of gcd increased both cell numbers and alginate production levels, while this mutation had no positive effect on growth in a non-alginate-producing strain. A possible explanation is that alginate synthesis might function as a sink for surplus hexose phosphates that could otherwise be detrimental to the cell.

  17. In vivo lability of glucose-6-phosphate dehydrogenase in GdA- and Gdmediterranean deficiency

    PubMed Central

    Piomelli, Sergio; Corash, Laurence M.; Davenport, Deatra D.; Miraglia, Janet; Amorosi, Edward L.

    1968-01-01

    A decreased level of glucose-6-phosphate dehydrogenase might result from decreased rate of synthesis, synthesis of an enzyme of lower catalytic efficiency, increased lability, or a combined mechanism. To test the hypothesis of increased lability, the rate of decline of the enzyme in vivo was measured in three groups of individuals, controls, Gd(—),A-males, and Gd(—), Mediterranean males, by the slope of decline of activity in fractions containing erythrocytes of progressively increasing mean age. These fractions were obtained by ultracentrifugation on a discontinuous density gradient of erythrocyte suspensions free of contaminating platelets and leukocytes. The rate of in vivo decline of pyruvate kinase (another age-dependent enzyme) was also measured and found very similar in the three groups. The in vivo decline of glucose-6-phosphate dehydrogenase was found to follow an exponential rate, with a half-life of 62 days for controls and 13 days for Gd(—),A- erythrocytes. The activity in normal reticulocytes was estimated at 9.7 U and in Gd(—),A- reticulocytes at 8.8 U. These estimates were confirmed by direct measurements in reticulocytes isolated from patients with extreme reticulocytosis. In Gd(—),Mediterranean erythrocytes activity could be demonstrated only in reticulocytes, which were estimated to average 1.4 U. The rate of decline is so extreme that no activity could be detected in mature erythrocytes. These data suggest that the glucose-6-phosphate dehydrogenase deficiency of both the GdA- and the GdMediterranean variant results from different degrees of in vivo instability of the abnormal enzyme. PMID:5641629

  18. Structural insight into dephosphorylation by trehalose 6-phosphate phosphatase (OtsB2) from Mycobacterium tuberculosis.

    PubMed

    Shan, Shan; Min, Haowei; Liu, Ting; Jiang, Dunquan; Rao, Zihe

    2016-12-01

    Trehalose serves as a key structural component in the cell wall of Mycobacterium tuberculosis. M. tuberculosis trehalose-6-phosphate phosphatase (MtbTPP), an essential enzyme in the trehalose biosynthesis OtsAB pathway, catalyzes the dephosphorylation of trehalose-6-phosphate (trehalose-6-P) to generate trehalose, and plays a critical role in M. tuberculosis survival-associated cell wall formation and permeability. Therefore, MtbTPP (OtsB2) is considered a promising potential target for discovery of antimicrobial drugs. However, the absence of structural information of MtbTPP restrains our understanding of its underlying catalytic mechanism. Here, we report the high-resolution crystal structures of apo active MtbTPP and its trehalose-6-P bound complex. The apo structure presents a canonical haloacid dehalogenase superfamily structural fold plus an extra N-terminal domain. The catalytic center is located in a positively charged cleft between the hydrolase domain and the cap domain, demonstrating a highly conserved substrate binding pocket. The role of residues interacting with the substrate in catalysis were probed by site-directed mutagenesis. Asp147, Asp149, Asp330, and Asp331 were found to be pivotal for the enzymatic activity of MtbTPP. The MtbTPP structures reported here provide insight into a key step in the biosynthesis of trehalose, which would facilitate future development of anti-TB therapeutics.-Shan, S., Min, H., Liu, T., Jiang, D., Rao, Z. Structural insight into dephosphorylation by trehalose 6-phosphate phosphatase (OtsB2) from Mycobacterium tuberculosis.

  19. Mimicked translocation of glucose and glucose 6-phosphate with artificial enzyme membranes.

    PubMed Central

    Maïsterrena, B; Coulet, P R

    1989-01-01

    An approach to the mechanism which may govern the behaviour of biological compartmentalized systems is presented. Artificial enzyme membranes with immobilized glucose oxidase, invertase or hexokinase were used to separate two compartments of a specially designed diffusion cell. Asymmetry in volume, hydrodynamic conditions and enzyme location was purposely chosen in order to create situations which could not be obtained with an enzyme free in solution, and was then used to tentatively mimic situations existing in vivo. Experiments were conducted and a translocation effect of H2O2, glucose and glucose 6-phosphate was obtained. A theoretical analysis taking into account the different identified parameters of the system was elaborated. PMID:2764883

  20. Gas Phase Spectra and Structural Determination of Glucose 6 Phosphate Using Cryogenic Ion Vibrational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kregel, Steven J.; Voss, Jonathan; Marsh, Brett; Garand, Etienne

    2014-06-01

    Glucose-6-Phosphate (G6P) is one member of a class of simple phosphorylated sugars that are relevant in biological processes. We have acquired a gas phase infrared spectrum of G6P- using cryogenic ion vibrational spectroscopy (CIVS) in a home-built spectrometer. The experimental spectrum was compared with calculated vibrational spectra from a systematic conformer search. For both of the α and β anomers, results show that only the lowest energy conformers are present in the gas phase. If spectral signatures for similar sugars could be cataloged, it would allow for conformer-specific determination of mixture composition, for example, for glycolyzation processes.

  1. Bio-catalytic nanocompartments for in situ production of glucose-6-phosphate.

    PubMed

    Lomora, M; Gunkel-Grabole, G; Mantri, S; Palivan, C G

    2017-08-29

    Cells are sophisticated biocatalytic systems driving a complex network of biochemical reactions. A bioinspired strategy to create advanced functional systems is to design confined spaces for complex enzymatic reactions by using a combination of synthetic polymer assemblies and natural cell components. Here, we developed bio-catalytic nanocompartments that contain phosphoglucomutase protected by a biomimetic polymer membrane, which was permeabilized for reactants through insertion of an engineered α-hemolysin pore protein. These bio-catalytic nanocompartments serve for production of glucose-6-phosphate, and thus possess great potential for applications in an incomplete glycolysis, pentose phosphate pathway, or in plant biological reactions.

  2. Glucose-6-Phosphate Dehydrogenase Deficiency and Haemoglobinophaties in Resident of Arso PIR, Irian Jaya

    DTIC Science & Technology

    1990-01-01

    and drug treatment . Another factor is play a part in innate resistance. 0-6-PD the ’internal environment’ of the host and deficiency can also complicate...response to and treatment of glucose-6-phosphate. The amount of of malaria, epidemiologic and immuno- NADPH produced is detected spectropho- logic...Ohio inherited along with a B- thalassemia gene 9-66. producing Hb-E thalassemia . Although 2. Kellermeyer, R.W., A.R. Tarlov, G.J. this condition can

  3. Is glucose-6-phosphate dehydrogenase deficiency more prevalent in Carrion's disease endemic areas in Latin America?

    PubMed

    Mazulis, Fernando; Weilg, Claudia; Alva-Urcia, Carlos; Pons, Maria J; Del Valle Mendoza, Juana

    2015-12-01

    Glucose-6-phosphate dehydrogenase (G6PD) is a cytoplasmic enzyme with an important function in cell oxidative damage prevention. Erythrocytes have a predisposition towards oxidized environments due to their lack of mitochondria, giving G6PD a major role in its stability. G6PD deficiency (G6PDd) is the most common enzyme deficiency in humans; it affects approximately 400 million individuals worldwide. The overall G6PDd allele frequency across malaria endemic countries is estimated to be 8%, corresponding to approximately 220 million males and 133 million females. However, there are no reports on the prevalence of G6PDd in Andean communities where bartonellosis is prevalent.

  4. Glucose-6-phosphate dehydrogenase deficiency: an unusual cause of acute jaundice after paracetamol overdose.

    PubMed

    Phillpotts, Simon; Tash, Elliot; Sen, Sambit

    2014-11-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the commonest human enzyme defect causing haemolytic anaemia after exposure to specific triggers. Paracetamol-induced haemolysis in G6PD deficiency is a rare complication and mostly reported in children. We report the first case (to the best of our knowledge) of acute jaundice without overt clinical features of a haemolytic crisis, in an otherwise healthy adult female following paracetamol overdose, due to previously undiagnosed G6PD deficiency. It is important that clinicians consider this condition when a patient presents following a paracetamol overdose with significant and disproportionate jaundice, without transaminitis or coagulopathy.

  5. Glucose-6-phosphate dehydrogenase deficiency in the Greek population of Cape Town.

    PubMed

    Bonafede, R P; Botha, M C; Beighton, P

    1984-04-07

    A sample of 250 unrelated members of the Greek community of Cape Town was studied in order to establish the prevalence of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in the community. A gene frequency of 0,067 in males and a prevalence of 6,7% are estimated for this group. It is recommended that persons with G-6-PD deficiency should have access to a list of medicinal agents which have the potential for precipitating acute haemolytic crises and that they should wear Medic-Alert discs bearing information concerning the disorder.

  6. Differential behaviour of glucose 6-phosphate dehydrogenase in two morphological forms of Trypanosoma cruzi.

    PubMed

    Lupiañez, J A; Adroher, F J; Vargas, A M; Osuna, A

    1987-01-01

    1. Glucose 6-phosphate dehydrogenase activity (EC 1.1.1.49) of two morphological forms of Trypanosoma cruzi, epimastigotes and metacyclics, are reported. 2. The kinetic behaviour and some of the kinetic parameters of the enzyme in both forms were studied. The enzymes showed a simple Michaelis-Menten kinetic. 3. The activity in epimastigote forms was alway higher than the metacyclic ones. At subsaturating concentrations of substrate was almost 10-fold higher, whereas at saturating concentrations was about 2-fold higher. 4. In epimastigote forms the specific activity and Km values, at pH 7.5 and 37 degrees C, was found to be 142 mUnits x mg-1 of protein and 0.23 mM, respectively. 5. In the same conditions, the specific activity and Km values in metacyclic forms was 75 mUnits x mg-1 of protein and 1.06 mM, respectively. 6. A possible role in the carbohydrate metabolism of glucose 6-phosphate dehydrogenase in both forms of Trypanosoma cruzi is discussed.

  7. Glucose-6-phosphate mediates activation of the carbohydrate responsive binding protein (ChREBP)

    SciTech Connect

    Li, Ming V.; Chen, Weiqin; Harmancey, Romain N.; Nuotio-Antar, Alli M.; Imamura, Minako; Saha, Pradip; Taegtmeyer, Heinrich; Chan, Lawrence

    2010-05-07

    Carbohydrate response element binding protein (ChREBP) is a Mondo family transcription factor that activates a number of glycolytic and lipogenic genes in response to glucose stimulation. We have previously reported that high glucose can activate the transcriptional activity of ChREBP independent of the protein phosphatase 2A (PP2A)-mediated increase in nuclear entry and DNA binding. Here, we found that formation of glucose-6-phosphate (G-6-P) is essential for glucose activation of ChREBP. The glucose response of GAL4-ChREBP is attenuated by D-mannoheptulose, a potent hexokinase inhibitor, as well as over-expression of glucose-6-phosphatase (G6Pase); kinetics of activation of GAL4-ChREBP can be modified by exogenously expressed GCK. Further metabolism of G-6-P through the two major glucose metabolic pathways, glycolysis and pentose-phosphate pathway, is not required for activation of ChREBP; over-expression of glucose-6-phosphate dehydrogenase (G6PD) diminishes, whereas RNAi knockdown of the enzyme enhances, the glucose response of GAL4-ChREBP, respectively. Moreover, the glucose analogue 2-deoxyglucose (2-DG), which is phosphorylated by hexokinase, but not further metabolized, effectively upregulates the transcription activity of ChREBP. In addition, over-expression of phosphofructokinase (PFK) 1 and 2, synergistically diminishes the glucose response of GAL4-ChREBP. These multiple lines of evidence support the conclusion that G-6-P mediates the activation of ChREBP.

  8. Purification of a novel coenzyme F420-dependent glucose-6-phosphate dehydrogenase from Mycobacterium smegmatis.

    PubMed Central

    Purwantini, E; Daniels, L

    1996-01-01

    A variety of Mycobacterium species contained the 5-deazaflavin coenzyme known as F420. Mycobacterium smegmatis was found to have a glucose-6-phosphate dehydrogenase that was dependent on F420 as an electron acceptor and which did not utilize NAD or NADP. The enzyme was purified by ammonium sulfate fractionation, phenyl-Sepharose column chromatography, F420-ether-linked aminohexyl-Sepharose 4B affinity chromatography, and quaternary aminoethyl-Sephadex column chromatography, and the sequence of the first 26 N-terminal amino acids has been determined. The response of enzyme activity to a range of pHs revealed a two-peak pattern, with maxima at pH 5.5 and 8.0. The apparent Km values for F420 and glucose-6-phosphate were, respectively, 0.004 and 1.6 mM. The apparent native and subunit molecular masses were 78,000 and approximately 40,000 Da, respectively. PMID:8631674

  9. Glucose-6-phosphate dehydrogenase deficiency and Alzheimer's disease: Partners in crime? The hypothesis.

    PubMed

    Ulusu, N Nuray

    2015-08-01

    Alzheimer's disease is a multifaceted brain disorder which involves various coupled irreversible, progressive biochemical reactions that significantly reduce quality of life as well as the actual life expectancy. Aging, genetic predispositions, head trauma, diabetes, cardiovascular disease, deficiencies in insulin signaling, dysfunction of mitochondria-associated membranes, cerebrovascular changes, high cholesterol level, increased oxidative stress and free radical formation, DNA damage, disturbed energy metabolism, and synaptic dysfunction, high blood pressure, obesity, dietary habits, exercise, social engagement, and mental stress are noted among the risk factors of this disease. In this hypothesis review I would like to draw the attention on glucose-6-phosphate dehydrogenase deficiency and its relationship with Alzheimer's disease. This enzymopathy is the most common human congenital defect of metabolism and defined by decrease in NADPH+H(+) and reduced form of glutathione concentration and that might in turn, amplify oxidative stress due to essentiality of the enzyme. This most common enzymopathy may manifest itself in severe forms, however most of the individuals with this deficiency are not essentially symptomatic. To understand the sporadic Alzheimer's disease, the writer of this paper thinks that, looking into a crystal ball might not yield much of a benefit but glucose-6-phosphate dehydrogenase deficiency could effortlessly give some clues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Glucose-6-Phosphate Dehydrogenase Protects Escherichia coli from Tellurite-Mediated Oxidative Stress

    PubMed Central

    Sandoval, Juan M.; Arenas, Felipe A.; Vásquez, Claudio C.

    2011-01-01

    The tellurium oxyanion tellurite induces oxidative stress in most microorganisms. In Escherichia coli, tellurite exposure results in high levels of oxidized proteins and membrane lipid peroxides, inactivation of oxidation-sensitive enzymes and reduced glutathione content. In this work, we show that tellurite-exposed E. coli exhibits transcriptional activation of the zwf gene, encoding glucose 6-phosphate dehydrogenase (G6PDH), which in turn results in augmented synthesis of reduced nicotinamide adenine dinucleotide phosphate (NADPH). Increased zwf transcription under tellurite stress results mainly from reactive oxygen species (ROS) generation and not from a depletion of cellular glutathione. In addition, the observed increase of G6PDH activity was paralleled by accumulation of glucose-6-phosphate (G6P), suggesting a metabolic flux shift toward the pentose phosphate shunt. Upon zwf overexpression, bacterial cells also show increased levels of antioxidant molecules (NADPH, GSH), better-protected oxidation-sensitive enzymes and decreased amounts of oxidized proteins and membrane lipids. These results suggest that by increasing NADPH content, G6PDH plays an important role in E. coli survival under tellurite stress. PMID:21984934

  11. Extremely high intracellular concentration of glucose-6-phosphate and NAD(H) in Deinococcus radiodurans.

    PubMed

    Yamashiro, Takumi; Murata, Kousaku; Kawai, Shigeyuki

    2017-03-01

    Deinococcus radiodurans is highly resistant to ionizing radiation and UV radiation, and oxidative stress caused by such radiations. NADP(H) seems to be important for this resistance (Slade and Radman, Microbiol Mol Biol Rev 75:133-191; Slade, Radman, Microbiol Mol Biol Rev 75:133-191, 2011), but the mechanism underlying the generation of NADP(H) or NAD(H) in D. radiodurans has not fully been addressed. Intracellular concentrations of NAD(+), NADH, NADP(+), and NADPH in D. radiodurans are also not determined yet. We found that cell extracts of D. radiodurans catalyzed reduction of NAD(P)(+) in vitro, indicating that D. radiodurans cells contain both enzymes and a high concentration of substrates for this activity. The enzyme and the substrate were attributed to glucose-6-phosphate dehydrogenase and glucose-6-phosphate of which intracellular concentration was extremely high. Unexpectedly, the intracellular concentration of NAD(H) was also much greater than that of NADP(H), suggesting some significant roles of NADH. These unusual features of this bacterium would shed light on a new aspect of physiology of this bacterium.

  12. Biosynthesis and turnover of the mannose 6-phosphate receptor in cultured Chinese hamster ovary cells.

    PubMed

    Sahagian, G G; Neufeld, E F

    1983-06-10

    The natural history of the mannose 6-phosphate receptor was examined by radiolabeling cells in monolayers or in suspension; the receptor was isolated by immuno- or affinity precipitation followed by polyacrylamide gel electrophoresis. The receptor was found to contain asparagine-linked oligosaccharide chains and phosphorylated serine residues. Newly made receptor was sensitive to endo-beta-N-acetylglucosaminidase H (endo-H) and was slowly converted to a mature endo-H resistant form; phosphate was found on the mature receptor only. The receptor had an apparent molecular weight of 215,000 at all times, as determined under reducing and denaturing conditions; unreduced receptor had a greater electrophoretic mobility, suggesting the presence of intrachain disulfide linkages. The synthesis of immunoreactive receptor occurred with a lag of 50 min and of functional receptor with a lag of 70 min, indicating a requirement for some post-translational event(s) for acquisition of immunoreactivity and binding activity. Maturation of asparagine-linked oligosaccharides was not the requisite modification, since endo-H sensitive or deglycosylated receptor bound to both antibody and to insoluble phosphomannan; however, much less immunoreactive and functional receptor was detected in the presence of tunicamycin. Immunoprecipitable [3H]leucine-labeled receptor was degraded with a t1/2 of 16 h and 6 h for cells in monolayers and suspension, respectively, whereas 32P was lost with a corresponding t1/2 of 2.3 and 4 h. A pool of cell surface mannose 6-phosphate receptor was identified by separation on Percoll gradients as well as by iodination of cells with 125I; receptor in this pool was resistant to endo-H and had a t1/2 similar to that of the total [3H]leucine-labeled receptor, even in the presence of a saturating concentration of ligand. During endocytosis, ligand (beta-galactosidase) and 125I-receptor separated, the ligand accumulating within lysosomes. These results are consistent

  13. Cryopreservation of glucose-6-phosphate dehydrogenase activity inside red blood cells: developing a specimen repository in support of development and evaluation of glucose-6-phosphate dehydrogenase deficiency tests.

    PubMed

    Kahn, Maria; LaRue, Nicole; Bansil, Pooja; Kalnoky, Michael; McGray, Sarah; Domingo, Gonzalo J

    2013-08-20

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common human enzyme deficiency. It is characterized by abnormally low levels of G6PD activity. Individuals with G6PD deficiency are at risk of undergoing acute haemolysis when exposed to 8‒aminoquinoline-based drugs, such as primaquine. For this reason it is imperative to identify individuals with G6PD deficiency prior to administering these anti-malarial drugs. There is a need for the development and evaluation of point-of-care G6PD deficiency screening tests suitable for areas of the developing world where malarial treatments are frequently administered. The development and evaluation of new G6PD tests will be greatly assisted with the availability of specimen repositories. Cryopreservation of erythrocytes was evaluated as a means to preserve G6PD activity. Blood specimens from 31 patients including ten specimens with normal G6PD activity, three with intermediate activity, and 18 with deficient activity were cryopreserved for up to six months. Good correlation in G6PD activity between fresh and cryopreserved specimens (R2 = 0.95). The cryopreserved specimens show an overall small drop in mean G6PD activity of 0.23 U/g Hb (P=0.23). Cytochemical staining showed that intracellular G6PD activity distribution within the red blood cell populations is preserved during cryopreservation. Furthermore, the mosaic composition of red blood cells in heterozygous women is also preserved for six months or more. The fluorescent spot and the BinaxNOW qualitative tests for G6PD deficiency also showed high concordance in G6PD status determination between cryopreserved specimens and fresh specimens. A methodology for establishing a specimen panel for evaluation of G6PD tests is described. The approach is similar to that used in several malaria research facilities for the cryopreservation of parasites in clinical specimens and axenic cultures. Specimens stored in this manner will aid both the development and evaluation of

  14. Cloning and expression of trehalose-6-phosphate synthase 1 from Rhizopus oryzae.

    PubMed

    Ozer Uyar, Ebru; Yücel, Meral; Hamamcı, Haluk

    2016-05-01

    Trehalose is a reducing disaccharide acting as a protectant against environmental stresses in many organisms. In fungi, Trehalose-6-phosphate synthase 1 (TPS1) plays a key role in the biosynthesis of trehalose. In this study, a full-length cDNA from Rhizopus oryzae encoding TPS1 (designated as RoTPS1) was isolated. The RoTPS1 cDNA is composed of 2505 nucleotides and encodes a protein of 834 amino acids with a molecular mass of 97.8 kDa. The amino acid sequence of RoTPS1 has a relatively high homology with the TPS1s in several other filamentous fungi. RoTPS1 was cloned into Saccharomyces cerevisiae and secretively expressed.

  15. Apert syndrome with glucose-6-phosphate dehydrogenase deficiency: a case report.

    PubMed

    Tosun, G; Sener, Y

    2006-05-01

    Apert syndrome is characterized by midface hypoplasia, syndactyly of the hands and feet, proptosis of eyes, steep and flat frontal bones, and premature union of cranial sutures. Maxillary hypoplasia, deep palatal vault, anterior open bite, crowding of the dental arch, severely delayed tooth eruption, and dental malocclusion are the main oral manifestations of this syndrome. In this report, a case of Apert syndrome with glucose-6-phosphate dehydrogenase (G(6)PD) deficiency is presented. The patient, a 4-year-old male and the fourth child of healthy parents, was admitted to our department because of delayed tooth eruption. He had all the cardinal symptoms of the Apert syndrome. Clinical examination revealed that primary centrals, canines and first molars erupted; however, primary second molars and laterals had not erupted. The patient had no dental caries. Preventive treatments were applied, and subsequently, the patient was taken to long-term follow up.

  16. Changing kinetic properties of glucose-6-phosphate dehydrogenase from pea chloroplasts during photosynthetic induction

    SciTech Connect

    Yuan, X.; Anderson, L.E.

    1987-04-01

    The first enzyme of the oxidative pentose phosphate pathway, glucose-6-P dehydrogenase (EC 1.1.1.49), is inactivated when pea chloroplasts are irradiated. They have examined the kinetics of light inactivation of glucose-6-P dehydrogenase in intact chloroplasts during photosynthetic induction and the kinetic parameters of the active (dark) and less active (light) form of the dehydrogenase. Light inactivation of the dehydrogenase is rapid and occurs before photosynthetic O/sub 2/ evolution is measureable in intact chloroplasts. Likewise dark activation is quite rapid. The major change in the kinetic parameters of glucose-6-phosphate dehydrogenase is in maximal velocity. This light inactivation probably prevents operation of a futile cycle involving glucose-6-P, NADPH and oxidative and reductive pentose phosphate pathway enzymes.

  17. Glutathion peroxidase and glucose-6-phosphate dehydrogenase activities in bovine blood and liver.

    PubMed

    Abd Ellah, Mahmoud Rushdi; Niishimori, Kazuhiro; Goryo, Masanobu; Okada, Keiji; Yasuda, Jun

    2004-10-01

    A total of 46 cattle, including 25 as control, 16 with glycogen degeneration and 5 with severe fatty degeneration were studied. Whole blood and liver tissue specimens were used to measure glutathione peroxidase (GSH-Px) and Glucose-6-Phosphate Dehydrogenase (G6PD) activities. The present study determined the value of these parameters in diagnosing glycogen and fatty degeneration in cattle from the point of the status of antioxidation and lipid peroxidation. The results showed a significant decrease in hepatic GSH-Px activity and a significant increase in hepatic G6PD activity in cases of fatty degeneration. On the other hand, there were no significant changes in erythrocytic and hepatic GSH-Px and G6PD activities in cases of glycogen degeneration. The results indicated lipoperoxidation process in the liver tissues increased in cases of fatty degeneration. Therefore, supplying animals suffering from fatty liver with sufficient quantities of nutrient antioxidants may be valuable when treatment is considered.

  18. Glucose-6-Phosphate Dehydrogenase of Trypanosomatids: Characterization, Target Validation, and Drug Discovery

    PubMed Central

    Gupta, Shreedhara; Igoillo-Esteve, Mariana; Michels, Paul A. M.; Cordeiro, Artur T.

    2011-01-01

    In trypanosomatids, glucose-6-phosphate dehydrogenase (G6PDH), the first enzyme of the pentosephosphate pathway, is essential for the defense of the parasite against oxidative stress. Trypanosoma brucei, Trypanosoma cruzi, and Leishmania mexicana G6PDHs have been characterized. The parasites' G6PDHs contain a unique 37 amino acid long N-terminal extension that in T. cruzi seems to regulate the enzyme activity in a redox-state-dependent manner. T. brucei and T. cruzi G6PDHs, but not their Leishmania spp. counterpart, are inhibited, in an uncompetitive way, by steroids such as dehydroepiandrosterone and derivatives. The Trypanosoma enzymes are more susceptible to inhibition by these compounds than the human G6PDH. The steroids also effectively kill cultured trypanosomes but not Leishmania and are presently considered as promising leads for the development of new parasite-selective chemotherapeutic agents. PMID:22091394

  19. Should we screen newborns for glucose-6-phosphate dehydrogenase deficiency in the United States?

    PubMed

    Watchko, J F; Kaplan, M; Stark, A R; Stevenson, D K; Bhutani, V K

    2013-07-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency, a common X-linked enzymopathy can lead to severe hyperbilirubinemia, acute bilirubin encephalopathy and kernicterus in the United States. Neonatal testing for G6PD deficiency is not yet routine and the American Academy of Pediatrics recommends testing only in jaundiced newborns who are receiving phototherapy whose family history, ethnicity, or geographic origin suggest risk for the condition, or for infants whose response to phototherapy is poor. Screening tests for G6PD deficiency are available, are suitable for use in newborns and have been used in birth hospitals. However, US birth hospitals experience is limited and no national consensus has emerged regarding the need for newborn G6PD testing, its effectiveness or the best approach. Our review of current state of G6PD deficiency screening highlights research gaps and informs specific operational challenges to implement universal newborn G6PD testing concurrent to bilirubin screening in the United States.

  20. Molecular analysis of glucose-6-phosphate dehydrogenase variants in the Solomon Islands

    SciTech Connect

    Hirono, A.; Ishii, A.; Hirono, K.; Miwa, S.; Kere, N.; Fujii, H.

    1995-05-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most prevalent genetic disorders, and >100 million people are considered to have mutant genes. G6PD deficiency is frequent in the area where plasmodium falciparum infection is endemic, probably because the G6PD-deficient subjects are resistant to the parasite. Falciparum and vivax malarias have been highly endemic in the Solomon Islands, and a high frequency of G6PD deficiency has also been expected. A recent investigation showed that the frequency of G6PD deficiency in the Solomon Islands was 8.4%-14.4%. Although >80 G6PD variants from various populations have been molecularly analyzed, little is known about those in Melanesians. G6PD Maewo, which was originally found in Vanuatu, has so far been the only Melanesian variant whose structural abnormality was determined. 14 refs., 1 fig.

  1. Structural Analysis of N-acetylglucosamine-6-phosphate Deacetylase Apoenzyme from Escherichia coli

    SciTech Connect

    Ferreira,F.; Mendoza-Hernandez, G.; Castaneda-Bueno, M.; Aparicio, R.; Fischer, H.; Calcagno, M.; Oliva, G.

    2006-01-01

    We report the crystal structure of the apoenzyme of N-acetylglucosamine-6-phosphate (GlcNAc6P) deacetylase from Escherichia coli (EcNAGPase) and the spectrometric evidence of the presence of Zn{sup 2+} in the native protein. The GlcNAc6P deacetylase is an enzyme of the amino sugar catabolic pathway that catalyzes the conversion of the GlcNAc6P into glucosamine 6-phosphate (GlcN6P). The crystal structure was phased by the single isomorphous replacement with anomalous scattering (SIRAS) method using low-resolution (2.9 Angstroms) iodine anomalous scattering and it was refined against a native dataset up to 2.0 Angstroms resolution. The structure is similar to two other NAGPases whose structures are known from Thermotoga maritima (TmNAGPase) and Bacillus subtilis (BsNAGPase); however, it shows a phosphate ion bound at the metal-binding site. Compared to these previous structures, the apoenzyme shows extensive conformational changes in two loops adjacent to the active site. The E. coli enzyme is a tetramer and its dimer-dimer interface was analyzed. The tetrameric structure was confirmed in solution by small-angle X-ray scattering data. Although no metal ions were detected in the present structure, experiments of photon-induced X-ray emission (PIXE) spectra and of inductively coupled plasma emission spectroscopy (ICP-AES) with enzyme that was neither exposed to chelating agents nor metal ions during purification, revealed the presence of 1.4 atoms of Zn per polypeptide chain. Enzyme inactivation by metal-sequestering agents and subsequent reactivation by the addition of several divalent cations, demonstrate the role of metal ions in EcNAGPase structure and catalysis.

  2. Fed-Batch Production of Glucose 6-Phosphate Dehydrogenase Using Recombinant Saccharomyces cerevisiae

    NASA Astrophysics Data System (ADS)

    Das Neves, Luiz Carlos Martins; Pessoa, Adalberto; Vitolo, Michele

    The strain Saccharomyces cerevisiae W303-181, having the plasmid YEpPGK-G6P (built by coupling the vector YEPLAC 181 with the promoter phosphoglycerate kinase 1), was cultured by fed-batch process in order to evaluate its capability in the formation of glucose 6-phosphate dehydrogenase (EC.1.1.1.49). Two liters of culture medium (10.0 g/L glucose, 3.7 g/L yeast nitrogen broth (YNB), 0.02 g/L l-tryptophan, 0.02 g/L l-histidine, 0.02 g/L uracil, and 0.02 g/L adenine) were inoculated with 1.5 g dry cell/L and left fermenting in the batch mode at pH 5.7, aeration of 2.2 vvm, 30°C, and agitation of 400 rpm. After glucose concentration in the medium was lower than 1.0 g/L, the cell culture was fed with a solution of glucose (10.0 g/L) or micronutrients (l-tryptophan, l-histidine, uracil, and adenine each one at a concentration of 0.02 g/L) following the constant, linear, or exponential mode. The volume of the culture medium in the fed-batch process was varied from 2 L up to 3 L during 5 h. The highest glucose 6-phosphate dehydrogenase activity (350 U/L; 1 U=1 μmol of NADP/min) occurred when the glucose solution was fed into the fermenter through the decreasing linear mode.

  3. Annexin VI is a mannose-6-phosphate-independent endocytic receptor for bovine β-glucuronidase.

    PubMed

    Ramírez-Mata, Alberto; Michalak, Colette; Mendoza-Hernández, Guillermo; León-Del-Río, Alfonso; González-Noriega, Alfonso

    2011-10-01

    Endocytosis and transport of bovine liver β-glucuronidase to lysosomes in human fibroblasts are mediated by two receptors: the well-characterized cation-independent mannose 6-phosphate receptor (IGF-II/Man6PR) and an IGF-II/Man6PR-independent receptor, which recognizes a Ser-Trp*-Ser sequence present on the ligand. The latter receptor was detergent extracted from bovine liver membranes and purified. LC/ESI-MS/MS analysis revealed that this endocytic receptor was annexin VI (AnxA6). Several approaches were used to confirm this finding. First, the binding of bovine β-glucuronidase to the purified receptor from bovine liver membranes and His-tagged recombinant human AnxA6 protein was confirmed using ligand-blotting assays. Second, western blot analysis using antibodies raised against IGF-II/Man6PR-independent receptor as well as commercial antibodies against AnxA6 confirmed that the receptor and AnxA6 were indeed the same protein. Third, double immunofluorescence experiments in human fibroblasts confirmed a complete colocalization of the bovine β-glucuronidase and the AnxA6 receptor on the plasma membrane. Lastly, two cell lines were stably transfected with a plasmid containing the cDNA for human AnxA6. In both transfected cell lines, an increase in cell surface AnxA6 and in mannose 6-phosphate-independent endocytosis of bovine β-glucuronidase was detected. These results indicate that AnxA6 is a novel receptor that mediates the endocytosis of the bovine β-glucuronidase. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Expansive evolution of the trehalose-6-phosphate phosphatase gene family in Arabidopsis.

    PubMed

    Vandesteene, Lies; López-Galvis, Lorena; Vanneste, Kevin; Feil, Regina; Maere, Steven; Lammens, Willem; Rolland, Filip; Lunn, John E; Avonce, Nelson; Beeckman, Tom; Van Dijck, Patrick

    2012-10-01

    Trehalose is a nonreducing sugar used as a reserve carbohydrate and stress protectant in a variety of organisms. While higher plants typically do not accumulate high levels of trehalose, they encode large families of putative trehalose biosynthesis genes. Trehalose biosynthesis in plants involves a two-step reaction in which trehalose-6-phosphate (T6P) is synthesized from UDP-glucose and glucose-6-phosphate (catalyzed by T6P synthase [TPS]), and subsequently dephosphorylated to produce the disaccharide trehalose (catalyzed by T6P phosphatase [TPP]). In Arabidopsis (Arabidopsis thaliana), 11 genes encode proteins with both TPS- and TPP-like domains but only one of these (AtTPS1) appears to be an active (TPS) enzyme. In addition, plants contain a large family of smaller proteins with a conserved TPP domain. Here, we present an in-depth analysis of the 10 TPP genes and gene products in Arabidopsis (TPPA-TPPJ). Collinearity analysis revealed that all of these genes originate from whole-genome duplication events. Heterologous expression in yeast (Saccharomyces cerevisiae) showed that all encode active TPP enzymes with an essential role for some conserved residues in the catalytic domain. These results suggest that the TPP genes function in the regulation of T6P levels, with T6P emerging as a novel key regulator of growth and development in higher plants. Extensive gene expression analyses using a complete set of promoter-β-glucuronidase/green fluorescent protein reporter lines further uncovered cell- and tissue-specific expression patterns, conferring spatiotemporal control of trehalose metabolism. Consistently, phenotypic characterization of knockdown and overexpression lines of a single TPP, AtTPPG, points to unique properties of individual TPPs in Arabidopsis, and underlines the intimate connection between trehalose metabolism and abscisic acid signaling.

  5. Purification and Characterization of N-Acetylglucosamine-6-phosphate Deacetylase from a Psychrotrophic Marine Bacterium, Alteromonas Species.

    PubMed

    Yamano; Higashida; Endo; Sakata; Fujishima; Maruyama; Higashihara

    2000-01-01

    A psychrotrophic bacterium, strain Mct-9, which produced an N-acetylglucosamine-6-phosphate deacetylase, was isolated from a deep-seawater sample in the Mariana Trough. The Mct-9 strain was identified as Alteromonas sp. The native enzyme had a molecular mass of 164,000 Da, and was predicted to be composed of four identical subunits with molecular masses of 41,000 Da. The purified enzyme hydrolyzed N-acetylglucosamine (GlcNAc), GlcNAc-6-phosphate, and GlcNAc-6-sulfate. Considering the low K(m) and high k(cat)/K(m) for GlcNAc-6-phosphate, it probably acts as a GlcNAc-6-phosphate deacetylase in vivo. The enzyme was functional in the temperature range of 5 degrees to 70 degrees C and displayed optimal activity at 55 degrees C. The optimal temperature was higher than that of the deacetylase from the mesophilic bacterium Vibrio cholerae non-O1. The characteristics of the GlcNAc-6-phosphate deacetylase from Alteromonas sp. are unique among psychrotrophs and psychrophiles, whose intracellular enzymes are mostly thermolabile.

  6. [Attempt at characterization of 2 erythrocyte variants of glucose-6-phosphate dehydrogenase in a patient with a partial enzymatic deficit].

    PubMed

    Bansard-Desmidt, N

    1975-09-01

    The electrophoresis shows, in red blood cells of a North African man affected by a glucose-6-phosphate dehydrogenase deficiency, the presence of two enzymes differing by their electrophoretic mobilities: one of them presents in the same mobility as variant Gd (+) B, the other being faster. After partial purification of the enzymes by ionic exchange chromatography on cellex D BIO-RAD, the preparation obtained shows some kinetic abnormalities: an increased value of 2-deoxy-glucose-6-phosphate utilisation and a non linear plot of 1/v versus 1/s, inadequate for Km determination. Assuming that our preparation contains two enzymes differing by their affinities for glucose-6-phosphate, were carried out a study of their Michaelis constants for glucose-6-phosphate by a method based on the densitometric determination of colored spots corresponding to these two variants after electrophoretic separation on cellogel strips. One of these variants is similar to Gd (+) B, the other being characterised by increased values of: electrophoretic mobility (+ 110%), Km for glucose-6-hosphate (194 +/- 38 muM, normal range being 55 to 70 muM), utilisation coefficient of 2-deoxy-glucose-6-phosphate.

  7. Plasmid linkage of the D-tagatose 6-phosphate pathway in Streptococcus lactis: effect on lactose and galactose metabolism.

    PubMed Central

    Crow, V L; Davey, G P; Pearce, L E; Thomas, T D

    1983-01-01

    The three enzymes of the D-tagatose 6-phosphate pathway (galactose 6-phosphate isomerase, D-tagatose 6-phosphate kinase, and tagatose 1,6-diphosphate aldolase) were absent in lactose-negative (Lac-) derivatives of Streptococcus lactis C10, H1, and 133 grown on galactose. The lactose phosphoenolpyruvate-dependent phosphotransferase system and phospho-beta-galactosidase activities were also absent in Lac- derivatives of strains H1 and 133 and were low (possibly absent) in C10 Lac-. In all three Lac- derivatives, low galactose phosphotransferase system activity was found. On galactose, Lac- derivatives grew more slowly (presumably using the Leloir pathway) than the wild-type strains and accumulated high intracellular concentrations of galactose 6-phosphate (up to 49 mM); no intracellular tagatose 1,6-diphosphate was detected. The data suggest that the Lac phenotype is plasmid linked in the three strains studied, with the evidence being more substantial for strain H1. A Lac- derivative of H1 contained a single plasmid (33 megadaltons) which was absent from the Lac- mutant. We suggest that the genes linked to the lactose plasmid in S. lactis are more numerous than previously envisaged, coding for all of the enzymes involved in lactose metabolism from initial transport to the formation of triose phosphates via the D-tagatose 6-phosphate pathway. Images PMID:6294064

  8. Effect of chronologic age on induction of cystathionine synthase, uroporphyrinogen I synthase, and glucose-6-phosphate dehydrogenase activities in lymphocytes.

    PubMed Central

    Gartler, S M; Hornung, S K; Motulsky, A G

    1981-01-01

    The activities of cystathionine synthase [L-serine hydro-lyase (adding homocysteine), EC 4.2.1.22], uroporphyrinogen I synthase [porphobilinogen ammonia-lyase (polymerizing), EC 4.3.1.8], and glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1-oxidoreductase, EC 1.1.1.49) have been measured in phytohemagglutinin-stimulated lymphocytes of young and old human subjects. A significant decrease in activity with age was observed for cystathionine synthase and uroporphyrinogen I synthase but not for glucose-6-phosphate dehydrogenase. These changes could not be related to declining phytohemagglutinin response with aging. Age-related decreases in activity of some enzymes may be relevant for an understanding of the biology of aging. False assignment of heterozygosity, and even homozygosity, for certain genetic disorders, such as homocystinuria, may result when low enzyme levels are detected in the lymphocytes of older people. PMID:6940198

  9. Structural Basis for Substrate Specificity in Phosphate Binding (beta/alpha)8-Barrels: D-Allulose 6-Phosphate 3-Epimerase from Escherichia coli K-12

    SciTech Connect

    Chan,K.; Fedorov, A.; Almo, S.; Gerlt, J.

    2008-01-01

    Enzymes that share the ({beta}/{alpha})8-barrel fold catalyze a diverse range of reactions. Many utilize phosphorylated substrates and share a conserved C-terminal ({beta}/a)2-quarter barrel subdomain that provides a binding motif for the dianionic phosphate group. We recently reported functional and structural studies of d-ribulose 5-phosphate 3-epimerase (RPE) from Streptococcus pyogenes that catalyzes the equilibration of the pentulose 5-phosphates d-ribulose 5-phosphate and d-xylulose 5-phosphate in the pentose phosphate pathway [J. Akana, A. A. Fedorov, E. Fedorov, W. R. P. Novack, P. C. Babbitt, S. C. Almo, and J. A. Gerlt (2006) Biochemistry 45, 2493-2503]. We now report functional and structural studies of d-allulose 6-phosphate 3-epimerase (ALSE) from Escherichia coli K-12 that catalyzes the equilibration of the hexulose 6-phosphates d-allulose 6-phosphate and d-fructose 6-phosphate in a catabolic pathway for d-allose. ALSE and RPE prefer their physiological substrates but are promiscuous for each other's substrate. The active sites (RPE complexed with d-xylitol 5-phosphate and ALSE complexed with d-glucitol 6-phosphate) are superimposable (as expected from their 39% sequence identity), with the exception of the phosphate binding motif. The loop following the eighth {beta}-strand in ALSE is one residue longer than the homologous loop in RPE, so the binding site for the hexulose 6-phosphate substrate/product in ALSE is elongated relative to that for the pentulose 5-phosphate substrate/product in RPE. We constructed three single-residue deletion mutants of the loop in ALSE, ?T196, ?S197 and ?G198, to investigate the structural bases for the differing substrate specificities; for each, the promiscuity is altered so that d-ribulose 5-phosphate is the preferred substrate. The changes in kcat/Km are dominated by changes in kcat, suggesting that substrate discrimination results from differential transition state stabilization. In both ALSE and RPE, the phosphate

  10. HIV-1 Nef binds with human GCC185 protein and regulates mannose 6 phosphate receptor recycling

    SciTech Connect

    Kumar, Manjeet; Kaur, Supinder; Nazir, Aamir; Tripathi, Raj Kamal

    2016-05-20

    HIV-1 Nef modulates cellular function that enhances viral replication in vivo which culminate into AIDS pathogenesis. With no enzymatic activity, Nef regulates cellular function through host protein interaction. Interestingly, trans-cellular introduction of recombinant Nef protein in Caenorhabditis elegans results in AIDS like pathogenesis which might share common pathophysiology because the gene sequence of C. elegans and humans share considerable homology. Therefore employing C. elegans based initial screen complemented with sequence based homology search we identified GCC185 as novel host protein interacting with HIV-1 Nef. The detailed molecular characterization revealed N-terminal EEEE{sub 65} acidic domain of Nef as key region for interaction. GCC185 is a tethering protein that binds with Rab9 transport vesicles. Our results show that Nef-GCC185 interaction disrupts Rab9 interaction resulting in delocalization of CI-MPR (cation independent Mannose 6 phosphate receptor) resulting in elevated secretion of hexosaminidase. In agreement with this, our studies identified novel host GCC185 protein that interacts with Nef EEEE65 acidic domain interfering GCC185-Rab9 vesicle membrane fusion responsible for retrograde vesicular transport of CI-MPR from late endosomes to TGN. In light of existing report suggesting critical role of Nef-GCC185 interaction reveals valuable mechanistic insights affecting specific protein transport pathway in docking of late endosome derived Rab9 bearing transport vesicle at TGN elucidating role of Nef during viral pathogenesis. -- Highlights: •Nef, an accessory protein of HIV-1 interacts with host factor and culminates into AIDS pathogenesis. •Using Caenorhabditis elegans based screen system, novel Nef interacting cellular protein GCC185 was identified. •Molecular characterization of Nef and human protein GCC185 revealed Nef EEEE{sub 65} key region interacted with full length GCC185. •Nef impeded the GCC185-Rab 9 interaction and

  11. Galactose Expulsion during Lactose Metabolism in Lactococcus lactis subsp. cremoris FD1 Due to Dephosphorylation of Intracellular Galactose 6-Phosphate

    PubMed Central

    Benthin, Stig; Nielsen, Jens; Villadsen, John

    1994-01-01

    In Lactococcus lactis subsp. cremoris FD1, galactose and lactose are both transported and phosphorylated by phosphotransferase systems. Lactose 6-phosphate (lactose-6P) is hydrolyzed intracellularly to galactose-6P and glucose. Glucose enters glycolysis as glucose-6P, whereas galactose-6P is metabolized via the tagatose-6P pathway and enters glycolysis at the tagatose diphosphate and fructose diphosphate pool. Galactose would therefore be a gluconeogenic sugar in L. lactis subsp. cremoris FD1, but since fructose 1,6-diphosphatase is not present in this strain, galactose cannot serve as an essential biomass precursor (glucose-6P or fructose-6P) but only as an energy (ATP) source. Analysis of the growth energetics shows that transition from N limitation to limitation by glucose-6P or fructose-6P gives rise to a very high growth-related ATP consumption (152 mmol of ATP per g of biomass) compared with the value in cultures which are not limited by glucose-6P or fructose-6P (15 to 50 mmol of ATP per g of biomass). During lactose metabolism, the galactose flux through the tagatose-6P pathway (rmax = 1.2 h-1) is lower than the glucose flux through glycolysis (rmax = 1.5 h-1) and intracellular galactose-6P is dephosphorylated; this is followed by expulsion of galactose. Expulsion of a metabolizable sugar has not been reported previously, and the specific rate of galactose expulsion is up to 0.61 g of galactose g of biomass -1 h-1 depending on the lactose flux and the metabolic state of the bacteria. Galactose excreted during batch fermentation on lactose is reabsorbed and metabolized when lactose is depleted from the medium. In vitro incubation of galactose-6P (50 mM) and permeabilized cells (8 g/liter) gives a supernatant containing free galactose (50 mM) but no Pi (less than 0.5 mM). No organic compound except the liberated galactose is present in sufficient concentration to bind the phosphate. Phosphate is quantitatively recovered in the supernatant as Pi by hydrolysis

  12. Characterizing the hexose-6-phosphate transport system of Vibrio cholerae, a utilization system for carbon and phosphate sources.

    PubMed

    Moisi, Manuel; Lichtenegger, Sabine; Tutz, Sarah; Seper, Andrea; Schild, Stefan; Reidl, Joachim

    2013-04-01

    The facultative human pathogen Vibrio cholerae transits between the gastrointestinal tract of its host and aquatic reservoirs. V. cholerae adapts to different situations by the timely coordinated expression of genes during its life cycle. We recently identified a subclass of genes that are induced at late stages of infection. Initial characterization demonstrated that some of these genes facilitate the transition of V. cholerae from host to environmental conditions. Among these genes are uptake systems lacking detailed characterization or correct annotation. In this study, we comprehensively investigated the function of the VCA0682-to-VCA0687 gene cluster, which was previously identified as in vivo induced. The results presented here demonstrate that the operon encompassing open reading frames VCA0685 to VCA0687 encodes an ABC transport system for hexose-6-phosphates with Km values ranging from 0.275 to 1.273 μM for glucose-6P and fructose-6P, respectively. Expression of the operon is induced by the presence of hexose-6P controlled by the transcriptional activator VCA0682, representing a UhpA homolog. Finally, we provide evidence that the operon is essential for the utilization of hexose-6P as a C and P source. Thereby, a physiological role can be assigned to hexose-6P uptake, which correlates with increased fitness of V. cholerae after a transition from the host into phosphate-limiting environments.

  13. Overexpression of glucose-6-phosphate dehydrogenase enhances riboflavin production in Bacillus subtilis.

    PubMed

    Duan, Yun Xia; Chen, Tao; Chen, Xun; Zhao, Xue Ming

    2010-02-01

    Carbon flow in Bacillus subtilis through the pentose phosphate (PP) pathway was modulated by overexpression of glucose-6-phosphate dehydrogenase (G6PDH) under the control of the inducible Pxyl promoter in B. subtilis PY. Alteration of carbon flow into the PP pathway will affect the availability of ribulose-5-phosphate (Ru5P) and the riboflavin yield. Overexpression of G6PDH resulted in the glucose consumption rate increasing slightly, while the specific growth rate was unchanged. An improvement by 25% + or - 2 of the riboflavin production was obtained. Compared to by-products formation in flask culture, low acid production (acetate and pyruvate) and more acetoin were observed. Metabolic analysis, together with carbon flux redistribution, indicated that the PP pathway fluxes are increased in response to overexpression of G6PDH. Moreover, increased flux of the PP pathway is associated with an increased intracellular pool of Ru5P, which is a precursor for riboflavin biosynthesis. The high concentrations of Ru5P could explain the increased riboflavin production.

  14. Detection of Occult Acute Kidney Injury in Glucose-6-Phosphate Dehydrogenase Deficiency Anemia

    PubMed Central

    Abdel Hakeem, Gehan Lotfy; Abdel Naeem, Emad Allam; Swelam, Salwa Hussein; El Morsi Aboul Fotoh, Laila; El Mazary, Abdel Azeem Mohamed; Abdel Fadil, Ashraf Mohamed; Abdel Hafez, Asmaa Hosny

    2016-01-01

    Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency anemia is associated with intravascular hemolysis. The freely filtered hemoglobin can damage the kidney. We aimed to assess any subclinical renal injury in G6PD children. Methods Sixty children were included. Thirty G6PD deficiency anemia children were enrolled during the acute hemolytic crisis and after the hemolytic episode had elapsed. Another thirty healthy children were included as controls. Serum cystatin C, creatinine levels, and urinary albumin/creatinine (A/C) ratio were measured, and the glomerular filtration rate (GFR) was calculated. Results Significantly higher urinary A/C ratio (p=0.001,0.002 respectively) and lower GFR (p=0.001 for both) were found during hemolysis and after the hemolytic episode compared to the controls. Also, significant higher serum cystatin C (p=0.001), creatinine (p=0.05) and A/C (p= 0.001) ratio and insignificant lower GFR (p=0.3) during acute hemolytic crisis compared to the same children after the hemolytic episode subsided. Conclusions G6PD deficiency anemia is associated with a variable degree of acute renal injury during acute hemolytic episodes which may persist after elapsing of the hemolytic crises. PMID:27648201

  15. The role of glucose-6-phosphate dehydrogenase in adipose tissue inflammation in obesity.

    PubMed

    Park, Yoon Jeong; Choe, Sung Sik; Sohn, Jee Hyung; Kim, Jae Bum

    2017-04-03

    Obesity is closely associated with metabolic diseases including type 2 diabetes. One hallmark characteristics of obesity is chronic inflammation that is coordinately controlled by complex signaling networks in adipose tissues. Compelling evidence indicates that reactive oxygen species (ROS) and its related signaling pathways play crucial roles in the progression of chronic inflammation in obesity. The pentose phosphate pathway (PPP) is an anabolic pathway that utilizes the glucoses to generate molecular building blocks and reducing equivalents in the form of NADPH. In particular, NADPH acts as one of the key modulators in the control of ROS through providing an electron for both ROS generation and scavenging. Recently, we have reported that glucose-6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme of the PPP, is implicated in adipose tissue inflammation and systemic insulin resistance in obesity. Mechanistically, G6PD potentiates generation of ROS that augments pro-inflammatory responses in adipose tissue macrophages, leading to systemic insulin resistance. Here, we provide an overview of cell type- specific roles of G6PD in the regulation of ROS balance as well as additional details on the significance of G6PD that contributes to pro-oxidant NADPH generation in obesity-related chronic inflammation and insulin resistance.

  16. A hemolysis trigger in glucose-6-phosphate dehydrogenase enzyme deficiency. Vicia sativa (Vetch).

    PubMed

    Bicakci, Zafer

    2009-02-01

    Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme, playing an important role in the redox metabolism of all aerobic cells. It was reported that certain medications, fava beans, and infections can trigger acute hemolytic anemia in patients with G6PD deficiency. An 8-year-old male patient was admitted to the hospital with blood in the urine, headache, dizziness, fatigue, loss of appetite, and jaundice in the eyes, 24 hours after eating large amounts of fresh, vetch grains. Laboratory investigation revealed hemolytic anemia, hyperbilirubinemia, and G6PD deficiency. Approximately 0.5% of fava bean seeds have 2 pyrimidine beta-glycosides called, vicine and convicine. Vetch has 0.731% vicine, 0.081% convicine, and 0.530% beta cyanoalanine glycosides. The aim of this case report is to emphasize the importance of vetch seeds as a cause for hemolytic crisis in our country, where approximately one million tons of vetch is produced per year, especially in the agricultural regions.

  17. Metabolic phenotypes of Saccharomyces cerevisiae mutants with altered trehalose 6-phosphate dynamics.

    PubMed

    Walther, Thomas; Mtimet, Narjes; Alkim, Ceren; Vax, Amélie; Loret, Marie-Odile; Ullah, Azmat; Gancedo, Carlos; Smits, Gertien J; François, Jean Marie

    2013-09-01

    In Saccharomyces cerevisiae, synthesis of T6P (trehalose 6-phosphate) is essential for growth on most fermentable carbon sources. In the present study, the metabolic response to glucose was analysed in mutants with different capacities to accumulate T6P. A mutant carrying a deletion in the T6P synthase encoding gene, TPS1, which had no measurable T6P, exhibited impaired ethanol production, showed diminished plasma membrane H⁺-ATPase activation, and became rapidly depleted of nearly all adenine nucleotides which were irreversibly converted into inosine. Deletion of the AMP deaminase encoding gene, AMD1, in the tps1 strain prevented inosine formation, but did not rescue energy balance or growth on glucose. Neither the 90%-reduced T6P content observed in a tps1 mutant expressing the Tps1 protein from Yarrowia lipolytica, nor the hyperaccumulation of T6P in the tps2 mutant had significant effects on fermentation rates, growth on fermentable carbon sources or plasma membrane H⁺-ATPase activation. However, intracellular metabolite dynamics and pH homoeostasis were strongly affected by changes in T6P concentrations. Hyperaccumulation of T6P in the tps2 mutant caused an increase in cytosolic pH and strongly reduced growth rates on non-fermentable carbon sources, emphasizing the crucial role of the trehalose pathway in the regulation of respiratory and fermentative metabolism.

  18. Incidence and mutation analysis of glucose-6-phosphate dehydrogenase deficiency in eastern Indonesian populations.

    PubMed

    Tantular, Indah S; Matsuoka, Hiroyuki; Kasahara, Yuichi; Pusarawati, Suhintam; Kanbe, Toshio; Tuda, Josef S B; Kido, Yasutoshi; Dachlan, Yoes P; Kawamoto, Fumihiko

    2010-12-01

    We conducted a field survey of glucose-6-phosphate dehydrogenese (G6PD) deficiency in the eastern Indonesian islands, and analyzed G6PD variants molecularly. The incidence of G6PD deficiency in 5 ethnic groups (Manggarai, Bajawa, Nage-Keo, Larantuka, and Palue) on the Flores and Palue Islands was lower than that of another native group, Sikka, or a nonnative group, Riung. Molecular analysis of G6PD variants indicated that 19 cases in Sikka had a frequency distribution of G6PD variants similar to those in our previous studies, while 8 cases in Riung had a different frequency distribution of G6PD variants. On the other hand, from field surveys in another 8 ethnic groups (Timorese, Sumbanese, Savunese, Kendari, Buton, Muna, Minahasa, and Sangirese) on the islands of West Timor, Sumba, Sulawesi, Muna and Bangka, a total of 49 deficient cases were detected. Thirty-nine of these 49 cases had G6PD Vanua Lava (383T>C) of Melanesian origin. In our previous studies, many cases of G6PD Vanua Lava were found on other eastern Indonesian islands. Taken together, these findings may indicate that G6PD Vanua Lava is the most common variant in eastern Indonesian populations, except for Sikka.

  19. Comparison of quantitative and qualitative tests for glucose-6-phosphate dehydrogenase deficiency in the neonatal period.

    PubMed

    Keihanian, F; Basirjafari, S; Darbandi, B; Saeidinia, A; Jafroodi, M; Sharafi, R; Shakiba, M

    2017-06-01

    Considering the high prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency among newborns, different screening methods have been established in various countries. In this study, we aimed to assess the prevalence of G6PD deficiency among newborns in Rasht, Iran, and compare G6PD activity in cord blood samples, using quantitative and qualitative tests. This cross-sectional, prospective study was performed at five largest hospitals in Rasht, Guilan Province, Iran. The screening tests were performed for all the newborns, referred to these hospitals. Specimens were characterized in terms of G6PD activity under ultraviolet light, using the kinetic method and the qualitative fluorescent spot test (FST). We also determined the sensitivity, specificity, negative predictive value, and positive predictive value of the qualitative assay. Blood samples were collected from 1474 newborns. Overall, 757 (51.4%) subjects were male. As the findings revealed, 1376 (93.4%) newborns showed normal G6PD activity, while 98 (6.6%) had G6PD deficiency. There was a significant difference in the mean G6PD level between males and females (P = 0.0001). Also, a significant relationship was detected between FST results and the mean values obtained in the quantitative test (P < 0.0001). According to the present study, FST showed acceptable sensitivity and specificity for G6PD activity, although it appeared inefficient for diagnostic purposes in some cases. © 2017 John Wiley & Sons Ltd.

  20. Multiple Independent Fusions of Glucose-6-Phosphate Dehydrogenase with Enzymes in the Pentose Phosphate Pathway

    PubMed Central

    Stover, Nicholas A.; Dixon, Thomas A.; Cavalcanti, Andre R. O.

    2011-01-01

    Fusions of the first two enzymes in the pentose phosphate pathway, glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconolactonase (6PGL), have been previously described in two distant clades, chordates and species of the malarial parasite Plasmodium. We have analyzed genome and expressed sequence data from a variety of organisms to identify the origins of these gene fusion events. Based on the orientation of the domains and range of species in which homologs can be found, the fusions appear to have occurred independently, near the base of the metazoan and apicomplexan lineages. Only one of the two metazoan paralogs of G6PD is fused, showing that the fusion occurred after a duplication event, which we have traced back to an ancestor of choanoflagellates and metazoans. The Plasmodium genes are known to contain a functionally important insertion that is not seen in the other apicomplexan fusions, highlighting this as a unique characteristic of this group. Surprisingly, our search revealed two additional fusion events, one that combined 6PGL and G6PD in an ancestor of the protozoan parasites Trichomonas and Giardia, and another fusing G6PD with phosphogluconate dehydrogenase (6PGD) in a species of diatoms. This study extends the range of species known to contain fusions in the pentose phosphate pathway to many new medically and economically important organisms. PMID:21829610

  1. Aldosterone impairs vascular reactivity by decreasing glucose-6-phosphate dehydrogenase activity

    PubMed Central

    Leopold, Jane A.; Dam, Aamir; Maron, Bradley A.; Scribner, Anne W.; Liao, Ronglih; Handy, Diane E.; Stanton, Robert C.; Pitt, Bertram; Loscalzo, Joseph

    2013-01-01

    Hyperaldosteronism is associated with impaired vascular reactivity; however, the mechanism by which aldosterone promotes endothelial dysfunction remains unknown. Glucose-6-phosphate dehydrogenase (G6pd), the principal source of Nadph, modulates vascular function by limiting oxidant stress to preserve bioavailable nitric oxide (NO•). In these studies, we show that aldosterone (10−9-10−7 mol/l) decreases endothelial G6pd expression and activity in vitro resulting in increased oxidant stress and decreased cGMP levels similar to what is observed in G6pd-deficient cells. Aldosterone decreases G6pd expression by protein kinase A activation to increase expression of Crem, which interferes with Creb binding to the G6pd promoter. In vivo, infusion of aldosterone decreases vascular G6pd expression and impairs vascular reactivity. These effects are abrogated by spironolactone or vascular gene transfer of G6pd. These studies demonstrate that aldosterone induces a G6pd-deficient phenotype to impair endothelial function; aldosterone antagonism or gene transfer of G6pd improves vascular reactivity by restoring G6pd activity. PMID:17273168

  2. Trehalose 6-phosphate coordinates organic and amino acid metabolism with carbon availability.

    PubMed

    Figueroa, Carlos M; Feil, Regina; Ishihara, Hirofumi; Watanabe, Mutsumi; Kölling, Katharina; Krause, Ursula; Höhne, Melanie; Encke, Beatrice; Plaxton, William C; Zeeman, Samuel C; Li, Zhi; Schulze, Waltraud X; Hoefgen, Rainer; Stitt, Mark; Lunn, John E

    2016-02-01

    Trehalose 6-phosphate (Tre6P) is an essential signal metabolite in plants, linking growth and development to carbon metabolism. The sucrose-Tre6P nexus model postulates that Tre6P acts as both a signal and negative feedback regulator of sucrose levels. To test this model, short-term metabolic responses to induced increases in Tre6P levels were investigated in Arabidopsis thaliana plants expressing the Escherichia coli Tre6P synthase gene (otsA) under the control of an ethanol-inducible promoter. Increased Tre6P levels led to a transient decrease in sucrose content, post-translational activation of nitrate reductase and phosphoenolpyruvate carboxylase, and increased levels of organic and amino acids. Radio-isotope ((14)CO2) and stable isotope ((13)CO2) labelling experiments showed no change in the rates of photoassimilate export in plants with elevated Tre6P, but increased labelling of organic acids. We conclude that high Tre6P levels decrease sucrose levels by stimulating nitrate assimilation and anaplerotic synthesis of organic acids, thereby diverting photoassimilates away from sucrose to generate carbon skeletons and fixed nitrogen for amino acid synthesis. These results are consistent with the sucrose-Tre6P nexus model, and implicate Tre6P in coordinating carbon and nitrogen metabolism in plants.

  3. Glucosamine and Glucosamine-6-phosphate Derivatives: Catalytic Cofactor Analogs for the glmS Ribozyme

    PubMed Central

    Posakony, Jeffrey J.; Ferré-D'Amaré, Adrian R.

    2013-01-01

    Two analogues of glucosamine-6-phosphate (GlcN6P, 1) and five of glucosamine (GlcN, 2) were prepared for evaluation as catalytic cofactor of the glmS ribozyme, a bacterial gene-regulatory RNA that controls cell wall biosynthesis. Glucosamine and allosamine with 3-azido substitutions were prepared by SN2 reactions of the respective 1,2,4,6-protected sugars; final acidic hydrolysis afforded the fully deprotected compounds as their TFA salts. A 6-phospho-2-aminoglucolactam (31) was prepared from glucosamine in a 13-step synthesis, which included a late-stage POCl3-phosphorylation. A simple and widely applicable 2-step procedure with the triethylsilyl (TES) protecting group was developed to selectively expose the 6-OH group in N-protected glucosamine analogs, which provided another route to chemical phosphorylation. Mitsunobu chemistry afforded 6-cyano (35) and 6-azido (36) analogues of GlcN-(Cbz) and the selectivity for the 6-position was confirmed by NMR (COSY, HMBC, HMQC) experiments. Compound 36 was converted to the fully deprotected 6-azido-GlcN (37) and 2,6-diaminoglucose (38) analogs. A 2-hydroxylamino glucose (42) analogue was prepared via an oxaziridine (41). Enzymatic phosphorylation of 42 and chemical phosphorylation of its 6-OH precursor (43) were possible, but 42 and the 6-phospho product (44) were unstable under neutral or basic conditions. Chemical phosphorylation of the previously described 2-guanidinyl-glucose (46) afforded its 6-phospho analogue (49) after final deprotection. PMID:23578404

  4. Molecular characterization of a German variant of glucose-6-phosphate dehydrogenase deficiency (G6PD Aachen).

    PubMed

    Efferth, T; Osieka, R; Beutler, E

    2000-02-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-chromosome-linked hereditary disorder. Clinically, patients with G6PD deficiency often present with drug- or food-induced hemolytic crises or neonatal jaundice. G6PD is involved in the generation of NADPH and reduced glutathione. In contrast to American, Mediterranean, and African ancestries, only few variants are known from Middle and Northern Europe. We describe the molecular characterization of a distinct variant from the northwestern area of Germany, G6PD Aachen. The sequence of the G6PD gene from three afflicted males was found to be hemizygous at cDNA residue 1089 for a C-->G mutation with a predicted amino acid change of Asn363Lys. The 1089 C-->G point mutation is unique, but produces the identical amino acid change found in a Mexican variant of G6PD deficiency, G6PD Loma Linda. This G6PD-deficient variant is caused by a 1089 C-->A mutation. The 363-amino-acid replacement is located outside a known mutation cluster region between amino acid residues 380 and 450, but may disrupt or weaken dimer interactions of G6PD enzyme subunits.

  5. Cloning of the bovine 215-kDa cation-independent mannose 6-phosphate receptor.

    PubMed Central

    Lobel, P; Dahms, N M; Breitmeyer, J; Chirgwin, J M; Kornfeld, S

    1987-01-01

    Four overlapping cDNA clones encoding a partial sequence of the cation-independent 215-kDa mannose 6-phosphate receptor have been identified by screening a fetal calf liver cDNA library with oligonucleotide probes. RNA hybridization analysis showed that the length of the mRNA is approximately 9.5 kilobases. Sequence analysis demonstrated that the clones consist of 4647 contiguous nucleotides and contain an open reading frame coding for a polypeptide of 1461 amino acids, which we estimate represents greater than 75% of the primary structure of the receptor. The deduced amino acid sequence indicates that the receptor has a carboxyl-terminal cytoplasmic domain of 163 amino acids that is rich in acidic residues, a 23-amino acid transmembrane segment, and an extracellular domain containing at least eight homologous repeats of approximately 145 amino acids. One of the repeats contains an additional 43-residue segment that is similar to the type II repeat of fibronectin. Each repeat contains a highly conserved 13-amino acid unit bordered by cysteine residues that may be functionally important. Images PMID:2951738

  6. [Glucose 6-phosphate dehydrogenase deficiency: a protection against malaria and a risk for hemolytic accidents].

    PubMed

    Wajcman, Henri; Galactéros, Frédéric

    2004-08-01

    Glucose 6-phosphate dehydrogenase (G6PD) catalyses the first step of the pentose phosphate pathway, which in the RBC leads to the formation of NADPH, essential to prevent the cell from an oxidative stress. Worldwide, more than 400 million people (90% being males) are affected by G6PD deficiency, in regions that are, or have been, endemic for malaria and in populations originating from these regions. RBCs with low G6PD activity offer a hostile environment to parasite growth and thus an advantage to G6PD deficiency carriers. The counterpart of this protective effect is an increased susceptibility to oxidants such as some foods (fava beans), drugs (anti-malarial or sulphonamides), or various chemicals. In the case of G6PD deficiency, the hypothesis of a convergent evolution between parasite, protecting mutation, and cultural traditions (food, skin painting...) has been proposed. Near to 150 different G6PD variants have been described, which are classified into four types, according to their clinical effects. Several variants, such as the G6PD A- or the Mediterranean variant, reach the polymorphism level in endemic regions. The recent determination of the three-dimensional structure of this enzyme allows one to explain now the mechanisms of the disorders in terms of structure-function relationship.

  7. Glucose-6-Phosphate Dehydrogenase-Deficiency in Transfusion Medicine: The Unknown Risks

    PubMed Central

    Francis, Richard O.; Jhang, Jeffrey S.; Pham, Huy P.; Hod, Eldad A.; Zimring, James C.; Spitalnik, Steven L.

    2013-01-01

    The hallmark of glucose-6-phosphate dehydrogenase (G6PD) deficiency is red blood cell (RBC) destruction in response to oxidative stress. Patients requiring RBC transfusions may simultaneously receive oxidative medications or have concurrent infections, both of which can induce hemolysis in G6PD-deficient RBCs. Although it is not routine practice to screen healthy blood donors for G6PD deficiency, case reports identified transfusion of G6PD-deficient RBCs as causing hemolysis and other adverse events. In addition, some patient populations may be more at risk for complications associated with transfusions of G6PD-deficient RBCs because they receive RBCs from donors who are more likely to have G6PD deficiency. This review discusses G6PD deficiency, its importance in transfusion medicine, changes in the RBC antioxidant system (of which G6PD is essential) during refrigerated storage, and mechanisms of hemolysis. In addition, as yet unanswered questions that could be addressed by translational and clinical studies are identified and discussed. PMID:23815264

  8. Testis-specific expression of a functional retroposon encoding glucose-6-phosphate dehydrogenase in the mouse

    SciTech Connect

    Hendriksen, P.J.M. |; Hoogerbrugge, J.W.; Baarends, W.M.

    1997-05-01

    The X-chromosomal gene glucose-6-phosphate dehydrogenase (G6pd) is known to be expressed in most cell types of mammalian species. In the mouse, we have detected a novel gene, designated G6pd-2, encoding a G6PD isoenzyme. G6pd-2 does not contain introns and appears to represent a retroposed gene. This gene is uniquely transcribed in postmeiotic spermatogenic cells in which the X-encoded G6pd gene is not transcribed. Expression of the G6pd-2 sequence in a bacterial system showed that the encoded product is an active enzyme. Zymogramic analysis demonstrated that recombinant G6PD-2, but not recombinant G6PD-1 (the X-chromosome-encoded G6PD), formed tetramers under reducing conditions. Under the same conditions, G6PD tetramers were also found in extracts of spermatids and spermatozoa, indicating the presence of G6pd-2-encoded isoenzyme in these cell types. G6pd-2 is one of the very few known expressed retroposons encoding a functional protein, and the presence of this gene is probably related to X chromosome inactivation during spermatogenesis. 62 refs., 7 figs.

  9. Nitrogen Assimilation, Abiotic Stress and Glucose 6-Phosphate Dehydrogenase: The Full Circle of Reductants

    PubMed Central

    Esposito, Sergio

    2016-01-01

    Glucose 6 phosphate dehydrogenase (G6PDH; EC 1.1.1.49) is well-known as the main regulatory enzyme of the oxidative pentose phosphate pathway (OPPP) in living organisms. Namely, in Planta, different G6PDH isoforms may occur, generally localized in cytosol and plastids/chloroplasts. These enzymes are differently regulated by distinct mechanisms, still far from being defined in detail. In the last decades, a pivotal function for plant G6PDHs during the assimilation of nitrogen, providing reductants for enzymes involved in nitrate reduction and ammonium assimilation, has been described. More recently, several studies have suggested a main role of G6PDH to counteract different stress conditions, among these salinity and drought, with the involvement of an ABA depending signal. In the last few years, this recognized vision has been greatly widened, due to studies clearly showing the non-conventional subcellular localization of the different G6PDHs, and the peculiar regulation of the different isoforms. The whole body of these considerations suggests a central question: how do the plant cells distribute the reductants coming from G6PDH and balance their equilibrium? This review explores the present knowledge about these mechanisms, in order to propose a scheme of distribution of reductants produced by G6PDH during nitrogen assimilation and stress. PMID:27187489

  10. Splenic artery pseudoaneurysm due to seatbelt injury in a glucose-6-phosphate dehydrogenase-deficient adult.

    PubMed

    Lau, Yu Zhen; Lau, Yuk Fai; Lai, Kang Yiu; Lau, Chu Pak

    2013-11-01

    A 23-year-old man presented with abdominal pain after suffering blunt trauma caused by a seatbelt injury. His low platelet count of 137 × 10(9)/L was initially attributed to trauma and his underlying hypersplenism due to glucose-6-phosphate dehydrogenase (G6PD) deficiency. Despite conservative management, his platelet count remained persistently reduced even after his haemoglobin and clotting abnormalities were stabilised. After a week, follow-up imaging revealed an incidental finding of a pseudoaneurysm (measuring 9 mm × 8 mm × 10 mm) adjacent to a splenic laceration. The pseudoaneurysm was successfully closed via transcatheter glue embolisation; 20% of the spleen was also embolised. A week later, the platelet count normalised, and the patient was subsequently discharged. This case highlights the pitfalls in the detection of a delayed occurrence of splenic artery pseudoaneurysm after blunt injury via routine delayed phase computed tomography. While splenomegaly in G6PD may be a predisposing factor for injury, a low platelet count should arouse suspicion of internal haemorrhage rather than hypersplenism.

  11. Competitive inhibition of phosphoglucose isomerase of apple leaves by sorbitol 6-phosphate.

    PubMed

    Zhou, Rui; Cheng, Lailiang

    2008-06-16

    Apple leaf cytosolic phosphoglucose isomerase (PGI, EC 5.3.1.9) was purified to an apparent homogeneity with a specific activity of 2456 units/mg protein, and chloroplastic PGI was partially purified to a specific activity of 72 units/mg protein to characterize their biochemical properties. These two isoforms showed differential responses to heat treatment; incubation at 50 degrees C for 10 min resulted in a complete loss of the chloroplastic PGI activity, whereas the cytosolic PGI only lost 50% of its activity. Apple cytosolic PGI is a dimeric enzyme with a molecular mass of 66 kDa for each monomer. The activity of both isoforms was strongly inhibited by erythrose 4-phosphate (E4P) with a K(i) of 1.2 and 3.0 microM for the cytosolic PGI and chloroplastic PGI, respectively. Sorbitol 6-phosphate (Sor6P), an intermediate in sorbitol biosynthesis, was found to be a competitive inhibitor for both cytosolic and chloroplastic PGIs with a K(i) of 61 and 40 microM, respectively. PGIs from both spinach and tomato leaves were also inhibited by Sor6P in a similar manner. The possible physiological significance of this finding is discussed.

  12. Glucose-6-phosphate dehydrogenase and red cell pyruvate kinase deficiency in neonatal jaundice cases in egypt.

    PubMed

    Abdel Fattah, Mohammed; Abdel Ghany, Eman; Adel, Alia; Mosallam, Dalia; Kamal, Shahira

    2010-05-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency can lead to acute hemolytic anemia, chronic nonspherocytic hemolytic anemia, and neonatal jaundice. Neonatal red cell pyruvate kinase (PK) deficiency may cause clinical patterns, ranging from extremely severe hemolytic anemia to moderate jaundice. The authors aimed at studying the prevalence of G6PD and PK deficiency among Egyptian neonates with pathological indirect hyperbilirubinemia in Cairo. This case-series study included 69 newborns with unconjugated hyperbilirubinemia. All were subjected to clinical history, laboratory investigations, e.g., complete blood counts, reticulocytic counts, direct and indirect serum bilirubin levels, Coombs tests, qualitative assay of G6PD activity by methemoglobin reduction test, and measurement of erythrocytic PK levels. The study detected 10 neonates with G6PD deficiency, which means that the prevalence of G6PD deficiency among Egyptian neonates with hyperbilirubinemia is 14.4% (21.2% of males). G6PD deficiency was significantly higher in males than females (P = .01). The authors detected 2 cases with PK deficiency, making the prevalence of its deficiency 2.8%. These data demonstrate that G6PD deficiency is an important cause for neonatal jaundice in Egyptians. Neonatal screening for its deficiency is recommended. PK deficiency is not a common cause of neonatal jaundice. However, this needs further investigation on a larger scale.

  13. Control of glycolytic flux in Zymomonas mobilis by glucose 6-phosphate dehydrogenase activity

    SciTech Connect

    Snoep, J.L. |; Arfman, N.; Yomano, L.P.; Ingram, L.O.; Westerhoff, H.V.; Conway, T.

    1996-07-20

    Alycolytic genes in Zymomonas mobilis are highly expressed and constitute half of the cytoplasmic protein. The first four genes (glf, zwf, edd, glk) in this pathway form an operon encoding a glucose permease, glucose 6-phosphate dehydrogenase (G6-P dehydrogenase), 6-phosphogluconate dehydratase, and glucokinase, respectively. Each gene was overexpressed from a tac promoter to investigate the control of glycolysis during the early stages of batch fermentation when flux (qCO{sub 2}) is highest. Almost half of flux control appears to reside with G6-P dehydrogenase (C{sub G6-P dehydrogenase}{sup J} = 0.4). Although Z. mobilis exhibits one of the highest rates of glycolysis known, recombinants with elevated G6-P dehydrogenase had a 10% to 13% higher glycolytic flux than the native organism. A small increase in flux was also observed for recombinants expressing glf. Results obtained did not allow a critical evaluation of glucokinase and this enzyme may also represent an important control point. 6-Phosphogluconate dehydratase appears to be saturating at native levels. With constructs containing the full operon, growth rate and flux were both reduced, complicating interpretations. However, results obtained were also consistent with G6-P dehydrogenase as a primary site of control. Flux was 17% higher in operon constructs which exhibited a 17% increase in G6-P dehydrogenase specific activity, relative to the average of other operon constructs which contain a frameshift mutation in zwf.

  14. Comparison of quantitative and qualitative tests for glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    LaRue, Nicole; Kahn, Maria; Murray, Marjorie; Leader, Brandon T; Bansil, Pooja; McGray, Sarah; Kalnoky, Michael; Zhang, Hao; Huang, Huiqiang; Jiang, Hui; Domingo, Gonzalo J

    2014-10-01

    A barrier to eliminating Plasmodium vivax malaria is inadequate treatment of infected patients. 8-Aminoquinoline-based drugs clear the parasite; however, people with glucose-6-phosphate dehydrogenase (G6PD) deficiency are at risk for hemolysis from these drugs. Understanding the performance of G6PD deficiency tests is critical for patient safety. Two quantitative assays and two qualitative tests were evaluated. The comparison of quantitative assays gave a Pearson correlation coefficient of 0.7585 with significant difference in mean G6PD activity, highlighting the need to adhere to a single reference assay. Both qualitative tests had high sensitivity and negative predictive value at a cutoff G6PD value of 40% of normal activity if interpreted conservatively and performed under laboratory conditions. The performance of both tests dropped at a cutoff level of 45%. Cytochemical staining of specimens confirmed that heterozygous females with > 50% G6PD-deficient cells can seem normal by phenotypic tests. © The American Society of Tropical Medicine and Hygiene.

  15. Haemoglobinopathies, glucose-6-phosphate dehydrogenase deficiency and allied problems in the Indian subcontinent

    PubMed Central

    Chatterjea, J. B.

    1966-01-01

    The present world-wide interest in haemoglobinopathies and allied disorders has given rise to a very considerable literature over the past two decades. This communication reviews this literature in so far as it refers to the Indian subcontinent. The most common abnormality is thalassaemia, which has been discovered in all regions under consideration: India, Pakistan, Nepal, Bhutan and Ceylon. Haemoglobins S, D and E are also quite common: Hb S has been found mostly in the aboriginal tribes, Hb D in Gujaratis and Punjabis and Hb E in Bengalis, Assamese and Nepalese. A few instances of haemoglobins F, H, J, K, L and M have also been reported. However, there remain many population groups to be investigated. Studies of the distribution of glucose-6-phosphate dehydrogenase deficiency are also reviewed, and the correlation between the various haemoglobin disorders and various environmental factors is discussed, but it is pointed out that the relevant data are still insufficient to allow any definite conclusions to be drawn. PMID:5338376

  16. Glucose-6-Phosphate Dehydrogenase: Update and Analysis of New Mutations around the World

    PubMed Central

    Gómez-Manzo, Saúl; Marcial-Quino, Jaime; Vanoye-Carlo, America; Serrano-Posada, Hugo; Ortega-Cuellar, Daniel; González-Valdez, Abigail; Castillo-Rodríguez, Rosa Angélica; Hernández-Ochoa, Beatriz; Sierra-Palacios, Edgar; Rodríguez-Bustamante, Eduardo; Arreguin-Espinosa, Roberto

    2016-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme in the pentose phosphate pathway which produces nicotinamide adenine dinucleotide phosphate (NADPH) to maintain an adequate reducing environment in the cells and is especially important in red blood cells (RBC). Given its central role in the regulation of redox state, it is understandable that mutations in the gene encoding G6PD can cause deficiency of the protein activity leading to clinical manifestations such as neonatal jaundice and acute hemolytic anemia. Recently, an extensive review has been published about variants in the g6pd gene; recognizing 186 mutations. In this work, we review the state of the art in G6PD deficiency, describing 217 mutations in the g6pd gene; we also compile information about 31 new mutations, 16 that were not recognized and 15 more that have recently been reported. In order to get a better picture of the effects of new described mutations in g6pd gene, we locate the point mutations in the solved three-dimensional structure of the human G6PD protein. We found that class I mutations have the most deleterious effects on the structure and stability of the protein. PMID:27941691

  17. Glucose-6-Phosphate Dehydrogenase: Update and Analysis of New Mutations around the World.

    PubMed

    Gómez-Manzo, Saúl; Marcial-Quino, Jaime; Vanoye-Carlo, America; Serrano-Posada, Hugo; Ortega-Cuellar, Daniel; González-Valdez, Abigail; Castillo-Rodríguez, Rosa Angélica; Hernández-Ochoa, Beatriz; Sierra-Palacios, Edgar; Rodríguez-Bustamante, Eduardo; Arreguin-Espinosa, Roberto

    2016-12-09

    Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme in the pentose phosphate pathway which produces nicotinamide adenine dinucleotide phosphate (NADPH) to maintain an adequate reducing environment in the cells and is especially important in red blood cells (RBC). Given its central role in the regulation of redox state, it is understandable that mutations in the gene encoding G6PD can cause deficiency of the protein activity leading to clinical manifestations such as neonatal jaundice and acute hemolytic anemia. Recently, an extensive review has been published about variants in the g6pd gene; recognizing 186 mutations. In this work, we review the state of the art in G6PD deficiency, describing 217 mutations in the g6pd gene; we also compile information about 31 new mutations, 16 that were not recognized and 15 more that have recently been reported. In order to get a better picture of the effects of new described mutations in g6pd gene, we locate the point mutations in the solved three-dimensional structure of the human G6PD protein. We found that class I mutations have the most deleterious effects on the structure and stability of the protein.

  18. Enhanced expression of glucose-6-phosphate dehydrogenase in human cells sustaining oxidative stress.

    PubMed Central

    Ursini, M V; Parrella, A; Rosa, G; Salzano, S; Martini, G

    1997-01-01

    Recent reports have demonstrated that glucose-6-phosphate dehydrogenase (G6PD) activity in mammalian cells is necessary in order to ensure cell survival when damage is produced by reactive oxygen intermediates. In this paper we demonstrate that oxidative stress, caused by agents acting at different steps in the biochemical pathway controlling the intracellular redox status, determines the increase in G6PD-specific activity in human cell lines of different tissue origins. The intracellular level of G6PD-specific mRNA also increases, with kinetics compatible with the induction of new enzyme synthesis. We carried out experiments in which cells were exposed to oxidative stress in the presence of inhibitors of protein or RNA synthesis. These demonstrated that increased G6PD expression is mainly due to an increased rate of transcription, with a minor but significant contribution of regulatory mechanisms acting at post-transcriptional levels. These results provide new information on the defence systems that eukaryotic cells possess in order to prevent damage caused by potentially harmful oxygen derivatives. PMID:9169615

  19. Trehalose 6-phosphate is involved in triggering axillary bud outgrowth in garden pea (Pisum sativum L.).

    PubMed

    Fichtner, Franziska; Barbier, Francois F; Feil, Regina; Watanabe, Mutsumi; Annunziata, Maria Grazia; Chabikwa, Tinashe G; Höfgen, Rainer; Stitt, Mark; Beveridge, Christine A; Lunn, John E

    2017-09-04

    Trehalose 6-phosphate (Tre6P) is a signal of sucrose availability in plants, and has been implicated in regulation of shoot branching by the abnormal branching phenotypes of Arabidopsis (Arabidopsis thaliana) and maize (Zea mays) mutants with altered Tre6P metabolism. Decapitation of garden pea (Pisum sativum) plants has been proposed to release the dormancy of axillary buds lower down the stem due to changes in sucrose supply, and we hypothesized that this response is mediated by Tre6P. Decapitation led to a rapid and sustained rise in Tre6P levels in axillary buds, coinciding with the onset of bud outgrowth. This response was suppressed by simultaneous defoliation that restricts the supply of sucrose to axillary buds in decapitated plants. Decapitation also led to a rise in amino acid levels in buds, but a fall in phosphoenolpyruvate and 2-oxoglutarate. Supplying sucrose to stem node explants in vitro triggered a concentration-dependent increase in the Tre6P content of the buds that was highly correlated with their rate of outgrowth. These data show that changes in bud Tre6P levels are correlated with initiation of bud outgrowth following decapitation, suggesting that Tre6P is involved in the release of bud dormancy by sucrose. Tre6P might also be linked to a reconfiguration of carbon and nitrogen metabolism to support the subsequent growth of the bud into a new shoot. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. New PCR Assay Using Glucose-6-Phosphate Dehydrogenase for Identification of Leishmania Species

    PubMed Central

    Castilho, Tiago M.; Shaw, Jeffrey Jon; Floeter-Winter, Lucile M.

    2003-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) is one of the multilocus enzymes used to identify Leishmania by zymodeme analysis. The polymorphic pattern revealed by partial characterization of the gene encoding G6PD generated molecular markers useful in the identification of different Leishmania species by PCR. Initially degenerate oligonucleotides were designed on the basis of data on the conserved active center described for other organisms. Primers for reverse transcription-PCR experiments, designed from the nucleotide sequence of the PCR product, enabled us to characterize the 5′ and 3′ untranslated regions and the G6PD open reading frame of reference strains of Leishmania (Viannia) braziliensis, Leishmania (Viannia) guyanensis, Leishmania (Leishmania) mexicana, and Leishmania (Leishmania) amazonensis. Sets of paired primers were designed and used in PCR assays to discriminate between the parasites responsible for tegumentar leishmaniasis of the subgenera Leishmania (Leishmania) and Leishmania (Viannia) and to distinguish L. (Viannia) braziliensis from others organisms of the subgenus Leishmania (Viannia). No amplification products were detected for the DNA of Crithidia fasciculata, Trypanosoma cruzi, or Leishmania (Sauroleishmania) tarentolae or DNA from a healthy human control. The tests proved to be specific and were sensitive enough to detect parasites in human biopsy specimens. The successful discrimination of L. (Viannia) braziliensis from other parasites of the subgenus Leishmania (Viannia) opens the way to epidemiological studies in areas where more than one species of the subgenus Leishmania (Viannia) exist, such as Amazonia, as well as follow-up studies after chemotherapy and assessment of clinical prognoses. PMID:12574243

  1. Glucose-6-phosphate dehydrogenase deficiency and risk of diabetes: a systematic review and meta-analysis.

    PubMed

    Lai, Yin Key; Lai, Nai Ming; Lee, Shaun Wen Huey

    2017-05-01

    Emerging epidemiological evidence suggests that patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency may have a higher risk of developing diabetes. The aim of the review was to synthesise the evidence on the association between G6PD deficiency and diabetes. A systematic search on Medline, EMBASE, AMED and CENTRAL databases for studies published between January 1966 and September 2016 that assessed the association between G6PD deficiency and diabetes was conducted. This was supplemented by a review of the reference list of retrieved articles. We extracted data on study characteristics, outcomes and performed an assessment on the methodological quality of the studies. A random-effects model was used to compute the summary risk estimates. Fifteen relevant publications involving 949,260 participants were identified, from which seven studies contributed to the meta-analysis. G6PD deficiency was associated with a higher odd of diabetes (odds ratio 2.37, 95% confidence interval 1.50-3.73). The odds ratio of diabetes among men was higher (2.22, 1.31-3.75) compared to women (1.87, 1.12-3.12). This association was broadly consistent in the sensitivity analysis. Current evidence suggests that G6PD deficiency may be a risk factor for diabetes, with higher odds among men compared to women. Further research is needed to determine how G6PD deficiency moderates diabetes.

  2. Glucose-6-phosphate dehydrogenase deficiency in northern Mexico and description of a novel mutation.

    PubMed

    García-Magallanes, N; Luque-Ortega, F; Aguilar-Medina, E M; Ramos-Payán, R; Galaviz-Hernández, C; Romero-Quintana, J G; Del Pozo-Yauner, L; Rangel-Villalobos, H; Arámbula-Meraz, E

    2014-08-01

    Glucose-6-phosphate dehydrogenase deficiency (G6PD) is the most common enzyme pathology in humans; it is X-linked inherited and causes neonatal hyperbilirubinaemia, chronic nonspherocytic haemolytic anaemia and drug-induced acute haemolytic anaemia. G6PD deficiency has scarcely been studied in the northern region of Mexico, which is important because of the genetic heterogeneity described in Mexican population. Therefore, samples from the northern Mexico were biochemically screened for G6PD deficiency, and PCR-RFLPs, and DNA sequencing used to identify mutations in positive samples. The frequency of G6PD deficiency in the population was 0.95% (n = 1993); the mutations in 86% of these samples were G6PD A(-202A/376G), G6PDA(-376G/968C) and G6PD Santamaria(376G/542T). Contrary to previous reports, we demonstrated that G6PD deficiency distribution is relatively homogenous throughout the country (P = 0.48336), and the unique exception with high frequency of G6PD deficiency does not involve a coastal population (Chihuahua: 2.4%). Analysis of eight polymorphic sites showed only 10 haplotypes. In one individual we identified a new G6PD mutation named Mexico DF(193A>G) (rs199474830), which probably results in a damaging functional effect, according to PolyPhen analysis. Proteomic impact of the mutation is also described.

  3. Glucose-6-phosphate dehydrogenase deficiency A- variant in febrile patients in Haiti.

    PubMed

    Carter, Tamar E; Maloy, Halley; von Fricken, Michael; St Victor, Yves; Romain, Jean R; Okech, Bernard A; Mulligan, Connie J

    2014-08-01

    Haiti is one of two remaining malaria-endemic countries in the Caribbean. To decrease malaria transmission in Haiti, primaquine was recently added to the malaria treatment public health policy. One limitation of primaquine is that, at certain doses, primaquine can cause hemolytic anemia in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency (G6PDd). In this study, we genotyped two mutations (A376G and G202A), which confer the most common G6PDd variant in West African populations, G6PDd A-. We estimated the frequency of G6PDd A- in a sample of febrile patients enrolled in an on-going malaria study who represent a potential target population for a primaquine mass drug administration. We found that 33 of 168 individuals carried the G6PDd A- allele (includes A- hemizygous males, A- homozygous or heterozygous females) and could experience toxicity if treated with primaquine. These data inform discussions on safe and effective primaquine dosing and future malaria elimination strategies for Haiti.

  4. Glucose-6-phosphate dehydrogenase deficiency (G6PD) as a risk factor of male neonatal sepsis.

    PubMed

    Rostami-Far, Z; Ghadiri, K; Rostami-Far, M; Shaveisi-Zadeh, F; Amiri, A; Rahimian Zarif, B

    2016-01-01

    Introduction.Neonatal sepsis is a disease process, which represents the systemic response of bacteria entering the bloodstream during the first 28 days of life. The prevalence of sepsis is higher in male infants than in females, but the exact cause is unknown. Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme in the pentose phosphate pathway, which leads to the production of NADPH. NADPH is required for the respiratory burst reaction in white blood cells (WBCs) to destroy microorganisms. The purpose of this study was to evaluate the prevalence of G6PD deficiency in neonates with sepsis. Materials and methods.This study was performed on 76 neonates with sepsis and 1214 normal neonates from February 2012 to November 2014 in the west of Iran. The G6PD deficiency status was determined by fluorescent spot test. WBCs number and neutrophils percentages were measured and compared in patients with and without G6PD deficiency. Results.The prevalence of the G6PD deficiency in neonates with sepsis was significantly higher compared to the control group (p=0.03). WBCs number and neutrophils percentages in G6PD deficient patients compared with patients without G6PD deficiency were decreased, but were not statistically significant (p=0.77 and p=0.86 respectively). Conclusions.G6PD deficiency is a risk factor of neonatal sepsis and also a justification for more male involvement in this disease. Therefore, newborn screening for this disorder is recommended.

  5. Anemia in patients with coinherited thalassemia and glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Pornprasert, Sakorn; Phanthong, Siratcha

    2013-01-01

    Thalassemia and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency are genetic disorders that cause hemolytic anemia. In areas with high frequencies of both hematological disorders, coinheritance of G-6-PD deficiency with thalassemia can be found. Whether G-6-PD deficiency, coinherited with thalassemia, enhances severe anemia is still unclear. Hematological parameters between thalassemia carriers with G-6-PD deficiency and those without G-6-PD deficiency were compared. The G-6-PD deficiency was diagnosed in 410 blood samples from thalassemia patients using a fluorescent spot test. The levels of hemoglobin (Hb), packed cell volume (PCV), mean corpuscular volume (MCV) and Hb A2/Hb E [β26(B8)Glu→Lys; HBB: c.79G>A] were measured using an automated blood counter and high performance liquid chromatography (HPLC), respectively. The G-6-PD deficiency was found in 37 samples (9.02%). Mean levels of Hb, PCV, MCV and Hb A2/E were similar between the two groups. Thus, G-6-PD deficiency did not enhance red blood cell pathology or induce more anemic severity in thalassemia patients.

  6. Glucose-6-phosphate dehydrogenase (G6PD) deficiency among tribal populations of India - Country scenario.

    PubMed

    Mukherjee, Malay B; Colah, Roshan B; Martin, Snehal; Ghosh, Kanjaksha

    2015-05-01

    It is believed that the tribal people, who constitute 8.6 per cent of the total population (2011 census of India), are the original inhabitants of India. Glucose-6-phosphate-dehydrogenase (G6PD) deficiency is an X-linked genetic defect, affecting around 400 million people worldwide and is characterized by considerable biochemical and molecular heterogeneity. Deficiency of this enzyme is highly polymorphic in those areas where malaria is/has been endemic. G6PD deficiency was reported from India more than 50 years ago. t0 he prevalence varies from 2.3 to 27.0 per cent with an overall prevalence of 7.7 per cent in different tribal groups. Since the tribal populations live in remote areas where malaria is/has been endemic, irrational use of antimalarial drugs could result in an increased number of cases with drug induced haemolysis. Therefore, before giving antimalarial therapy, routine screening for G6PD deficiency should be undertaken in those tribal communities where its prevalence is high.

  7. Prevalence and molecular characterization of glucose-6-phosphate dehydrogenase deficiency in northern Thailand.

    PubMed

    Charoenkwan, Pimlak; Tantiprabha, Watcharee; Sirichotiyakul, Supatra; Phusua, Arunee; Sanguansermsri, Torpong

    2014-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common inherited enzymopathies in endemic areas of malaria including Southeast Asia. The molecular features of G6PD deficiency are similar among Southeast Asian population, with differences in the type of the prominent variants in each region. This study determined the prevalence and molecular characteristics of G6PD deficiency in northern Thailand. Quantitative assay of G6PD activity was conducted in 566 neonatal cord blood samples and 6 common G6PD mutations were determined by PCR-restriction fragment length polymorphism method on G6PD complete and intermediate deficiency samples. Ninety newborns had G6PD deficiency, with prevalence in male newborns of 17% and that of female newborns having an intermediate and complete deficiency of 13% and 2%, respectively. From 95 G6PD alleles tested, G6PD Mahidol, G6PD Kaiping, G6PD Canton, G6PD Viangchan, G6PD Union, and G6PD Chinese-5 was detected in 19, 17, 15, 13, 7, and 2 alleles, respectively. Our study shows that the prevalence of G6PD deficiency in northern Thai population is high and combination of the common Chinese mutations is the majority, a distribution different from central and southern Thailand where G6PD Viangchan is the prominent variant. These findings suggest a higher proportion of assimilated Chinese ethnic group in the northern Thai population.

  8. Glucose-6-phosphate dehydrogenase deficiency in transfusion medicine: the unknown risks.

    PubMed

    Francis, R O; Jhang, J S; Pham, H P; Hod, E A; Zimring, J C; Spitalnik, S L

    2013-11-01

    The hallmark of glucose-6-phosphate dehydrogenase (G6PD) deficiency is red blood cell (RBC) destruction in response to oxidative stress. Patients requiring RBC transfusions may simultaneously receive oxidative medications or have concurrent infections, both of which can induce haemolysis in G6PD-deficient RBCs. Although it is not routine practice to screen healthy blood donors for G6PD deficiency, case reports identified transfusion of G6PD-deficient RBCs as causing haemolysis and other adverse events. In addition, some patient populations may be more at risk for complications associated with transfusions of G6PD-deficient RBCs because they receive RBCs from donors who are more likely to have G6PD deficiency. This review discusses G6PD deficiency, its importance in transfusion medicine, changes in the RBC antioxidant system (of which G6PD is essential) during refrigerated storage and mechanisms of haemolysis. In addition, as yet unanswered questions that could be addressed by translational and clinical studies are identified and discussed.

  9. Neonatal screening for glucose-6-phosphate dehydrogenase deficiency: biochemical versus genetic technologies.

    PubMed

    Kaplan, Michael; Hammerman, Cathy

    2011-06-01

    Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, a commonly occurring genetic condition, is associated in neonates with severe hemolytic episodes, extreme hyperbilirubinemia, and bilirubin encephalopathy. Neonatal screening programs for the condition should increase parental and caretaker awareness, thereby facilitating early access to treatment with resultant diminished mortality and morbidity. However, screening for G-6-PD deficiency is not widely performed. Although G-6-PD-deficient males may be accurately identified, females are more difficult to categorize because many in this group may be heterozygotes with phenotype overlap between normal homozygotes, heterozygotes, and deficient homozygotes. Screening methodologies include biochemical qualitative assays, quantitative enzymatic activity measurements and DNA-based polymerase chain reaction molecular screening. The appropriateness of any of these technologies for any particular population group or geographic area must be assessed before setting up a screening program. The pros and cons of each method, including ease of testing, cost, need for sophisticated laboratory equipment and degree of personnel training, as well as the ability to identify females, are discussed.

  10. Nitrogen Assimilation, Abiotic Stress and Glucose 6-Phosphate Dehydrogenase: The Full Circle of Reductants.

    PubMed

    Esposito, Sergio

    2016-05-11

    Glucose 6 phosphate dehydrogenase (G6PDH; EC 1.1.1.49) is well-known as the main regulatory enzyme of the oxidative pentose phosphate pathway (OPPP) in living organisms. Namely, in Planta, different G6PDH isoforms may occur, generally localized in cytosol and plastids/chloroplasts. These enzymes are differently regulated by distinct mechanisms, still far from being defined in detail. In the last decades, a pivotal function for plant G6PDHs during the assimilation of nitrogen, providing reductants for enzymes involved in nitrate reduction and ammonium assimilation, has been described. More recently, several studies have suggested a main role of G6PDH to counteract different stress conditions, among these salinity and drought, with the involvement of an ABA depending signal. In the last few years, this recognized vision has been greatly widened, due to studies clearly showing the non-conventional subcellular localization of the different G6PDHs, and the peculiar regulation of the different isoforms. The whole body of these considerations suggests a central question: how do the plant cells distribute the reductants coming from G6PDH and balance their equilibrium? This review explores the present knowledge about these mechanisms, in order to propose a scheme of distribution of reductants produced by G6PDH during nitrogen assimilation and stress.

  11. Humanized mouse model of glucose 6-phosphate dehydrogenase deficiency for in vivo assessment of hemolytic toxicity.

    PubMed

    Rochford, Rosemary; Ohrt, Colin; Baresel, Paul C; Campo, Brice; Sampath, Aruna; Magill, Alan J; Tekwani, Babu L; Walker, Larry A

    2013-10-22

    Individuals with glucose 6-phosphate dehydrogenase (G6PD) deficiency are at risk for the development of hemolytic anemia when given 8-aminoquinolines (8-AQs), an important class of antimalarial/antiinfective therapeutics. However, there is no suitable animal model that can predict the clinical hemolytic potential of drugs. We developed and validated a human (hu)RBC-SCID mouse model by giving nonobese diabetic/SCID mice daily transfusions of huRBCs from G6PD-deficient donors. Treatment of SCID mice engrafted with G6PD-deficient huRBCs with primaquine, an 8-AQ, resulted in a dose-dependent selective loss of huRBCs. To validate the specificity of this model, we tested known nonhemolytic antimalarial drugs: mefloquine, chloroquine, doxycycline, and pyrimethamine. No significant loss of G6PD-deficient huRBCs was observed. Treatment with drugs known to cause hemolytic toxicity (pamaquine, sitamaquine, tafenoquine, and dapsone) resulted in loss of G6PD-deficient huRBCs comparable to primaquine. This mouse model provides an important tool to test drugs for their potential to cause hemolytic toxicity in G6PD-deficient populations.

  12. Humanized mouse model of glucose 6-phosphate dehydrogenase deficiency for in vivo assessment of hemolytic toxicity

    PubMed Central

    Rochford, Rosemary; Ohrt, Colin; Baresel, Paul C.; Campo, Brice; Sampath, Aruna; Magill, Alan J.; Tekwani, Babu L.; Walker, Larry A.

    2013-01-01

    Individuals with glucose 6-phosphate dehydrogenase (G6PD) deficiency are at risk for the development of hemolytic anemia when given 8-aminoquinolines (8-AQs), an important class of antimalarial/antiinfective therapeutics. However, there is no suitable animal model that can predict the clinical hemolytic potential of drugs. We developed and validated a human (hu)RBC-SCID mouse model by giving nonobese diabetic/SCID mice daily transfusions of huRBCs from G6PD-deficient donors. Treatment of SCID mice engrafted with G6PD-deficient huRBCs with primaquine, an 8-AQ, resulted in a dose-dependent selective loss of huRBCs. To validate the specificity of this model, we tested known nonhemolytic antimalarial drugs: mefloquine, chloroquine, doxycycline, and pyrimethamine. No significant loss of G6PD-deficient huRBCs was observed. Treatment with drugs known to cause hemolytic toxicity (pamaquine, sitamaquine, tafenoquine, and dapsone) resulted in loss of G6PD-deficient huRBCs comparable to primaquine. This mouse model provides an important tool to test drugs for their potential to cause hemolytic toxicity in G6PD-deficient populations. PMID:24101478

  13. Expression and characterization of a cytosolic glucose 6 phosphate dehydrogenase isoform from barley (Hordeum vulgare) roots.

    PubMed

    Castiglia, Daniela; Cardi, Manuela; Landi, Simone; Cafasso, Donata; Esposito, Sergio

    2015-08-01

    In plant cells, glucose 6 phosphate dehydrogenase (G6PDH-EC 1.1.1.49) regulates the oxidative pentose phosphate pathway (OPPP), a metabolic route involved in the production of NADPH for various biosynthetic processes and stress response. In this study, we report the overexpression of a cytosolic G6PDH isoform from barley (Hordeum vulgare) roots in bacteria, and the biochemical characterization of the purified recombinant enzyme (HvCy-G6PDH). A full-length cDNA coding for a cytosolic isoform of G6PDH was isolated, and the sequence was cloned into pET3d vector; the protein was overexpressed in Escherichia coli BL21 (DE3) and purified by anion exchange and affinity chromatography. The kinetic properties were calculated: the recombinant HvCy-G6PDH showed KMs and KINADPH comparable to those observed for the enzyme purified from barley roots; moreover, the analysis of NADPH inhibition suggested a competitive mechanism. Therefore, this enzyme could be utilised for the structural and regulatory characterization of this isoform in higher plants.

  14. Design of an interface peptide as new inhibitor of human glucose-6-phosphate dehydrogenase.

    PubMed

    Obiol-Pardo, Cristian; Alcarraz-Vizán, Gema; Díaz-Moralli, Santiago; Cascante, Marta; Rubio-Martinez, Jaime

    2014-04-01

    Glucose-6-phosphate dehydrogenase (G6PDH) is an essential enzyme involved in the first reaction of the oxidative branch of the pentose phosphate pathway (PPP). Recently, G6PDH was suggested as a novel target protein for cancer therapy as one of the final products of the PPP, ribose-5-phosphate, is necessary for nucleic acid synthesis and tumor progression. After analyzing the protein-protein interface of the crystal structure of human G6PDH by means of molecular dynamics simulations, we designed six interface peptides based on the natural sequence of the protein. The three most promising peptides, as predicted by binding free energy calculations, were synthesized and one of them was confirmed as a novel inhibitor of human G6PDH in experimental assays. Together, the active peptide found and its suggested binding mode proposes a new strategy for inhibiting this enzyme and should aid the further design of novel, potent and non-peptidic G6PDH inhibitors. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Glucose-6-Phosphate Isomerase (G6PI) Mediates Hypoxia-Induced Angiogenesis in Rheumatoid Arthritis

    PubMed Central

    Lu, Ying; Yu, Shan-Shan; Zong, Ming; Fan, Sha-Sha; Lu, Tian-Bao; Gong, Ru-Han; Sun, Li-Shan; Fan, Lie-Ying

    2017-01-01

    The higher level of Glucose-6-phosphate isomerase (G6PI) has been found in both synovial tissue and synovial fluid of rheumatoid arthritis (RA) patients, while the function of G6PI in RA remains unclear. Herein we found the enrichment of G6PI in microvascular endothelial cells of synovial tissue in RA patients, where a 3% O2 hypoxia environment has been identified. In order to determine the correlation between the high G6PI level and the low oxygen concentration in RA, a hypoxia condition (~3% O2) in vitro was applied to mimic the RA environment in vivo. Hypoxia promoted cellular proliferation of rheumatoid arthritis synovial fibroblasts (RASFs), and induced cell migration and angiogenic tube formation of human dermal microvascular endothelial cells (HDMECs), which were accompanied with the increased expression of G6PI and HIF-1α. Through application of G6PI loss-of-function assays, we confirmed the requirement of G6PI expression for those hypoxia-induced phenotype in RA. In addition, we demonstrated for the first time that G6PI plays key roles in regulating VEGF secretion from RASFs to regulate the hypoxia-induced angiogenesis in RA. Taken together, we demonstrated a novel pathway regulating hypoxia-induced angiogenesis in RA mediated by G6PI. PMID:28067317

  16. Trehalose-6-phosphate synthase/phosphatase regulates cell shape and plant architecture in Arabidopsis.

    PubMed

    Chary, S Narasimha; Hicks, Glenn R; Choi, Yoon Gi; Carter, David; Raikhel, Natasha V

    2008-01-01

    The vacuole occupies most of the volume of plant cells; thus, the tonoplast marker delta-tonoplast intrinsic protein-green fluorescent protein delineates cell shape, for example, in epidermis. This permits rapid identification of mutants. Using this strategy, we identified the cell shape phenotype-1 (csp-1) mutant in Arabidopsis thaliana. Beyond an absence of lobes in pavement cells, phenotypes included reduced trichome branching, altered leaf serration and stem branching, and increased stomatal density. This result from a point mutation in AtTPS6 encoding a conserved amino-terminal domain, thought to catalyze trehalose-6-phosphate synthesis and a carboxy-terminal phosphatase domain, is catalyzing a two-step conversion to trehalose. Expression of AtTPS6 in the Saccharomyces cerevisiae mutants tps1 (encoding a synthase domain) and tps2 (encoding synthase and phosphatase domains) indicates that AtTPS6 is an active trehalose synthase. AtTPS6 fully complemented defects in csp-1. Mutations in class I genes (AtTPS1-AtTPS4) indicate a role in regulating starch storage, resistance to drought, and inflorescence architecture. Class II genes (AtTPS5-AtTPS11) encode multifunctional enzymes having synthase and phosphatase activity. We show that class II AtTPS6 regulates plant architecture, shape of epidermal pavement cells, and branching of trichomes. Thus, beyond a role in development, we demonstrate that the class II gene AtTPS6 is important for controlling cellular morphogenesis.

  17. Glucose-induced glycogenesis in the liver involves the glucose-6-phosphate-dependent dephosphorylation of glycogen synthase.

    PubMed Central

    Cadefau, J; Bollen, M; Stalmans, W

    1997-01-01

    Non-metabolized glucose derivatives may cause inactivation of phosphorylase but, unlike glucose, they are unable to elicit activation of glycogen synthase in isolated hepatocytes. We report here that, after the previous inactivation of phosphorylase by one of these glucose derivatives (2-deoxy-2-fluoro-alpha-glucosyl fluoride), glycogen synthase was progressively activated by addition of increasing concentrations of glucose. Under these conditions, the degree of activation of glycogen synthase was linearly correlated with the intracellular glucose-6-phosphate (Glc-6-P) concentration. Addition of glucosamine, an inhibitor of glucokinase, decreased both parameters in parallel. Further experiments using an inhibitor of either protein kinases (5-iodotubercidin) or protein phosphatases (microcystin) in isolated hepatocytes indicated that Glc-6-P does not affect glycogen-synthase kinase activity but enhances the glycogen-synthase phosphatase reaction. Experiments in vitro showed that the synthase phosphatase activity of glycogen-bound type-1 protein phosphatase was increased by physiological concentrations of Glc-6-P (0.1-0.5 mM), but not by 2.5 mM fructose-6-P, fructose-1-P or glucose-1-P. At physiological ionic strength, the glycogen-associated synthase phosphatase activity was nearly entirely Glc-6-P-dependent, but Glc-6-P did not relieve the strong inhibitory effect of phosphorylase a. The large stimulatory effects of 2.5 mM Glc-6-P, with glycogen synthase b and phosphorylase a as substrates, appeared to be mostly substrate-directed, while the modest effects observed with casein and histone IIA pointed to an additional stimulation of glycogen-bound protein phosphatase-1 by Glc-6-P. We conclude that glucose elicits hepatic synthase phosphatase activity both by removal of the inhibitor, phosphorylase a, and by generation of the stimulator, Glc-6-P. PMID:9148744

  18. Glucose-induced glycogenesis in the liver involves the glucose-6-phosphate-dependent dephosphorylation of glycogen synthase.

    PubMed

    Cadefau, J; Bollen, M; Stalmans, W

    1997-03-15

    Non-metabolized glucose derivatives may cause inactivation of phosphorylase but, unlike glucose, they are unable to elicit activation of glycogen synthase in isolated hepatocytes. We report here that, after the previous inactivation of phosphorylase by one of these glucose derivatives (2-deoxy-2-fluoro-alpha-glucosyl fluoride), glycogen synthase was progressively activated by addition of increasing concentrations of glucose. Under these conditions, the degree of activation of glycogen synthase was linearly correlated with the intracellular glucose-6-phosphate (Glc-6-P) concentration. Addition of glucosamine, an inhibitor of glucokinase, decreased both parameters in parallel. Further experiments using an inhibitor of either protein kinases (5-iodotubercidin) or protein phosphatases (microcystin) in isolated hepatocytes indicated that Glc-6-P does not affect glycogen-synthase kinase activity but enhances the glycogen-synthase phosphatase reaction. Experiments in vitro showed that the synthase phosphatase activity of glycogen-bound type-1 protein phosphatase was increased by physiological concentrations of Glc-6-P (0.1-0.5 mM), but not by 2.5 mM fructose-6-P, fructose-1-P or glucose-1-P. At physiological ionic strength, the glycogen-associated synthase phosphatase activity was nearly entirely Glc-6-P-dependent, but Glc-6-P did not relieve the strong inhibitory effect of phosphorylase a. The large stimulatory effects of 2.5 mM Glc-6-P, with glycogen synthase b and phosphorylase a as substrates, appeared to be mostly substrate-directed, while the modest effects observed with casein and histone IIA pointed to an additional stimulation of glycogen-bound protein phosphatase-1 by Glc-6-P. We conclude that glucose elicits hepatic synthase phosphatase activity both by removal of the inhibitor, phosphorylase a, and by generation of the stimulator, Glc-6-P.

  19. Exploring the role of trehalose-6-phosphate synthase in oxidation and desiccation stress tolerance of Fusarium verticillioides

    USDA-ARS?s Scientific Manuscript database

    Fusarium verticillioides is a pathogenic filamentous fungus that primarily affects maize. We are exploring stress response mechanisms in F. verticillioides, particularly the role of the disaccharide trehalose. Trehalose-6-phosphate synthase, coded for by the TPS1 gene, catalyzes the first of two ste...

  20. Glucose-6-Phosphate Dehydrogenase Deficiency Improves Insulin Resistance With Reduced Adipose Tissue Inflammation in Obesity.

    PubMed

    Ham, Mira; Choe, Sung Sik; Shin, Kyung Cheul; Choi, Goun; Kim, Ji-Won; Noh, Jung-Ran; Kim, Yong-Hoon; Ryu, Je-Won; Yoon, Kun-Ho; Lee, Chul-Ho; Kim, Jae Bum

    2016-09-01

    Glucose-6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme of the pentose phosphate pathway, plays important roles in redox regulation and de novo lipogenesis. It was recently demonstrated that aberrant upregulation of G6PD in obese adipose tissue mediates insulin resistance as a result of imbalanced energy metabolism and oxidative stress. It remains elusive, however, whether inhibition of G6PD in vivo may relieve obesity-induced insulin resistance. In this study we showed that a hematopoietic G6PD defect alleviates insulin resistance in obesity, accompanied by reduced adipose tissue inflammation. Compared with wild-type littermates, G6PD-deficient mutant (G6PD(mut)) mice were glucose tolerant upon high-fat-diet (HFD) feeding. Intriguingly, the expression of NADPH oxidase genes to produce reactive oxygen species was alleviated, whereas that of antioxidant genes was enhanced in the adipose tissue of HFD-fed G6PD(mut) mice. In diet-induced obesity (DIO), the adipose tissue of G6PD(mut) mice decreased the expression of inflammatory cytokines, accompanied by downregulated proinflammatory macrophages. Accordingly, macrophages from G6PD(mut) mice greatly suppressed lipopolysaccharide-induced proinflammatory signaling cascades, leading to enhanced insulin sensitivity in adipocytes and hepatocytes. Furthermore, adoptive transfer of G6PD(mut) bone marrow to wild-type mice attenuated adipose tissue inflammation and improved glucose tolerance in DIO. Collectively, these data suggest that inhibition of macrophage G6PD would ameliorate insulin resistance in obesity through suppression of proinflammatory responses. © 2016 by the American Diabetes Association.

  1. Feedback inhibition of starch degradation in Arabidopsis leaves mediated by trehalose 6-phosphate.

    PubMed

    Martins, Marina Camara Mattos; Hejazi, Mahdi; Fettke, Joerg; Steup, Martin; Feil, Regina; Krause, Ursula; Arrivault, Stéphanie; Vosloh, Daniel; Figueroa, Carlos María; Ivakov, Alexander; Yadav, Umesh Prasad; Piques, Maria; Metzner, Daniela; Stitt, Mark; Lunn, John Edward

    2013-11-01

    Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by β-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 µm in the cytosol, 0.2 to 0.5 µm in the chloroplasts, and 0.05 µm in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night.

  2. Producing glucose 6-phosphate from cellulosic biomass: Structural insights into levoglucosan bioconversion

    SciTech Connect

    Bacik, John -Paul; Klesmith, Justin R.; Whitehead, Timothy A.; Jarboe, Laura R.; Unkefer, Clifford J.; Mark, Brian L.; Michalczyk, Ryszard

    2015-09-09

    The most abundant carbohydrate product of cellulosic biomass pyrolysis is the anhydrosugar levoglucosan (1,6-anhydro-β-d-glucopyranose), which can be converted to glucose 6-phosphate by levoglucosan kinase (LGK). In addition to the canonical kinase phosphotransfer reaction, the conversion requires cleavage of the 1,6-anhydro ring to allow ATP-dependent phosphorylation of the sugar O6 atom. Using x-ray crystallography, we show that LGK binds two magnesium ions in the active site that are additionally coordinated with the nucleotide and water molecules to result in ideal octahedral coordination. To further verify the metal binding sites, we co-crystallized LGK in the presence of manganese instead of magnesium and solved the structure de novo using the anomalous signal from four manganese atoms in the dimeric structure. The first metal is required for catalysis, whereas our work suggests that the second is either required or significantly promotes the catalytic rate. Although the enzyme binds its sugar substrate in a similar orientation to the structurally related 1,6-anhydro-N-acetylmuramic acid kinase (AnmK), it forms markedly fewer bonding interactions with the substrate. In this orientation, the sugar is in an optimal position to couple phosphorylation with ring cleavage. We also observed a second alternate binding orientation for levoglucosan, and in these structures, ADP was found to bind with lower affinity. These combined observations provide an explanation for the high Km of LGK for levoglucosan. Furthermore, greater knowledge of the factors that contribute to the catalytic efficiency of LGK can be used to improve applications of this enzyme for levoglucosan-derived biofuel production.

  3. Data mining and pathway analysis of glucose-6-phosphate dehydrogenase with natural language processing.

    PubMed

    Chen, Long; Zhang, Chunhua; Wang, Yanling; Li, Yuqian; Han, Qiaoqiao; Yang, Huixin; Zhu, Yuechun

    2017-08-01

    Human glucose-6-phosphate dehydrogenase (G6PD) is a crucial enzyme in the pentose phosphate pathway, and serves an important role in biosynthesis and the redox balance. G6PD deficiency is a major cause of neonatal jaundice and acute hemolyticanemia, and recently, G6PD has been associated with diseases including inflammation and cancer. The aim of the present study was to conduct a search of the National Center for Biotechnology Information PubMed library for articles discussing G6PD. Genes that were identified to be associated with G6PD were recorded, and the frequency at which each gene appeared was calculated. Gene ontology (GO), pathway and network analyses were then performed. A total of 98 G6PD‑associated genes and 33 microRNAs (miRNAs) that potentially regulate G6PD were identified. The 98 G6PD‑associated genes were then sub‑classified into three functional groups by GO analysis, followed by analysis of function, pathway, network, and disease association. Out of the 47 signaling pathways identified, seven were significantly correlated with G6PD‑associated genes. At least two out of four independent programs identified the 33 miRNAs that were predicted to target G6PD. miR‑1207‑5P, miR‑1 and miR‑125a‑5p were predicted by all four software programs to target G6PD. The results of the present study revealed that dysregulation of G6PD was associated with cancer, autoimmune diseases, and oxidative stress‑induced disorders. These results revealed the potential roles of G6PD‑regulated signaling and metabolic pathways in the etiology of these diseases.

  4. Antimalarial NADPH-Consuming Redox-Cyclers As Superior Glucose-6-Phosphate Dehydrogenase Deficiency Copycats

    PubMed Central

    Bielitza, Max; Belorgey, Didier; Ehrhardt, Katharina; Johann, Laure; Lanfranchi, Don Antoine; Gallo, Valentina; Schwarzer, Evelin; Mohring, Franziska; Jortzik, Esther; Williams, David L.; Becker, Katja; Arese, Paolo; Elhabiri, Mourad

    2015-01-01

    Abstract Aims: Early phagocytosis of glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes parasitized by Plasmodium falciparum were shown to protect G6PD-deficient populations from severe malaria. Here, we investigated the mechanism of a novel antimalarial series, namely 3-[substituted-benzyl]-menadiones, to understand whether these NADPH-consuming redox-cyclers, which induce oxidative stress, mimic the natural protection of G6PD deficiency. Results: We demonstrated that the key benzoylmenadione metabolite of the lead compound acts as an efficient redox-cycler in NADPH-dependent methaemoglobin reduction, leading to the continuous formation of reactive oxygen species, ferrylhaemoglobin, and subsequent haemichrome precipitation. Structure–activity relationships evidenced that both drug metabolites and haemoglobin catabolites contribute to potentiate drug effects and inhibit parasite development. Disruption of redox homeostasis by the lead benzylmenadione was specifically induced in Plasmodium falciparum parasitized erythrocytes and not in non-infected cells, and was visualized via changes in the glutathione redox potential of living parasite cytosols. Furthermore, the redox-cycler shows additive and synergistic effects in combination with compounds affecting the NADPH flux in vivo. Innovation: The lead benzylmenadione 1c is the first example of a novel redox-active agent that mimics the behavior of a falciparum parasite developing inside a G6PD-deficient red blood cell (RBC) giving rise to malaria protection, and it exerts specific additive effects that are inhibitory to parasite development, without harm for non-infected G6PD-sufficient or -deficient RBCs. Conclusion: This strategy offers an innovative perspective for the development of future antimalarial drugs for G6PD-sufficient and -deficient populations. Antioxid. Redox Signal. 22, 1337–1351. PMID:25714942

  5. Importance of glucose-6-phosphate dehydrogenase (G6PDH) for vanillin tolerance in Saccharomyces cerevisiae.

    PubMed

    Nguyen, Trinh Thi My; Kitajima, Sakihito; Izawa, Shingo

    2014-09-01

    Vanillin is derived from lignocellulosic biomass and, as one of the major biomass conversion inhibitors, inhibits yeast growth and fermentation. Vanillin was recently shown to induce the mitochondrial fragmentation and formation of mRNP granules such as processing bodies and stress granules in Saccharomyces cerevisiae. Furfural, another major biomass conversion inhibitor, also induces oxidative stress and is reduced in an NAD(P)H-dependent manner to its less toxic alcohol derivative. Therefore, the pentose phosphate pathway (PPP), through which most NADPH is generated, plays a role in tolerance to furfural. Although vanillin also induces oxidative stress and is reduced to vanillyl alcohol in a NADPH-dependent manner, the relationship between vanillin and PPP has not yet been investigated. In the present study, we examined the importance of glucose-6-phosphate dehydrogenase (G6PDH), which catalyzes the rate-limiting NADPH-producing step in PPP, for yeast tolerance to vanillin. The growth of the null mutant of G6PDH gene (zwf1Δ) was delayed in the presence of vanillin, and vanillin was efficiently reduced in the culture of wild-type cells but not in the culture of zwf1Δ cells. Furthermore, zwf1Δ cells easily induced the activation of Yap1, an oxidative stress responsive transcription factor, mitochondrial fragmentation, and P-body formation with the vanillin treatment, which indicated that zwf1Δ cells were more susceptible to vanillin than wild type cells. These findings suggest the importance of G6PDH and PPP in the response of yeast to vanillin.

  6. Molecular study of ovine glucose 6-phosphate dehydrogenase gene expression in respect to different energy intake.

    PubMed

    Laliotis, George P; Vitsa, Alkistis; Bizelis, Iosif; Charismiadou, Maria A; Rogdakis, Emmanuel

    2010-06-01

    Glucose 6-phosphate dehydrogenase (G6PD) plays an important role in a ruminant's metabolism catalyzing the first committed reaction in the pentose phosphate pathway as it provides necessary compounds of NADPH for the synthesis of fatty acids. The cloning of ovine (Ovis aries) G6PD gene revealed the presence of two cDNA transcripts (oG6PD(A) and oG6PD(B)), with oG6PD(B) being a product of alternative splicing and with no similarity to any other previously reported G6PD transcript. Here, we attempt to study the effect of energy balance in ovine G6PD transcript expression, trying simultaneously to find out any potential physiological role of the oG6PD(B) transcript. Changes of energy balance that lead to synergistic changes in the expression of both transcripts, but in opposite directions and not in a proportional way. Negative energy balance favours the presence of the oG6PD(B) transcript leading to a significant increase of its expression, compared to oG6PD(A) expression (P<0.05). In contrast, positive energy balance leads to a significant increase of oG6PD(A) compared to oG6PD(B) expression (P<0.05). In either condition oG6PD(B) expression is unchanged. Regression analysis showed that there is an energy balance threshold where the expression of both transcripts shows no change. 2010 Elsevier Inc. All rights reserved.

  7. Genetic Profiles of Korean Patients With Glucose-6-Phosphate Dehydrogenase Deficiency

    PubMed Central

    Lee, Jaewoong; Choi, Hayoung; Kim, Jiyeon; Kwon, Ahlm; Jang, Woori; Chae, Hyojin; Kim, Myungshin; Kim, Yonggoo; Lee, Jae Wook; Chung, Nack-Gyun

    2017-01-01

    Background We describe the genetic profiles of Korean patients with glucose-6-phosphate dehydrogenase (G6PD) deficiencies and the effects of G6PD mutations on protein stability and enzyme activity on the basis of in silico analysis. Methods In parallel with a genetic analysis, the pathogenicity of G6PD mutations detected in Korean patients was predicted in silico. The simulated effects of G6PD mutations were compared to the WHO classes based on G6PD enzyme activity. Four previously reported mutations and three newly diagnosed patients with missense mutations were estimated. Results One novel mutation (p.Cys385Gly, labeled G6PD Kangnam) and two known mutations [p.Ile220Met (G6PD São Paulo) and p.Glu416Lys (G6PD Tokyo)] were identified in this study. G6PD mutations identified in Koreans were also found in Brazil (G6PD São Paulo), Poland (G6PD Seoul), United States of America (G6PD Riley), Mexico (G6PD Guadalajara), and Japan (G6PD Tokyo). Several mutations occurred at the same nucleotide, but resulted in different amino acid residue changes in different ethnic populations (p.Ile380 variant, G6PD Calvo Mackenna; p.Cys385 variants, Tomah, Madrid, Lynwood; p.Arg387 variant, Beverly Hills; p.Pro396 variant, Bari; and p.Pro396Ala in India). On the basis of the in silico analysis, Class I or II mutations were predicted to be highly deleterious, and the effects of one Class IV mutation were equivocal. Conclusions The genetic profiles of Korean individuals with G6PD mutations indicated that the same mutations may have arisen by independent mutational events, and were not derived from shared ancestral mutations. The in silico analysis provided insight into the role of G6PD mutations in enzyme function and stability. PMID:28028996

  8. Prevalence of glucose-6-phosphate dehydrogenase deficiency in jaundiced Egyptian neonates.

    PubMed

    M Abo El Fotoh, Wafaa Moustafa; Rizk, Mohammed Soliman

    2016-12-01

    The enzyme, Glucose-6-phosphate dehydrogenase (G6PD), deficiency leads to impaired production of reduced glutathione and predisposes the red cells to be damaged by oxidative metabolites, causing hemolysis. Deficient neonates may manifest clinically as hyperbilirubinemia or even kernicterus. This study was carried out to detect erythrocyte G6PD deficiency in neonatal hyperbilirubinemia. To determine the frequency and effect of G6PD deficiency, this study was conducted on 202 neonates with indirect hyperbilirubinemia. All term and preterm babies up to 13 day of age admitted with clinically evident jaundice were taken for the study. G6PD activity is measured by the UV-Kinetic Method using cellular enzyme determination reagents by spectrophotometry according to manufacturer's instructions. A total of 202 babies were enrolled in this study. Male babies outnumbered the female (71.3% versus 28.7%). Mean age of the study newborns was 3.75 ± 2.5 days. Eighteen neonates (8.9%) had G6PD deficiency, all are males. One case had combined G6PD deficiency and RH incompatibility. Mean serum total bilirubin was 17.2 ± 4.4 in G6PD deficient cases. There was significant positive correlation between the time of appearance of jaundice in days and G6PD levels in G6PD deficient cases. Neonatal hyperbilirubinemia is associated with various clinical comorbidities. G6PD deficiency is found to one important cause of neonatal jaundice developing on day 2 onwards.

  9. Association of glucose-6-phosphate dehydrogenase deficiency and malaria: a systematic review and meta-analysis

    PubMed Central

    Mbanefo, Evaristus Chibunna; Ahmed, Ali Mahmoud; Titouna, Afaf; Elmaraezy, Ahmed; Trang, Nguyen Thi Huyen; Phuoc Long, Nguyen; Hoang Anh, Nguyen; Diem Nghi, Tran; The Hung, Bui; Van Hieu, Mai; Ky Anh, Nguyen; Huy, Nguyen Tien; Hirayama, Kenji

    2017-01-01

    Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency overlaps with malaria endemicity although it predisposes carriers to hemolysis. This fact supports the protection hypothesis against malaria. The aim of this systematic review is to assess the presence and the extent of protective association between G6PD deficiency and malaria. Thirteen databases were searched for papers reporting any G6PD alteration in malaria patients. Twenty-eight of the included 30 studies were eligible for the meta-analysis. Results showed absence of negative association between G6PD deficiency and uncomplicated falciparum malaria (odds ratio (OR), 0.77; 95% confidence interval (CI), 0.59–1.02; p = 0.07). However, this negative association happened in Africa (OR, 0.59; 95% CI, 0.40–0.86; p = 0.007) but not in Asia (OR, 1.24; 95% CI, 0.96–1.61; p = 0.10), and in the heterozygotes (OR, 0.70; 95% CI, 0.57–0.87; p = 0.001) but not the homo/hemizygous (OR, 0.70; 95% CI, 0.46–1.07; p = 0.10). There was no association between G6PD deficiency and total severe malaria (OR, 0.82; 95% CI, 0.61–1.11; p = 0.20). Similarly, there was no association with other malaria species. G6PD deficiency can potentially protect against uncomplicated malaria in African countries, but not severe malaria. Interestingly, this protection was mainly in heterozygous, being x-linked thus related to gender. PMID:28382932

  10. A new paper-based analytical device for detection of Glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Kaewarsa, Phuritat; Laiwattanapaisal, Wanida; Palasuwan, Attakorn; Palasuwan, Duangdao

    2017-03-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic haemolytic disorder. Most persons with G6PD deficiency are asymptomatic, but exposure to oxidant drugs, such as the anti-malarial drug primaquine, may induce haemolysis, which is commonly found in Asian countries. A reliable test is necessary for diagnosing the deficiency to prevent an acute haemolytic crisis. This study proposes a novel quantitative method to detect G6PD deficiency using paper-based analytical devices (G6PDD-PAD). Wax printing was utilized for fabricating circular reaction zone patterns in paper. The colorimetric assay is based on the formation of formazan via a reduction of tetra-nitro blue tetrazolium (TNBT) by the G6PD enzyme on G6PDD-PAD. Detection was achieved by capturing the colour using a desktop scanner and the colour intensity was analysed with Adobe Photoshop C56. The results showed that the G6PD activity analysed by G6PDD-PAD was highly correlated with the standard biochemical assay (SBA) (r(2)=0.87, p<0.01). Moreover, good agreement by Bland-Altman bias plot was demonstrated between G6PDD-PAD and the SBA (mean bias 1.4 IU/gHb). The detection limit was 0 IU/gHb of G6PD activity. This study demonstrates the feasibility of using G6PDD-PAD. This simple, low-cost test ($0.1/test) should be useful for diagnosing G6PD deficiency in resource-limited settings. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Cloning and truncation modification of trehalose-6-phosphate synthase gene from Selaginella pulvinata.

    PubMed

    Zhao, Sheng-Mei; Fu, Feng-Ling; Gou, Lin; Wang, Han-Guang; He, Gang; Li, Wan-Chen

    2013-01-10

    A homologous sequence was amplified from resurrection plant Selaginella pulvinta by RACE technique, proved to be the full-length cDNA of trehalose-6-phosphate synthase gene by homologous alignment and yeast complementation assay, and nominated as SpTPS1 gene. The open reading frame of this gene was truncated 225bp at the 5'-end, resulting the N-terminal truncation modification of 75 amino acids for its encoding protein. The TPS1 deletion mutant strain YSH290 of the brewer's yeast transformed by the truncated gene SpTPS1Δ and its original full-length version restored growth on the medium with glucose as a sole carbon source and displayed growth curves with no significant difference, indicating their encoding proteins functioning as TPS enzyme. The TPS activity of the mutant strain transformed by the truncated gene SpTPS1Δ was about six fold higher than that transformed by its original version, reasoning that the extra N-terminal extension of the full-length amino acid sequence acts as an inhibitory domain to trehalose synthesis. However, the trehalose accumulation of the mutant strain transformed by the truncated gene SpTPS1Δ was only 8% higher than that transformed by its original version. This result is explained by the feedback balance of trehalose content coordinated by the comparative activities between trehalose synthase and trehalase. The truncated gene SpTPS1Δ is suggested to be used in transgenic operation, together with the inhibition of trehalase activity by the application of validamycin A or genetic deficiency of the endogenous trehalase gene, for the enhancement of trehalose accumulation and improvement of abiotic tolerance in transgenic plants.

  12. Biochemical characterization and ligand-binding properties of trehalose-6-phosphate phosphatase from Mycobacterium tuberculosis.

    PubMed

    Shi, Lina; Zhang, Haiping; Qiu, Yu; Wang, Qian; Wu, Xueji; Wang, Honghai; Zhang, Xuelian; Lin, Donghai

    2013-10-01

    Trehalose-6-phosphate phosphatase (TPP) is an essential enzyme for growth of mycobacteria, which has been identified to be a potential anti-tuberculosis drug target. However, the biochemical and ligand-binding properties and the 3D structure of TPP remain unclear so far. In the present study, we expressed the recombinant TPP protein from Mycobacterium tuberculosis (otsB2/Rv3372). Results from the far-ultraviolet circular dichroism experiments indicated that the secondary structure of TPP was rich in α-helix with a lower structural stability (Cm = 2.099 ± 0.134 M). Ligand-binding assay by isothermal titration calorimetry demonstrated that the recombinant TPP protein could bind with trehalose-6-P in the presence of Mg(2+) (Kd = 39.52 ± 1.78 μM) with a molar ratio of 1 : 1. In addition, the 3D structure of TPP was modeled by I-TASSER, indicating that the TPP protein was composed of a hydrolase domain, a cap domain, and an N-terminal domain. Flexible docking was further conducted by using the Simulations/Dock module of the Molecular Operating Environment software. The binding pocket of TPP for both trehalose-6-P and Mg(2+) was determined, which was located on the interface between the hydrolase domain and the cap domain. Asp149, Gly186, Arg187, Arg291, and Glu295 were identified to be the key residues for TPP binding with trehalose-6-P. This work may lay the basis for further structural and functional studies of TPP and TPP-related novel drug development.

  13. Diversity in expression of glucose-6-phosphate dehydrogenase deficiency in females.

    PubMed

    Abdulrazzaq, Y M; Micallef, R; Qureshi, M; Dawodu, A; Ahmed, I; Khidr, A; Bastaki, S M; Al-Khayat, A; Bayoumi, R A

    1999-01-01

    The aims of this study were to determine the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in the United Arab Emirates (UAE), to describe the different mutations in the population, to determine its prevalence, and to study inheritance patterns in families of G6PD-deficient individuals. All infants born at Tawam Hospital, Al-Ain, UAE from January 1994 to September 1996 were screened at birth for their G6PD status. In addition, those attending well-baby clinics during the period were also screened for the disorder. Families of 40 known G6PD-deficient individuals, selected randomly from the records of three hospitals in the country, were assessed for G6PD deficiency. Where appropriate, this was followed by definition of G6PD mutations. Of 8198 infants, 746 (9.1%), comprising 15% of males and 5% of females tested, were found to be G6PD deficient. A total of 27 families were further assessed: of these, all but one family had the nt563 Mediterranean mutation. In one family, two individuals had the nt202 African mutation. The high manifestation of G6PD deficiency in women may be due to the preferential expression of the G6PD-deficient gene and X-inactivation of the normal gene, and/or to the presence of an 'enhancer' gene that makes the expression of the G6PD deficiency more likely. The high level of consanguinity which, theoretically, should result in a high proportion of homozygotes and consequently a higher proportion of females with the deficiency, was not found to be a significant factor.

  14. Glucose-6-Phosphate Dehydrogenase Deficiency and Physical and Mental Health until Adolescence

    PubMed Central

    Kwok, Man Ki; Leung, Gabriel M.; Schooling, C. Mary

    2016-01-01

    Background To examine the association of glucose-6-phosphate dehydrogenase (G6PD) deficiency with adolescent physical and mental health, as effects of G6PD deficiency on health are rarely reported. Methods In a population-representative Chinese birth cohort: “Children of 1997” (n = 8,327), we estimated the adjusted associations of G6PD deficiency with growth using generalized estimating equations, with pubertal onset using interval censored regression, with hospitalization using Cox proportional hazards regression and with size, blood pressure, pubertal maturation and mental health using linear regression with multiple imputation and inverse probability weighting. Results Among 5,520 screened adolescents (66% follow-up), 4.8% boys and 0.5% girls had G6PD deficiency. G6PD-deficiency was not associated with birth weight-for-gestational age or length/height gain into adolescence, but was associated with lower childhood body mass index (BMI) gain (-0.38 z-score, 95% confidence interval (CI) -0.57, -0.20), adjusted for sex and parental education, and later onset of pubic hair development (time ratio = 1.029, 95% CI 1.007, 1.050). G6PD deficiency was not associated with blood pressure, height, BMI or mental health in adolescence, nor with serious infectious morbidity until adolescence. Conclusions G6PD deficient adolescents had broadly similar physical and mental health indicators, but transiently lower BMI gain and later pubic hair development, whose long-term implications warrant investigation. PMID:27824927

  15. A Tale of Two Sugars: Trehalose 6-Phosphate and Sucrose1[OPEN

    PubMed Central

    2016-01-01

    Trehalose 6-phosphate (Tre6P), the intermediate of trehalose biosynthesis, is an essential signal metabolite in plants, linking growth and development to carbon status. The Suc-Tre6P nexus model postulates that Tre6P is both a signal and negative feedback regulator of Suc levels, forming part of a mechanism to maintain Suc levels within an optimal range and functionally comparable to the insulin-glucagon system for regulating blood Glc levels in animals. The target range and sensitivity of the Tre6P-Suc feedback control circuit can be adjusted according to the cell type, developmental stage, and environmental conditions. In source leaves, Tre6P modulates Suc levels by affecting Suc synthesis, whereas in sink organs it regulates Suc consumption. In illuminated leaves, Tre6P influences the partitioning of photoassimilates between Suc, organic acids, and amino acids via posttranslational regulation of phosphoenolpyruvate carboxylase and nitrate reductase. At night, Tre6P regulates the remobilization of leaf starch reserves to Suc, potentially linking starch turnover in source leaves to carbon demand from developing sink organs. Use of Suc for growth in developing tissues is strongly influenced by the antagonistic activities of two protein kinases: SUC-NON-FERMENTING-1-RELATED KINASE1 (SnRK1) and TARGET OF RAPAMYCIN (TOR). The relationship between Tre6P and SnRK1 in developing tissues is complex and not yet fully resolved, involving both direct and indirect mechanisms, and positive and negative effects. No direct connection between Tre6P and TOR has yet been described. The roles of Tre6P in abiotic stress tolerance and stomatal regulation are also discussed. PMID:27482078

  16. Recognition of mannose 6-phosphate ligands by dystrophic rat retinal pigment epithelium

    SciTech Connect

    Tarnowski, B.; Shepherd, V.; McLaughlin, B.

    1986-05-01

    Retinal pigment epithelium (RPE) phagocytize discarded rod outer segments (ROS) during normal eye function. In the dystrophic rat, an animal model for retinitis pigmentosa in humans, ROS phagocytosis is defective. Dystrophic RPE can phagocytize particles other than ROS, suggesting that the defect may be in the RPE phagocytic recognition. They are currently investigating the recognition markers on RPE in dystrophic rats. In studies using ligand-coated latex beads, no uptake of mannose-coated beads was found in dystrophic rat RPE. They found that dystrophic RPE could specifically phagocytize phosphomannan-coated beads. Studies were begun to examine the presence and function of a phosphomannan receptor (PMR) on dystrophic RPE. ..cap alpha..-Mannosidase, isolated from D. discoideum has been shown to be an efficient ligand for the PMR in fibroblasts and macrophages. It is also recognized by the macrophage mannose receptor. Dystrophic rat RPE and retina explants were placed in culture dishes (5-7/well). /sup 125/I-Labelled ..cap alpha..-mannosidase was added to each well in the presence or absence of 10 mM mannose 6-phosphate (M6P) or yeast mannan (lmg/ml). Explants were incubated at 37/sup 0/ for 2 hr., washed and bound /sup 125/I-mannosidase quantitated. Approximately 2-3% of total counts added were bound to the RPE via a M6P-inhibitable recognition process. The binding to RPE was not blocked by mannan. No mannan or M6P-specific binding was found in retina explants. These results support the findings of specific uptake of phosphomannan-coated beads and demonstrate the presence of a specific PMR on dystrophic RPE phagocytic membranes.

  17. Impact of glucose-6-phosphate dehydrogenase deficiency on the pathophysiology of cardiovascular disease

    PubMed Central

    Hecker, Peter A.; Leopold, Jane A.; Gupte, Sachin A.; Recchia, Fabio A.

    2013-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the rate-determining step in the pentose phosphate pathway and produces NADPH to fuel glutathione recycling. G6PD deficiency is the most common enzyme deficiency in humans and affects over 400 million people worldwide; however, its impact on cardiovascular disease is poorly understood. The glutathione pathway is paramount to antioxidant defense, and G6PD-deficient cells do not cope well with oxidative damage. Limited clinical evidence indicates that G6PD deficiency may be associated with hypertension. However, there are also data to support a protective role of G6PD deficiency in decreasing the risk of heart disease and cardiovascular-associated deaths, perhaps through a decrease in cholesterol synthesis. Studies in G6PD-deficient (G6PDX) mice are mixed and provide evidence for both protective and deleterious effects. G6PD deficiency may provide a protective effect through decreasing cholesterol synthesis, superoxide production, and reductive stress. However, recent studies indicate that G6PDX mice are moderately more susceptible to ventricular dilation in response to myocardial infarction or pressure overload-induced heart failure. Furthermore, G6PDX hearts do not recover as well as nondeficient mice when faced with ischemia-reperfusion injury, and G6PDX mice are susceptible to the development of age-associated cardiac hypertrophy. Overall, the limited available data indicate a complex interplay in which adverse effects of G6PD deficiency may outweigh potential protective effects in the face of cardiac stress. Definitive clinical studies in large populations are needed to determine the effects of G6PD deficiency on the development of cardiovascular disease and subsequent outcomes. PMID:23241320

  18. Structural features of the lysosomal hydrolase mannose 6-phosphate uncovering enzyme.

    PubMed

    Wei, Yuqiang; Yen, Ten-Yang; Cai, Jian; Trent, John O; Pierce, William M; Young, William W

    2005-02-01

    The uncovering enzyme (UCE) removes N-acetylglucosamine from lysosomal enzymes to uncover the mannose 6-phosphate (Man-6-P) determinant necessary for targeting these enzymes to lysosomes. Failure to create the Man-6-P determinant is one cause of lysosomal storage diseases. Despite its medical importance, little structural information about UCE is available. In this report we have developed a model for the membrane proximal portion of the lumenal domain of UCE based on the structure of the EFG-3 and -4 domains of the extracellular segment of the beta chain of integrin alpha Vbeta 3. In this model the EGF-like domains of UCE (residues 285-345) are predicted to form a rod-shaped stalk region, similar to the stem region in Golgi glycosyltransferases. This stalk causes the proposed catalytic domain (residues 1-277) to be extended away from the Golgi membrane. A portion of the proposed catalytic domain (residues 85-256) resides in Cluster of Orthologous Group (COG) 4632 with four bacterial proteins but is not homologous to any known eukaryotic proteins. Thus, UCE may have evolved from the fusion of a unique catalytic domain with a common EGF-like stalk domain. We have determined by mass spectrometry that the four disulfide bonds of the proposed catalytic domain are located between Cys(2)-Cys(172), Cys(66)-Cys(99), Cys(83)-Cys(274), and Cys(258)-Cys(265). Finally, we determined that four of the six potential N-linked glycosylation sites are glycosylated (Asn 159, Asn 165, Asn 247, and Asn 317) in COS cells.

  19. Association of glucose-6-phosphate dehydrogenase deficiency and malaria: a systematic review and meta-analysis.

    PubMed

    Mbanefo, Evaristus Chibunna; Ahmed, Ali Mahmoud; Titouna, Afaf; Elmaraezy, Ahmed; Trang, Nguyen Thi Huyen; Phuoc Long, Nguyen; Hoang Anh, Nguyen; Diem Nghi, Tran; The Hung, Bui; Van Hieu, Mai; Ky Anh, Nguyen; Huy, Nguyen Tien; Hirayama, Kenji

    2017-04-06

    Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency overlaps with malaria endemicity although it predisposes carriers to hemolysis. This fact supports the protection hypothesis against malaria. The aim of this systematic review is to assess the presence and the extent of protective association between G6PD deficiency and malaria. Thirteen databases were searched for papers reporting any G6PD alteration in malaria patients. Twenty-eight of the included 30 studies were eligible for the meta-analysis. Results showed absence of negative association between G6PD deficiency and uncomplicated falciparum malaria (odds ratio (OR), 0.77; 95% confidence interval (CI), 0.59-1.02; p = 0.07). However, this negative association happened in Africa (OR, 0.59; 95% CI, 0.40-0.86; p = 0.007) but not in Asia (OR, 1.24; 95% CI, 0.96-1.61; p = 0.10), and in the heterozygotes (OR, 0.70; 95% CI, 0.57-0.87; p = 0.001) but not the homo/hemizygous (OR, 0.70; 95% CI, 0.46-1.07; p = 0.10). There was no association between G6PD deficiency and total severe malaria (OR, 0.82; 95% CI, 0.61-1.11; p = 0.20). Similarly, there was no association with other malaria species. G6PD deficiency can potentially protect against uncomplicated malaria in African countries, but not severe malaria. Interestingly, this protection was mainly in heterozygous, being x-linked thus related to gender.

  20. Screening and prevention of neonatal glucose 6-phosphate dehydrogenase deficiency in Guangzhou, China.

    PubMed

    Jiang, J; Li, B; Cao, W; Jiang, X; Jia, X; Chen, Q; Wu, J

    2014-06-09

    We aimed to summarize the results of screening protocol and prevention of neonatal glucose 6-phosphate dehydrogenase (G6PD) deficiency during a 22-year-long period to provide a basis of reference for the screening of this disease. About 1,705,569 newborn subjects in Guangzhou City were screened for this deficiency. Specimens were collected according to the conventional method of specimen acquisition for "newborn dried bloodspot screening", preserved, and inspected. The specimens were studied with fluorescent spot test and quantitative fluorescence assay. Diagnosis was performed using the modified NBTG6PD/6PGD ratio method. Bloodspot filter paper specimens were sent to the laboratory within 24 h via EMS Express, and the G6PD test was performed on the same day. The G6PD deficiency-positive rate was 4.2% in the samples screened using the fluorescent spot test, while it was 5% in case of the quantitative fluorescence assay. Neonatal screening for G6PD deficiency for 11,437 cases (6117 boys and 5320 girls) showed positive results in 481 cases. About 420 cases (318 boys and 102 girls) of G6PD deficiency were confirmed with the modified Duchenne NBT ratio method. The total detection rate was 3.7:5.2% for boys and 1.9% for girls. Quantitative fluorescence assay improved the sensitivity and detection rate. Accelerating the speed of sample delivery by using Internet network systems and ensuring online availability of screening results can aid the screening and diagnosis of this deficiency within 1 week of birth.

  1. Glucose-6-phosphate dehydrogenase deficiency in Tunisia: molecular data and phenotype-genotype association.

    PubMed

    Laouini, N; Bibi, A; Ammar, H; Kazdaghli, K; Ouali, F; Othmani, R; Amdouni, S; Haloui, S; Sahli, C A; Jouini, L; Hadj Fredj, S; Siala, H; Ben Romdhane, N; Toumi, N E; Fattoum, S; Messsaoud, T

    2013-02-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect. In this study, we aimed to perform a molecular investigation of G6PD deficiency in Tunisia and to associate clinical manifestations and the degree of deficiency with the genotype. A total of 161 Tunisian subjects of both sexes were screened by spectrophotometric assay for enzyme activity. Out of these, 54 unrelated subjects were selected for screening of the most frequent mutations in Tunisia by PCR/RFLP, followed by size-based separation of double-stranded fragments under non-denaturing conditions on a denaturing high performance liquid chromatography system. Of the 56 altered chromosomes examined, 75 % had the GdA(-) mutation, 14.28 % showed the GdB(-) mutation and no mutations were identified in 10.72 % of cases. Hemizygous males with GdA(-) mutation were mostly of class III, while those with GdB(-) mutation were mainly of class II. The principal clinical manifestation encountered was favism. Acute hemolytic crises induced by drugs or infections and neonatal jaundice were also noted. Less severe clinical features such as low back pain were present in heterozygous females and in one homozygous female. Asymptomatic individuals were in majority heterozygote females and strangely one hemizygous male. The spectrum of mutations seems to be homogeneous and similar to that of Mediterranean countries; nevertheless 10.72 % of cases remain with undetermined mutation thus suggesting a potential heterogeneity of the deficiency at the molecular level. On the other hand, we note a better association of the molecular defects with the severity of the deficiency than with clinical manifestations.

  2. Single Cell Cytochemistry Illustrated by the Demonstration of Glucose-6-Phosphate Dehydrogenase Deficiency in Erythrocytes.

    PubMed

    Peters, Anna L; van Noorden, Cornelis J F

    2017-01-01

    Cytochemistry is the discipline that is applied to visualize specific molecules in individual cells and has become an essential tool in life sciences. Immunocytochemistry was developed in the sixties of last century and is the most frequently used cytochemical application. However, metabolic mapping is the oldest cytochemical approach to localize activity of specific enzymes, but in the last decades of the previous century and the first decade of the present century it almost became obsolete. The popularity of this approach revived in the past few years. Metabolism gained interest as player in chronic and complex diseases such as cancer, diabetes, neurodegenerative diseases, and vascular diseases and both enzyme cytochemistry and metabolic mapping have become important tools in life sciences.In this chapter, we present glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most prevalent enzyme deficiency worldwide, to illustrate recent developments in enzyme cytochemistry or metabolic mapping. The first assays which were developed quantified enzyme activity but were unreliable for single cell evaluation. The field has expanded with the development of cytochemical single cell assays and DNA testing. Still, all assays-from the earliest developed tests up to the most recently developed tests-have their place in investigations on G6PD activity. Recently, nanoscopy has become available for light and fluorescence microscopy at the nanoscale. For nanoscopy, cytochemistry is an essential tool to visualize intracellular molecular processes. The ultimate goal in the coming years will be nanoscopy of living cells so that the molecular dynamics can be studied. Cytochemistry will undoubtedly play a critical role in these developments.

  3. Contribution of haemolysis to jaundice in Sephardic Jewish glucose-6-phosphate dehydrogenase deficient neonates.

    PubMed

    Kaplan, M; Vreman, H J; Hammerman, C; Leiter, C; Abramov, A; Stevenson, D K

    1996-06-01

    We determined the contribution of haemolysis to the development of hyperbilirubinaemia in glucose-6-phosphate dehydrogenase (G-6-PD) deficient neonates and G-6-PD normal controls. Blood carboxyhaemoglobin (COHb), sampled on the third day of life, was measured by gas chromatography, corrected for inhaled carbon monoxide (COHbC), and expressed as a percentage of total haemoglobin concentration (Hb). Serum bilirubin was tested as clinically necessary. 37 non-jaundiced (peak serum total bilirubin (PSTB) < or = 255 mumol/l) and 20 jaundiced (PSTB > or = 257 mumol/l) G-6-PD-deficient neonates were compared to 31 non-jaundiced and 24 jaundiced controls with comparable PSTB values, respectively. COHbC values for the entire G-6-PD deficient group were higher than in the controls (0.75 +/- 0.17% v 0.62 +/- 0.19%, P < 0.001). COHbC and PSTB values did not correlate in the G-6-PD-deficient group (r = 0.15, P > 0.05) but did in the controls (r = 0.58, P < 0.001). COHbC values were increased to a similar extent in the G-6-PD-deficient, non-jaundiced (0.72 +/- 0.16%), the G-6-PD-deficient, jaundiced (0.80 +/- 0.19%) and the control, jaundiced (0.75 +/- 0.18%) subgroups, compared to the control, non-jaundiced subgroup (0.53 +/- 0.13%) (P < 0.05). Although present in G-6-PD deficient neonates, increased haemolysis was not directly related to the PSTB.

  4. DHEA prevents ribavirin-induced anemia via inhibition of glucose-6-phosphate dehydrogenase.

    PubMed

    Handala, Lynda; Domange, Barbara; Ouled-Haddou, Hakim; Garçon, Loïc; Nguyen-Khac, Eric; Helle, Francois; Bodeau, Sandra; Duverlie, Gilles; Brochot, Etienne

    2017-09-08

    Ribavirin has been widely used for antiviral therapy. Unfortunately, ribavirin-induced anemia is often a cause of limiting or interrupting treatment. Our team has observed that dehydroepiandrosterone (DHEA) has a protective effect against in vitro and in vivo ribavirin-induced hemolysis. The aim of this study was to better understand this effect as well as the underlying mechanism(s). DHEA was able to reduce in vitro intraerythrocytic ATP depletion induced by ribavirin. Only 1% of ATP remained after incubation with ribavirin (2 mM) at 37 °C for 24 h vs. 37% if DHEA (200 μM) was added (p < 0.01). DHEA also helped erythrocytes conserve their size, with a shrinkage of only 10% vs 40% at 24 h with ribavirin alone (p < 0.01), and reduced phosphatidylserine exposure at the outer membrane, i.e. 27% vs 40% at 48 h, (p < 0.05). DHEA also inhibits ribavirin-induced hemolysis, i.e. 34% vs 46.5% at 72 h (p < 0.01). DHEA is an inhibitor of glucose-6-phosphate dehydrogenase (G6PD), a key enzyme in the hexose monophosphate shunt connected to the glycolytic pathway which is the only energy supplier of the red blood cell in the form of ATP. We have confirmed this inhibitory effect in the presence of ribavirin. All these observations suggest that ribavirin-induced hemolysis was initiated by ATP depletion, and that the inhibitory effect of DHEA on G6PD was able to rescue enough ATP to limit this hemolysis. This mechanism could be important for improving the therapeutic management of patients treated with ribavirin. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Producing glucose 6-phosphate from cellulosic biomass: structural insights into levoglucosan bioconversion.

    PubMed

    Bacik, John-Paul; Klesmith, Justin R; Whitehead, Timothy A; Jarboe, Laura R; Unkefer, Clifford J; Mark, Brian L; Michalczyk, Ryszard

    2015-10-30

    The most abundant carbohydrate product of cellulosic biomass pyrolysis is the anhydrosugar levoglucosan (1,6-anhydro-β-d-glucopyranose), which can be converted to glucose 6-phosphate by levoglucosan kinase (LGK). In addition to the canonical kinase phosphotransfer reaction, the conversion requires cleavage of the 1,6-anhydro ring to allow ATP-dependent phosphorylation of the sugar O6 atom. Using x-ray crystallography, we show that LGK binds two magnesium ions in the active site that are additionally coordinated with the nucleotide and water molecules to result in ideal octahedral coordination. To further verify the metal binding sites, we co-crystallized LGK in the presence of manganese instead of magnesium and solved the structure de novo using the anomalous signal from four manganese atoms in the dimeric structure. The first metal is required for catalysis, whereas our work suggests that the second is either required or significantly promotes the catalytic rate. Although the enzyme binds its sugar substrate in a similar orientation to the structurally related 1,6-anhydro-N-acetylmuramic acid kinase (AnmK), it forms markedly fewer bonding interactions with the substrate. In this orientation, the sugar is in an optimal position to couple phosphorylation with ring cleavage. We also observed a second alternate binding orientation for levoglucosan, and in these structures, ADP was found to bind with lower affinity. These combined observations provide an explanation for the high Km of LGK for levoglucosan. Greater knowledge of the factors that contribute to the catalytic efficiency of LGK can be used to improve applications of this enzyme for levoglucosan-derived biofuel production. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Evaluation of the blue formazan spot test for screening glucose 6 phosphate dehydrogenase deficiency.

    PubMed

    Pujades, A; Lewis, M; Salvati, A M; Miwa, S; Fujii, H; Zarza, R; Alvarez, R; Rull, E; Corrons, J L

    1999-06-01

    Several screening tests for glucose 6 phosphate dehydrogenase (G6PD) deficiency have been reported thus far, and a standardized method of testing was proposed by the International Council for Standardization in Hematology (ICSH). The screening test used in any particular laboratory depends upon a number of factors such as cost, time required, temperature, humidity, and availability of reagents. In this study, a direct comparison between three different G6PD screening methods has been undertaken. In 71 cases (50 hematologically normal volunteers, 9 hemizygous G6PD-deficient males, and 12 heterozygous deficient females), the blue formazan spot test (BFST) was compared with the conventional methemoglobin reduction test (HiRT) and the ICSH-recommended fluorescent spot test (FST-ICSH). In all cases, the results obtained with the three screening tests were correlated with the enzyme activity assayed spectrophotometrically. In hemizygous G6PD-deficient males, all cases were equally detected with the three methods: BFST (4.7-6.64, controls: 11.1-13.4), BMRT (score +3 in all 9 cases), and FST (no fluorescence in 9 cases). In heterozygous G6PD-deficient females, two methods detected 7 out of 12 cases (BFST: 8.71-11.75, controls: 11.1-13.4; and BMRT: score +3 in 7 cases), whereas the FST-ICSH missed all 12 cases that presented a variable degree of fluorescence. Although the sensitivity for G6PD-deficient carrier detection is the same for the BMRT and the BFST, the latter has the advantage of being semiquantitative and not merely qualitative. Unfortunately, none of the three screening tests compared here allowed the detection of the 100% heterozygote carrier state of G6PD deficiency.

  7. Glucose-6-phosphate dehydrogenase enzyme stability in filter paper dried blood spots.

    PubMed

    Flores, Sharon R; Hall, Elizabeth M; De Jesús, Víctor R

    2017-10-01

    Prior to initial distribution of Glucose-6-phosphate dehydrogenase (G6PD) proficiency testing (PT) materials, we evaluated G6PD enzyme stability in dried blood spots (DBS) under various temperature and humidity environments to develop storage and usage guidelines for our new materials. We prepared fresh G6PD-normal DBS materials and conducted stability evaluations of daily use and short and long-term storage under various temperature and humidity environments. G6PD DBS PT materials retained 92% of initial activity after 30days of use at 4°C. Materials stored at -20°C and 4°C with desiccant for 30days retained 95% and 90% of initial activity, respectively. When stored for one year at -20°C or six months at 4°C specimens retained >90% of initial activity. Specimens stored at 37°C with desiccant lost 10% activity in three days. At the end of 30days, specimens stored under 'Extreme'-humidity >50% without desiccant- conditions at 37°C assayed below the NSQAP cut off for G6PD. Humidity exacerbated loss of enzyme activity with increasing temperature and time duration. Data suggest that G6PD PT materials can be stored at 4°C and used for up to one month and can be stored at -20°C for one year and yield >90% enzyme activity. Exposure to warm temperatures, especially with elevated humidity, should be avoided. Desiccant should always be used to mitigate humidity effects. Published by Elsevier Inc.

  8. Deletion of hexose-6-phosphate dehydrogenase activates the unfolded protein response pathway and induces skeletal myopathy.

    PubMed

    Lavery, Gareth G; Walker, Elizabeth A; Turan, Nil; Rogoff, Daniela; Ryder, Jeffery W; Shelton, John M; Richardson, James A; Falciani, Francesco; White, Perrin C; Stewart, Paul M; Parker, Keith L; McMillan, Daniel R

    2008-03-28

    Hexose-6-phosphate dehydrogenase (H6PD) is the initial component of a pentose phosphate pathway inside the endoplasmic reticulum (ER) that generates NADPH for ER enzymes. In liver H6PD is required for the 11-oxoreductase activity of 11beta-hydroxysteroid dehydrogenase type 1, which converts inactive 11-oxo-glucocorticoids to their active 11-hydroxyl counterparts; consequently, H6PD null mice are relatively insensitive to glucocorticoids, exhibiting fasting hypoglycemia, increased insulin sensitivity despite elevated circulating levels of corticosterone, and increased basal and insulin-stimulated glucose uptake in muscles normally enriched in type II (fast) fibers, which have increased glycogen content. Here, we show that H6PD null mice develop a severe skeletal myopathy characterized by switching of type II to type I (slow) fibers. Running wheel activity and electrically stimulated force generation in isolated skeletal muscle are both markedly reduced. Affected muscles have normal sarcomeric structure at the electron microscopy level but contain large intrafibrillar membranous vacuoles and abnormal triads indicative of defects in structure and function of the sarcoplasmic reticulum (SR). SR proteins involved in calcium metabolism, including the sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA), calreticulin, and calsequestrin, show dysregulated expression. Microarray analysis and real-time PCR demonstrate overexpression of genes encoding proteins in the unfolded protein response pathway. We propose that the absence of H6PD induces a progressive myopathy by altering the SR redox state, thereby impairing protein folding and activating the unfolded protein response pathway. These studies thus define a novel metabolic pathway that links ER stress to skeletal muscle integrity and function.

  9. Hexose-6-phosphate dehydrogenase: a new risk gene for multiple sclerosis

    PubMed Central

    Alcina, Antonio; Ramagopalan, Sreeram V; Fernández, Óscar; Catalá-Rabasa, Antonio; Fedetz, María; Ndagire, Dorothy; Leyva, Laura; Arnal, Carmen; Delgado, Concepción; Lucas, Miguel; Izquierdo, Guillermo; Ebers, George C; Matesanz, Fuencisla

    2010-01-01

    A recent genome-wide association study (GWAS) performed by the The Wellcome Trust Case–Control Consortium based on 12 374 nonsynonymous single-nucleotide polymorphisms (SNPs) provided evidence for several genes involved in multiple sclerosis (MS) susceptibility. In this study, we aimed at verifying the association of 19 SNPs with MS, with P-values ≤0.005, in an independent cohort of 732 patients and 974 controls, all Caucasian from the South of Spain. We observed an association of the rs17368528 polymorphism with MS (P=0.04, odds ratio (OR)=0.801, 95% confidence interval (CI)=0.648–0.990). The association of this polymorphism with MS was further validated in an independent set of 1318 patients from the Canadian Collaborative Project (P=0.04, OR=0.838, 95% CI=0.716–0.964). This marker is located on chromosome 1p36.22, which is 1 Mb away from the MS-associated kinesin motor protein KIF1B, although linkage disequilibrium was not observed between these two markers. The rs17368528 SNP results in an amino-acid substitution (proline to leucine) in the fifth exon of the hexose-6-phosphate dehydrogenase (H6PD) gene, in which some variants have been reported to attenuate or abolish H6PD activity, in individuals with cortisone reductase deficiency. This study corroborates the association of one locus determined by GWAS and points to H6PD as a new candidate gene for MS. PMID:19935835

  10. Producing glucose 6-phosphate from cellulosic biomass: Structural insights into levoglucosan bioconversion

    DOE PAGES

    Bacik, John -Paul; Klesmith, Justin R.; Whitehead, Timothy A.; ...

    2015-09-09

    The most abundant carbohydrate product of cellulosic biomass pyrolysis is the anhydrosugar levoglucosan (1,6-anhydro-β-d-glucopyranose), which can be converted to glucose 6-phosphate by levoglucosan kinase (LGK). In addition to the canonical kinase phosphotransfer reaction, the conversion requires cleavage of the 1,6-anhydro ring to allow ATP-dependent phosphorylation of the sugar O6 atom. Using x-ray crystallography, we show that LGK binds two magnesium ions in the active site that are additionally coordinated with the nucleotide and water molecules to result in ideal octahedral coordination. To further verify the metal binding sites, we co-crystallized LGK in the presence of manganese instead of magnesium andmore » solved the structure de novo using the anomalous signal from four manganese atoms in the dimeric structure. The first metal is required for catalysis, whereas our work suggests that the second is either required or significantly promotes the catalytic rate. Although the enzyme binds its sugar substrate in a similar orientation to the structurally related 1,6-anhydro-N-acetylmuramic acid kinase (AnmK), it forms markedly fewer bonding interactions with the substrate. In this orientation, the sugar is in an optimal position to couple phosphorylation with ring cleavage. We also observed a second alternate binding orientation for levoglucosan, and in these structures, ADP was found to bind with lower affinity. These combined observations provide an explanation for the high Km of LGK for levoglucosan. Furthermore, greater knowledge of the factors that contribute to the catalytic efficiency of LGK can be used to improve applications of this enzyme for levoglucosan-derived biofuel production.« less

  11. A Ralstonia solanacearum type III effector directs the production of the plant signal metabolite trehalose-6-phosphate.

    PubMed

    Poueymiro, M; Cazalé, A C; François, J M; Parrou, J L; Peeters, N; Genin, S

    2014-12-23

    The plant pathogen Ralstonia solanacearum possesses two genes encoding a trehalose-6-phosphate synthase (TPS), an enzyme of the trehalose biosynthetic pathway. One of these genes, named ripTPS, was found to encode a protein with an additional N-terminal domain which directs its translocation into host plant cells through the type 3 secretion system. RipTPS is a conserved effector in the R. solanacearum species complex, and homologues were also detected in other bacterial plant pathogens. Functional analysis of RipTPS demonstrated that this type 3 effector synthesizes trehalose-6-phosphate and identified residues essential for this enzymatic activity. Although trehalose-6-phosphate is a key signal molecule in plants that regulates sugar status and carbon assimilation, the disruption of ripTPS did not alter the virulence of R. solanacearum on plants. However, heterologous expression assays showed that this effector specifically elicits a hypersensitive-like response on tobacco that is independent of its enzymatic activity and is triggered by the C-terminal half of the protein. Recognition of this effector by the plant immune system is suggestive of a role during the infectious process. Ralstonia solanacearum, the causal agent of bacterial wilt disease, infects more than two hundred plant species, including economically important crops. The type III secretion system plays a major role in the pathogenicity of this bacterium, and approximately 70 effector proteins have been shown to be translocated into host plant cells. This study provides the first description of a type III effector endowed with a trehalose-6-phosphate synthase enzymatic activity and illustrates a new mechanism by which the bacteria may manipulate the plant metabolism upon infection. In recent years, trehalose-6-phosphate has emerged as an essential signal molecule in plants, connecting plant metabolism and development. The finding that a bacterial pathogen could induce the production of trehalose-6

  12. Analysis of the Escherichia coli glucosamine-6-phosphate synthase activity by isothermal titration calorimetry and differential scanning calorimetry.

    PubMed

    Valerio-Lepiniec, Marie; Aumont-Nicaise, Magali; Roux, Céline; Raynal, Bertrand; England, Patrick; Badet, Bernard; Badet-Denisot, Marie-Ange; Desmadril, Michel

    2010-06-15

    Glucosamine-6-phosphate synthase (GlmS) is responsible for the first and rate-limiting step in the hexosamine biosynthetic pathway. It catalyzes the conversion of D-fructose-6P (F6P) into D-glucosamine-6P (GlcN6P) using L-glutamine (Gln) as nitrogen donor (synthase activity) according to an ordered bi-bi process where F6P binds first. In the absence of F6P, the enzyme exhibits a weak hydrolyzing activity of Gln into Glu and ammonia (glutaminase activity), whereas the presence of F6P strongly stimulates it (hemi-synthase activity). Until now, these different activities were indirectly measured using either coupled enzyme or colorimetric methods. In this work, we have developed a direct assay monitoring the heat released by the reaction. Isothermal titration calorimetry and differential scanning calorimetry were used to determine kinetic and thermodynamic parameters of GlmS. The direct determination at 37 degrees C of kinetic parameters and affinity constants for both F6P and Gln demonstrated that part of the ammonia produced by Gln hydrolysis in the presence of both substrates is not used for the formation of the GlcN6P. The full characterization of this phenomenon allowed to identify experimental conditions where this leak of ammonia is negligible. Enthalpy measurements at 25 degrees C in buffers of various heats of protonation demonstrated that no proton exchange with the medium occurred during the enzyme-catalyzed glutaminase or synthase reaction suggesting for the first time that both products are released as a globally neutral pair composed by the Glu carboxylic side chain and the GlcN6P amine function. Finally we showed that the oligomerization state of GlmS is concentration-dependent. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  13. Trehalose 6-Phosphate Is Required for the Onset of Leaf Senescence Associated with High Carbon Availability1[W][OA

    PubMed Central

    Wingler, Astrid; Delatte, Thierry L.; O’Hara, Liam E.; Primavesi, Lucia F.; Jhurreea, Deveraj; Paul, Matthew J.; Schluepmann, Henriette

    2012-01-01

    Trehalose 6-phosphate (T6P) is an important regulator of plant metabolism and development. T6P content increases when carbon availability is high, and in young growing tissue, T6P inhibits the activity of Snf1-related protein kinase (SnRK1). Here, strong accumulation of T6P was found in senescing leaves of Arabidopsis (Arabidopsis thaliana), in parallel with a rise in sugar contents. To determine the role of T6P in senescence, T6P content was altered by expressing the bacterial T6P synthase gene, otsA (to increase T6P), or the T6P phosphatase gene, otsB (to decrease T6P). In otsB-expressing plants, T6P accumulated less strongly during senescence than in wild-type plants, while otsA-expressing plants contained more T6P throughout. Mature otsB-expressing plants showed a similar phenotype as described for plants overexpressing the SnRK1 gene, KIN10, including reduced anthocyanin accumulation and delayed senescence. This was confirmed by quantitative reverse transcription-polymerase chain reaction analysis of senescence-associated genes and genes involved in anthocyanin synthesis. To analyze if the senescence phenotype was due to decreased sugar sensitivity, the response to sugars was determined. In combination with low nitrogen supply, metabolizable sugars (glucose, fructose, or sucrose) induced senescence in wild-type and otsA-expressing plants but to a smaller extent in otsB-expressing plants. The sugar analog 3-O-methyl glucose, on the other hand, did not induce senescence in any of the lines. Transfer of plants to and from glucose-containing medium suggested that glucose determines senescence during late development but that the effects of T6P on senescence are established by the sugar response of young plants. PMID:22247267

  14. The sucrose–trehalose 6-phosphate (Tre6P) nexus: specificity and mechanisms of sucrose signalling by Tre6P

    PubMed Central

    Yadav, Umesh Prasad; Ivakov, Alexander; Feil, Regina; Lunn, John Edward

    2014-01-01

    Trehalose 6-phosphate (Tre6P), the intermediate of trehalose biosynthesis, has a profound influence on plant metabolism, growth, and development. It has been proposed that Tre6P acts as a signal of sugar availability and is possibly specific for sucrose status. Short-term sugar-feeding experiments were carried out with carbon-starved Arabidopsis thaliana seedlings grown in axenic shaking liquid cultures. Tre6P increased when seedlings were exogenously supplied with sucrose, or with hexoses that can be metabolized to sucrose, such as glucose and fructose. Conditional correlation analysis and inhibitor experiments indicated that the hexose-induced increase in Tre6P was an indirect response dependent on conversion of the hexose sugars to sucrose. Tre6P content was affected by changes in nitrogen status, but this response was also attributable to parallel changes in sucrose. The sucrose-induced rise in Tre6P was unaffected by cordycepin but almost completely blocked by cycloheximide, indicating that de novo protein synthesis is necessary for the response. There was a strong correlation between Tre6P and sucrose even in lines that constitutively express heterologous trehalose-phosphate synthase or trehalose-phosphate phosphatase, although the Tre6P:sucrose ratio was shifted higher or lower, respectively. It is proposed that the Tre6P:sucrose ratio is a critical parameter for the plant and forms part of a homeostatic mechanism to maintain sucrose levels within a range that is appropriate for the cell type and developmental stage of the plant. PMID:24420566

  15. Hereditary sideroblastic anemia and glucose-6-phosphate dehydrogenase deficiency in a Negro family.

    PubMed

    Prasad, A S; Tranchida, L; Konno, E T; Berman, L; Albert, S; Sing, C F; Brewer, G J

    1968-06-01

    Detailed clinical and genetic studies have been performed in a Negro family, which segregated for sex-linked sideroblastic anemia and glucose-6-phosphate dehydrogenase (G-6-DP) deficiency. This is the first such pedigree reported. Males affected with sideroblastic anemia had growth retardation, hypochromic microcytic anemia, elevated serum iron, decreased unsaturated iron-binding capacity, increased (59)Fe clearance, low (59)Fe incorporation into erythrocytes, normal erythrocyte survival ((51)Cr), normal hemoglobin electrophoretic pattern, erythroblastic hyperplasia of marrow with increased iron, and marked increase in marrow sideroblasts, particularly ringed sideroblasts. Perinuclear deposition of ferric aggregates was demonstrated to be intramitochondrial by electron microscopy. Female carriers of the sideroblastic gene were normal but exhibited a dimorphic population of erythrocytes including normocytic and microcytic cells. The bone marrow studies in the female (mother) showed ringed marrow sideroblasts. Studies of G-6-PD involved the methemoglobin elution test for G-6-PD activity of individual erythrocytes, quantitative G-6-PD assay, and electrophoresis. In the pedigree, linkage information was obtained from a doubly heterozygous woman, four of her sons, and five of her daughters. Three sons were doubly affected, and one was normal. One daughter appeared to be a recombinant. The genes appeared to be linked in the coupling phase in the mother. The maximum likelihood estimate of the recombination value was 0.14. By means of Price-Jones curves, the microcytic red cells in peripheral blood were quantitated in female carriers. The sideroblast count in the bone marrow in the mother corresponded closely to the percentage of microcytic cells in peripheral blood. This is the second example in which the cellular expression of a sex-linked trait has been documented in the human red cells, the first one being G-6-PD deficiency. The coexistence of the two genes in doubly

  16. An optimised system for refolding of human glucose 6-phosphate dehydrogenase

    PubMed Central

    Wang, Xiao-Tao; Engel, Paul C

    2009-01-01

    Background Human glucose 6-phosphate dehydrogenase (G6PD), active in both dimer and tetramer forms, is the key entry enzyme in the pentose phosphate pathway (PPP), providing NADPH for biosynthesis and various other purposes, including protection against oxidative stress in erythrocytes. Accordingly haemolytic disease is a major consequence of G6PD deficiency mutations in man, and many severe disease phenotypes are attributed to G6PD folding problems. Therefore, a robust refolding method with high recovery yield and reproducibility is of particular importance to study those clinical mutant enzymes as well as to shed light generally on the refolding process of large multi-domain proteins. Results The effects of different chemical and physical variables on the refolding of human recombinant G6PD have been extensively investigated. L-Arg, NADP+ and DTT are all major positive influences on refolding, and temperature, protein concentration, salt types and other additives also have significant impacts. With the method described here, ~70% enzyme activity could be regained, with good reproducibility, after denaturation with Gdn-HCl, by rapid dilution of the protein, and the refolded enzyme displays kinetic and CD properties indistinguishable from those of the native protein. Refolding under these conditions is relatively slow, taking about 7 days to complete at room temperature even in the presence of cyclophilin A, a peptidylprolyl isomerase reported to increase refolding rates. The refolded protein intermediates shift from dominant monomer to dimer during this process, the gradual emergence of dimer correlating well with the regain of enzyme activity. Conclusion L-Arg is the key player in the refolding of human G6PD, preventing the aggregation of folding intermediate, and NADP+ is essential for the folding intermediate to adopt native structure. The refolding protocol can be applied to produce high recovery yield of folded protein with unaltered properties, paving the

  17. Molecular Analysis of Glucose-6-Phosphate Dehydrogenase Gene Mutations in Bangladeshi Individuals

    PubMed Central

    Sarker, Suprovath Kumar; Hossain, Mohammad Amir; Qadri, Syeda Kashfi; Muraduzzaman, A. K. M.; Bhuyan, Golam Sarower; Shahidullah, Mohammod; Mannan, Mohammad Abdul; Tahura, Sarabon; Hussain, Manzoor; Akhter, Shahida; Nahar, Nazmun; Shirin, Tahmina; Qadri, Firdausi; Mannoor, Kaiissar

    2016-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked human enzyme defect of red blood cells (RBCs). Individuals with this gene defect appear normal until exposed to oxidative stress which induces hemolysis. Consumption of certain foods such as fava beans, legumes; infection with bacteria or virus; and use of certain drugs such as primaquine, sulfa drugs etc. may result in lysis of RBCs in G6PD deficient individuals. The genetic defect that causes G6PD deficiency has been identified mostly as single base missense mutations. One hundred and sixty G6PD gene mutations, which lead to amino acid substitutions, have been described worldwide. The purpose of this study was to detect G6PD gene mutations in hospital-based settings in the local population of Dhaka city, Bangladesh. Qualitative fluorescent spot test and quantitative enzyme activity measurement using RANDOX G6PDH kit were performed for analysis of blood specimens and detection of G6PD-deficient participants. For G6PD-deficient samples, PCR was done with six sets of primers specific for G6PD gene. Automated Sanger sequencing of the PCR products was performed to identify the mutations in the gene. Based on fluorescence spot test and quantitative enzyme assay followed by G6PD gene sequencing, 12 specimens (11 males and one female) among 121 clinically suspected patient-specimens were found to be deficient, suggesting a frequency of 9.9% G6PD deficiency. Sequencing of the G6PD-deficient samples revealed c.C131G substitution (exon-3: Ala44Gly) in six samples, c.G487A substitution (exon-6:Gly163Ser) in five samples and c.G949A substitution (exon-9: Glu317Lys) of coding sequence in one sample. These mutations either affect NADP binding or disrupt protein structure. From the study it appears that Ala44Gly and Gly163Ser are the most common G6PD mutations in Dhaka, Bangladesh. This is the first study of G6PD mutations in Bangladesh. PMID:27880809

  18. Glucose-6-phosphate dehydrogenase deficiency prevalence and genetic variants in malaria endemic areas of Colombia.

    PubMed

    Valencia, Sócrates Herrera; Ocampo, Iván Darío; Arce-Plata, María Isabel; Recht, Judith; Arévalo-Herrera, Myriam

    2016-05-26

    Glucose 6-phosphate dehydrogenase (G6PD) is an enzyme involved in prevention of cellular oxidative damage, particularly protecting erythrocytes from haemolysis. An estimated 400 million people present variable degrees of inherited G6PD deficiency (G6PDd) which puts them at risk for developing haemolysis triggered by several risk factors including multiple drugs and certain foods. Primaquine (PQ) is a widely used anti-malarial drug that can trigger haemolysis in individuals with G6PDd. Intensification of malaria control programmes worldwide and particularly malaria elimination planning in some regions recommend a more extensive use of PQ and related drugs in populations with different G6PDd prevalence. This a preliminary study to assess the prevalence of G6PDd in representative malaria endemic areas of Colombia by measuring G6PD phonotype and genotypes. Volunteers (n = 426) from four malaria endemic areas in Colombia (Buenaventura, Tumaco, Tierralta and Quibdo) were enrolled. Blood samples were drawn to evaluate G6PD enzymatic activity by using a quantitative G6PD test and a subset of samples was analysed by PCR-RFLP to determine the frequency of the three most common G6PD genotypic variants: A-, A+ and Mediterranean. A total of 28 individuals (6.56 %) displayed either severe or intermediate G6PDd. The highest prevalence (3.51 %) was in Buenaventura, whereas G6PDd prevalence was lower (<1 %) in Tierralta and Quibdo. G6PD A alleles were the most frequent (15.23 %) particularly in Buenaventura and Tumaco. Overall, a high frequency of G6PD A- genotype, followed by A+ genotype was found in the analysed population. G6PDd based on enzymatic activity as well as G6PD A allelic variants were found in malaria-endemic populations on the Pacific coast of Colombia, where most of malaria cases are caused by Plasmodium vivax infections. These infections are treated for 14 days with PQ, however there are no official reports of PQ-induced haemolytic crises. Further

  19. Glucose 6-phosphate dehydrogenase deficiency enhances germ cell apoptosis and causes defective embryogenesis in Caenorhabditis elegans.

    PubMed

    Yang, H-C; Chen, T-L; Wu, Y-H; Cheng, K-P; Lin, Y-H; Cheng, M-L; Ho, H-Y; Lo, S J; Chiu, D T-Y

    2013-05-02

    Glucose 6-phosphate dehydrogenase (G6PD) deficiency, known as favism, is classically manifested by hemolytic anemia in human. More recently, it has been shown that mild G6PD deficiency moderately affects cardiac function, whereas severe G6PD deficiency leads to embryonic lethality in mice. How G6PD deficiency affects organisms has not been fully elucidated due to the lack of a suitable animal model. In this study, G6PD-deficient Caenorhabditis elegans was established by RNA interference (RNAi) knockdown to delineate the role of G6PD in animal physiology. Upon G6PD RNAi knockdown, G6PD activity was significantly hampered in C. elegans in parallel with increased oxidative stress and DNA oxidative damage. Phenotypically, G6PD-knockdown enhanced germ cell apoptosis (2-fold increase), reduced egg production (65% of mock), and hatching (10% of mock). To determine whether oxidative stress is associated with G6PD knockdown-induced reproduction defects, C. elegans was challenged with a short-term hydrogen peroxide (H2O2). The early phase egg production of both mock and G6PD-knockdown C. elegans were significantly affected by H2O2. However, H2O2-induced germ cell apoptosis was more dramatic in mock than that in G6PD-deficient C. elegans. To investigate the signaling pathways involved in defective oogenesis and embryogenesis caused by G6PD knockdown, mutants of p53 and mitogen-activated protein kinase (MAPK) pathways were examined. Despite the upregulation of CEP-1 (p53), cep-1 mutation did not affect egg production and hatching in G6PD-deficient C. elegans. Neither pmk-1 nor mek-1 mutation significantly affected egg production, whereas sek-1 mutation further decreased egg production in G6PD-deficient C. elegans. Intriguingly, loss of function of sek-1 or mek-1 dramatically rescued defective hatching (8.3- and 9.6-fold increase, respectively) induced by G6PD knockdown. Taken together, these findings show that G6PD knockdown reduces egg production and hatching in C. elegans

  20. Prevalence and Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Deficiency at the China-Myanmar Border.

    PubMed

    Li, Qing; Yang, Fang; Liu, Rong; Luo, Lan; Yang, Yuling; Zhang, Lu; Liu, Huaie; Zhang, Wen; Fan, Zhixiang; Yang, Zhaoqing; Cui, Liwang; He, Yongshu

    2015-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked hereditary disease that predisposes red blood cells to oxidative damage. G6PD deficiency is particularly prevalent in historically malaria-endemic areas. Use of primaquine for malaria treatment may result in severe hemolysis in G6PD deficient patients. In this study, we systematically evaluated the prevalence of G6PD deficiency in the Kachin (Jingpo) ethnic group along the China-Myanmar border and determined the underlying G6PD genotypes. We surveyed G6PD deficiency in 1770 adult individuals (671 males and 1099 females) of the Kachin ethnicity using a G6PD fluorescent spot test. The overall prevalence of G6PD deficiency in the study population was 29.6% (523/1770), among which 27.9% and 30.6% were males and females, respectively. From these G6PD deficient samples, 198 unrelated individuals (147 females and 51 males) were selected for genotyping at 11 known G6PD single nucleotide polymorphisms (SNPs) in Southeast Asia (ten in exons and one in intron 11) using a multiplex SNaPshot assay. Mutations with known association to a deficient phenotype were detected in 43.9% (87/198) of cases, intronic and synonymous mutations were detected alone in 34.8% (69/198) cases and no mutation were found in 21.2% (42/198) cases. Five non-synonymous mutations, Mahidol 487G>A, Kaiping 1388G>A, Canton 1376G>T, Chinese 4 392G>T, and Viangchan 871G>A were detected. Of the 87 cases with known deficient mutations, the Mahidol variant was the most common (89.7%; 78/87), followed by the Kaiping (8.0%; 7/87) and the Viangchan (2.2%; 2/87) variants. The Canton and Chinese 4 variants were found in 1.1% of these 87 cases. Among them, two females carried the Mahidol/Viangchan and Mahidol/Kaiping double mutations, respectively. Interestingly, the silent SNPs 1311C>T and IVS11nt93T>C both occurred in the same 95 subjects with frequencies at 56.4% and 23.5% in tested females and males, respectively (P<0.05). It is noteworthy that 24

  1. [Significance of glucose-6-phosphate isomerase assay in early diagnosis of rheumatoid arthritis].

    PubMed

    Xu, J; Liu, J; Zhu, L; Zhang, X W; Li, Z G

    2016-12-18

    To explore the titer of glucose-6-phosphate isomerase (GPI) for early diagnosis of the outpatient with rheumatoid arthritis (RA) in real life, and to analyze its relationship with disease activity. In the study, 1 051 patients with arthritis were collected in the group who had joints tender and swelling, and 90 cases of healthy people as a control group. ELISA method was used to detect the serum level of GPI, and according to clinical features and laboratory test, all the patients including 525 RA patients, the other patients including osteoarthritis (OA), 134 cases of seronegative spine joint disease (SpA), 104 cases of systemic lupus erythematosus (SLE), 31 cases of primary Sjogren syndrome (pSS), 24 cases of gout arthritis (GA), 22 cases of other connective tissue diseases (including polymyalgia rheumatica, dermatomyositis, systemic sclerosis, adult Still disease) and 46 cases of other diseases (including 165 cases of osteoporosis, avascular necrosis of the femoral head, traumatic osteomyelitis, bone and joint disease, juvenile rheumatoid arthritis, tumor). The diagnostic values of GPI were assessed, and the differences between the GPI positive and negative groups of the RA patients in clinical characteristics, disease activity, severity and inflammatory index analyzed. The positive rate of serum GPI in the patients with RA was 55.4%, contrasting to other autoimmune diseases (14.3%) and healthy controls (7.78%)(P<0.001). Compared with the OA and SpA patients, the RA group was increased more significantly, and the difference was statistically significant (P<0.001). The diagnostic value of GPI alone for RA was 0.39 mg/L, the sensitivity was 54.2%, and specificity was 87.3%. The positive rate of GPI in RF negative patients was 36.1%; the positive rate of GPI in anti-CCP antibody negative patients was 34.2%; the positive rate of GPI in RF and anti-CCP antibody negative patients was 24.1%. The level of GPI had positive correlation (P<0.05) with ESR, RF, anti

  2. Glucose-6-phosphate dehydrogenase deficiency among malaria suspects attending Gambella hospital, southwest Ethiopia.

    PubMed

    Tsegaye, Arega; Golassa, Lemu; Mamo, Hassen; Erko, Berhanu

    2014-11-18

    Glucose-6-phosphate dehydrogenase deficiency (G6PDd) is widespread across malaria endemic regions. G6PD-deficient individuals are at risk of haemolysis when exposed, among other agents, to primaquine and tafenoquine, which are capable of blocking malaria transmission by killing Plasmodium falciparum gametocytes and preventing Plasmodium vivax relapses by targeting hypnozoites. It is evident that no measures are currently in place to ensure safe delivery of these drugs within the context of G6PDd risk. Thus, determining G6PDd prevalence in malarious areas would contribute towards avoiding possible complications in malaria elimination using the drugs. This study, therefore, was aimed at determining G6PDd prevalence in Gambella hospital, southwest Ethiopia, using CareStart™ G6PDd fluorescence spot test. Venous blood samples were collected from febrile patients (n = 449) attending Gambella hospital in November-December 2013. Malaria was diagnosed using blood films and G6PDd was screened using CareStart™ G6PDd screening test (Access Bio, New Jersey, USA). Haematological parameters were also measured. The association of G6PD phenotype with sex, ethnic group and malaria smear positivity was tested. Malaria prevalence was 59.2% (96.6% of the cases being P. falciparum mono infections). Totally 33 participants (7.3%) were G6PD-deficient with no significant difference between the sexes. The chance of being G6PD-deficient was significantly higher for the native ethnic groups (Anuak and Nuer) compared to the 'highlanders'/settlers (odds ratio (OD) = 3.9, 95% confidence interval (CI) 0.481-31.418 for Anuak vs 'highlanders'; OD = 4.9, 95% CI 0.635-38.00 for Nuer vs 'highlanders'). G6PDd prevalence among the Nuer (14.3%) was significantly higher than that for the Anuak (12.0%). G6PDd prevalence in the area is substantial with 30 (90.9%) of the 33 deficient individuals having malaria suggesting the non-protective role of the disorder at least from clinical malaria

  3. Glucose-6-phosphate dehydrogenase polymorphisms and susceptibility to mild malaria in Dogon and Fulani, Mali.

    PubMed

    Maiga, Bakary; Dolo, Amagana; Campino, Susana; Sepulveda, Nuno; Corran, Patrick; Rockett, Kirk A; Troye-Blomberg, Marita; Doumbo, Ogobara K; Clark, Taane G

    2014-07-11

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with protection from severe malaria, and potentially uncomplicated malaria phenotypes. It has been documented that G6PD deficiency in sub-Saharan Africa is due to the 202A/376G G6PD A-allele, and association studies have used genotyping as a convenient technique for epidemiological studies. However, recent studies have shown discrepancies in G6PD202/376 associations with severe malaria. There is evidence to suggest that other G6PD deficiency alleles may be common in some regions of West Africa, and that allelic heterogeneity could explain these discrepancies. A cross-sectional epidemiological study of malaria susceptibility was conducted during 2006 and 2007 in the Sahel meso-endemic malaria zone of Mali. The study included Dogon (n = 375) and Fulani (n = 337) sympatric ethnic groups, where the latter group is characterized by lower susceptibility to Plasmodium falciparum malaria. Fifty-three G6PD polymorphisms, including 202/376, were genotyped across the 712 samples. Evidence of association of these G6PD polymorphisms and mild malaria was assessed in both ethnic groups using genotypic and haplotypic statistical tests. It was confirmed that the Fulani are less susceptible to malaria, and the 202A mutation is rare in this group (<1% versus Dogon 7.9%). The Betica-Selma 968C/376G (~11% enzymatic activity) was more common in Fulani (6.1% vs Dogon 0.0%). There are differences in haplotype frequencies between Dogon and Fulani, and association analysis did not reveal strong evidence of protective G6PD genetic effects against uncomplicated malaria in both ethnic groups and gender. However, there was some evidence of increased risk of mild malaria in Dogon with the 202A mutation, attaining borderline statistical significance in females. The rs915942 polymorphism was found to be associated with asymptomatic malaria in Dogon females, and the rs61042368 polymorphism was associated with clinical malaria in

  4. Glucose-6-phosphate dehydrogenase polymorphisms and susceptibility to mild malaria in Dogon and Fulani, Mali

    PubMed Central

    2014-01-01

    Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with protection from severe malaria, and potentially uncomplicated malaria phenotypes. It has been documented that G6PD deficiency in sub-Saharan Africa is due to the 202A/376G G6PD A-allele, and association studies have used genotyping as a convenient technique for epidemiological studies. However, recent studies have shown discrepancies in G6PD202/376 associations with severe malaria. There is evidence to suggest that other G6PD deficiency alleles may be common in some regions of West Africa, and that allelic heterogeneity could explain these discrepancies. Methods A cross-sectional epidemiological study of malaria susceptibility was conducted during 2006 and 2007 in the Sahel meso-endemic malaria zone of Mali. The study included Dogon (n = 375) and Fulani (n = 337) sympatric ethnic groups, where the latter group is characterized by lower susceptibility to Plasmodium falciparum malaria. Fifty-three G6PD polymorphisms, including 202/376, were genotyped across the 712 samples. Evidence of association of these G6PD polymorphisms and mild malaria was assessed in both ethnic groups using genotypic and haplotypic statistical tests. Results It was confirmed that the Fulani are less susceptible to malaria, and the 202A mutation is rare in this group (< 1% versus Dogon 7.9%). The Betica-Selma 968C/376G (~11% enzymatic activity) was more common in Fulani (6.1% vs Dogon 0.0%). There are differences in haplotype frequencies between Dogon and Fulani, and association analysis did not reveal strong evidence of protective G6PD genetic effects against uncomplicated malaria in both ethnic groups and gender. However, there was some evidence of increased risk of mild malaria in Dogon with the 202A mutation, attaining borderline statistical significance in females. The rs915942 polymorphism was found to be associated with asymptomatic malaria in Dogon females, and the rs61042368 polymorphism was

  5. Glucose 6-phosphate dehydrogenase variants: a unique variant (G6PD Kobe) showed an extremely increased affinity for galactose 6-phosphate and a new variant (G6PD Sapporo) resembling G6PD Pea Ridge.

    PubMed

    Fujii, H; Miwa, S; Tani, K; Takegawa, S; Fujinami, N; Takahashi, K; Nakayama, S; Konno, M; Sato, T

    1981-01-01

    Two new glucose 6-phosphate dehydrogenase (G6PD) variants associated with chronic nonspherocytic hemolytic anemia were discovered, G6PD Kobe was found in a 16-year-old male associated with hemolytic crisis after upper respiratory infection. The enzyme activity of the variant was about 22% of that of the normal enzyme. The main enzymatic characteristics were slower than normal anodal electrophoretic mobility, high Km G6P, increased thermal-instability, an acidic pH optimum, and an extremely increased affinity for the substrate analogue, galactose 6-phosphate (Gal-6P). G6PD Sapporo was found in a 3-year-old male associated with drug-induced hemolysis. The enzyme activity was extremely low, being 3.6% of normal. In addition, this variant showed high Ki NADPH and thermal-instability. G6PD Kobe utilized the artificial substrate Gal-6P effectively as compared with the common natural substrate, glucose 6-phosphate. In G6PD Sapporo, NADPH could not exert the effect of product inhibition. The structural changes of these variants are expected to occur at the portions inducing conformational changes of the substrate binding site of the enzyme.

  6. Protein preparation and preliminary X-ray crystallographic analysis of a putative glucosamine 6-phosphate deaminase from Streptococcus mutants

    SciTech Connect

    Hu, Guan-Jing; Li, Lan-Fen; Li, Dan; Liu, Cong; Wei, Shi-Cheng; Liang, Yu-He Su, Xiao-Dong

    2007-09-01

    A glucosamine 6-phosphate deaminase homologue from S. mutans was expressed, purified and crystallized. Diffraction data have been collected to 2.4 Å resolution. The SMU.636 protein from Streptococcus mutans is a putative glucosamine 6-phosphate deaminase with 233 residues. The smu.636 gene was PCR-amplified from S. mutans genomic DNA and cloned into the expression vector pET-28a(+). The resultant His-tagged fusion protein was expressed in Escherichia coli and purified to homogeneity in two steps. Crystals of the fusion protein were obtained by the hanging-drop vapour-diffusion method. The crystals diffracted to 2.4 Å resolution and belong to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 53.83, b = 82.13, c = 134.70 Å.

  7. A case of ataxia telangiectasia with unbalanced glucose 6-phosphate dehydrogenase mosaicism in the granulocytic/monocytic lineages.

    PubMed Central

    Ferraris, A M; Melani, C; Canepa, L; Meloni, T; Forteleoni, G; Gaetani, G F

    1987-01-01

    Ataxia telangiectasia is a genetically determined disease with multi-system abnormalities and a high incidence of neoplasia. In order to define the nature of the association between ataxia telangiectasia and malignancy, we investigated a patient with the disease and heterozygote for the Mediterranean variant of the X-linked marker glucose 6-phosphate dehydrogenase. Enzymatic mosaicism in hemopoietic and nonhemopoietic cells was evaluated with the 2-deoxy glucose 6-phosphate technique. While erythrocytes, platelets, and lymphocytes expressed the same double-enzyme phenotype as tissues of nonhemopoietic origin, granulocytes and monocytes expressed almost exclusively the Mediterranean-type enzyme. We suggest that, as the result of genetic instability at the hemopoietic stem-cell level, the granulocytic/monocytic progeny enjoyed a proliferative advantage and became the predominant clone. PMID:3812485

  8. Crystallization and preliminary X-ray analysis of the isomerase domain of glucosamine-6-phosphate synthase from Candida albicans

    PubMed Central

    Olchowy, Jaroslaw; Jedrzejczak, Robert; Milewski, Slawomir; Rypniewski, Wojciech

    2005-01-01

    Glucosamine-6-phosphate synthase (EC 2.6.1.16) catalyses the first and practically irreversible step in the hexosamine metabolism pathway, the end product of which, uridine 5′-diphospho-N-acetyl d-glucosamine, is an essential substrate for assembly of the cell wall. The isomerase domain, consisting of residues 346–712 (42 kDa), of glucosamine-6-phosphate synthase from Candida albicans has been crystallized. X-ray analysis revealed that the crystals belonged to space group I4, with unit-cell parameters a = b = 149, c = 103 Å. Diffraction data were collected to 3.8 Å. Preliminary results from molecular replacement using the homologous bacterial monomer reveal that the asymmetric unit contains two monomers that resemble a bacterial dimer. The crystal lattice consists of pairs of such symmetry-related dimers forming elongated tetramers. PMID:16511216

  9. Lysine-21 of Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase participates in substrate binding through charge-charge interaction.

    PubMed Central

    Lee, W. T.; Levy, H. R.

    1992-01-01

    Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase (G6PD) was isolated in high yield and purified to homogeneity from a newly constructed strain of Escherichia coli which lacks its own glucose 6-phosphate dehydrogenase gene. Lys-21 is one of two lysyl residues in the enzyme previously modified by the affinity labels pyridoxal 5'-phosphate and pyridoxal 5'-diphosphate-5'-adenosine, which are competitive inhibitors of the enzyme with respect to glucose 6-phosphate (LaDine, J.R., Carlow, D., Lee, W.T., Cross, R.L., Flynn, T.G., & Levy, H.R., 1991, J. Biol. Chem. 266, 5558-5562). K21R and K21Q mutants of the enzyme were purified to homogeneity and characterized kinetically to determine the function of Lys-21. Both mutant enzymes showed increased Km-values for glucose 6-phosphate compared to wild-type enzyme: 1.4-fold (NAD-linked reaction) and 2.1-fold (NADP-linked reaction) for the K21R enzyme, and 36-fold (NAD-linked reaction) and 53-fold (NADP-linked reaction) for the K21Q enzyme. The Km for NADP+ was unchanged in both mutant enzymes. The Km for NAD+ was increased 1.5- and 3.2-fold, compared to the wild-type enzyme, in the K21R and K21Q enzymes, respectively. For the K21R enzyme the kcat for the NAD- and NADP-linked reactions was unchanged. The kcat for the K21Q enzyme was increased in the NAD-linked reaction by 26% and decreased by 30% in the NADP-linked reaction from the values for the wild-type enzyme. The data are consistent with Lys-21 participating in the binding of the phosphate group of the substrate to the enzyme via charge-charge interaction. PMID:1304341

  10. Structure of the Trehalose-6-phosphate Phosphatase from Brugia malayi Reveals Key Design Principles for Anthelmintic Drugs

    PubMed Central

    Farelli, Jeremiah D.; Galvin, Brendan D.; Li, Zhiru; Liu, Chunliang; Aono, Miyuki; Garland, Megan; Hallett, Olivia E.; Causey, Thomas B.; Ali-Reynolds, Alana; Saltzberg, Daniel J.; Carlow, Clotilde K. S.; Dunaway-Mariano, Debra; Allen, Karen N.

    2014-01-01

    Parasitic nematodes are responsible for devastating illnesses that plague many of the world's poorest populations indigenous to the tropical areas of developing nations. Among these diseases is lymphatic filariasis, a major cause of permanent and long-term disability. Proteins essential to nematodes that do not have mammalian counterparts represent targets for therapeutic inhibitor discovery. One promising target is trehalose-6-phosphate phosphatase (T6PP) from Brugia malayi. In the model nematode Caenorhabditis elegans, T6PP is essential for survival due to the toxic effect(s) of the accumulation of trehalose 6-phosphate. T6PP has also been shown to be essential in Mycobacterium tuberculosis. We determined the X-ray crystal structure of T6PP from B. malayi. The protein structure revealed a stabilizing N-terminal MIT-like domain and a catalytic C-terminal C2B-type HAD phosphatase fold. Structure-guided mutagenesis, combined with kinetic analyses using a designed competitive inhibitor, trehalose 6-sulfate, identified five residues important for binding and catalysis. This structure-function analysis along with computational mapping provided the basis for the proposed model of the T6PP-trehalose 6-phosphate complex. The model indicates a substrate-binding mode wherein shape complementarity and van der Waals interactions drive recognition. The mode of binding is in sharp contrast to the homolog sucrose-6-phosphate phosphatase where extensive hydrogen-bond interactions are made to the substrate. Together these results suggest that high-affinity inhibitors will be bi-dentate, taking advantage of substrate-like binding to the phosphoryl-binding pocket while simultaneously utilizing non-native binding to the trehalose pocket. The conservation of the key residues that enforce the shape of the substrate pocket in T6PP enzymes suggest that development of broad-range anthelmintic and antibacterial therapeutics employing this platform may be possible. PMID:24992307

  11. Crystallization and preliminary X-ray analysis of the isomerase domain of glucosamine-6-phosphate synthase from Candida albicans

    SciTech Connect

    Olchowy, Jaroslaw; Milewski, Slawomir

    2005-11-01

    The isomerase domain of glucosamine-6-phosphate synthase from C. albicans has been crystallized and X-ray diffraction data have been collected. Preliminary analysis of the data reveals the oligomeric structure of the eukaryotic synthase to be a ‘dimer’ of prokaryotic-like dimers. Glucosamine-6-phosphate synthase (EC 2.6.1.16) catalyses the first and practically irreversible step in the hexosamine metabolism pathway, the end product of which, uridine 5′-diphospho-N-acetyl d-glucosamine, is an essential substrate for assembly of the cell wall. The isomerase domain, consisting of residues 346–712 (42 kDa), of glucosamine-6-phosphate synthase from Candida albicans has been crystallized. X-ray analysis revealed that the crystals belonged to space group I4, with unit-cell parameters a = b = 149, c = 103 Å. Diffraction data were collected to 3.8 Å. Preliminary results from molecular replacement using the homologous bacterial monomer reveal that the asymmetric unit contains two monomers that resemble a bacterial dimer. The crystal lattice consists of pairs of such symmetry-related dimers forming elongated tetramers.

  12. Structural and Chemical Basis for Glucosamine 6-Phosphate Binding and Activation of the glmS Ribozyme

    SciTech Connect

    Cochrane, J.; Lipchock, S; Smith, K; Strobel, S

    2009-01-01

    The glmS ribozyme is the first naturally occurring catalytic RNA that relies on an exogenous, nonnucleotide cofactor for reactivity. From a biochemical perspective, the glmS ribozyme derived from Bacillus anthracis is the best characterized. However, much of the structural work to date has been done on a variant glmS ribozyme, derived from Thermoanaerobacter tengcongensis. Here we present structures of the B. anthracis glmS ribozyme in states before the activating sugar, glucosamine 6-phosphate (GlcN6P), has bound and after the reaction has occurred. These structures show an active site preorganized to bind GlcN6P that retains some affinity for the sugar even after cleavage of the RNA backbone. A structure of an inactive glmS ribozyme with a mutation distal from the ligand-binding pocket highlights a nucleotide critical to the reaction that does not affect GlcN6P binding. Structures of the glmS ribozyme bound to a naturally occurring inhibitor, glucose 6-phosphate (Glc6P), and a nonnatural activating sugar, mannosamine 6-phosphate (MaN6P), reveal a binding mode similar to that of GlcN6P. Kinetic analyses show a pH dependence of ligand binding that is consistent with titration of the cofactor's phosphate group and support a model in which the major determinant of activity is the sugar amine independent of its stereochemical presentation.

  13. Substrate specificity of a galactose 6-phosphate isomerase from Lactococcus lactis that produces d-allose from d-psicose.

    PubMed

    Park, Ha-Young; Park, Chang-Su; Kim, Hye-Jung; Oh, Deok-Kun

    2007-10-15

    We purified recombinant galactose 6-phosphate isomerase (LacAB) from Lactococcus lactis using HiTrap Q HP and Phenyl-Sepharose columns. The purified LacAB had a final specific activity of 1.79units/mg to produce d-allose. The molecular mass of native galactose 6-phosphate isomerase was estimated at 135.5kDa using Sephacryl S-300 gel filtration, and the enzyme exists as a hetero-octamer of LacA and LacB subunits. The activity of galactose 6-phosphate isomerase was maximal at pH 7.0 and 30 degrees C, and enzyme activity was independent of metal ions. When 100g/L of d-psicose was used as the substrate, 25g/L of d-allose and 13g/L of d-altrose were simultaneously produced at pH 7.0 and 30 degrees C after 12h of incubation. The enzyme had broad specificity for various aldoses and ketoses. The interconversion of sugars with the same configuration except at the C2 position was driven by using a large amount of enzyme in extended reactions. The interconversion occurred via two isomerization reactions, i.e., the interconversion of d-allose<-->d-psicose<-->d-altrose, and d-allose to d-psicose reaction was faster than d-altrose to d-psicose reaction.

  14. Lowering effect of firefly squid powder on triacylglycerol content and glucose-6-phosphate dehydrogenase activity in rat liver.

    PubMed

    Takeuchi, Hiroyuki; Morita, Ritsuko; Shirai, Yoko; Nakagawa, Yoshihisa; Terashima, Teruya; Ushikubo, Shun; Matsuo, Tatsuhiro

    2014-01-01

    Effects of dietary firefly squid on serum and liver lipid levels were investigated. Male Wistar rats were fed a diet containing 5% freeze-dried firefly squid or Japanese flying squid for 2 weeks. There was no significant difference in the liver triacylglycerol level between the control and Japanese flying squid groups, but the rats fed the firefly squid diet had a significantly lower liver triacylglycerol content than those fed the control diet. No significant difference was observed in serum triacylglycerol levels between the control and firefly squid groups. The rats fed the firefly squid had a significantly lower activity of liver glucose-6-phosphate dehydrogenase compared to the rats fed the control diet. There was no significant difference in liver fatty acid synthetase activity among the three groups. Hepatic gene expression and lipogenic enzyme activity were investigated; a DNA microarray showed that the significantly enriched gene ontology category of down-regulated genes in the firefly squid group was "lipid metabolic process". The firefly squid group had lower mRNA level of glucose-6-phosphate dehydrogenase compared to the controls. These results suggest that an intake of firefly squid decreases hepatic triacylglycerol in rats, and the reduction of mRNA level and enzyme activity of glucose-6-phosphate dehydrogenase might be related to the mechanisms.

  15. The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of. beta. -glucuronidase

    SciTech Connect

    Watanabe, H.; Grubb, J.H.; Sly, W.S. )

    1990-10-01

    The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human {beta}-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3{percent} of the total functional receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of {beta}-glucuronidase. At pH 7.5, the rate of endocytosis was only 14{percent} the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized {beta}-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized {beta}-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor.

  16. Regulatory functions of trehalose-6-phosphate synthase in the chitin biosynthesis pathway in Tribolium castaneum (Coleoptera: Tenebrionidae) revealed by RNA interference.

    PubMed

    Chen, Q W; Jin, S; Zhang, L; Shen, Q D; Wei, P; Wei, Z M; Wang, S G; Tang, B

    2017-09-18

    RNA interference (RNAi) is a very effective technique for studying gene function and may be an efficient method for controlling pests. Trehalose-6-phosphate synthase (TPS), which plays a key role in the synthesis of trehalose and insect development, was cloned in Tribolium castaneum (Herbst) (TcTPS) and the putative functions were studied using RNAi via the injection of double-stranded RNA (dsRNA) corresponding to conserved TPS and trehalose-6-phosphate phosphatase domains. Expression analyses show that TcTPS is expressed higher in the fat body, while quantitative real-time polymerase chain reaction results show that the expression of four trehalase isoforms was significantly suppressed by dsTPS injection. Additionally, the expression of six chitin synthesis-related genes, such as hexokinase 2 and glutamine-fructose-6-phosphate aminotransferase, was suppressed at 48 and 72 h post-dsTPS-1 and dsTPS-2 RNA injection, which were two dsTPS fragments that had been designed for two different locations in TcTPS open reading frame, and that trehalose content and trehalase 1 activity decreased significantly at 72 h post-dsRNA injection. Furthermore, T. castaneum injected with dsTPS-1 and dsTPS-2 RNA displayed significantly lower levels of chitin and could not complete the molting process from larvae to pupae, revealing abnormal molting phenotypes. These results demonstrate that silencing TPS gene leads to molting deformities and high mortality rates via regulation of gene expression in the chitin biosynthetic pathway, and may be a promising approach for pest control in the future.

  17. Glucose-6-phosphate dehydrogenase deficiency in people living in malaria endemic districts of Nepal.

    PubMed

    Ghimire, Prakash; Singh, Nihal; Ortega, Leonard; Rijal, Komal Raj; Adhikari, Bipin; Thakur, Garib Das; Marasini, Baburam

    2017-05-23

    Glucose-6-phosphate dehydrogenase (G6PD) is a rate limiting enzyme of the pentose phosphate pathway and is closely associated with the haemolytic disorders among patients receiving anti-malarial drugs, such as primaquine. G6PD deficiency (G6PDd) is an impending factor for radical treatment of malaria which affects the clearance of gametocytes from the blood and subsequent delay in the achievement of malaria elimination. The main objective of this study was to assess the prevalence of G6PD deficiency in six malaria endemic districts in Southern Nepal. A cross-sectional population based prevalence survey was conducted in six malaria endemic districts of Nepal, during April-Dec 2013. A total of 1341 blood samples were tested for G6PDd using two different rapid diagnostic test kits (Binax-Now(®) and Care Start™). Equal proportions of participants from each district (n ≥ 200) were enrolled considering ethnic and demographic representation of the population groups. Out of total 1341 blood specimens collected from six districts, the overall prevalence of G6PDd was 97/1341; 7.23% on Binax Now and 81/1341; 6.0% on Care Start test. Higher prevalence was observed in male than females [Binax Now: male 10.2%; 53/521 versus female 5.4%; 44/820 (p = 0.003) and Care Start: male 8.4%; 44/521 versus female 4.5%; 37/820 (p = 0.003)]. G6PDd was higher in ethnic groups Rajbanshi (11.7%; 19/162) and Tharu (5.6%; 56/1005) (p = 0.006), major inhabitant of the endemic districts. Higher prevalence of G6PDd was found in Jhapa (22/224; 9.8%) and Morang districts (18/225; 8%) (p = 0.031). In a multivariate analysis, male were found at more risk for G6PDd than females, on Binax test (aOR = 1.97; CI 1.28-3.03; p = 0.002) and Care Start test (aOR = 1.86; CI 1.16-2.97; p = 0.009). The higher prevalence of G6PDd in certain ethnic group, gender and geographical region clearly demonstrates clustering of the cases and ascertained the risk groups within the population. This is

  18. [Significance of antibodies to the citrullinated glucose-6-phosphate isomerase peptides in rheumatoid arthritis].

    PubMed

    Wu, D; Sun, L; Li, C H; Yang, L; Zhao, J X; Liu, X Y

    2016-12-18

    To detect the anti-citrullinated glucose-6-phosphate isomerase (GPI) 70-88 peptide antibody (anti-C-GPI(70-88) antibody), anti-citrullinated GPI 435-453 peptide antibody (anti-C-GPI(435-453) antibody), anti-GPI 70-88 peptide antibody (anti-GPI(70-88) antibody) and anti-GPI 435-453 peptide antibody(anti-GPI(435-453) antibody) in the serum of rheumatoid arthritis (RA) patients, and examine the diagnostic values of the anti-C-GPI peptide antibodies in RA. The anti-C-GPI(70-88) antibody, anti-C-GPI(435-453) antibody, anti-GPI(70-88) antibody and anti-GPI(435-453) antibody were detected by enzyme-linked immunosorbent assay (ELISA) in 191 RA patients, 129 other rheumatic diseases and 74 healthy controls. The clinical and laboratory data of the patients with RA were collected, and the values of anti-C-GPI peptide antibodies in the diagnosis of RA and the relationships of anti-C-GPI peptide antibodies with the clinical and laboratory parameters analyzed. (1) The mean titers of the anti-C-GPI(70-88) antibody and the anti-C-GPI(435-453) antibody in the RA patients (respectively, 68.71 ± 4.20 and 51.78 ± 3.13) were significantly higher than those with other rheumatic diseases and healthy individuals (P <0.05). However, the mean titers of the anti-GPI(70-88) antibody and anti-GPI(435-453) antibody in the RA patients were similar to those with other rheumatic diseases and healthy individuals. (2) The diagnostic sensitivity and specificity of the anti-C-GPI(70-88) antibody for RA were 41.88% and 84.50% respectively; and the diagnostic sensitivity and specificity of the anti-C-GPI(435-453) antibody for RA were 46.05% and 86.05% respectively. The sensitivity of combined detection of the two anti-C-GPI peptide antibodies was 50.79%, and the specificity was 81.40%. (3) The positive rates of the anti-C-GPI(70-88) antibody and the anti-C-GPI(435-453) antibody were 35% and 45% respectively in those patients with negative anti-cyclic citrullinated peptide antibody, anti

  19. Purification and investigation of some kinetic properties of glucose-6-phosphate dehydrogenase from parsley (Petroselinum hortense) leaves.

    PubMed

    Coban, T Abdül Kadir; Ciftçi, Mehmet; Küfrevioğlu, O Irfan

    2002-05-01

    In this study, glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ oxidoreductase, EC 1.1.1.49; G6PD) was purified from parsley (Petroselinum hortense) leaves, and analysis of the kinetic behavior and some properties of the enzyme were investigated. The purification consisted of three steps: preparation of homogenate, ammonium sulfate fractionation, and DEAE-Sephadex A50 ion exchange chromatography. The enzyme was obtained with a yield of 8.79% and had a specific activity of 2.146 U (mg protein)(-1). The overall purification was about 58-fold. Temperature of +4 degrees C was maintained during the purification process. Enzyme activity was spectrophotometrically measured according to the Beutler method, at 340 nm. In order to control the purification of enzyme, SDS-polyacrylamide gel electrophoresis was carried out in 4% and 10% acrylamide for stacking and running gel, respectively. SDS-polyacrylamide gel electrophoresis showed a single band for enzyme. The molecular weight was found to be 77.6 kDa by Sephadex G-150 gel filtration chromatography. A protein band corresponding to a molecular weight of 79.3 kDa was obtained on SDS-polyacrylamide gel electrophoresis. For the enzymes, the stable pH, optimum pH, and optimum temperature were found to be 6.0, 8.0, and 60 degrees C, respectively. Moreover, KM and Vmax values for NADP+ and G6-P at optimum pH and 25 degrees C were determined by means of Lineweaver-Burk graphs. Additionally, effects of streptomycin sulfate and tetracycline antibiotics were investigated for the enzyme activity of glucose-6-phosphate dehydrogenase in vitro.

  20. Dental Considerations in Children with Glucose-6-phosphate Dehydrogenase Deficiency (Favism): A Review of the Literature and Case Report.

    PubMed

    Hernández-Pérez, Daniela; Butrón-Téllez Girón, Claudia; Ruiz-Rodríguez, Socorro; Garrocho-Rangel, Arturo; Pozos-Guillén, Amaury

    2015-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an uncommon inherited enzyme deficiency characterized by hemolytic anemia, caused by the inability of erythrocytes to detoxify oxidizing agents such as drugs, infectious diseases, or fava bean ingestion. In this later case, the disorder is known as favism. The aim of the present report was to present a review of the literature in this disease, to describe a case report concerning an affected 9-year-old male, and to review the main implications and precautions in pediatric dental management.

  1. Dental Considerations in Children with Glucose-6-phosphate Dehydrogenase Deficiency (Favism): A Review of the Literature and Case Report

    PubMed Central

    Hernández-Pérez, Daniela; Butrón-Téllez Girón, Claudia; Ruiz-Rodríguez, Socorro; Garrocho-Rangel, Arturo; Pozos-Guillén, Amaury

    2015-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an uncommon inherited enzyme deficiency characterized by hemolytic anemia, caused by the inability of erythrocytes to detoxify oxidizing agents such as drugs, infectious diseases, or fava bean ingestion. In this later case, the disorder is known as favism. The aim of the present report was to present a review of the literature in this disease, to describe a case report concerning an affected 9-year-old male, and to review the main implications and precautions in pediatric dental management. PMID:26435857

  2. Glucose 6-phosphate dehydrogenase is required for sucrose and trehalose to be efficient osmoprotectants in Sinorhizobium meliloti.

    PubMed

    Barra, Lise; Pica, Nathalie; Gouffi, Kamila; Walker, Graham C; Blanco, Carlos; Trautwetter, Annie

    2003-12-12

    Inactivation of the zwf gene in Sinorhizobium meliloti induces an osmosensitive phenotype and the loss of osmoprotection by trehalose and sucrose, but not by ectoine and glycine betaine. This phenotype is not linked to a defect in the biosynthesis of endogenous solutes. zwf expression is induced by high osmolarity, sucrose and trehalose, but is repressed by betaine. A zwf mutant is more sensitive than its parental strain to superoxide ions, suggesting that glucose 6-phosphate dehydrogenase involvement in the osmotic response most likely results from the production of reactive oxygen species during osmotic stress.

  3. Structures of trehalose-6-phosphate phosphatase from pathogenic fungi reveal the mechanisms of substrate recognition and catalysis

    PubMed Central

    Miao, Yi; Tenor, Jennifer L.; Toffaletti, Dena L.; Washington, Erica J.; Liu, Jiuyu; Shadrick, William R.; Schumacher, Maria A.; Lee, Richard E.; Perfect, John R.; Brennan, Richard G.

    2016-01-01

    Trehalose is a disaccharide essential for the survival and virulence of pathogenic fungi. The biosynthesis of trehalose requires trehalose-6-phosphate synthase, Tps1, and trehalose-6-phosphate phosphatase, Tps2. Here, we report the structures of the N-terminal domain of Tps2 (Tps2NTD) from Candida albicans, a transition-state complex of the Tps2 C-terminal trehalose-6-phosphate phosphatase domain (Tps2PD) bound to BeF3 and trehalose, and catalytically dead Tps2PD(D24N) from Cryptococcus neoformans bound to trehalose-6-phosphate (T6P). The Tps2NTD closely resembles the structure of Tps1 but lacks any catalytic activity. The Tps2PD–BeF3–trehalose and Tps2PD(D24N)–T6P complex structures reveal a “closed” conformation that is effected by extensive interactions between each trehalose hydroxyl group and residues of the cap and core domains of the protein, thereby providing exquisite substrate specificity. Disruption of any of the direct substrate–protein residue interactions leads to significant or complete loss of phosphatase activity. Notably, the Tps2PD–BeF3–trehalose complex structure captures an aspartyl-BeF3 covalent adduct, which closely mimics the proposed aspartyl-phosphate intermediate of the phosphatase catalytic cycle. Structures of substrate-free Tps2PD reveal an “open” conformation whereby the cap and core domains separate and visualize the striking conformational changes effected by substrate binding and product release and the role of two hinge regions centered at approximately residues 102–103 and 184–188. Significantly, tps2Δ, tps2NTDΔ, and tps2D705N strains are unable to grow at elevated temperatures. Combined, these studies provide a deeper understanding of the substrate recognition and catalytic mechanism of Tps2 and provide a structural basis for the future design of novel antifungal compounds against a target found in three major fungal pathogens. PMID:27307435

  4. Hemizygous Expression of Glucose-6-Phosphate Dehydrogenase in Erythrocytes of Heterozygotes for the Lesch-Nyhan Syndrome*

    PubMed Central

    Nyhan, William L.; Bakay, Bohdan; Connor, James D.; Marks, James F.; Keele, Doman K.

    1970-01-01

    In women heterozygous for hypoxanthine guanine phosphoribosyl trasferase deficiency, the activity of this enzyme in the erythrocyte is usually normal. In a key kindred two such obligate heterozygotes were also heterozygous for glucose-6-phosphate dehydrogenase types A and B. The AB genotype was confirmed in one by assay of skin fibroblasts. Erythrocytes were exclusively of type B. These observations suggest the clonal origin of the hematopoietic system in these women from a primordial cell line with a single active X chromosome. Images PMID:5263751

  5. The Preterm Infant: A High-Risk Situation for Neonatal Hyperbilirubinemia Due to Glucose-6-Phosphate Dehydrogenase Deficiency.

    PubMed

    Kaplan, Michael; Hammerman, Cathy; Bhutani, Vinod K

    2016-06-01

    Prematurity and glucose-6-phosphate dehydrogenase (G6PD) deficiency are risk factors for neonatal hyperbilirubinemia. The 2 conditions may interact additively or synergistically, contributing to extreme hyperbilirubinemia, with the potential for bilirubin neurotoxicity. This hyperbilirubinemia is the result of sudden, unpredictable, and acute episodes of hemolysis in combination with immaturity of bilirubin elimination, primarily of conjugation. Avoidance of contact with known triggers of hemolysis in G6PD-deficient individuals will prevent some, but not all, episodes of hemolysis. All preterm infants with G6PD deficiency should be vigilantly observed for the development of jaundice both in hospital and after discharge home.

  6. Cloning and expression of the cDNA of chicken cation-independent mannose-6-phosphate receptor.

    PubMed Central

    Zhou, M; Ma, Z; Sly, W S

    1995-01-01

    We cloned and sequenced the 8767-bp full-length cDNA for the chicken cation-independent mannose-6-phosphate receptor (CI-MPR), of interest because, unlike its mammalian homologs, it does not bind insulin-like growth factor II (IGF-II). The cDNA encodes a protein of 2470 aa that includes a putative signal sequence, an extracytoplasmic domain consisting of 15 homologous repeat sequences, a 23-residue transmembrane sequence, and a 161-residue cytoplasmic sequence. Overall, it shows 60% sequence identity with human and bovine CI-MPR homologs, and all but two of 122 cysteine residues are conserved. However, it shows much less homology in the N-terminal signal sequence, in repeat 11, which is proposed to contain the IGF-II-binding site in mammalian CI-MPR homologs, and in the 14-aa residue segment in the cytoplasmic sequence that has been proposed to mediate G-protein-coupled signal transduction in response to IGF-II binding by the human CI-MPR. Transient expression in COS-7 cells produced a functional CI-MPR which exhibited mannose-6-phosphate-inhibitable binding and mediated endocytosis of recombinant human beta-glucuronidase. Expression of the functional chicken CI-MPR in mice lacking the mammalian CI-MPR should clarify the controversy over the physiological role of the IGF-II-binding site in mammalian CI-MPR homologs. Images Fig. 4 PMID:7568213

  7. Protective effects of glucose-6-phosphate and NADP against alpha-chaconine-induced developmental toxicity in Xenopus embryos.

    PubMed

    Rayburn, J R; Bantle, J A; Qualls, C W; Friedman, M

    1995-12-01

    In previous studies a metabolic activation system (MAS) composed of Aroclor 1254-induced rat liver microsomes led to an apparent reduction of potato glycoalkaloid developmental toxicity in the frog embryo teratogenesis assay-Xenopus (FETAX). The reasons for this reduction were investigated in this study. The effect of the exogenous MAS on glycoalkaloid developmental toxicity was examined in two experiments in which a concentration series of alpha-chaconine was tested with a MAS with and without a reduced nicotinamide adenine dinucleotide (NADPH) generator system consisting of NADPH, oxidized nicotinamide adenine dinucleotide (NADP), glucose-6-phosphate (G6P) and glucose-6-phosphate dehydrogenase. The NADPH generator system and each of its individual components were tested at a single high concentration of alpha-chaconine to evaluate their potential effects on toxicity. The findings indicated that the protective effect of the MAS was not the result of detoxification by microsomal enzyme systems, but was caused by two components of the NADPH generator system, namely NADP and G6P. G6P was more protective of alpha-chaconine-induced toxicity than NADP at the concentrations tested. Thus, FETAX with a MAS must be performed with appropriate controls that take into account the possible interactions with individual components of the system.

  8. Amperometric biosensor based on Prussian Blue nanoparticle-modified screen-printed electrode for estimation of glucose-6-phosphate.

    PubMed

    Banerjee, Suchanda; Sarkar, Priyabrata; Turner, Anthony P F

    2013-08-15

    Glucose-6-phosphate (G6P) plays an important role in carbohydrate metabolism of all living organisms. Compared with the conventional analytical methods available for estimation of G6P, the biosensors having relative simplicity, specificity, low cost, and fast response time are a promising alternative. We have reported a G6P biosensor based on screen-printed electrode using Prussian Blue (PB) nanoparticles and enzymes, glucose-6-phosphate dehydrogenase, and glutathione reductase. The PB nanoparticles acted as a mediator and thereby enhanced the rate of electron transfer in a bienzymatic reaction. The Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy study confirmed the formation of PB, whereas atomic force microscopy revealed that PB nanoparticles were approximately 25 to 30 nm in diameter. Various optimization studies, such as pH, enzyme, and cofactor loading, were conducted to obtain maximum amperometric responses for G6P measurement. The developed G6P biosensor showed a broad linear response in the range of 0.01 to 1.25 mM, with a detection limit of 2.3 μM and sensitivity of 63.3 μA/mM at a signal-to-noise ratio of 3 within 15s at an applied working potential of -100 mV. The proposed G6P biosensor also exhibited good stability and excellent anti-interference ability, and it worked well for serum samples. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Glucose-6-phosphate dehydrogenase deficiency and risk of colorectal cancer in Northern Sardinia: A retrospective observational study.

    PubMed

    Dore, Maria P; Davoli, Agnese; Longo, Nunzio; Marras, Giuseppina; Pes, Giovanni M

    2016-11-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency has been associated with a lower cancer risk, possibly via a reduction of mutagenic oxygen-free radicals and by reducing nicotinamide-adeninedinucleotide-phosphate for replicating cells. In Sardinia, the enzyme defect is frequent as a consequence of selection by malaria in the past. This study investigated the relationship between G6PD deficiency and colorectal cancer (CRC).A retrospective case-control study of 3901 patients from Sardinia, who underwent a colonoscopy between 2006 and 2016, was performed. G6PD phenotype was assessed for each subject. The proportion of pre and malignant colorectal lesions was compared in cases (G6PD-deficient) and controls (G6PD-normal). Data concerning age, sex, family history of CRC, smoking habits, body height, and weight, and also associated diseases were collected.The CRC risk reduction was 43.2% among G6PD-deficient compared with G6PD-normal subjects (odds ratio 0.57, 95% confidence interval 0.37-0.87, P = 0.010). Age, sex, family history of CRC, and also comorbidities such as type 1 diabetes and ischemic heart disease, were significantly associated with CRC risk. The protective effect of G6PD deficiency remained significant after adjusting for all covariates by logistic regression analysis, and was consistently lower across all age groups.Glucose-6-phosphate dehydrogenase enzyme deficiency is associated with a reduced risk of CRC.

  10. Structures of Staphylococcus aureus D-tagatose-6-phosphate kinase implicate domain motions in specificity and mechanism.

    PubMed

    Miallau, Linda; Hunter, William N; McSweeney, Sean M; Leonard, Gordon A

    2007-07-06

    High resolution structures of Staphylococcus aureus d-tagatose-6-phosphate kinase (LacC) in two crystal forms are herein reported. The structures define LacC in apoform, in binary complexes with ADP or the co-factor analogue AMP-PNP, and in a ternary complex with AMP-PNP and D-tagatose-6-phosphate. The tertiary structure of the LacC monomer, which is closely related to other members of the pfkB subfamily of carbohydrate kinases, is composed of a large alpha/beta core domain and a smaller, largely beta "lid." Four extended polypeptide segments connect these two domains. Dimerization of LacC occurs via interactions between lid domains, which come together to form a beta-clasp structure. Residues from both subunits contribute to substrate binding. LacC adopts a closed structure required for phosphoryl transfer only when both substrate and co-factor are bound. A reaction mechanism similar to that used by other phosphoryl transferases is proposed, although unusually, when both substrate and co-factor are bound to the enzyme two Mg(2+) ions are observed in the active site. A new motif of amino acid sequence conservation common to the pfkB subfamily of carbohydrate kinases is identified.

  11. Comparison of glucose, glucose 6-phosphate, ribose, and mannose as flavour precursors in pork; the effect of monosaccharide addition on flavour generation.

    PubMed

    Meinert, Lene; Schäfer, Annette; Bjergegaard, Charlotte; Aaslyng, Margit D; Bredie, Wender L P

    2009-03-01

    The effect of glucose, glucose 6-phosphate, mannose and ribose on the generation of aroma volatiles in pork was investigated. The monosaccharides were added individually to minced pork prior to heat treatment (160°C for 10min) in the following concentrations: glucose (27.5μmol/g), ribose (1.2μmol/g), mannose (8.3μmol/g) and glucose 6-phosphate (0.5μmol/g). The natural concentrations of the monosaccharides in the pork used were found to be 4.0μmol/g for glucose, 0.1μmol/g for ribose, 0.3μmol/g for mannose and 2.6μmol/g for glucose 6-phosphate. The major aroma compounds identified in the headspace of the heated samples were pyrazines, aldehydes (Strecker and lipid-derived), ketones, and sulphides. Glucose generated the highest amounts of volatiles followed by glucose 6-phosphate. However, when related to the added concentration of glucose 6-phosphate, this phosphorylated monosaccharide showed the highest aroma generating potential. The addition of ribose did not increase the concentration of volatiles compared with pork without the added monosaccharide. The fates of ribose 5-phosphate and ribose in pork were studied over time. The concentrations of ribose and ribose 5-phosphate clearly decreased during 2h equilibration, which may be due to enzymatic activities. These precursors may, therefore, be less important pork flavour precursors than glucose and glucose 6-phosphate.

  12. Genetic Evidence for the Physiological Significance of the d-Tagatose 6-Phosphate Pathway of Lactose and d-Galactose Degradation in Staphylococcus aureus1

    PubMed Central

    Bissett, Donald L.; Anderson, Richard L.

    1974-01-01

    Mutants of Staphylococcus aureus were isolated which were unable to utilize d-galactose or lactose, but which were able to utilize all other carbohydrates tested. Growth of the mutants on a peptone-containing medium was inhibited by d-galactose. Of those mutants selected for further study, one (tagI2) was missing d-galactose 6-phosphate isomerase, one (tagK3) was missing d-tagatose 6-phosphate kinase, and one (tagA4) was missing d-tagatose 1, 6-diphosphate aldolase. Each of these mutants accumulated the substrate of the missing enzyme intracellularly. Spontaneous revertants of each of the mutants simultaneously regained their ability to utilize d-galactose and lactose, lost their sensitivity to d-galactose, regained the missing enzymatic activities, and no longer accumulated intermediates of the d-tagatose 6-phosphate pathway. These data support our previous contention that the physiologically significant route for the metabolism of d-galactose and the d-galactosyl moiety of lactose in S. aureus is the d-tagatose 6-phosphate pathway. Furthermore, a mutant constitutive for all three enzymes of this pathway was isolated, indicating that the products of the tagI, tagK, and tagA genes are under common genetic control. This conclusion was supported by the demonstration that d-galactose 6-phosphate isomerase, d-tagatose 6-phosphate kinase, and d-tagatose 1, 6-diphosphate aldolase are coordinately induced in the parental strain. PMID:4277494

  13. An audit of the precipitating factors for haemolytic crisis among glucose-6-phosphate dehydrogenase-deficient paediatric patients.

    PubMed

    Al-Azzam, Sayer I; Al-Ajlony, Mohammad J; Al-Khateeb, Taqwa; Alzoubi, Karem H; Mhaidat, Nizar; Ayoub, Abeer

    2009-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common genetic enzyme deficiencies leading to haemolytic anaemia. This study aimed to investigate the precipitating factors for haemolytic crisis in G6PD-deficient paediatric patients in Jordan. A retrospective study of data from the records of 258 paediatric patients admitted to a major paediatric hospital in North Jordan from January 2001 until April 2007. Patients included were G6PD-deficient children who were admitted to the hospital secondary to an episode of haemolytic anaemia. Of 258 paediatric patients, 244 (94.2%) had developed a haemolytic episode secondary to ingestion of fava beans. The remaining 14 children (5.8%) developed a haemolytic episode triggered by other factors, such as drugs and upper respiratory infections. Fava bean ingestion is the major precipitating factor for haemolytic anaemia episodes among G6PD-deficient children in Jordan.

  14. Enhanced thermotolerance for ethanol fermentation of Saccharomyces cerevisiae strain by overexpression of the gene coding for trehalose-6-phosphate synthase.

    PubMed

    An, Ming-Zhe; Tang, Yue-Qin; Mitsumasu, Kanako; Liu, Ze-Shen; Shigeru, Morimura; Kenji, Kida

    2011-07-01

    The effect of overexpression of the trehalose-6-phosphate (T6P) synthase gene (TPS1) on ethanol fermentation of Saccharomyces cerevisiae has been studied at 30 and 38°C. The activity of T6P synthase and the accumulation of trehalose during ethanol fermentation were significantly improved by overexpression of TPS1, and especially at 38°C. Ethanol produced by transformants with and without TPS1 gene overexpression at 38°C was approx. 60 and 37 g/l, respectively. The fermentation efficiency of transformants with TPS1 gene overexpression at 38°C was similar to that at 30°C. The critical growth temperature was increased from 36 to 42°C by TPS1 gene overexpression. These results indicated that overexpression of the TPS1 gene had a beneficial effect on the fermentation capacity of the title yeast strain at high temperatures.

  15. Beneficial effect of sugar osmolytes on the refolding of guanidine hydrochloride-denatured trehalose-6-phosphate hydrolase from Bacillus licheniformis.

    PubMed

    Chen, Jiau-Hua; Chi, Meng-Chun; Lin, Min-Guan; Lin, Long-Liu; Wang, Tzu-Fan

    2015-01-01

    The influence of three sugar osmolytes on the refolding of guanidine hydrochloride- (GdnHCl-) denatured trehalose-6-phosphate hydrolase of Bacillus licheniformis (BlTreA) was studied by circular dichroism (CD) spectra, fluorescence emission spectra, and the recovery of enzymatic activity. These experimental results clearly indicated that sorbitol, sucrose, and trehalose at a concentration of 0.75 M improved the refolding yields of GdnHCl-denatured  BlTreA, probably due to the fact that these sugars favored the formation of tertiary architectures. Far-UV CD measurements demonstrated the ability of sugar osmolytes to shift the secondary structure of GdnHCl-denatured enzyme towards near-native conformations. ANS fluorescence intensity measurements revealed a reduction of exposed hydrophobic surfaces upon the treatment of denatured enzyme with sugar osmolytes. These observations suggest that sugar osmolytes possibly play a chaperone role in the refolding of chemically denatured BlTreA.

  16. Beneficial Effect of Sugar Osmolytes on the Refolding of Guanidine Hydrochloride-Denatured Trehalose-6-phosphate Hydrolase from Bacillus licheniformis

    PubMed Central

    Chen, Jiau-Hua; Chi, Meng-Chun; Lin, Min-Guan; Lin, Long-Liu; Wang, Tzu-Fan

    2015-01-01

    The influence of three sugar osmolytes on the refolding of guanidine hydrochloride- (GdnHCl-) denatured trehalose-6-phosphate hydrolase of Bacillus licheniformis (BlTreA) was studied by circular dichroism (CD) spectra, fluorescence emission spectra, and the recovery of enzymatic activity. These experimental results clearly indicated that sorbitol, sucrose, and trehalose at a concentration of 0.75 M improved the refolding yields of GdnHCl-denatured  BlTreA, probably due to the fact that these sugars favored the formation of tertiary architectures. Far-UV CD measurements demonstrated the ability of sugar osmolytes to shift the secondary structure of GdnHCl-denatured enzyme towards near-native conformations. ANS fluorescence intensity measurements revealed a reduction of exposed hydrophobic surfaces upon the treatment of denatured enzyme with sugar osmolytes. These observations suggest that sugar osmolytes possibly play a chaperone role in the refolding of chemically denatured BlTreA. PMID:25667926

  17. Co-occurrence of biphenotypic acute leukaemia, glucose 6-phosphate dehydrogenase deficiency and haemoglobin E trait in a single child.

    PubMed

    Mallick, Debkrishna; Thapa, Rajoo; Biswas, Biswajit

    2016-02-01

    Acute leukaemias occur as the result of clonal expansion subsequent to transformation and arrest at a normal differentiation stage of haematopoietic precursors, which commit to a single lineage, such as myeloid or B-lymphoid or T-lymphoid cells. Biphenotypic acute leukaemia (BAL) constitutes a biologically different group of leukaemia arising from a precursor stem cell and co-expressing more than one lineage specific marker. The present report describes a child with unusual co-occurrence of biphenotypic (B-precursor cell and Myeloid) acute leukaemia, haemoglobin E trait and glucose 6-phosphate dehydrogenase (G6-PD) deficiency. To the best of our knowledge, this constellation of haematological conditions in a single child has never been described before.

  18. Periodontal considerations in a patient with glucose-6-phosphate dehydrogenase deficiency with associated pancytopenia: A rare case report.

    PubMed

    Gupta, Harinder; Arora, Ruchika; Kamboj, Monika

    2014-03-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme defect in humans. G6PD deficiency is widely distributed in tropical and subtropical parts of the world and a conservative estimate is that at least 500 million people have a G6PD deficient gene. In several of these areas, the frequency of a G6PD deficiency gene may be as high as 20% or more. The vast majority of people with G6PD deficiency remain clinically asymptomatic throughout their lifetime. However, all of them have an increased risk of developing neonatal jaundice and a risk of developing acute hemolytic anemia when challenged by a number of oxidative agents. The most important treatment measure is prevention: Avoidance of the drugs and foods that cause hemolysis.

  19. X-linked glucose-6-phosphate dehydrogenase (G6PD) and autosomal 6-phosphogluconate dehydrogenase (6PGD) polymorphisms in baboons

    SciTech Connect

    VandeBerg, J.L.; Aivaliotis, M.J.; Samollow, P.B. )

    1992-12-01

    Electrophoretic polymorphisms of glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were examined in captive colonies of five subspecies of baboons (Papio hamadryas). Phenotype frequencies and family data verified the X-linked inheritance of the G6PD polymorphism. Insufficient family data were available to confirm autosomal inheritance of the 6PGD polymorphism, but the electrophoretic patterns of variant types (putative heterozygotes) suggested the codominant expression of alleles at an autosomal locus. Implications of the G6PD polymorphism are discussed with regard to its utility as a marker system for research on X-chromosome inactivation during baboon development and for studies of clonal cell proliferation and/or cell selection during the development of atherosclerotic lesions in the baboon model. 61 refs., 1 fig., 4 tabs.

  20. Inhibition of catalase by aminotriazole in vivo results in reduction of glucose-6-phosphate dehydrogenase activity in Saccharomyces cerevisiae cells.

    PubMed

    Bayliak, M; Gospodaryov, D; Semchyshyn, H; Lushchak, V

    2008-04-01

    The inhibitor of catalase 3-amino-1,2,4-triazole (AMT) was used to study the physiological role of catalase in the yeast Saccharomyces cerevisiae under starvation. It was shown that AMT at the concentration of 10 mM did not affect the growth of the yeast. In vivo and in vitro the degree of catalase inhibition by AMT was concentration- and time-dependent. Peroxisomal catalase in bakers' yeast was more sensitive to AMT than the cytosolic one. In vivo inhibition of catalase by AMT in S. cerevisiae caused a simultaneous decrease in glucose-6-phosphate dehydrogenase activity and an increase in glutathione reductase activity. At the same time, the level of protein carbonyls, a marker of oxidative modification, was not affected. Possible mechanisms compensating the negative effects caused by AMT inhibition of catalase are discussed.

  1. The kangaroo cation-independent mannose 6-phosphate receptor binds insulin-like growth factor II with low affinity.

    PubMed

    Yandell, C A; Dunbar, A J; Wheldrake, J F; Upton, Z

    1999-09-17

    The mammalian cation-independent mannose 6-phosphate receptor (CI-MPR) binds mannose 6-phosphate-bearing glycoproteins and insulin-like growth factor (IGF)-II. However, the CI-MPR from the opossum has been reported to bind bovine IGF-II with low affinity (Dahms, N. M., Brzycki-Wessell, M. A., Ramanujam, K. S., and Seetharam, B. (1993) Endocrinology 133, 440-446). This may reflect the use of a heterologous ligand, or it may represent the intrinsic binding affinity of this receptor. To examine the binding of IGF-II to a marsupial CI-MPR in a homologous system, we have previously purified kangaroo IGF-II (Yandell, C. A., Francis, G. L., Wheldrake, J. F., and Upton, Z. (1998) J. Endocrinol. 156, 195-204), and we now report the purification and characterization of the CI-MPR from kangaroo liver. The interaction of the kangaroo CI-MPR with IGF-II has been examined by ligand blotting, radioreceptor assay, and real-time biomolecular interaction analysis. Using both a heterologous and homologous approach, we have demonstrated that the kangaroo CI-MPR has a lower binding affinity for IGF-II than its eutherian (placental mammal) counterparts. Furthermore, real-time biomolecular interaction analysis revealed that the kangaroo CI-MPR has a higher affinity for kangaroo IGF-II than for human IGF-II. The cDNA sequence of the kangaroo CI-MPR indicates that there is considerable divergence in the area corresponding to the IGF-II binding site of the eutherian receptor. Thus, the acquisition of a high-affinity binding site for regulating IGF-II appears to be a recent event specific to the eutherian lineage.

  2. The Production and Utilization of GDP-glucose in the Biosynthesis of Trehalose 6-Phosphate by Streptomyces venezuelae.

    PubMed

    Asención Diez, Matías D; Miah, Farzana; Stevenson, Clare E M; Lawson, David M; Iglesias, Alberto A; Bornemann, Stephen

    2017-01-20

    Trehalose-6-phosphate synthase OtsA from streptomycetes is unusual in that it uses GDP-glucose as the donor substrate rather than the more commonly used UDP-glucose. We now confirm that OtsA from Streptomyces venezuelae has such a preference for GDP-glucose and can utilize ADP-glucose to some extent too. A crystal structure of the enzyme shows that it shares twin Rossmann-like domains with the UDP-glucose-specific OtsA from Escherichia coli However, it is structurally more similar to Streptomyces hygroscopicus VldE, a GDP-valienol-dependent pseudoglycosyltransferase enzyme. Comparison of the donor binding sites reveals that the amino acids associated with the binding of diphosphoribose are almost all identical in these three enzymes. By contrast, the amino acids associated with binding guanine in VldE (Asn, Thr, and Val) are similar in S. venezuelae OtsA (Asp, Ser, and Phe, respectively) but not conserved in E. coli OtsA (His, Leu, and Asp, respectively), providing a rationale for the purine base specificity of S. venezuelae OtsA. To establish which donor is used in vivo, we generated an otsA null mutant in S. venezuelae The mutant had a cell density-dependent growth phenotype and accumulated galactose 1-phosphate, glucose 1-phosphate, and GDP-glucose when grown on galactose. To determine how the GDP-glucose is generated, we characterized three candidate GDP-glucose pyrophosphorylases. SVEN_3027 is a UDP-glucose pyrophosphorylase, SVEN_3972 is an unusual ITP-mannose pyrophosphorylase, and SVEN_2781 is a pyrophosphorylase that is capable of generating GDP-glucose as well as GDP-mannose. We have therefore established how S. venezuelae can make and utilize GDP-glucose in the biosynthesis of trehalose 6-phosphate.

  3. The glucose-6-phosphate dehydrogenase from Trypanosoma cruzi: its role in the defense of the parasite against oxidative stress.

    PubMed

    Igoillo-Esteve, Mariana; Cazzulo, Juan José

    2006-10-01

    The Trypanosoma cruzi glucose-6-phosphate dehydrogenase (G6PDH) is encoded by several genes located in three of the parasite chromosomes. All the sequences present two possible start codons, 111bp apart, also present in its Trypanosoma brucei counterpart. As the 37 residues comprised between the two candidate initiator methionines of T. brucei and T. cruzi G6PDHs constitute an unusual N-terminal extension only present in trypanosomatids, two forms of the T. cruzi G6PDH were expressed in Escherichia coli: a long one (Tc-G6PDH-L) translated from the first ATG codon, and a short one (Tc-G6PDH-S) translated from the second. Both were purified and their kinetic constants determined. The apparent K(m) for glucose-6-phosphate was 189.9, 98.4, and 288microM, for Tc-G6PDH-L, Tc-G6PDH-S and native Tc-G6PDH, respectively. The apparent K(m) for NADP was similar for both recombinant proteins. The Tc-G6PDH-L as well as the native enzyme, was inactivated by DTT while the Tc-G6PDH-S was unaffected by the reducing agent. This behavior could be related to the presence of two Cys groups in the N-terminal extension of the Tc-G6PDH-L similarly to the redox regulated G6PDHs from chloroplasts and cyanobacteria. This property, together with a remarkable induction (up to 46-fold) of the T. cruzi G6PDH in metacyclic trypomastigotes under oxidative stress conditions, suggests that the enzyme may play a prominent role in the defense mechanisms of the parasite against oxidative stress becoming an important target for chemotherapy. Western blots using antibodies against the N-terminal extension in Tc-G6PDH-L show that this form is expressed in the parasite.

  4. Human immunodeficiency virus-1 uses the mannose-6-phosphate receptor to cross the blood-brain barrier.

    PubMed

    Dohgu, Shinya; Ryerse, Jan S; Robinson, Sandra M; Banks, William A

    2012-01-01

    HIV-1 circulates both as free virus and within immune cells, with the level of free virus being predictive of clinical course. Both forms of HIV-1 cross the blood-brain barrier (BBB) and much progress has been made in understanding the mechanisms by which infected immune cells cross the blood-brain barrier BBB. How HIV-1 as free virus crosses the BBB is less clear as brain endothelial cells are CD4 and galactosylceramide negative. Here, we found that HIV-1 can use the mannose-6 phosphate receptor (M6PR) to cross the BBB. Brain perfusion studies showed that HIV-1 crossed the BBB of all brain regions consistent with the uniform distribution of M6PR. Ultrastructural studies showed HIV-1 crossed by a transcytotic pathway consistent with transport by M6PR. An in vitro model of the BBB was used to show that transport of HIV-1 was inhibited by mannose, mannan, and mannose-6 phosphate and that enzymatic removal of high mannose oligosaccharide residues from HIV-1 reduced transport. Wheatgerm agglutinin and protamine sulfate, substances known to greatly increase transcytosis of HIV-1 across the BBB in vivo, were shown to be active in the in vitro model and to act through a mannose-dependent mechanism. Transport was also cAMP and calcium-dependent, the latter suggesting that the cation-dependent member of the M6PR family mediates HIV-1 transport across the BBB. We conclude that M6PR is an important receptor used by HIV-1 to cross the BBB.

  5. The Production and Utilization of GDP-glucose in the Biosynthesis of Trehalose 6-Phosphate by Streptomyces venezuelae*

    PubMed Central

    Asención Diez, Matías D.; Miah, Farzana; Stevenson, Clare E. M.; Lawson, David M.; Iglesias, Alberto A.; Bornemann, Stephen

    2017-01-01

    Trehalose-6-phosphate synthase OtsA from streptomycetes is unusual in that it uses GDP-glucose as the donor substrate rather than the more commonly used UDP-glucose. We now confirm that OtsA from Streptomyces venezuelae has such a preference for GDP-glucose and can utilize ADP-glucose to some extent too. A crystal structure of the enzyme shows that it shares twin Rossmann-like domains with the UDP-glucose-specific OtsA from Escherichia coli. However, it is structurally more similar to Streptomyces hygroscopicus VldE, a GDP-valienol-dependent pseudoglycosyltransferase enzyme. Comparison of the donor binding sites reveals that the amino acids associated with the binding of diphosphoribose are almost all identical in these three enzymes. By contrast, the amino acids associated with binding guanine in VldE (Asn, Thr, and Val) are similar in S. venezuelae OtsA (Asp, Ser, and Phe, respectively) but not conserved in E. coli OtsA (His, Leu, and Asp, respectively), providing a rationale for the purine base specificity of S. venezuelae OtsA. To establish which donor is used in vivo, we generated an otsA null mutant in S. venezuelae. The mutant had a cell density-dependent growth phenotype and accumulated galactose 1-phosphate, glucose 1-phosphate, and GDP-glucose when grown on galactose. To determine how the GDP-glucose is generated, we characterized three candidate GDP-glucose pyrophosphorylases. SVEN_3027 is a UDP-glucose pyrophosphorylase, SVEN_3972 is an unusual ITP-mannose pyrophosphorylase, and SVEN_2781 is a pyrophosphorylase that is capable of generating GDP-glucose as well as GDP-mannose. We have therefore established how S. venezuelae can make and utilize GDP-glucose in the biosynthesis of trehalose 6-phosphate. PMID:27903647

  6. Cloning, expression and characterization of trehalose-6-phosphate phosphatase from a psychrotrophic bacterium, Arthrobacter strain A3.

    PubMed

    Li, Yuan-Ting; Zhang, Hai-Hong; Sheng, Hong-Mei; An, Li-Zhe

    2012-08-01

    A trehalose-6-phosphate phosphatase (TPP) gene, otsB, from a psychrotrophic bacterium, Arthrobacter strain A3, was identified. The product of this otsB gene is 266 amino acids in length with a calculated molecular weight of 27,873 Da. The protein was expressed in Escherichia coli and purified to apparent homogeneity. The purified recombinant TPP catalyzed the dephosphorylation of trehalose-6-phosphate to form trehalose and showed a broad optimum pH range from 5.0 to 7.5. This enzyme also showed an absolute requirement for Mg(2+) or Co(2+) for catalytic activity. The recombinant TPP had a maximum activity at 30 °C and maintained activity over a temperature range of 4-30 °C. TPP was generally heat-labile, losing 70 % of its activity when subjected to heat treatment at 50 °C for 6 min. Kinetic analysis of the Arthrobacter strain A3 TPP showed ~tenfold lower K (m) values when compared with values derived from other bacterial TPP enzymes. The highest k (cat)/K (m) value was 37.5 mM(-1) s(-1) (repeated three times), which is much higher than values published for mesophilic E. coli TPP, indicating that the Arthrobacter strain A3 TPP possessed excellent catalytic activity at low temperatures. Accordingly, these characteristics suggest that the TPP from the Arthrobacter strain A3 is a new cold-adapted enzyme. In addition, this is the first report characterizing the enzymatic properties of a TPP from a psychrotrophic organism.

  7. Fluoride-containing bioactive glasses inhibit pentose phosphate oxidative pathway and glucose 6-phosphate dehydrogenase activity in human osteoblasts.

    PubMed

    Bergandi, Loredana; Aina, Valentina; Garetto, Stefano; Malavasi, Gianluca; Aldieri, Elisabetta; Laurenti, Enzo; Matera, Lina; Morterra, Claudio; Ghigo, Dario

    2010-02-12

    Bioactive glasses such as Hench's 45S5 (Bioglass) have applications to tissue engineering as well as bone repair, and the insertion of fluoride in their composition has been proposed to enhance their bioactivity. In view of a potential clinical application, we investigated whether fluoride-containing glasses exert toxic effects on human MG-63 osteoblasts, and whether and how fluoride, which is released in the cell culture medium, might play a role in such cytotoxicity. A 24h incubation with 50 microg/ml (12.5 microg/cm(2)) of fluoride-containing bioactive glasses termed HCaCaF(2) (F content: 5, 10 and 15 mol.%) caused the release of lactate dehydrogenase in the extracellular medium (index of cytotoxicity), the accumulation of intracellular malonyldialdehyde (index of lipoperoxidation), and the increase of glutathione consumption. Furthermore, fluoride-containing glasses inhibited the pentose phosphate oxidative pathway and the glucose 6-phosphate dehydrogenase activity. These effects are ascribable to the fluoride content/release of glass powders, since they were mimicked by NaF solutions and were prevented by dimethyl sulfoxide and tempol (two radical scavengers), by superoxide dismutase (a superoxide scavenger), and by glutathione (the most important intracellular antioxidant molecule), but not by apocynin (an inhibitor of NADPH oxidase). The presence of fluoride-containing glasses and NaF caused also the generation of reactive oxygen species, which was prevented by superoxide dismutase and catalase. The data suggest that fluoride released from glasses is the cause of MG-63 cell oxidative damage and is independent of NADPH oxidase activation. Our data provide a new mechanism to explain F(-) ions toxicity: fluoride could trigger, at least in part, an oxidative stress via inhibition of the pentose phosphate oxidative pathway and, in particular, through the oxidative inhibition of glucose 6-phosphate dehydrogenase.

  8. On the multiple functional roles of the active site histidine in catalysis and allosteric regulation of Escherichia coli glucosamine 6-phosphate deaminase.

    PubMed

    Montero-Morán, G M; Lara-González, S; Alvarez-Añorve, L I; Plumbridge, J A; Calcagno, M L

    2001-08-28

    The active site of glucosamine-6-phosphate deaminase (EC 3.5.99.6, formerly 5.3.1.10) from Escherichia coli was first characterized on the basis of the crystallographic structure of the enzyme bound to the competitive inhibitor 2-amino-2-deoxy-glucitol 6-phosphate. The structure corresponds to the R allosteric state of the enzyme; it shows the side-chain of His143 in close proximity to the O5 atom of the inhibitor. This arrangement suggests that His143 could have a role in the catalysis of the ring-opening step of glucosamine 6-phosphate whose alpha-anomer is the true substrate. The imidazole group of this active-site histidine contacts the carboxy groups from Glu148 and Asp141, via its Ndelta1 atom [Oliva et al. (1995) Structure 3, 1323-1332]. These interactions change in the T state because the side chain of Glu148 moves toward the allosteric site, leaving at the active site the dyad Asp141-His143 [Horjales et al. (1999) Structure 7, 527-536]. In this research, a dual approach using site-directed mutagenesis and controlled chemical modification of histidine residues has been used to investigate the role of the active-site histidine. Our results support a multifunctional role of His143; in the forward reaction, it is involved in the catalysis of the ring-opening step of the substrate, glucosamine 6-P. In the reverse reaction, the substrate fructose 6-P binds in its open chain, carbonylic form. The role of His143 in the binding of both glucosamine 6-P and reaction intermediates in their extended-chain forms was demonstrated by binding experiments using the reaction intermediate analogue, 2-amino-2-deoxy-D-glucitol 6-phosphate. His143 was also shown to be a critical residue for the conformational coupling between active and allosteric sites. From the pH dependence of the reactivity of the active site histidine to diethyl dicarbonate, we observed a pK(a) change of 1.2 units to the acid side when the enzyme undergoes the allosteric T to R transition during which the

  9. The preparation of nylon-tube-supported hexokinase and glucose 6-phosphate dehydrogenase and the use of the co-immobilized enzymes in the automated determination of glucose.

    PubMed Central

    Morris, D L; Campbell, J; Hornby, W E

    1975-01-01

    Triethyloxonium tetrafluoroborate was used to O-alkylate nylon-tube thus producing the imidate salt of the nylon which was further made to react with 1,6-diaminohexane. 2. Hexokinase (EC 2.7.1.1) and glucose 6-phosphate dehydrogenase (EC 1.1.1.49) were immobilized on the amino-substituted nylon tube through glutaraldeyde and bisimidates. 3. The effect of varying the conditions of O-alkylation and the amount of enzyme immobilized on the activity of nylon tube-hexokinase derivatives was determined. 4. The effect of varying the amount of enzyme immobilized on the activity of nylon-tube-glucose 6-phosphate dehydrogenase derivatives was determined. 5. The thermal stability of nylon-tube-hexokinase and nylon-tube-glucose 6-phosphate dehydrogenase derivatives was studied. 6. Different ratios of hexokinase and glucose 6-phosphate dehydrogenase were co-immobilized on nylon tube, and the rate of conversion of glucose into 6-phosphogluconolactone was compared with the individual activities of the immobilized enzymes. 7. Hexokinase and glucose 6-phosphate dehydrogenase co-immobilized on nylon tube were used in the automated analysis of glucose. PMID:1167161

  10. Type I glycogen storage diseases: disorders of the glucose-6-phosphatase/glucose-6-phosphate transporter complexes.

    PubMed

    Chou, Janice Y; Jun, Hyun Sik; Mansfield, Brian C

    2015-05-01

    Disorders of the glucose-6-phosphatase (G6Pase)/glucose-6-phosphate transporter (G6PT) complexes consist of three subtypes: glycogen storage disease type Ia (GSD-Ia), deficient in the liver/kidney/intestine-restricted G6Pase-α (or G6PC); GSD-Ib, deficient in a ubiquitously expressed G6PT (or SLC37A4); and G6Pase-β deficiency or severe congenital neutropenia syndrome type 4 (SCN4), deficient in the ubiquitously expressed G6Pase-β (or G6PC3). G6Pase-α and G6Pase-β are glucose-6-phosphate (G6P) hydrolases with active sites lying inside the endoplasmic reticulum (ER) lumen and as such are dependent upon the G6PT to translocate G6P from the cytoplasm into the lumen. The tissue expression profiles of the G6Pase enzymes dictate the disease's phenotype. A functional G6Pase-α/G6PT complex maintains interprandial glucose homeostasis, while a functional G6Pase-β/G6PT complex maintains neutrophil/macrophage energy homeostasis and functionality. G6Pase-β deficiency is not a glycogen storage disease but biochemically it is a GSD-I related syndrome (GSD-Irs). GSD-Ia and GSD-Ib patients manifest a common metabolic phenotype of impaired blood glucose homeostasis not shared by GSD-Irs. GSD-Ib and GSD-Irs patients manifest a common myeloid phenotype of neutropenia and neutrophil/macrophage dysfunction not shared by GSD-Ia. While a disruption of the activity of the G6Pase-α/G6PT complex readily explains why GSD-Ia and GSD-Ib patients exhibit impaired glucose homeostasis, the basis for neutropenia and myeloid dysfunction in GSD-Ib and GSD-Irs are only now starting to be understood. Animal models of all three disorders are now available and are being exploited to both delineate the disease more precisely and develop new treatment approaches, including gene therapy.

  11. Developmentally regulated mannose 6-phosphate receptor-mediated transport of a lysosomal enzyme across the blood-brain barrier.

    PubMed

    Urayama, Akihiko; Grubb, Jeffrey H; Sly, William S; Banks, William A

    2004-08-24

    Mucopolysaccharidosis type VII is a lysosomal storage disorder resulting from inherited deficiency of beta-glucuronidase (GUS). Mucopolysaccharidosis type VII is characterized by glycosaminoglycan storage in most tissues, including brain. In these disorders, enzyme delivery across the blood-brain barrier (BBB) is the main obstacle to correction of lysosomal storage in the CNS. Prior studies suggested mouse brain is accessible to GUS in the first 2 weeks of life but not later. To explore a possible role for the mannose 6-phosphate/insulin-like growth factor II receptor in GUS transport across the BBB in neonatal mice, we compared brain uptake of phosphorylated GUS (P-GUS) and nonphosphorylated GUS (NP-GUS) in newborn and adult mice. (131)I-P-GUS was transported across the BBB after i.v. injection in 2-day-old mice. The brain influx rate (K(in)) of (131)I-P-GUS in 2-day-old mice was 0.21 microl/g.min and decreased with age. By 7 weeks of age, transport of (131)I-P-GUS was not significant. Capillary depletion revealed that 62% of the (131)I-P-GUS in brain was in brain parenchyma in 2-day-old mice. In addition, uptake of (131)I-P-GUS into brain was significantly reduced by coinjection of unlabeled P-GUS or M6P in a dose-dependent manner. In contrast, the K(in) of (131)I-NP-GUS (0.04 microl/g.min) was significantly lower than (131)I-P-GUS in 2-day-old mice. Transcardiac brain perfusion confirmed that neither (131)I-P-GUS nor (131)I-NP-GUS crossed the BBB in adult mice. These results indicate that (131)I-P-GUS transport into brain parenchyma in early postnatal life is mediated by the mannose 6-phosphate/insulin-like growth factor II receptor. This receptor-mediated transport is not observed in adult mice.

  12. High frequency of diabetes and impaired fasting glucose in patients with glucose-6-phosphate dehydrogenase deficiency in the Western brazilian Amazon.

    PubMed

    Santana, Marli S; Monteiro, Wuelton M; Costa, Mônica R F; Sampaio, Vanderson S; Brito, Marcelo A M; Lacerda, Marcus V G; Alecrim, Maria G C

    2014-07-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human genetic abnormalities, and it has a significant prevalence in the male population (X chromosome linked). The purpose of this study was to estimate the frequency of impaired fasting glucose and diabetes among G6PD-deficient persons in Manaus, Brazil, an area in the Western Brazilian Amazon to which malaria is endemic. Glucose-6-phosphate dehydrogenase-deficient males had more impaired fasting glucose and diabetes. This feature could be used as a screening tool for G6PD-deficient persons who are unable to use primaquine for the radical cure of Plasmodium vivax malaria.

  13. L-Ribose isomerase and mannose-6-phosphate isomerase: properties and applications for L-ribose production.

    PubMed

    Xu, Zheng; Sha, Yuanyuan; Liu, Chao; Li, Sha; Liang, Jinfeng; Zhou, Jiahai; Xu, Hong

    2016-11-01

    L-Ribose is a synthetic L-form monosaccharide. It is a building block of many novel nucleotide analog anti-viral drugs. Bio-production of L-ribose relies on a two-step reaction: (i) conversion of L-arabinose to L-ribulose by the catalytic action of L-arabinose isomerase (L-AI) and (ii) conversion of L-ribulose to L-ribose by the catalytic action of L-ribose isomerase (L-RI, EC 5.3.1.B3) or mannose-6-phosphate isomerase (MPI, EC 5.3.1.8, alternately named as phosphomannose isomerase). Between the two enzymes, L-RI is a rare enzyme that was discovered in 1996 by Professor Izumori's group, whereas MPI is an essential enzyme in metabolic pathways in humans and microorganisms. Recent studies have focused on their potentials for industrial production of L-ribose. This review summarizes the applications of L-RI and MPI for L-ribose production.

  14. An unexpected emergency request for glucose-6-phosphate dehydrogenase testing in a 9-year-old African American boy.

    PubMed

    Platteborze, Peter; Matos, Renee; Gidvany-Diaz, Vinod; Wilhelms, Kelly

    2015-01-01

    9-year-old African American male. Recently diagnosed with acute lymphoblastic leukemia (ALL) after investigation into a large anterior mediastinal mass causing airway compression. The day before the unexpected urgent glucose-6-phosphate dehydrogenase (G6PD) request, the patient was diagnosed with an aggressive form of leukemia and a significant tumor mass causing airway compression. A computed tomography (CT) scan indicated potential renal involvement. Based on this information and the size of the mass, the patient was referred for immediate chemotherapy. However, there was a concern that he could develop tumor lysis syndrome (TLS) during treatment. To avoid this condition, the pediatric intensive care unit (ICU) sought to pretreat the child with rasburicase, which led to the emergency G6PD request. Unknown. Largely unknown, but no apparent chronic diseases. Three weeks of progressively worsening lymphadenopathy, coughing, night sweats, mild hepatosplenomegaly, and breathing difficulty when supine. The patient arrived at the medical center for airway management and had a temperature of 36.1°C; blood pressure, 120/87 mmHg; pulse, 115 bpm; respiratory rate, 22 breaths per minute, with labored breathing but normal O(2) saturation while upright and awake, in room air. Table 1. Copyright© by the American Society for Clinical Pathology (ASCP).

  15. The Class II Trehalose 6-phosphate Synthase Gene PvTPS9 Modulates Trehalose Metabolism in Phaseolus vulgaris Nodules

    PubMed Central

    Barraza, Aarón; Contreras-Cubas, Cecilia; Estrada-Navarrete, Georgina; Reyes, José L.; Juárez-Verdayes, Marco A.; Avonce, Nelson; Quinto, Carmen; Díaz-Camino, Claudia; Sanchez, Federico

    2016-01-01

    Legumes form symbioses with rhizobia, producing nitrogen-fixing nodules on the roots of the plant host. The network of plant signaling pathways affecting carbon metabolism may determine the final number of nodules. The trehalose biosynthetic pathway regulates carbon metabolism and plays a fundamental role in plant growth and development, as well as in plant-microbe interactions. The expression of genes for trehalose synthesis during nodule development suggests that this metabolite may play a role in legume-rhizobia symbiosis. In this work, PvTPS9, which encodes a Class II trehalose-6-phosphate synthase (TPS) of common bean (Phaseolus vulgaris), was silenced by RNA interference in transgenic nodules. The silencing of PvTPS9 in root nodules resulted in a reduction of 85% (± 1%) of its transcript, which correlated with a 30% decrease in trehalose contents of transgenic nodules and in untransformed leaves. Composite transgenic plants with PvTPS9 silenced in the roots showed no changes in nodule number and nitrogen fixation, but a severe reduction in plant biomass and altered transcript profiles of all Class II TPS genes. Our data suggest that PvTPS9 plays a key role in modulating trehalose metabolism in the symbiotic nodule and, therefore, in the whole plant. PMID:27847509

  16. Determination of the inhibitory effect of green tea extract on glucose-6-phosphate dehydrogenase based on multilayer capillary enzyme microreactor.

    PubMed

    Camara, Mohamed Amara; Tian, Miaomiao; Liu, Xiaoxia; Liu, Xin; Wang, Yujia; Yang, Jiqing; Yang, Li

    2016-08-01

    Natural herbal medicines are an important source of enzyme inhibitors for the discovery of new drugs. A number of natural extracts such as green tea have been used in prevention and treatment of diseases due to their low-cost, low toxicity and good performance. The present study reports an online assay of the activity and inhibition of the green tea extract of the Glucose 6-phosphate dehydrogenase (G6PDH) enzyme using multilayer capillary electrophoresis based immobilized enzyme microreactors (CE-IMERs). The multilayer CE-IMERs were produced with layer-by-layer electrostatic assembly, which can easily enhance the enzyme loading capacity of the microreactor. The activity of the G6PDH enzyme was determined and the enzyme inhibition by the inhibitors from green tea extract was investigated using online assay of the multilayer CE-IMERs. The Michaelis constant (Km ) of the enzyme, the IC50 and Ki values of the inhibitors were achieved and found to agree with those obtained using offline assays. The results show a competitive inhibition of green tea extract on the G6PDH enzyme. The present study provides an efficient and easy-to-operate approach for determining G6PDH enzyme reaction and the inhibition of green tea extract, which may be beneficial in research and the development of natural herbal medicines. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Identification of the trehalose-6-phosphate synthase gene family in winter wheat and expression analysis under conditions of freezing stress.

    PubMed

    Xie, D W; Wang, X N; Fu, L S; Sun, J; Zheng, W; Li, Z F

    2015-03-01

    Trehalose plays an important role in metabolic regulation and abiotic stress tolerance in plants. Trehalose contents are potentially modulated by trehalose-6-phosphate synthase (TPS), which is a key enzyme in the trehalose biosynthetic pathway. Using available wheat expressed sequence tag sequence information from NCBI and two wheat genome databases, we identified 12 wheat TPS genes and performed a comprehensive study on their structural, evolutionary and functional properties. The estimated divergence time of wheat TPS gene pairs and wheat-rice orthologues suggested that wheat and rice have a common ancestor. The number of TPS genes in the wheat genome was estimated to be at least 12, which is close to the number found in rice, Arabidopsis and soybean. Moreover, it has been reported earlier in other plants that TPS genes respond to abiotic stress, however, our study mainly analysed the TPS gene family under freezing conditions in winter wheat, and determined that most of the TPS gene expression in winter wheat was induced by freezing conditions, which further suggested that wheat TPS genes were involved in winter wheat freeze-resistance signal transduction pathways. Taken together, the current study represents the first comprehensive study of TPS genes in winter wheat and provides a foundation for future functional studies of this important gene family in Triticeae.

  18. Effect of feeding and of DDT on the activity of hepatic glucose 6- phosphate dehydrogenase in two salmonids

    USGS Publications Warehouse

    Buhler, Donald R.; Benville, P.

    1969-01-01

    The specific activity of liver glucose 6-phosphate dehydrogenase in yearling rainbow trout remained unchanged when the fish were starved for periods as long as 8 weeks and when starved animals were fed diets of various compositions. Injection of insulin concurrently with refeeding also failed to alter the specific activity of the enzyme in trout. The absence of a dietary or insulin influence on the teleost enzyme system is to be contrasted with studies in mammals in which the activity of hepatic glucose 6-P dehydrogenase was markedly stimulated after refeeding starved animals or injection of insulin.Ingestion of the pesticide DDT by juvenile coho salmon or adult rainbow trout also had no effect on the specific activity of liver glucose 6-P dehydrogenase and DDT failed to inhibit the rainbow trout enzyme in vitro. These results also differ considerably from those found in higher animals.These results suggest that the glucose 6-P dehydrogenase enzyme in teleosts may be under a different type of regulatory control from that found in mammals.

  19. Application of capillary enzyme micro-reactor in enzyme activity and inhibitors studies of glucose-6-phosphate dehydrogenase.

    PubMed

    Camara, Mohamed Amara; Tian, Miaomiao; Guo, Liping; Yang, Li

    2015-05-15

    In this study, we present an on-line measurement of enzyme activity and inhibition of Glucose-6-phosphate dehydrogenase (G6PDH) enzyme using capillary electrophoresis based immobilized enzyme micro-reactor (CE-based IMER). The IMER was prepared using a two-step protocol based on electrostatic assembly. The micro-reactor exhibited good stability and reproducibility for on-line assay of G6PDH enzyme. Both the activity as well as the inhibition of the G6PDH enzyme by six inhibitors, including three metals (Cu(2+), Pb(2+), Cd(2+)), vancomycin, urea and KMnO4, were investigated using on-line assay of the CE-based IMERs. The enzyme activity and inhibition kinetic constants were measured using the IMERs which were found to be consistent with those using traditional off-line enzyme assays. The kinetic mechanism of each inhibitor was also determined. The present study demonstrates the feasibility of using CE-based IMERs for rapid and efficient on-line assay of G6PDH, an important enzyme in the pentosephosphate pathway of human metabolism.

  20. The Class II Trehalose 6-phosphate Synthase Gene PvTPS9 Modulates Trehalose Metabolism in Phaseolus vulgaris Nodules.

    PubMed

    Barraza, Aarón; Contreras-Cubas, Cecilia; Estrada-Navarrete, Georgina; Reyes, José L; Juárez-Verdayes, Marco A; Avonce, Nelson; Quinto, Carmen; Díaz-Camino, Claudia; Sanchez, Federico

    2016-01-01

    Legumes form symbioses with rhizobia, producing nitrogen-fixing nodules on the roots of the plant host. The network of plant signaling pathways affecting carbon metabolism may determine the final number of nodules. The trehalose biosynthetic pathway regulates carbon metabolism and plays a fundamental role in plant growth and development, as well as in plant-microbe interactions. The expression of genes for trehalose synthesis during nodule development suggests that this metabolite may play a role in legume-rhizobia symbiosis. In this work, PvTPS9, which encodes a Class II trehalose-6-phosphate synthase (TPS) of common bean (Phaseolus vulgaris), was silenced by RNA interference in transgenic nodules. The silencing of PvTPS9 in root nodules resulted in a reduction of 85% (± 1%) of its transcript, which correlated with a 30% decrease in trehalose contents of transgenic nodules and in untransformed leaves. Composite transgenic plants with PvTPS9 silenced in the roots showed no changes in nodule number and nitrogen fixation, but a severe reduction in plant biomass and altered transcript profiles of all Class II TPS genes. Our data suggest that PvTPS9 plays a key role in modulating trehalose metabolism in the symbiotic nodule and, therefore, in the whole plant.

  1. Hemoglobin E and Glucose-6-Phosphate Dehydrogenase Deficiency and Plasmodium falciparum Malaria in the Chittagong Hill Districts of Bangladesh

    PubMed Central

    Shannon, Kerry L.; Ahmed, Sabeena; Rahman, Hafizur; Prue, Chai S.; Khyang, Jacob; Ram, Malathi; Zahirul Haq, M.; Chowdhury, Ashish; Akter, Jasmin; Glass, Gregory E.; Shields, Timothy; Nyunt, Myaing M.; Khan, Wasif A.; Sack, David A.; Sullivan, David J.

    2015-01-01

    Hemoglobin E is largely confined to south and southeast Asia. The association between hemoglobin E (HbE) and malaria is less clear than that of hemoglobin S and C. As part of a malaria study in the Chittagong Hill Districts of Bangladesh, an initial random sample of 202 individuals showed that 39% and 49% of Marma and Khyang ethnic groups, respectively, were positive for either heterozygous or homozygous hemoglobin E. In this group, 6.4% were also found to be severely deficient and 35% mildly deficient for glucose-6-phosphate dehydrogenase (G6PD). In a separate Plasmodium falciparum malaria case–uninfected control study, the odds of having homozygous hemoglobin E (HbEE) compared with normal hemoglobin (HbAA) were higher among malaria cases detected by passive surveillance than age and location matched uninfected controls (odds ratio [OR] = 5.0, 95% confidence interval [CI] = 1.07–46.93). The odds of heterozygous hemoglobin E (HbAE) compared with HbAA were similar between malaria cases and uninfected controls (OR = 0.71, 95% CI = 0.42–1.19). No association by hemoglobin type was found in the initial parasite density or the proportion parasite negative after 2 days of artemether/lumefantrine treatment. HbEE, but not HbAE status was associated with increased passive case detection of malaria. PMID:26101273

  2. Clathrin terminal domain-ligand interactions regulate sorting of mannose 6-phosphate receptors mediated by AP-1 and GGA adaptors.

    PubMed

    Stahlschmidt, Wiebke; Robertson, Mark J; Robinson, Phillip J; McCluskey, Adam; Haucke, Volker

    2014-02-21

    Clathrin plays important roles in intracellular membrane traffic including endocytosis of plasma membrane proteins and receptors and protein sorting between the trans-Golgi network (TGN) and endosomes. Whether clathrin serves additional roles in receptor recycling, degradative sorting, or constitutive secretion has remained somewhat controversial. Here we have used acute pharmacological perturbation of clathrin terminal domain (TD) function to dissect the role of clathrin in intracellular membrane traffic. We report that internalization of major histocompatibility complex I (MHCI) is inhibited in cells depleted of clathrin or its major clathrin adaptor complex 2 (AP-2), a phenotype mimicked by application of Pitstop® inhibitors of clathrin TD function. Hence, MHCI endocytosis occurs via a clathrin/AP-2-dependent pathway. Acute perturbation of clathrin also impairs the dynamics of intracellular clathrin/adaptor complex 1 (AP-1)- or GGA (Golgi-localized, γ-ear-containing, Arf-binding protein)-coated structures at the TGN/endosomal interface, resulting in the peripheral dispersion of mannose 6-phosphate receptors. By contrast, secretory traffic of vesicular stomatitis virus G protein, recycling of internalized transferrin from endosomes, or degradation of EGF receptor proceeds unperturbed in cells with impaired clathrin TD function. These data indicate that clathrin is required for the function of AP-1- and GGA-coated carriers at the TGN but may be dispensable for outward traffic en route to the plasma membrane.

  3. Incidence and molecular characterization of Glucose-6-Phosphate Dehydrogenase deficiency among neonates for newborn screening in Chaozhou, China.

    PubMed

    Yang, H; Wang, Q; Zheng, L; Zhan, X-F; Lin, M; Lin, F; Tong, X; Luo, Z-Y; Huang, Y; Yang, L-Y

    2015-06-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is highly prevalent in southern China. The aim of this study is to assess the extent of this disease in Chinese neonates and determine its molecular characteristics using a novel molecular screening method. A total of 2500 neonates were routinely screened for G6PD deficiency using a modified fluorescent spot test (FST). PCR-high-resolution melting (HRM) analysis was then used for the molecular assay. The overall incidence of G6PD deficiency was 2.68% in our study cohort. Frequency in male population was 3.22% (44 neonates of 1365 male neonates), and in female population was 2.03% (23 neonates of 1135 female neonates). Of the 67 newborns suspected to be G6PD deficient based on FST (44 males, 23 females), 58 of 67 (87%) were detected with gene alterations. Seven kinds of mutations [c.95A>G, c.392G>T, c.493A>G, c.871G>A, c.1360C>T, c.1376G>T, and c.1388G>A] were identified by HRM analysis. Routine newborn screening in Chaozhou, China with a relatively high prevalence of G6PD deficiency is justified and meets the World Health Organization recommendation. The usage of molecular diagnosis can favor the detection of heterozygotes which can be a supplement to regular newborn screening and useful for premarital and prenatal diagnosis for G6PD deficiency. © 2014 John Wiley & Sons Ltd.

  4. AB222. Enolase1 (ENO1) and glucose-6-phosphate isomerase (GPI) are good markers to predict human sperm freezability

    PubMed Central

    Jiang, Xuping; Wang, Shangqian; Wang, Wei; Xu, Yang; Sun, Hongyong; Wang, Zengjun; Zhang, Wei

    2016-01-01

    Objective Sperm cryopreservation is a method to preserve sperm samples for a long period. However, the fertility of sperm decreases markedly after freezing and thawing in a certain amount of samples. The aim of the present study was to find useful and reliable predictive biomarkers of the capacity to withstand the freeze-thawing process in human ejaculates. Methods We chose the two proteins as probable markers of sperm freezing capacity. Ejaculate samples were separated into good freezability ejaculates (GFE) and poor freezability ejaculates (PFE) according to progressive motility of the sperm after thawing. Before starting cryopreservation protocols, the two proteins from each group were compared using western blot analysis and immunofluorescence. Results Results showed that normalized content of enolase1 (ENO1) (P<0.05) and glucose-6-phosphate isomerase (GPI) (P<0.01) were both significantly higher in GFE than in PFE. The association of ENO1 and GPI with post thaw sperm viability and motility was confirmed using Pearson’s linear correlation. Conclusions In conclusion, ENO1 and GPI can be used as markers of human sperm freezability before starting the cryopreservation procedure.

  5. Cloning, characterization and computational analysis of the 5' regulatory region of ovine glucose 6-phosphate dehydrogenase gene.

    PubMed

    Laliotis, George P; Bizelis, Iosif; Argyrokastritis, Alexandros; Rogdakis, Emmanuel

    2007-08-01

    To better understand the structure and the function of ovine glucose 6-phosphate dehydrogenase (G6PD) promoter region, a genome-walking procedure was followed to isolate and sequence a 1628 bp fragment, containing the 5' regulatory region of the G6PD gene. In silico analysis of the sequence showed many conserved blocks and features with other known mammalian G6PD promoter regions. The analysis also revealed the presence of one TATA box, three GC boxes, two E-boxes and several binding sites for Stimulating Protein 1 (Sp1) and Activator Protein 2 (AP2). Moreover, elements involved in the regulation of lipogenesis like USF (Upstream stimulating factor), HSF (Heat Shock Factor), F2F (Prolactin receptor), RAR (Retinoid Acid Receptor), STRE (STress Response Element), RORa (Retinoid related Orphan Receptor alpha), GATA (GATA binding factor), RFX (Regulatory Factor X), SREBP (Sterol Regulatory Element Binding Protein), MEP (Metal Element Protein), CREB (insulin receptor), PRE (Progesterone receptor), and HNF4 (Hepatic Nuclear Factor 4) were detected. The most important regulatory motifs were found to be conserved as compared to those in human and mouse counterparts. However, some differences were noted, likely indicating differences in the transcription regulation of G6PD gene between ruminant and non-ruminant species.

  6. A comparative study of the anti-allergic effects of disodium baicalein 6-phosphate (BPS) and disodium cromoglycate (DSCG).

    PubMed

    Koda, A; Watanabe, S; Yanagihara, Y; Nagai, H; Sakamoto, K

    1977-02-01

    A comparative study was carried out on the effects of a soluble derivative of baicalein, disodium baicalein 6-phosphate (BPS) and disodium cromoglycate (DSCG) on the immediate type allergic reactions. BPS not only inhibited reaginic antibody-mediated reactions including antigen-induced mediator release from monkey lung, homologous PCA in rats, and reaginic antibody-mediated degranulation of mast cell, but also non-reaginic antibody-mediated reactions such as mediator release from guinea pig lung sensitized with ovalbumin and that from human lung caused by anti-IgE. The agent, however, did not affect the mediator release from lung of rats sensitized with dinitrophynylated ascaris extract plus Bordetella pertussis. On the other hand, DSCG showed characteristic properties as an inhibitor of reaginic antibody-mediated reaction. It is thus assumed that the functional site of reaginic antibody is well fixed with DSCG at a definite distance between the two-chromone-nuclei while that of IgG is readily fixed with the two molecules of baicalein or BPS.

  7. Chlamydia interfere with an interaction between the mannose-6-phosphate receptor and sorting nexins to counteract host restriction.

    PubMed

    Elwell, Cherilyn A; Czudnochowski, Nadine; von Dollen, John; Johnson, Jeffrey R; Nakagawa, Rachel; Mirrashidi, Kathleen; Krogan, Nevan J; Engel, Joanne N; Rosenberg, Oren S

    2017-03-02

    Chlamydia trachomatis is an obligate intracellular pathogen that resides in a membrane-bound compartment, the inclusion. The bacteria secrete a unique class of proteins, Incs, which insert into the inclusion membrane and modulate the host-bacterium interface. We previously reported that IncE binds specifically to the Sorting Nexin 5 Phox domain (SNX5-PX) and disrupts retromer trafficking. Here, we present the crystal structure of the SNX5-PX:IncE complex, showing IncE bound to a unique and highly conserved hydrophobic groove on SNX5. Mutagenesis of the SNX5-PX:IncE binding surface disrupts a previously unsuspected interaction between SNX5 and the cation-independent mannose-6-phosphate receptor (CI-MPR). Addition of IncE peptide inhibits the interaction of CI-MPR with SNX5. Finally, C. trachomatis infection interferes with the SNX5:CI-MPR interaction, suggesting that IncE and CI-MPR are dependent on the same binding surface on SNX5. Our results provide new insights into retromer assembly and underscore the power of using pathogens to discover disease-related cell biology.

  8. Immunization of Mastomys coucha with Brugia malayi recombinant trehalose-6-phosphate phosphatase results in significant protection against homologous challenge infection.

    PubMed

    Kushwaha, Susheela; Singh, Prashant Kumar; Rana, Ajay Kumar; Misra-Bhattacharya, Shailja

    2013-01-01

    Development of a vaccine to prevent or reduce parasite development in lymphatic filariasis would be a complementary approach to existing chemotherapeutic tools. Trehalose-6-phosphate phosphatase of Brugia malayi (Bm-TPP) represents an attractive vaccine target due to its absence in mammals, prevalence in the major life stages of the parasite and immunoreactivity with human bancroftian antibodies, especially from endemic normal subjects. We have recently reported on the cloning, expression, purification and biochemical characterization of this vital enzyme of B. malayi. In the present study, immunoprophylactic evaluation of Bm-TPP was carried out against B. malayi larval challenge in a susceptible host Mastomys coucha and the protective ability of the recombinant protein was evaluated by observing the adverse effects on microfilarial density and adult worm establishment. Immunization caused 78.4% decrease in microfilaremia and 71.04% reduction in the adult worm establishment along with sterilization of 70.06% of the recovered live females. The recombinant protein elicited a mixed Th1/Th2 type of protective immune response as evidenced by the generation of both pro- and anti-inflammatory cytokines IL-2, IFN-γ, TNF-α, IL-4 and an increased production of antibody isotypes IgG1, IgG2a, IgG2b and IgA. Thus immunization with Bm-TPP conferred considerable protection against B. malayi establishment by engendering a long-lasting effective immune response and therefore emerges as a potential vaccine candidate against lymphatic filariasis (LF).

  9. High hydrostatic pressure induces synthesis of heat-shock proteins and trehalose-6-phosphate synthase in Anastrepha ludens larvae.

    PubMed

    Vargas-Ortiz, Manuel A; Quintana-Castro, Rodolfo; Oliart-Ros, Rosa M; De la Cruz-Medina, Javier; Ramírez de León, José A; Garcia, Hugo S

    2013-04-01

    The Mexican fruit fly (Anastrepha ludens) is responsible for losses of up to 25% of crops such as mango and citrus fruits in Central America and México. The larval life cycle of A. ludens comprises three stages with a duration ranging from 3 to 8 days. Because of the damage caused by A. ludens, several methods of control have been studied and implemented. High hydrostatic pressures (HHP) are currently applied to foods and it is now proposed to be employed to inactivate eggs and larvae of A. ludens. Originally HHP was designed to inactivate microorganisms, since it exerts marked effects on cell morphology, and can affect enzymatic reactions and genetic mechanisms of microbial cells, with no major changes altering the sensory or nutritional quality of the foodstuff. In this study, A. ludens in two larval stages (5- and 8-day-old) were subjected to HHP treatments. The biochemical response of the larvae of A. ludens was dependent on their stage of development. The third larval stage (L3) developed a better protection mechanism based on the synthesis of stress proteins or heat-shock proteins (HSPs) and the enzyme trehalose-6-phosphate synthase, which are linked and possibly act together to achieve greater survivability to stress caused by hydrostatic pressure.

  10. Regulation of Enzyme Activities in Drosophila: Genetic Variation Affecting Induction of Glucose 6-Phosphate and 6-Phosphogluconate Dehydrogenases in Larvae

    PubMed Central

    Cochrane, Bruce J.; Lucchesi, John C.; Laurie-Ahlberg, C. C.

    1983-01-01

    The genetic basis of modulation by dietary sucrose of the enzyme activities glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) activities in third instar larvae of Drosophila melanogaster was investigated, using isogenic lines derived from wild populations. Considerable genetically determined variation in response was detected among lines that differed only in their third chromosome constitution. Comparison of crossreacting material between a responding and a nonresponding line showed that the G6PD activity variation is due to changes in G6PD protein level. These differences in responses are localized in the fat body, with 300 m m sucrose in the diet resulting in a sixfold stimulation of G6PD activity and a fourfold one of 6PGD in the line showing the strongest response. In this tissue, the responses of the two enzymes are closely correlated with one another. Using recombinant lines, we obtained data that suggested the existence of more than one gene on chromosome III involved in the regulation of G6PD in the fat body, and at least one of these genes affects the level of 6PGD as well. PMID:6416921

  11. Clathrin Terminal Domain-Ligand Interactions Regulate Sorting of Mannose 6-Phosphate Receptors Mediated by AP-1 and GGA Adaptors*

    PubMed Central

    Stahlschmidt, Wiebke; Robertson, Mark J.; Robinson, Phillip J.; McCluskey, Adam; Haucke, Volker

    2014-01-01

    Clathrin plays important roles in intracellular membrane traffic including endocytosis of plasma membrane proteins and receptors and protein sorting between the trans-Golgi network (TGN) and endosomes. Whether clathrin serves additional roles in receptor recycling, degradative sorting, or constitutive secretion has remained somewhat controversial. Here we have used acute pharmacological perturbation of clathrin terminal domain (TD) function to dissect the role of clathrin in intracellular membrane traffic. We report that internalization of major histocompatibility complex I (MHCI) is inhibited in cells depleted of clathrin or its major clathrin adaptor complex 2 (AP-2), a phenotype mimicked by application of Pitstop® inhibitors of clathrin TD function. Hence, MHCI endocytosis occurs via a clathrin/AP-2-dependent pathway. Acute perturbation of clathrin also impairs the dynamics of intracellular clathrin/adaptor complex 1 (AP-1)- or GGA (Golgi-localized, γ-ear-containing, Arf-binding protein)-coated structures at the TGN/endosomal interface, resulting in the peripheral dispersion of mannose 6-phosphate receptors. By contrast, secretory traffic of vesicular stomatitis virus G protein, recycling of internalized transferrin from endosomes, or degradation of EGF receptor proceeds unperturbed in cells with impaired clathrin TD function. These data indicate that clathrin is required for the function of AP-1- and GGA-coated carriers at the TGN but may be dispensable for outward traffic en route to the plasma membrane. PMID:24407285

  12. Molecular cloning and nucleotide sequence of cDNA for human glucose-6-phosphate dehydrogenase variant A(-)

    SciTech Connect

    Hirono, A.; Beutler, E. )

    1988-06-01

    Glucose-6-phosphate dehydrogenase A(-) is a common variant in Blacks that causes sensitivity to drug- and infection-induced hemolytic anemia. A cDNA library was constructed from Epstein-Barr virus-transformed lymphoblastoid cells from a male who was G6PD A(-). One of four cDNA clones isolated contained a sequence not found in the other clones nor in the published cDNA sequence. Consisting of 138 bases and coding 46 amino acids, this segment of cDNA apparently is derived from the alternative splicing involving the 3{prime} end of intron 7. Comparison of the remaining sequences of these clones with the published sequence revealed three nucleotide substitutions: C{sup 33} {yields} G, G{sup 202} {yields} A, and A{sup 376} {yields} G. Each change produces a new restriction site. Genomic DNA from five G6PD A(-) individuals was amplified by the polymerase chain reaction. The findings of the same mutation in G6PD A(-) as is found in G6PD A(+) strongly suggests that the G6PD A(-) mutation arose in an individual with G6PD A(+), adding another mutation that causes the in vivo instability of this enzyme protein.

  13. How do sugars regulate plant growth and development? New insight into the role of trehalose-6-phosphate.

    PubMed

    O'Hara, Liam E; Paul, Matthew J; Wingler, Astrid

    2013-03-01

    Plant growth and development are tightly controlled in response to environmental conditions that influence the availability of photosynthetic carbon in the form of sucrose. Trehalose-6-phosphate (T6P), the precursor of trehalose in the biosynthetic pathway, is an important signaling metabolite that is involved in the regulation of plant growth and development in response to carbon availability. In addition to the plant's own pathway for trehalose synthesis, formation of T6P or trehalose by pathogens can result in the reprogramming of plant metabolism and development. Developmental processes that are regulated by T6P range from embryo development to leaf senescence. Some of these processes are regulated in interaction with phytohormones, such as auxin. A key interacting factor of T6P signaling in response to the environment is the protein kinase sucrose non-fermenting related kinase-1 (SnRK1), whose catalytic activity is inhibited by T6P. SnRK1 is most likely involved in the adjustment of metabolism and growth in response to starvation. The transcription factor bZIP11 has recently been identified as a new player in the T6P/SnRK1 regulatory pathway. By inhibiting SnRK1, T6P promotes biosynthetic reactions. This regulation has important consequences for crop production, for example, in the developing wheat grain and during the growth of potato tubers.

  14. On-plate enzyme and inhibition assay of glucose-6-phosphate dehydrogenase using thin-layer chromatography.

    PubMed

    Tian, Miaomiao; Mohamed, Amara Camara; Wang, Shengtian; Yang, Li

    2015-08-01

    We performed on-plate enzyme and inhibition assays of glucose 6-phosphate dehydrogenase using thin-layer chromatography. The assays were accomplished based on different retardation factors of the substrates, enzyme, and products. All the necessary steps were integrated on-plate in one developing process, including substrate/enzyme mixing, reaction starting, and quenching as well as product separation. In order to quantitatively measure the enzyme reaction, the developed plate was then densitometrically evaluated to determine the peak area of the product. Rapid and high-throughput assays were achieved by loading different substrate spots and/or enzyme (and inhibition) spots in different tracks on the plate. The on-plate enzyme assay could be finished in a developing time of only 4 min, with good track-to-track and plate-to-plate repeatability. Moreover, we determined the Km values of the enzyme reaction and Ki values of the inhibition (Pb(2+) Cd(2+) and Cu(2+) as inhibitors), as well as the corresponding kinetics using the on-plate assay. Taken together, our method expanded the application of thin-layer chromatography in enzyme assays, and it could be potentially used in research fields for rapid and quantitative measurement of enzyme activity and inhibition. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Enhanced efficacy of enzyme replacement therapy in Pompe disease through mannose-6-phosphate receptor expression in skeletal muscle.

    PubMed

    Koeberl, Dwight D; Luo, Xiaoyan; Sun, Baodong; McVie-Wylie, Alison; Dai, Jian; Li, Songtao; Banugaria, Suhrad G; Chen, Y-T; Bali, Deeksha S

    2011-06-01

    Enzyme replacement therapy (ERT) with acid α-glucosidase has become available for Pompe disease; however, the response of skeletal muscle, as opposed to the heart, has been attenuated. The poor response of skeletal muscle has been attributed to the low abundance of the cation-independent mannose-6-phosphate receptor (CI-MPR) in skeletal muscle compared to heart. To further understand the role of CI-MPR in Pompe disease, muscle-specific CI-MPR conditional knockout (KO) mice were crossed with GAA-KO (Pompe disease) mice. We evaluated the impact of CI-MPR-mediated uptake of GAA by evaluating ERT in CI-MPR-KO/GAA-KO (double KO) mice. The essential role of CI-MPR was emphasized by the lack of efficacy of ERT as demonstrated by markedly reduced biochemical correction of GAA deficiency and of glycogen accumulations in double KO mice, in comparison with the administration of the same therapeutic doses in GAA-KO mice. Clenbuterol, a selective β(2)-agonist, enhanced the CI-MPR expression in skeletal tissue and also increased efficacy from GAA therapy, thereby confirming the key role of CI-MPR with regard to enzyme replacement therapy in Pompe disease. Biochemical correction improved in both muscle and non-muscle tissues, indicating that therapy could be similarly enhanced in other lysosomal storage disorders. In summary, enhanced CI-MPR expression might improve the efficacy of enzyme replacement therapy in Pompe disease through enhancing receptor-mediated uptake of GAA.

  16. Enhanced Efficacy of Enzyme Replacement Therapy in Pompe Disease Through Mannose-6-Phosphate Receptor Expression in Skeletal Muscle

    PubMed Central

    Koeberl, Dwight D.; Luo, Xiaoyan; Sun, Baodong; McVie-Wylie, Alison; Dai, Jian; Li, Songtao; Banugaria, Suhrad G.; Chen, Y-T; Bali, Deeksha S.

    2011-01-01

    Enzyme replacement therapy (ERT) with acid α-glucosidase has become available for Pompe disease; however, the response of skeletal muscle, as opposed to the heart, has been attenuated. The poor response of skeletal muscle has been attributed to the low abundance of the cation-independent mannose-6-phosphate receptor (CI-MPR) in skeletal muscle compared to heart. To further understand the role of CI-MPR in Pompe disease, muscle-specific CI-MPR conditional knockout (KO) mice were crossed with GAA-KO (Pompe disease) mice. We evaluated the impact of CI-MPR-mediated uptake of GAA by evaluating ERT in CI-MPR-KO/GAA-KO (double KO) mice. The essential role of CI-MPR was emphasized by the lack of efficacy of ERT as demonstrated by markedly reduced biochemical correction of GAA deficiency and of glycogen accumulations in double KO mice, in comparison with administration of the same therapeutic doses in GAA-KO mice. Clenbuterol, a selective β2-agonist, enhanced CI-MPR expression in skeletal tissue and also increased efficacy from GAA therapy, thereby confirming the key role of CI-MPR with regard to enzyme replacement therapy in Pompe disease. Biochemical correction improved in both muscle and non-muscle tissues, indicating that therapy could be similarly enhanced in other lysosomal storage disorders. In summary, enhanced CI-MPR expression might improve the efficacy of enzyme replacement therapy in Pompe disease through enhancing receptor-mediated uptake of GAA. PMID:21397538

  17. Functional and Biochemical Characterization of Three Recombinant Human Glucose-6-Phosphate Dehydrogenase Mutants: Zacatecas, Vanua-Lava and Viangchan

    PubMed Central

    Gómez-Manzo, Saúl; Marcial-Quino, Jaime; Vanoye-Carlo, America; Serrano-Posada, Hugo; González-Valdez, Abigail; Martínez-Rosas, Víctor; Hernández-Ochoa, Beatriz; Sierra-Palacios, Edgar; Castillo-Rodríguez, Rosa Angélica; Cuevas-Cruz, Miguel; Rodríguez-Bustamante, Eduardo; Arreguin-Espinosa, Roberto

    2016-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency in humans causes severe disease, varying from mostly asymptomatic individuals to patients showing neonatal jaundice, acute hemolysis episodes or chronic nonspherocytic hemolytic anemia. In order to understand the effect of the mutations in G6PD gene function and its relation with G6PD deficiency severity, we report the construction, cloning and expression as well as the detailed kinetic and stability characterization of three purified clinical variants of G6PD that present in the Mexican population: G6PD Zacatecas (Class I), Vanua-Lava (Class II) and Viangchan (Class II). For all the G6PD mutants, we obtained low purification yield and altered kinetic parameters compared with Wild Type (WT). Our results show that the mutations, regardless of the distance from the active site where they are located, affect the catalytic properties and structural parameters and that these changes could be associated with the clinical presentation of the deficiency. Specifically, the structural characterization of the G6PD Zacatecas mutant suggests that the R257L mutation have a strong effect on the global stability of G6PD favoring an unstable active site. Using computational analysis, we offer a molecular explanation of the effects of these mutations on the active site. PMID:27213370

  18. Functional and Biochemical Characterization of Three Recombinant Human Glucose-6-Phosphate Dehydrogenase Mutants: Zacatecas, Vanua-Lava and Viangchan.

    PubMed

    Gómez-Manzo, Saúl; Marcial-Quino, Jaime; Vanoye-Carlo, America; Serrano-Posada, Hugo; González-Valdez, Abigail; Martínez-Rosas, Víctor; Hernández-Ochoa, Beatriz; Sierra-Palacios, Edgar; Castillo-Rodríguez, Rosa Angélica; Cuevas-Cruz, Miguel; Rodríguez-Bustamante, Eduardo; Arreguin-Espinosa, Roberto

    2016-05-21

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency in humans causes severe disease, varying from mostly asymptomatic individuals to patients showing neonatal jaundice, acute hemolysis episodes or chronic nonspherocytic hemolytic anemia. In order to understand the effect of the mutations in G6PD gene function and its relation with G6PD deficiency severity, we report the construction, cloning and expression as well as the detailed kinetic and stability characterization of three purified clinical variants of G6PD that present in the Mexican population: G6PD Zacatecas (Class I), Vanua-Lava (Class II) and Viangchan (Class II). For all the G6PD mutants, we obtained low purification yield and altered kinetic parameters compared with Wild Type (WT). Our results show that the mutations, regardless of the distance from the active site where they are located, affect the catalytic properties and structural parameters and that these changes could be associated with the clinical presentation of the deficiency. Specifically, the structural characterization of the G6PD Zacatecas mutant suggests that the R257L mutation have a strong effect on the global stability of G6PD favoring an unstable active site. Using computational analysis, we offer a molecular explanation of the effects of these mutations on the active site.

  19. 2-Deoxy-2-fluoro-D-glucose as a functional probe for NMR: the unique metabolism beyond its 6-phosphate.

    PubMed

    Kanazawa, Y; Yamane, H; Shinohara, S; Kuribayashi, S; Momozono, Y; Yamato, Y; Kojima, M; Masuda, K

    1996-05-01

    Epimeric conversion of 2-deoxy-2-fluoro-D-glucose (FDG) to its 2-epimer 2-deoxy-2-fluoro-D-mannose (FDM) proved by 19F NMR has been shown to reflect the brain activity. To examine the feasibility of FDG as a new NMR probe for in vivo functional monitoring, we studied here the fundamental NMR properties of metabolites, spectral assignments, and reliability of NMR quantification. Metabolites confirmed in brain besides FDM-6-phosphate were as follows: FDG-1-phosphate, FDG-1,6-bisphosphate, FDM-1-phosphate, FDM-1,6-bisphosphate, and FDG and FDM derivatives of nucleotide diphosphate. NMR quantification of these metabolites was evaluated in comparison with the method of 18F-labeled FDG. In the NMR functional study using FDG, where a high dose is inevitable, the dose dependence of uptake was investigated. FDG uptake in mouse brain was shown to be in the range of interpretation using the biochemical parameters of enzymes for glucose uptake as long as a dose of < 200 mg/kg was used.

  20. Inhibition of Glucose-6-Phosphate Dehydrogenase Could Enhance 1,4-Benzoquinone-Induced Oxidative Damage in K562 Cells

    PubMed Central

    Cao, Meng; Yang, Wenwen; Sun, Fengmei; Xu, Cheng

    2016-01-01

    Benzene is a chemical contaminant widespread in industrial and living environments. The oxidative metabolites of benzene induce toxicity involving oxidative damage. Protecting cells and cell membranes from oxidative damage, glucose-6-phosphate dehydrogenase (G6PD) maintains the reduced state of glutathione (GSH). This study aims to investigate whether the downregulation of G6PD in K562 cell line can influence the oxidative toxicity induced by 1,4-benzoquinone (BQ). G6PD was inhibited in K562 cell line transfected with the specific siRNA of G6PD gene. An empty vector was transfected in the control group. Results revealed that G6PD was significantly upregulated in the control cells and in the cells with inhibited G6PD after they were exposed to BQ. The NADPH/NADP and GSH/GSSG ratio were significantly lower in the cells with inhibited G6PD than in the control cells at the same BQ concentration. The relative reactive oxygen species (ROS) level and DNA oxidative damage were significantly increased in the cell line with inhibited G6PD. The apoptotic rate and G2 phase arrest were also significantly higher in the cells with inhibited G6PD and exposed to BQ than in the control cells. Our results suggested that G6PD inhibition could reduce GSH activity and alleviate oxidative damage. G6PD deficiency is also a possible susceptible risk factor of benzene exposure. PMID:27656260

  1. Hemoglobin E and Glucose-6-Phosphate Dehydrogenase Deficiency and Plasmodium falciparum Malaria in the Chittagong Hill Districts of Bangladesh.

    PubMed

    Shannon, Kerry L; Ahmed, Sabeena; Rahman, Hafizur; Prue, Chai S; Khyang, Jacob; Ram, Malathi; Haq, M Zahirul; Chowdhury, Ashish; Akter, Jasmin; Glass, Gregory E; Shields, Timothy; Nyunt, Myaing M; Khan, Wasif A; Sack, David A; Sullivan, David J

    2015-08-01

    Hemoglobin E is largely confined to south and southeast Asia. The association between hemoglobin E (HbE) and malaria is less clear than that of hemoglobin S and C. As part of a malaria study in the Chittagong Hill Districts of Bangladesh, an initial random sample of 202 individuals showed that 39% and 49% of Marma and Khyang ethnic groups, respectively, were positive for either heterozygous or homozygous hemoglobin E. In this group, 6.4% were also found to be severely deficient and 35% mildly deficient for glucose-6-phosphate dehydrogenase (G6PD). In a separate Plasmodium falciparum malaria case-uninfected control study, the odds of having homozygous hemoglobin E (HbEE) compared with normal hemoglobin (HbAA) were higher among malaria cases detected by passive surveillance than age and location matched uninfected controls (odds ratio [OR] = 5.0, 95% confidence interval [CI] = 1.07-46.93). The odds of heterozygous hemoglobin E (HbAE) compared with HbAA were similar between malaria cases and uninfected controls (OR = 0.71, 95% CI = 0.42-1.19). No association by hemoglobin type was found in the initial parasite density or the proportion parasite negative after 2 days of artemether/lumefantrine treatment. HbEE, but not HbAE status was associated with increased passive case detection of malaria.

  2. False-Positive Newborn Screen Using the Beutler Spot Assay for Galactosemia in Glucose-6-Phosphate Dehydrogenase Deficiency.

    PubMed

    Stuhrman, Grace; Perez Juanazo, Stefanie J; Crivelly, Kea; Smith, Jennifer; Andersson, Hans; Morava, Eva

    2017-01-12

    Classical galactosemia is detected through newborn screening by measuring galactose-1-phosphate uridylyltransferase (GALT) in the USA primarily via the Beutler spot assay. We report on an 18-month-old patient with glucose-6-phosphate dehydrogenase (G6PD) deficiency that was originally diagnosed with classical galactosemia. The patient presented with elevated liver function enzymes and bilirubinemia and was immediately treated with soy-based formula. Confirmatory tests revealed deficiency of the GALT enzyme, however, full-sequencing of GALT was normal, suggestive of a different ideology. The Beutler spot assay uses three other enzymatic steps in addition to GALT. A deficiency in either of these enzymes can result in suspected decreased GALT activity when using the Beutler assay. Congenital Disorders of Glycosylation screening for phosphoglucomutase-1 deficiency was negative. Quantitative analysis of G6PD enzyme in red blood cells showed a severe deficiency and a deletion in G6PD. Soy-formula, the standard treatment for galactosemia, has been reported to trigger hemolysis in G6PD deficient patients. G6PD and phosphoglucomutase-1 deficiencies should be considered when confirmatory tests are negative for pathogenic variants in GALT and galactose-1-phosphate level is normal.

  3. Decreased Glutathione S-transferase Level and Neonatal Hyperbilirubinemia Associated with Glucose-6-phosphate Dehydrogenase Deficiency: A Perspective Review.

    PubMed

    Al-Abdi, Sameer Yaseen

    2017-02-01

    Classically, genetically decreased bilirubin conjugation and/or hemolysis account for the mechanisms contributing to neonatal hyperbilirubinemia associated with glucose-6-phosphate dehydrogenase (G6PD) deficiency. However, these mechanisms are not involved in most cases of this hyperbilirubinemia. Additional plausible mechanisms for G6PD deficiency-associated hyperbilirubinemia need to be considered. Glutathione S-transferases (GST) activity depends on a steady quantity of reduced form of glutathione (GSH). If GSH is oxidized, it is reduced back by glutathione reductase, which requires the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH). The main source of NADPH is the pentose phosphate pathway, in which G6PD is the first enzyme. Rat kidney GSH, rat liver GST, and human red blood cell GST levels have been found to positively correlate with G6PD levels in their respective tissues. As G6PD is expressed in hepatocytes, it is expected that GST levels would be significantly decreased in hepatocytes of G6PD-deficient neonates. As hepatic GST binds bilirubin and prevents their reflux into circulation, hypothesis that decreased GST levels in hepatocytes is an additional mechanism contributing to G6PD deficiency-associated hyperbilirubinemia seems plausible. Evidence for and against this hypothesis are discussed in this article hoping to stimulate further research on the role of GST in G6PD deficiency-associated hyperbilirubinemia.

  4. The ubiquitin ligase RNF126 regulates the retrograde sorting of the cation-independent mannose 6-phosphate receptor.

    PubMed

    Smith, Christopher J; McGlade, C Jane

    2014-01-15

    The ubiquitin proteasome system is central to the regulation of a number of intracellular sorting pathways in mammalian cells including quality control at the endoplasmic reticulum and the internalization and endosomal sorting of cell surface receptors. Here we describe that RNF126, an E3 ubiquitin ligase, is involved in the sorting of the cation-independent mannose 6-phosphate receptor (CI-MPR). In cells transiently depleted of RNF126, the CI-MPR is dispersed into Rab4 positive endosomes and the efficiency of retrograde sorting is delayed. Furthermore, the stable knockdown of RNF126 leads to the lysosomal degradation of CI-MPR and missorting of cathepsin D. RNF126 specifically regulates the sorting of the CI-MPR as other cargo that follow the retrograde sorting route including the cholera toxin, furin and TGN38 are unaffected in the absence of RNF126. Lastly we show that the RING finger domain of RNF126 is required to rescue the decrease in CI-MPR levels, suggesting that the ubiquitin ligase activity of RNF126 is required for CI-MPR sorting. Together, our data indicate that the ubiquitin ligase RNF126 has a role in the retrograde sorting of the CI-MPR.

  5. Cloning, expression, purification and characterization of his-tagged human glucose-6-phosphate dehydrogenase: a simplified method for protein yield.

    PubMed

    Gómez-Manzo, Saúl; Terrón-Hernández, Jessica; de la Mora-de la Mora, Ignacio; García-Torres, Itzhel; López-Velázquez, Gabriel; Reyes-Vivas, Horacio; Oria-Hernández, Jesús

    2013-10-01

    Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway. In erythrocytes, the functionality of the pathway is crucial to protect these cells against oxidative damage. G6PD deficiency is the most frequent enzymopathy in humans with a global prevalence of 4.9 %. The clinical picture is characterized by chronic or acute hemolysis in response to oxidative stress, which is related to the low cellular activity of G6PD in red blood cells. The disease is heterogeneous at genetic level with around 160 mutations described, mostly point mutations causing single amino acid substitutions. The biochemical studies aimed to describe the detrimental effects of mutations on the functional and structural properties of human G6PD are indispensable to understand the molecular physiopathology of this disease. Therefore, reliable systems for efficient expression and purification of the protein are highly desirable. In this work, human G6PD was heterologously expressed in Escherichia coli and purified by immobilized metal affinity chromatography in a single chromatographic step. The structural and functional characterization indicates that His-tagged G6PD resembles previous preparations of recombinant G6PD. In contrast with previous protein yield systems, our method is based on commonly available resources and fully accessible laboratory equipment; therefore, it can be readily implemented.

  6. Glucose-6-phosphate isomerase is an endogenous inhibitor to myofibril-bound serine proteinase of crucian carp (Carassius auratus).

    PubMed

    Sun, Le-Chang; Zhou, Li-Gen; Du, Cui-Hong; Cai, Qiu-Feng; Hara, Kenji; Su, Wen-Jin; Cao, Min-Jie

    2009-06-24

    Glucose-6-phosphate isomerase (GPI) was purified to homogeneity from the skeletal muscle of crucian carp ( Carassius auratus ) by ammonium sulfate fractionation, column chromatographies of Q-Sepharose, SP-Sepharose, and Superdex 200 with a yield of 8.0%, and purification folds of 468. The molecular mass of GPI was 120 kDa as estimated by gel filtration, while on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), two subunits (55 and 65 kDa) were identified, suggesting that it is a heterodimer. Interestingly, GPI revealed specific inhibitory activity toward a myofibril-bound serine proteinase (MBSP) from crucian carp, while no inhibitory activity was identified toward other serine proteinases, such as white croaker MBSP and crucian carp trypsin. Kinetic analysis showed that GPI is a competitive inhibitor toward MBSP, and the K(i) was 0.32 microM. Our present results indicated that the multifunctional protein GPI is an endogenous inhibitor to MBSP and may play a significant role in the regulation of muscular protein metabolism in vivo.

  7. Bidirectional apical-basal traffic of the cation-independent mannose-6-phosphate receptor in brain endothelial cells.

    PubMed

    Siupka, Piotr; Hersom, Maria Ns; Lykke-Hartmann, Karin; Johnsen, Kasper B; Thomsen, Louiza B; Andresen, Thomas L; Moos, Torben; Abbott, N Joan; Brodin, Birger; Nielsen, Morten S

    2017-07-01

    Brain capillary endothelium mediates the exchange of nutrients between blood and brain parenchyma. This barrier function of the brain capillaries also limits passage of pharmaceuticals from blood to brain, which hinders treatment of several neurological disorders. Receptor-mediated transport has been suggested as a potential pharmaceutical delivery route across the brain endothelium, e.g. reports have shown that the transferrin receptor (TfR) facilitates transcytosis of TfR antibodies, but it is not known whether this recycling receptor itself traffics from apical to basal membrane in the process. Here, we elucidate the endosomal trafficking of the retrograde transported cation-independent mannose-6-phosphate receptor (MPR300) in primary cultures of brain endothelial cells (BECs) of porcine and bovine origin. Receptor expression and localisation of MPR300 in the endo-lysosomal system and trafficking of internalised receptor are analysed. We also demonstrate that MPR300 can undergo bidirectional apical-basal trafficking in primary BECs in co-culture with astrocytes. This is, to our knowledge, the first detailed study of retrograde transported receptor trafficking in BECs, and the study demonstrates that MPR300 can be transported from the luminal to abluminal membrane and reverse. Such trafficking of MPR300 suggests that retrograde transported receptors in general may provide a mechanism for transport of pharmaceuticals into the brain.

  8. Canine malignant hyperthermia susceptibility: erythrocytic defects--osmotic fragility, glucose-6-phosphate dehydrogenase deficiency and abnormal Ca2+ homeostasis.

    PubMed Central

    O'Brien, P J; Forsyth, G W; Olexson, D W; Thatte, H S; Addis, P B

    1984-01-01

    Two dogs were diagnosed as malignant hyperthermia susceptible based on increased susceptibility (P less than 0.001) of biopsied muscle to caffeine-induced contracture. Erythrocytes from malignant hyperthermia and normal dogs were then examined for an antioxidant system deficiency. Values for serum muscle enzymes, reticulocytes and corpuscular hemoglobin were mildly elevated. Osmotic fragility was increased: hemolysis occurred at a NaCl concentration 10 mM higher than for normal dogs (P less than 0.001). A 35% glucose-6-phosphate dehydrogenase deficiency (P less than 0.001) with a 40% compensatory increase (P less than 0.01) in 6-phosphogluconate dehydrogenase activity was found. The membrane Ca2+-activated ATPase activity was abnormal: 100% increased with a 40% decreased Arrhenius activation energy (P less than 0.005) and increased thermostability. A 40% increased intracellular accumulation of total Ca2+ occurred in response to in vitro energy depletion in erythrocytes from one malignant hyperthermia dog (P less than 0.01). The multifactorial pattern of inheritance and the broad spectrum of malignant hyperthermia susceptibility are proposed to result from an antioxidant system deficit unmasking or aggravating an intrinsic muscle membrane anomaly. An individual from a family with a history of malignant hyperthermia or unexplained anesthetic death should be considered malignant hyperthermia susceptible if erythrocyte osmotic fragility is abnormal and there is a mild, unexplained elevation in serum creatine kinase. PMID:6150753

  9. Clonal evolution following chemotherapy-induced stem cell depletion in cats heterozygous for glucose-6-phosphate dehydrogenase

    SciTech Connect

    Abkowitz, J.L.; Ott, R.M.; Holly, R.D.; Adamson, J.W.

    1988-06-01

    The number of hematopoietic stem cells necessary to support normal hematopoiesis is not known but may be small. If so, the depletion or damage of such cells could result in apparent clonal dominance. To test this hypothesis, dimethylbusulfan (2 to 4 mg/kg intravenously (IV) x 3) was given to cats heterozygous for the X-linked enzyme glucose-6-phosphate dehydrogenase (G-6-PD). These cats were the daughters of domestic X Geoffroy parents. After the initial drug-induced cytopenias (2 to 4 weeks), peripheral blood counts and the numbers of marrow progenitors detected in culture remained normal, although the percentages of erythroid burst-forming cells (BFU-E) and granulocyte/macrophage colony-forming cells (CFU-GM) in DNA synthesis increased, as determined by the tritiated thymidine suicide technique. In three of six cats treated, a dominance of Geoffroy-type G-6-PD emerged among the progenitor cells, granulocytes, and RBCs. These skewed ratios of domestic to Geoffroy-type G-6-PD have persisted greater than 3 years. No changes in cell cycle kinetics or G-6-PD phenotypes were noted in similar studies in six control cats. These data suggest that clonal evolution may reflect the depletion or damage of normal stem cells and not only the preferential growth and dominance of neoplastic cells.

  10. Role of glucose-6-phosphate dehydrogenase inhibition in the antiproliferative effects of dehydroepiandrosterone on human breast cancer cells.

    PubMed Central

    Di Monaco, M.; Pizzini, A.; Gatto, V.; Leonardi, L.; Gallo, M.; Brignardello, E.; Boccuzzi, G.

    1997-01-01

    Epidemiological and experimental studies suggest that dehydroepiandrosterone (DHEA) exerts a protective effect against breast cancer. It has been proposed that the non-competitive inhibition of glucose-6-phosphate dehydrogenase (G6PD) contributes to DHEA antitumor action. We evaluated the effects of DHEA on G6PD activity and on the in vitro proliferation of two human breast cancer cell lines, MCF-7 (steroid receptor positive) and MDA-MB-231 (steroid receptor negative), in a serum-free assay. DHEA inhibition of G6PD was only found to occur at concentrations above 10 microM; at these high concentrations, the growth curve was parallel to the enzyme inhibition curve in both cell lines. In contrast, at concentrations in the in vivo breast tissue concentration range, neither cell growth nor enzyme activity was inhibited. The results failed to confirm DHEA's putative anti-tumor action on breast cancer through G6PD inhibition, as the enzyme blockade only becomes apparent at pharmacological concentrations of the steroid. PMID:9052415

  11. Chlamydia interfere with an interaction between the mannose-6-phosphate receptor and sorting nexins to counteract host restriction

    PubMed Central

    Elwell, Cherilyn A; Czudnochowski, Nadine; von Dollen, John; Johnson, Jeffrey R; Nakagawa, Rachel; Mirrashidi, Kathleen; Krogan, Nevan J; Engel, Joanne N; Rosenberg, Oren S

    2017-01-01

    Chlamydia trachomatis is an obligate intracellular pathogen that resides in a membrane-bound compartment, the inclusion. The bacteria secrete a unique class of proteins, Incs, which insert into the inclusion membrane and modulate the host-bacterium interface. We previously reported that IncE binds specifically to the Sorting Nexin 5 Phox domain (SNX5-PX) and disrupts retromer trafficking. Here, we present the crystal structure of the SNX5-PX:IncE complex, showing IncE bound to a unique and highly conserved hydrophobic groove on SNX5. Mutagenesis of the SNX5-PX:IncE binding surface disrupts a previously unsuspected interaction between SNX5 and the cation-independent mannose-6-phosphate receptor (CI-MPR). Addition of IncE peptide inhibits the interaction of CI-MPR with SNX5. Finally, C. trachomatis infection interferes with the SNX5:CI-MPR interaction, suggesting that IncE and CI-MPR are dependent on the same binding surface on SNX5. Our results provide new insights into retromer assembly and underscore the power of using pathogens to discover disease-related cell biology. DOI: http://dx.doi.org/10.7554/eLife.22709.001 PMID:28252385

  12. Red Cell Glucose-6-Phosphate Dehydrogenase Deficiency—A Newly Recognized Cause of Neonatal Jaundice and Kernicterus in Canada

    PubMed Central

    Naiman, J. Lawrence; Kosoy, Martin H.

    1964-01-01

    Seven male newborns of Chinese, Greek and Italian origin presented with severe hemolytic jaundice due to red cell glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. In five, the hemolysis was precipitated by inhalation of mothball vapours in the home. Kernicterus was evident upon admission in six infants and was fatal in four of these. G-6-PD deficiency should be suspected as a cause of jaundice in all full-term male infants of these ethnic groups. The diagnosis can be confirmed in any hospital by the methemoglobin reduction test. In areas similar to Toronto, Canada, where these high-risk ethnic groups prevail, the following measures are recommended: (1) detection of G-6-PD deficient newborns by screening cord bloods of all infants of these ethnic groups; (2) protection of affected infants from potentially hemolytic agents such as naphthalene, certain vitamin K preparations, and sulfonamides; and (3) observation of serum bilirubin levels to assess the need for exchange transfusion for hyperbilirubinemia. ImagesFig. 1 PMID:14226101

  13. Overexpression, purification and enzymatic characterization of a recombinant plastidial glucose-6-phosphate dehydrogenase from barley (Hordeum vulgare cv. Nure) roots.

    PubMed

    Cardi, Manuela; Chibani, Kamel; Castiglia, Daniela; Cafasso, Donata; Pizzo, Elio; Rouhier, Nicolas; Jacquot, Jean-Pierre; Esposito, Sergio

    2013-12-01

    In plant cells, the plastidial glucose 6-phosphate dehydrogenase (P2-G6PDH, EC 1.1.1.49) represents one of the most important sources of NADPH. However, previous studies revealed that both native and recombinant purified P2-G6PDHs show a great instability and a rapid loss of catalytic activity. Therefore it has been difficult to describe accurately the catalytic and physico-chemical properties of these isoforms. The plastidial G6PDH encoding sequence from barley roots (Hordeum vulgare cv. Nure), devoid of a long plastidial transit peptide, was expressed as recombinant protein in Escherichia coli, either untagged or with an N-terminal his-tag. After purification from both the soluble fraction and inclusion bodies, we have explored its kinetic parameters, as well as its sensitivity to reduction. The obtained results are consistent with values determined for other P2-G6PDHs previously purified from barley roots and from other land plants. Overall, these data shed light on the catalytic mechanism of plant P2-G6PDH, summarized in a proposed model in which the sequential mechanism is very similar to the mammalian cytosolic G6PDH. This study provides a rational basis to consider the recombinant barley root P2-G6PDH as a good model for further kinetic and structural studies.

  14. Allosteric transition and substrate binding are entropy-driven in glucosamine-6-phosphate deaminase from Escherichia coli.

    PubMed

    Bustos-Jaimes, I; Calcagno, M L

    2001-10-15

    Glucosamine-6P-deaminase (EC 3.5.99.6, formerly glucosamine-6-phosphate isomerase, EC 5.3.1.10) from Escherichia coli is an attractive experimental model for the study of allosteric transitions because it is both kinetically and structurally well-known, and follows rapid equilibrium random kinetics, so that the kinetic K(m) values are true thermodynamic equilibrium constants. The enzyme is a typical allosteric K-system activated by N-acetylglucosamine 6-P and displays an allosteric behavior that can be well described by the Monod-Wyman-Changeux model. This thermodynamic study based on the temperature dependence of allosteric parameters derived from this model shows that substrate binding and allosteric transition are both entropy-driven processes in E. coli GlcN6P deaminase. The analysis of this result in the light of the crystallographic structure of the enzyme implicates the active-site lid as the structural motif that could contribute significantly to this entropic component of the allosteric transition because of the remarkable change in its crystallographic B factors.

  15. Inhibition of insulin-like growth factor II (IGF-II)-dependent cell growth by multidentate pentamannosyl 6-phosphate-based ligands targeting the mannose 6-phosphate/IGF-II receptor

    PubMed Central

    Grosely, Rosslyn; MacDonald, Richard G.

    2016-01-01

    The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) binds M6P-capped ligands and IGF-II at different binding sites within the ectodomain and mediates ligand internalization and trafficking to the lysosome. Multivalent M6P-based ligands can cross-bridge the M6P/IGF2R, which increases the rate of receptor internalization, permitting IGF-II binding as a passenger ligand and subsequent trafficking to the lysosome, where the IGF-II is degraded. This unique feature of the receptor may be exploited to design novel therapeutic agents against IGF-II-dependent cancers that will lead to decreased bioavailable IGF-II within the tumor microenvironment. We have designed a panel of M6P-based ligands that bind to the M6P/IGF2R with high affinity in a bivalent manner and cause decreased cell viability. We present evidence that our ligands bind through the M6P-binding sites of the receptor and facilitate internalization and degradation of IGF-II from conditioned medium to mediate this cellular response. To our knowledge, this is the first panel of synthetic bivalent ligands for the M6P/IGF2R that can take advantage of the ligand-receptor interactions of the M6P/IGF2R to provide proof-of-principle evidence for the feasibility of novel chemotherapeutic agents that decrease IGF-II-dependent growth of cancer cells. PMID:27694692

  16. Evidence for the coordinate control of glycogen synthesis, glucose utilization, and glycolysis in Escherichia coli. II. Quantitative correlation of the inhibition of glycogen synthesis and the stimulation of glucose utilization by 2,4-dinitrophenol with the effects on the cellular levels of glucose 6-phosphate, fructose, 1,6-diphosphate, and total adenylates.

    PubMed

    Dietzler, D N; Leckie, M P; Magnani, J L; Sughrue, M J; Bergstein, P E

    1975-09-25

    In cultures of Escherichia coli W4597(K) and G34 under various nutritional conditions the rates of glucose utilization and cellular levels of fructose-1,6-P2 are quantitatively related by the Hill equation where the value of the Hill coefficient is approximately equal to 2. This is the first evidence that fructose-P2, or any metabolite which covaries with fructose-P2, modulates glucose utilization in E. coli. In light of previous observations from our laboratory this new observation and those in the succeeding report provide the first evidence that in E. coli glycolsis, glycogen synthesis and glucose utilization are coordinately regulated, thus providing for the coupling of ATP utilization and production under various metabolic circumstances. Alterations in the level of ATP apparently affect the velocity of phosphofructokinase, the rate-limiting enzyme in glycolsis, altering the cellular levels of glucose-6-P or fructose-P2. Changes in the levels of these hexose phosphates are quantitatively related to alterations in the rates of glucose utilization and glycogen synthesis in the intact E. coli cell.

  17. Effects of variant UDP-glucuronosyltransferase 1A1 gene, glucose-6-phosphate dehydrogenase deficiency and thalassemia on cholelithiasis

    PubMed Central

    Huang, Yang-Yang; Huang, Ching-Shui; Yang, Sien-Sing; Lin, Min-Shung; Huang, May-Jen; Huang, Ching-Shan

    2005-01-01

    AIM: To test the hypothesis that the variant UDP-glucuronosyltransferase 1A1 (UGT1A1) gene, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and thalassemia influence bilirubin metabolism and play a role in the development of cholelithiasis. METHODS: A total of 372 Taiwan Chinese with cholelithiasis who had undergone cholecystectomy and 293 healthy individuals were divided into case and control groups, respectively. PCR and restriction fragment length polymorphism were used to analyze the promoter area and nucleotides 211, 686, 1 091, and 1 456 of the UGT1A1 gene for all subjects and the gene variants for thalassemia and G6PD deficiency. RESULTS: Variation frequencies for the cholelithiasis patients were 16.1%, 25.8%, 5.4%, and 4.3% for A(TA)6 TAA/A(TA)7TAA (6/7), heterozygosity within the coding region, compound heterozygosity, and homozygosity of the UGT1A1 gene, respectively. Comparing the case and control groups, a statistically significant difference in frequency was demonstrated for the homozygous variation of the UGT1A1 gene (P = 0.012, χ2 test), but not for the other variations. Further, no difference was demonstrated in a between-group comparison of the incidence of G6PD deficiency and thalassemia (2.7% vs 2.4% and 5.1% vs 5.1%, respectively). The bilirubin levels for the cholelithiasis patients with the homozygous variant-UGT1A1 gene were significantly different from the control analog (18.0 ± 6.5 and 12.7 ± 2.9 μmol/L, respectively; P<0.001, Student’s t test). CONCLUSION: Our results show that the homozygous variation in the UGT1A1 gene is a risk factor for the development of cholelithiasis in Taiwan Chinese. PMID:16237771

  18. Feedback Inhibition of Starch Degradation in Arabidopsis Leaves Mediated by Trehalose 6-Phosphate1[W][OPEN

    PubMed Central

    Martins, Marina Camara Mattos; Hejazi, Mahdi; Fettke, Joerg; Steup, Martin; Feil, Regina; Krause, Ursula; Arrivault, Stéphanie; Vosloh, Daniel; Figueroa, Carlos María; Ivakov, Alexander; Yadav, Umesh Prasad; Piques, Maria; Metzner, Daniela; Stitt, Mark; Lunn, John Edward

    2013-01-01

    Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by β-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 µm in the cytosol, 0.2 to 0.5 µm in the chloroplasts, and 0.05 µm in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night. PMID:24043444

  19. Prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in the Ouest and Sud-Est departments of Haiti.

    PubMed

    von Fricken, Michael E; Weppelmann, Thomas A; Eaton, Will T; Alam, Meer T; Carter, Tamar E; Schick, Laura; Masse, Roseline; Romain, Jean R; Okech, Bernard A

    2014-07-01

    Malaria remains a significant public health issue in Haiti, with chloroquine (CQ) used almost exclusively for the treatment of uncomplicated infections. Recently, single dose primaquine (PQ) was added to the Haitian national malaria treatment policy, despite a lack of information on the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency within the population. G6PD deficient individuals who take PQ are at risk of developing drug induced hemolysis (DIH). In this first study to examine G6PD deficiency rates in Haiti, 22.8% (range 14.9%-24.7%) of participants were found to be G6PD deficient (class I, II, or III) with 2.0% (16/800) of participants having severe deficiency (class I and II). Differences in deficiency were observed by gender, with males having a much higher prevalence of severe deficiency (4.3% vs. 0.4%) compared to females. Male participants were 1.6 times more likely to be classified as deficient and 10.6 times more likely to be classified as severely deficient compared to females, as expected. Finally, 10.6% (85/800) of the participants were considered to be at risk for DIH. Males also had much higher rates than females (19.3% vs. 4.6%) with 4.9 times greater likelihood (p value 0.000) of having an activity level that could lead to DIH. These findings provide useful information to policymakers and clinicians who are responsible for the implementation of PQ to control and manage malaria in Haiti. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Genome-Wide Identification and Evolution Analysis of Trehalose-6-Phosphate Synthase Gene Family in Nelumbo nucifera

    PubMed Central

    Jin, Qijiang; Hu, Xin; Li, Xin; Wang, Bei; Wang, Yanjie; Jiang, Hongwei; Mattson, Neil; Xu, Yingchun

    2016-01-01

    Trehalose-6-phosphate synthase (TPS) plays a key role in plant carbohydrate metabolism and the perception of carbohydrate availability. In the present work, the publicly available Nelumbo nucifera (lotus) genome sequence database was analyzed which led to identification of nine lotus TPS genes (NnTPS). It was found that at least two introns are included in the coding sequences of NnTPS genes. When the motif compositions were analyzed we found that NnTPS generally shared the similar motifs, implying that they have similar functions. The dN/dS ratios were always less than 1 for different domains and regions outside domains, suggesting purifying selection on the lotus TPS gene family. The regions outside TPS domain evolved relatively faster than NnTPS domains. A phylogenetic tree was constructed using all predicted coding sequences of lotus TPS genes, together with those from Arabidopsis, poplar, soybean, and rice. The result indicated that those TPS genes could be clearly divided into two main subfamilies (I-II), where each subfamily could be further divided into 2 (I) and 5 (II) subgroups. Analyses of divergence and adaptive evolution show that purifying selection may have been the main force driving evolution of plant TPS genes. Some of the critical sites that contributed to divergence may have been under positive selection. Transcriptome data analysis revealed that most NnTPS genes were predominantly expressed in sink tissues. Expression pattern of NnTPS genes under copper and submergence stress indicated that NNU_014679 and NNU_022788 might play important roles in lotus energy metabolism and participate in stress response. Our results can facilitate further functional studies of TPS genes in lotus. PMID:27746792

  1. Glucose regulates enzymatic sources of mitochondrial NADPH in skeletal muscle cells; a novel role for glucose-6-phosphate dehydrogenase.

    PubMed

    Mailloux, Ryan J; Harper, Mary-Ellen

    2010-07-01

    Reduced nicotinamide adenine dinucleotide (NADPH) is a functionally important metabolite required to support numerous cellular processes. However, despite the identification of numerous NADPH-producing enzymes, the mechanisms underlying how the organellar pools of NADPH are maintained remain elusive. Here, we have identified glucose-6-phosphate dehydrogenase (G6PDH) as an important source of NADPH in mitochondria. Activity analysis, submitochondrial fractionation, fluorescence microscopy, and protease sensitivity assays revealed that G6PDH is localized to the mitochondrial matrix. 6-ANAM, a specific G6PDH inhibitor, depleted mitochondrial NADPH pools and increased oxidative stress revealing the importance of G6PDH in NADPH maintenance. We also show that glucose availability and differences in metabolic state modulate the enzymatic sources of NADPH in mitochondria. Indeed, cells cultured in high glucose (HG) not only adopted a glycolytic phenotype but also relied heavily on matrix-associated G6PDH as a source of NADPH. In contrast, cells exposed to low-glucose (LG) concentrations, which displayed increased oxygen consumption, mitochondrial metabolic efficiency, and decreased glycolysis, relied predominantly on isocitrate dehydrogenase (ICDH) as the principal NADPH-producing enzyme in the mitochondria. Culturing glycolytic cells in LG for 48 h decreased G6PDH and increased ICDH protein levels in the mitochondria, further pointing to the regulatory role of glucose. 2-Deoxyglucose treatment also prevented the increase of mitochondrial G6PDH in response to HG. The role of glucose in regulating enzymatic sources of mitochondrial NADPH pool maintenance was confirmed using human myotubes from obese adults with a history of type 2 diabetes mellitus (post-T2DM). Myotubes from post-T2DM participants failed to increase mitochondrial G6PDH in response to HG in contrast to mitochondria in myotubes from control participants (non-T2DM). Hence, we not only identified a matrix

  2. Hematological parameters and red blood cell morphological abnormality of Glucose-6-Phosphate dehydrogenase deficiency co-inherited with thalassemia.

    PubMed

    Pengon, Jutharat; Svasti, Saovaros; Kamchonwongpaisan, Sumalee; Vattanaviboon, Phantip

    2017-06-15

    Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and thalassemia are genetically independent hemolytic disorders. Co-inheritance of both disorders may affect red blood cell pathology to a greater extent than normally seen in either disorder alone. This study determines the prevalence and evaluates hematological changes of G-6-PD deficiency and thalassemia co-inheritance. G-6-PD deficiency was screened from 200 male thalassemia blood samples using a fluorescent spot test. Hematological parameters and red blood cell morphology were evaluated among G-6-PD deficiency/thalassemia co-inheritance, G-6-PD deficiency alone, thalassemia alone, and normal individuals. G-6-PD deficiency was detected together with hemoglobin (Hb) E heterozygote, Hb E homozygote, β-thalassemia trait, and β-thalassemia/Hb E, α-thalassemia-2 trait, and Hb H disease. Hb level, hematocrit, mean cell volume, and mean cell Hb of G-6-PD deficiency co-inherited with asymptomatic thalassemia carriers show significantly lower mean values compared to carriers with only the same thalassemia genotypes. Higher mean red blood cell distribution width was observed in G-6-PD deficiency co-inherited with Hb E heterozygote, as with numbers of hemighost cells in G-6-PD deficiency/thalassemia co-inheritance compared to those with either disorder. Apart from Hb level, hematological parameters of co-inheritance disorders were not different from individuals with a single thalassemia disease. G-6-PD deficiency co-inherited with thalassemia in males was present in 10% of the participants, resulting in worsening of red blood cell pathology compared with inheritance of thalassemia alone. Copyright © 2017 King Faisal Specialist Hospital & Research Centre. Published by Elsevier B.V. All rights reserved.

  3. Regulation of methyl-beta-d-thiogalactopyranoside-6-phosphate accumulation in Streptococcus lactis by exclusion and expulsion mechanisms.

    PubMed Central

    Thompson, J; Saier, M H

    1981-01-01

    Starved cells of Streptococcus lactis ML3 (grown previously on galactose, lactose, or maltose) accumulated methyl-beta-D-thiogalactopyranoside (TMG) by the lactose:phosphotransferase system. More than 98% of accumulated sugar was present as a phosphorylated derivative, TMG-6-phosphate (TMG-6P). When a phosphotransferase system sugar (glucose, mannose, 2-deoxyglucose, or lactose) was added to the medium simultaneously with TMG, the beta-galactoside was excluded from the cells. Galactose enhanced the accumulation of TMG-6P. Glucose, mannose, lactose, or maltose plus arginine, was added to a suspension of TMG-6P-loaded cells of S. lactis ML3, elicited rapid expulsion of intracellular solute. The material recovered in the medium was exclusively free TMG. Expulsion of galactoside required both entry and metabolism of an appropriate sugar, and intracellular dephosphorylation of TMG-6P preceded efflux of TMG. The rate of dephosphorylation of TMG-6P by permeabilized cells was increased two-to threefold by adenosine 5'-triphosphate but was strongly inhibited by fluoride. S. lactis ML3 (DGr) was derived from S. lactis ML3 by positive selection for resistance to 2-deoxy-D-glucose and was defective in the enzyme IIMan component of the glucose:phosphotransferase system. Neither glucose nor mannose excluded TMG from cells of S. lactic ML3 (DGr), and these two sugars failed to elicit TMG expulsion from preloaded cells of the mutant strain. Accumulation of TMG-6P by S. lactis ML3 can be regulation by two independent mechanisms whose activities promote exclusion or expulsion of galactoside from the cell. PMID:6787017

  4. Epinephrine enhances lysosomal enzyme delivery across the blood brain barrier by up-regulation of the mannose 6-phosphate receptor.

    PubMed

    Urayama, Akihiko; Grubb, Jeffrey H; Banks, William A; Sly, William S

    2007-07-31

    Delivering therapeutic levels of lysosomal enzymes across the blood-brain barrier (BBB) has been a pivotal issue in treating CNS storage diseases, including the mucopolysaccharidoses. An inherited deficiency of beta-glucuronidase (GUS) causes mucopolysaccharidosis type VII that is characterized by increased systemic and CNS storage of glycosaminoglycans. We previously showed that the neonate uses the mannose 6-phosphate (M6P) receptor to transport phosphorylated GUS (P-GUS) across the BBB and that this transporter is lost with maturation. Induction of expression of this BBB transporter would make enzyme replacement therapy in the adult possible. Here, we tested pharmacological manipulation with epinephrine to restore functional transport of P-GUS across the adult BBB. Epinephrine (40 nmol) coinjected i.v. with (131)I-P-GUS induced the transport across the BBB in 8-week-old mice. The brain influx rate of (131)I-P-GUS (0.29 mul/g per min) returned to the level seen in neonates. Capillary depletion showed that 49% of the (131)I-P-GUS in brain was in brain parenchyma. No increases of influx rate or the vascular space for (125)I-albumin, a vascular marker, was observed with epinephrine (40 nmol), showing that enhanced passage was not caused by disruption of the BBB. Brain uptake of (131)I-P-GUS was significantly inhibited by M6P in a dose-dependent manner, whereas epinephrine failed to increase brain uptake of nonphosphorylated GUS. Thus, the effect of epinephrine on the transport of (131)I-P-GUS was ligand specific. These results indicate that epinephrine restores the M6P receptor-mediated functional transport of (131)I-P-GUS across the BBB in adults to levels seen in the neonate.

  5. Reduction of Tendon Adhesions following Administration of Adaprev, a Hypertonic Solution of Mannose-6-Phosphate: Mechanism of Action Studies

    PubMed Central

    Wong, Jason K. F.; Metcalfe, Anthony D.; Wong, Richard; Bush, Jim; Platt, Chris; Garcon, Arnaud; Goldspink, Nick; McGrouther, Duncan A.; Ferguson, Mark W. J.

    2014-01-01

    Repaired tendons may be complicated by progressive fibrosis, causing adhesion formation or tendon softening leading to tendon rupture and subsequent reduced range of motion. There are few therapies available which improve the gliding of damaged tendons in the hand. We investigate the role of Mannose 6-phosphate (M6P) in a 600 mM hypertonic solution (Adaprev) on tendon adhesion formation in vivo using a mouse model of severed tendon in conjunction with analysis of collagen synthesis, cellular proliferation and receptors involved in TGF beta signalling. Cytotoxicity was assessed by measuring tissue residency, mechanical strength and cell viability of tendons after treatment with Adaprev. To elicit potential modes of action, in vitro and ex vivo studies were performed investigating phosphorylation of p38, cell migration and proliferation. Adaprev treatment significantly (p<0.05) reduced the development of adhesions and improved collagen organisation without reducing overall collagen synthesis following tendon injury in vivo. The bioavailability of Adaprev saw a 40% reduction at the site of administration over 45 minutes and tendon fibroblasts tolerated up to 120 minutes of exposure without significant loss of cell viability or tensile strength. These favourable effects were independent of CI-MPR and TGF-β signalling and possibly highlight a novel mechanism of action related to cellular stress demonstrated by phosphorylation of p38. The effect of treatment reduced tendon fibroblast migration and transiently halted tendon fibroblast proliferation in vitro and ex vivo. Our studies demonstrate that the primary mode of action for Adaprev is potentially via a physical, non-chemical, hyperosmotic effect. PMID:25383548

  6. Autosomal factors with correlated effects on the activities of the glucose 6-phosphate and 6-phosphogluconate dehydrogenases in Drosophila melanogaster.

    PubMed

    Laurie-Ahlberg, C C; Williamson, J H; Cochrane, B J; Wilton, A N; Chasalow, F I

    1981-09-01

    Isogenic lines, in which chromosomes sampled from natural populations of C. melanogaster are substituted into a common genetic background, were used to detect and partially characterize autosomal factors that affect the activities of the two pentose phosphate pathway enzymes, glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD). The chromosome 3 effects on G6PD and 6PGD are clearly correlated; the chromosome 2 effects, which are not so great, also appear to be correlated, but the evidence in this case is not so strong. Examination of activity variation of ten other enzymes revealed that G6PD and 6PGD are not the only pair of enzymes showing a high positive correlation, but it is among the highest in both sets of lines. In addition, there was some evidence that the factor(s) affecting G6PD and 6PGD may also affect two other metabolically related enzymes, transaldolase and phosphoglucose isomerase.--Rocket immunoelectrophoresis was used to estimate specific CRM levels for three of the enzymes studied: G6PD, 6PGD and ME. This experiment shows that a large part of the activity variation is accounted for by variation in CRM level (especially for chromosome 3 lines), but there remains a significant fraction of the genetic component of activity variation that is not explained by CRM level.--These results suggest that the autosomal factors are modifiers involved in regulation of the expression of the X-linked structural genes for G6PD and 6PGD, but a role in determining part of the enzymes' primary structure cannot be excluded with the present evidence.

  7. Autosomal Factors with Correlated Effects on the Activities of the Glucose 6-Phosphate and 6-Phosphogluconate Dehydrogenases in DROSOPHILA MELANOGASTER

    PubMed Central

    Laurie-Ahlberg, C. C.; Williamson, J. H.; Cochrane, B. J.; Wilton, A. N.; Chasalow, F. I.

    1981-01-01

    Isogenic lines, in which chromosomes sampled from natural populations of D. melanogaster are substituted into a common genetic background, were used to detect and partially characterize autosomal factors that affect the activities of the two pentose phosphate pathway enzymes, glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD). The chromosome 3 effects on G6PD and 6PGD are clearly correlated; the chromosome 2 effects, which are not so great, also appear to be correlated, but the evidence in this case is not so strong. Examination of activity variation of ten other enzymes revealed that G6PD and 6PGD are not the only pair of enzymes showing a high positive correlation, but it is among the highest in both sets of lines. In addition, there was some evidence that the factor(s) affecting G6PD and 6PGD may also affect two other metabolically related enzymes, transaldolase and phosphoglucose isomerase.—Rocket immunoelectrophoresis was used to estimate specific CRM levels for three of the enzymes studied: G6PD, 6PGD and ME. This experiment shows that a large part of the activity variation is accounted for by variation in CRM level (especially for chromosome 3 lines), but there remains a significant fraction of the genetic component of activity variation that is not explained by CRM level.—These results suggest that the autosomal factors are modifiers involved in regulation of the expression of the X-linked structural genes for G6PD and 6PGD, but a role in determining part of the enzymes' primary structure cannot be excluded with the present evidence. PMID:6804300

  8. Regulatory mechanism of the three-component system HptRSA in glucose-6-phosphate uptake in Staphylococcus aureus.

    PubMed

    Yang, Yifan; Sun, Haipeng; Liu, Xiaoyu; Wang, Mingxing; Xue, Ting; Sun, Baolin

    2016-06-01

    Glucose-6-phosphate (G6P) is a common alternative carbon source for various bacteria, and its uptake usually relies on the hexose phosphate antiporter UhpT. In the human pathogenic bacterium Staphylococcus aureus, the ability to utilize different nutrients, particularly alternative carbon source uptake in glucose-limiting conditions, is essential for its fitness in the host environment during the infectious process. It has been reported that G6P uptake in S. aureus is regulated by the three-component system HptRSA. When G6P is provided as the only carbon source, HptRSA could sense extracellular G6P and activate uhpT expression to facilitate G6P utilization. However, the regulatory mechanism of HptRSA is still unclear. In this study, we further investigated the HptRSA system in S. aureus. First, we confirmed that HptRSA is necessary for the normal growth of this pathogen in chemically defined medium with G6P supplementation, and we discovered that HptRSA could exclusively sense extracellular G6P compared to the other organophosphates we tested. Next, using isothermal titration calorimetry, we found that HptA could bind to G6P, suggesting that it may be the G6P sensor. After that experiment, using an electrophoresis mobility shift assay, we verified that the response regulator HptR could directly bind to the uhpT promoter and identified a putative binding site from -67 to -96-bp. Subsequently, we created different point mutations in the putative binding site and revealed that the entire 30-bp sequence is essential for HptR regulation. In summary, we unveiled the regulatory mechanism of the HptRSA system in S. aureus, HptA most likely functions as the G6P sensor, and HptR could implement its regulatory function by directly binding to a conserved, approximately 30-bp sequence in the uhpT promoter.

  9. A population survey of the glucose-6-phosphate dehydrogenase (G6PD) 563C>T (Mediterranean) mutation in Afghanistan.

    PubMed

    Jamornthanyawat, Natsuda; Awab, Ghulam R; Tanomsing, Naowarat; Pukrittayakamee, Sasithon; Yamin, Fazel; Dondorp, Arjen M; Day, Nicholas P J; White, Nicholas J; Woodrow, Charles J; Imwong, Mallika

    2014-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited enzyme defect and an important problem in areas with Plasmodium vivax infection because of the risk of haemolysis following administration of primaquine to treat the liver forms of the parasite. We undertook a genotypic survey of 713 male individuals across nine provinces of Afghanistan in which malaria is found, four in the north and five in the east. RFLP typing at nucleotide position 563 detected 40 individuals with the Mediterranean mutation 563C>T, an overall prevalence of 5.6%. This varied according to self-reported ethnicity, with prevalence in the Pashtun/Pashai group of 33/369 (8.9%) compared to 7/344 individuals in the rest of the population (2.0%; p<0.001, Chi-squared test). Multivariate analysis of ethnicity and geographical location indicated an adjusted odds ratio of 3.50 (95% CI 1.36-9.02) for the Pashtun/Pashai group, while location showed only a trend towards higher prevalence in eastern provinces (adjusted odds ratio = 1.73, 0.73-4.13). Testing of known polymorphic markers (1311C>T in exon 11, and C93T in intron XI) in a subset of 82 individuals wild-type at C563 revealed a mixture of 3 haplotypes in the background population and was consistent with data from the 1000 Genomes Project and published studies. By comparison individuals with G6PD deficiency showed a highly skewed haplotype distribution, with 95% showing the CT haplotype, a finding consistent with relatively recent appearance and positive selection of the Mediterranean variant in Afghanistan. Overall, the data confirm that the Mediterranean variant of G6PD is common in many ethnic groups in Afghanistan, indicating that screening for G6PD deficiency is required in all individuals before radical treatment of P. vivax with primaquine.

  10. Immunization of Mastomys coucha with Brugia malayi Recombinant Trehalose-6-Phosphate Phosphatase Results in Significant Protection against Homologous Challenge Infection

    PubMed Central

    Kushwaha, Susheela; Singh, Prashant Kumar; Rana, Ajay Kumar; Misra-Bhattacharya, Shailja

    2013-01-01

    Development of a vaccine to prevent or reduce parasite development in lymphatic filariasis would be a complementary approach to existing chemotherapeutic tools. Trehalose-6-phosphate phosphatase of Brugia malayi (Bm-TPP) represents an attractive vaccine target due to its absence in mammals, prevalence in the major life stages of the parasite and immunoreactivity with human bancroftian antibodies, especially from endemic normal subjects. We have recently reported on the cloning, expression, purification and biochemical characterization of this vital enzyme of B. malayi. In the present study, immunoprophylactic evaluation of Bm-TPP was carried out against B. malayi larval challenge in a susceptible host Mastomys coucha and the protective ability of the recombinant protein was evaluated by observing the adverse effects on microfilarial density and adult worm establishment. Immunization caused 78.4% decrease in microfilaremia and 71.04% reduction in the adult worm establishment along with sterilization of 70.06% of the recovered live females. The recombinant protein elicited a mixed Th1/Th2 type of protective immune response as evidenced by the generation of both pro- and anti-inflammatory cytokines IL-2, IFN-γ, TNF-α, IL-4 and an increased production of antibody isotypes IgG1, IgG2a, IgG2b and IgA. Thus immunization with Bm-TPP conferred considerable protection against B. malayi establishment by engendering a long-lasting effective immune response and therefore emerges as a potential vaccine candidate against lymphatic filariasis (LF). PMID:24015262

  11. Regulation of methyl-beta-d-thiogalactopyranoside-6-phosphate accumulation in Streptococcus lactis by exclusion and expulsion mechanisms.

    PubMed

    Thompson, J; Saier, M H

    1981-06-01

    Starved cells of Streptococcus lactis ML3 (grown previously on galactose, lactose, or maltose) accumulated methyl-beta-D-thiogalactopyranoside (TMG) by the lactose:phosphotransferase system. More than 98% of accumulated sugar was present as a phosphorylated derivative, TMG-6-phosphate (TMG-6P). When a phosphotransferase system sugar (glucose, mannose, 2-deoxyglucose, or lactose) was added to the medium simultaneously with TMG, the beta-galactoside was excluded from the cells. Galactose enhanced the accumulation of TMG-6P. Glucose, mannose, lactose, or maltose plus arginine, was added to a suspension of TMG-6P-loaded cells of S. lactis ML3, elicited rapid expulsion of intracellular solute. The material recovered in the medium was exclusively free TMG. Expulsion of galactoside required both entry and metabolism of an appropriate sugar, and intracellular dephosphorylation of TMG-6P preceded efflux of TMG. The rate of dephosphorylation of TMG-6P by permeabilized cells was increased two-to threefold by adenosine 5'-triphosphate but was strongly inhibited by fluoride. S. lactis ML3 (DGr) was derived from S. lactis ML3 by positive selection for resistance to 2-deoxy-D-glucose and was defective in the enzyme IIMan component of the glucose:phosphotransferase system. Neither glucose nor mannose excluded TMG from cells of S. lactic ML3 (DGr), and these two sugars failed to elicit TMG expulsion from preloaded cells of the mutant strain. Accumulation of TMG-6P by S. lactis ML3 can be regulation by two independent mechanisms whose activities promote exclusion or expulsion of galactoside from the cell.

  12. Enzymatic and regulatory attributes of trehalose-6-phosphate phosphatase from Candida utilis and its role during thermal stress.

    PubMed

    Lahiri, Sagar; Banerjee, Shakri; Dutta, Trina; Sengupta, Shinjinee; Dey, Sandip; Roy, Rusha; Sengupta, Devlina; Chattopadhyay, Krishnananda; Ghosh, Anil K

    2014-09-01

    Trehalose-6-phosphate phosphatase (TPP) catalyzes the final step in the biosynthesis of the anti-stress sugar trehalose. An 82 kDa TPP enzyme was isolated from Candida utilis with 61% yield and 43-fold purification. The protein sequence, determined by N-terminal sequencing and MALDI-TOF analysis, showed significant homology with known TPP sequences from related organisms. The full length gene sequence of TPP of C. utilis was identified using rapid amplification of cDNA ends-PCR reaction (RACE-PCR). The gene was cloned and expressed in Escherichia coli BL21. Recombinant TPP enzyme was isolated using affinity chromatography. CD spectroscopy and steady-state fluorescence revealed that the structural and conformational aspects were identical in both native and recombinant forms. The biochemical properties of the two forms were also similar. Km was determined to be ~0.8 mM. Optimum temperature and pH were found to be 30 °C and 8.5, respectively. Activity was dependent on the presence of divalent cations and inhibited by metal chelators. Methylation-mediated regulation of TPP enzyme and its effect on the overall survival of the organism under stress were investigated. The results indicated that enhancement of TPP activity by methylation at the Cysteine residues increased resistance of Candida cells against thermal stress. This work involves extensive investigations toward understanding the physico-chemical properties of the first TPP enzyme from any yeast strain. The mechanism by which methylation regulates its activity has also been studied. A correlation between regulation of trehalose synthesis and survivability of the organism under thermal stress was established.

  13. Altering trehalose-6-phosphate content in transgenic potato tubers affects tuber growth and alters responsiveness to hormones during sprouting.

    PubMed

    Debast, Stefan; Nunes-Nesi, Adriano; Hajirezaei, Mohammad R; Hofmann, Jörg; Sonnewald, Uwe; Fernie, Alisdair R; Börnke, Frederik

    2011-08-01

    Trehalose-6-phosphate (T6P) is a signaling metabolite that regulates carbon metabolism, developmental processes, and growth in plants. In Arabidopsis (Arabidopsis thaliana), T6P signaling is, at least in part, mediated through inhibition of the SNF1-related protein kinase SnRK1. To investigate the role of T6P signaling in a heterotrophic, starch-accumulating storage organ, transgenic potato (Solanum tuberosum) plants with altered T6P levels specifically in their tubers were generated. Transgenic lines with elevated T6P levels (B33-TPS, expressing Escherichia coli osmoregulatory trehalose synthesis A [OtsA], which encodes a T6P synthase) displayed reduced starch content, decreased ATP contents, and increased respiration rate diagnostic for high metabolic activity. On the other hand, lines with significantly reduced T6P (B33-TPP, expressing E. coli OtsB, which encodes a T6P phosphatase) showed accumulation of soluble carbohydrates, hexose phosphates, and ATP, no change in starch when calculated on a fresh weight basis, and a strongly reduced tuber yield. [¹⁴C]glucose feeding to transgenic tubers indicated that carbon partitioning between starch and soluble carbohydrates was not altered. Transcriptional profiling of B33-TPP tubers revealed that target genes of SnRK1 were strongly up-regulated and that T6P inhibited potato tuber SnRK1 activity in vitro. Among the SnRK1 target genes in B33-TPP tubers, those involved in the promotion of cell proliferation and growth were down-regulated, while an inhibitor of cell cycle progression was up-regulated. T6P-accumulating tubers were strongly delayed in sprouting, while those with reduced T6P sprouted earlier than the wild type. Early sprouting of B33-TPP tubers correlated with a reduced abscisic acid content. Collectively, our data indicate that T6P plays an important role for potato tuber growth.

  14. Diverse point mutations in the human glucose-6-phosphate dehydrogenase gene cause enzyme deficiency and mild or severe hemolytic anemia.

    PubMed Central

    Vulliamy, T J; D'Urso, M; Battistuzzi, G; Estrada, M; Foulkes, N S; Martini, G; Calabro, V; Poggi, V; Giordano, R; Town, M

    1988-01-01

    Glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.49) deficiency is a common genetic abnormality affecting an estimated 400 million people worldwide. Clinical and biochemical analyses have identified many variants exhibiting a range of phenotypes, which have been well characterized from the hematological point of view. However, until now, their precise molecular basis has remained unknown. We have cloned and sequenced seven mutant G6PD alleles. In the nondeficient polymorphic African variant G6PD A we have found a single point mutation. The other six mutants investigated were all associated with enzyme deficiency. In one of the commonest, G6PD Mediterranean, which is associated with favism among other clinical manifestations, a single amino acid replacement was found (serine----phenylalanine): it must be responsible for the decreased stability and the reduced catalytic efficiency of this enzyme. Single point mutations were also found in G6PD Metaponto (Southern Italy) and in G6PD Ilesha (Nigeria), which are asymptomatic, and in G6PD Chatham, which was observed in an Indian boy with neonatal jaundice. In G6PD "Matera," which is now known to be the same as G6PD A-, two separate point mutations were found, one of which is the same as in G6PD A. In G6PD Santiago, a de novo mutation (glycine----arginine) is associated with severe chronic hemolytic anemia. The mutations observed show a striking predominance of C----T transitions, with CG doublets involved in four of seven cases. Thus, diverse point mutations may account largely for the phenotypic heterogeneity of G6PD deficiency. Images PMID:3393536

  15. A Population Survey of the Glucose-6-Phosphate Dehydrogenase (G6PD) 563C>T (Mediterranean) Mutation in Afghanistan

    PubMed Central

    Jamornthanyawat, Natsuda; Awab, Ghulam R.; Tanomsing, Naowarat; Pukrittayakamee, Sasithon; Yamin, Fazel; Dondorp, Arjen M.; Day, Nicholas P. J.; White, Nicholas J.; Woodrow, Charles J.; Imwong, Mallika

    2014-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited enzyme defect and an important problem in areas with Plasmodium vivax infection because of the risk of haemolysis following administration of primaquine to treat the liver forms of the parasite. We undertook a genotypic survey of 713 male individuals across nine provinces of Afghanistan in which malaria is found, four in the north and five in the east. RFLP typing at nucleotide position 563 detected 40 individuals with the Mediterranean mutation 563C>T, an overall prevalence of 5.6%. This varied according to self-reported ethnicity, with prevalence in the Pashtun/Pashai group of 33/369 (8.9%) compared to 7/344 individuals in the rest of the population (2.0%; p<0.001, Chi-squared test). Multivariate analysis of ethnicity and geographical location indicated an adjusted odds ratio of 3.50 (95% CI 1.36–9.02) for the Pashtun/Pashai group, while location showed only a trend towards higher prevalence in eastern provinces (adjusted odds ratio = 1.73, 0.73–4.13). Testing of known polymorphic markers (1311C>T in exon 11, and C93T in intron XI) in a subset of 82 individuals wild-type at C563 revealed a mixture of 3 haplotypes in the background population and was consistent with data from the 1000 Genomes Project and published studies. By comparison individuals with G6PD deficiency showed a highly skewed haplotype distribution, with 95% showing the CT haplotype, a finding consistent with relatively recent appearance and positive selection of the Mediterranean variant in Afghanistan. Overall, the data confirm that the Mediterranean variant of G6PD is common in many ethnic groups in Afghanistan, indicating that screening for G6PD deficiency is required in all individuals before radical treatment of P. vivax with primaquine. PMID:24586352

  16. Targeting of Salmonella typhimurium to vesicles containing lysosomal membrane glycoproteins bypasses compartments with mannose 6-phosphate receptors

    PubMed Central

    1995-01-01

    Salmonella typhimurium is an intracellular bacterial pathogen that remains enclosed in vacuoles (SCV) upon entry into the host cell. In this study we have examined the intracellular trafficking route of S. typhimurium within epithelial cells. Indirect immunofluorescence analysis showed that bacteria initiated fusion with lysosomal membrane glycoprotein (lgp)-containing compartments approximately 15 min after bacterial internalization. This process was completed approximately 75 min later and did not require microtubules. Cation-independent (CI)- or cation-dependent (CD)-mannose 6-phosphate receptors (M6PRs) were not observed at detectable levels in SCV. Lysosomal enzymes showed a different distribution in SCV: lysosomal-acid phosphatase (LAP) was incorporated into these vacuoles with the same kinetics as lgps, while cathepsin D was present in a low proportion (approximately 30%) of SCV. Uptake experiments with fluid endocytic tracers such as fluorescein- dextran sulphate (F-DX) or horseradish-peroxidase (HRP) showed that after 2 h of uptake, F-DX was present in approximately 75% of lgp- containing vesicles in uninfected cells, while only approximately 15% of SCV contained small amounts of the tracer during the same uptake period. SCV also showed only partial fusion with HRP-preloaded secondary lysosomes, with approximately 30% of SCV having detectable amounts of HRP at 6 h after infection. These results indicate that SCV show limited accessibility to fluid endocytic tracers and mature lysosomes, and are therefore functionally separated from the endocytic route. Moreover, the unusual intracellular trafficking route of S. typhimurium inside epithelial cells has allowed us to establish the existence of two different lgp-containing vesicles in Salmonella- infected cells: one population is separated from the endocytic route, fusogenic with incoming SCV and may arise from a secretory pathway, while the second involves the classical secondary or mature lysosomes. PMID

  17. A comprehensive analysis of membrane and morphology of erythrocytes from patients with glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Fang, Zishui; Jiang, Chengrui; Tang, Jia; He, Ming; Lin, Xiaoying; Chen, Xiaodan; Han, Luhao; Zhang, Zhiqiang; Feng, Yi; Guo, Yibin; Li, Hongyi; Jiang, Weiying

    2016-06-01

    Acute hemolytic anemia could be triggered by oxidative stress in the patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. However, the underlying hemolytic mechanism is unknown. To make clear the hemolytic mechanisms, a systematic study on membrane ultrastructure had been undertaken. A comprehensive method was used including atomic force microscopy, scanning electron microscopy, flow cytometer and fluorescence microscopy to analyze the membrane ultrastructure, externalized phosphatidylserine (PS), intracellular Ca(2+) concentration, morphology and the distributions of band 3 protein in G6PD deficient red blood cells (RBCs) after tert-butyl-hydroperoxide (t-BHP) oxidation. The results showed that erythrocyte shrinkage, annexin-V binding to externalized PS on the membrane of early-stage apoptotic cells, the increased membrane roughness and intracellular Ca(2+) concentration, as well as the change of distributions of band 3 protein in RBCs. Compared with the control RBCs, as the concentration of t-BHP up to 0.1mM, the membrane roughness of G6PD deficient RBCs showed significant difference (p<0.05) and as the concentration of t-BHP up to 0.3mM, externalized PS showed significant difference (p<0.05). Furthermore, the population types of RBCs showed dramatic difference between control groups and G6PD deficient groups. Oxidative stress induced more serious erythrocyte apoptosis and resulted in increased roughness of erythrocyte membrane and abnormal distributed band 3 protein in G6PD deficient RBCs. Echinocytes are the predominant abnormal erythrocyte shape occurring in the peripheral blood from patients with G6PD deficiency, which may shorten the RBCs lifespan. The results in the present study will give an increased understanding for the hemolytic mechanism of G6PD deficiency.

  18. Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency in Greek newborns: the Mediterranean C563T mutation screening.

    PubMed

    Molou, Elina; Schulpis, Kleopatra H; Thodi, Georgia; Georgiou, Vassiliki; Dotsikas, Yannis; Papadopoulos, Konstantinos; Biti, Sofia; Loukas, Yannis L

    2014-04-01

    Glucose-6-Phosphate Dehydrogenase (G6PD) gene is located at the X-chromosome at Xq28 and the disease is recessively inherited predominantly in males. More than 400 variants have been proposed based on clinical and enzymatic studies. The aim of the current study was to identify C563T mutation in G6PD-deficient newborns and to correlate the enzyme residual activity with the presence of the mutation. Some 1189 full-term neonates aged 3-5 days old were tested for G6PD activity in dried blood spots from Guthrie cards using a commercial kit. DNA extraction from Guthrie cards and mutation identification among the deficient samples were performed with current techniques. A total of 92 (7.7%) newborns were G6PD-deficient. In 46 (50%), the mutation C563T was identified. The residual activity in C563T hemizygote males (n = 28) was statistically significantly lower (1.23 ± 0.93 U/g Hb) than that in non-C563T G6PD-deficient males (n = 25) (4.01 ± 1.20 U/g Hb, p < 0.0001) and in controls (13.6 ± 2.9 U/g Hb, p < 0.0001). In C563T heterozygote females, the estimated enzyme activity was lower than that determined in non-C563T females. Male C563T hemizygotes suffer from G6PD deficiency and severe neonatal jaundice. G6PD activity showed statistically significant correlation with total bilirubin blood levels.

  19. Screening for Glucose-6-Phosphate Dehydrogenase Deficiency Using Three Detection Methods: A Cross-Sectional Survey in Southwestern Uganda.

    PubMed

    Roh, Michelle E; Oyet, Caesar; Orikiriza, Patrick; Wade, Martina; Mwanga-Amumpaire, Juliet; Boum, Yap; Kiwanuka, Gertrude N; Parikh, Sunil

    2016-11-02

    Despite the potential benefit of primaquine in reducing Plasmodium falciparum transmission and radical cure of Plasmodium vivax and Plasmodium ovale infections, concerns over risk of hemolytic toxicity in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd) have hampered its deployment. A cross-sectional survey was conducted in 2014 to assess the G6PDd prevalence among 631 children between 6 and 59 months of age in southwestern Uganda, an area where primaquine may be a promising control measure. G6PDd prevalence was determined using three detection methods: a quantitative G6PD enzyme activity assay (Trinity Biotech(®) G-6-PDH kit), a qualitative point-of-care test (CareStart(™) G6PD rapid diagnostic test [RDT]), and molecular detection of the G6PD A- G202A allele. Qualitative tests were compared with the gold standard quantitative assay. G6PDd prevalence was higher by RDT (8.6%) than by quantitative assay (6.8%), using a < 60% activity threshold. The RDT performed optimally at a < 60% threshold and demonstrated high sensitivity (≥ 90%) and negative predictive values (100%) across three activity thresholds (below 60%, 30%, and 40%). G202A allele frequency was 6.4%, 7.9%, and 6.8% among females, males, and overall, respectively. Notably, over half of the G202A homo-/hemizygous children expressed ≥ 60% enzyme activity. Overall, the CareStart(™) G6PD RDT appears to be a viable screening test to accurately identify individuals with enzyme activities below 60%. The low prevalence of G6PDd across all three diagnostic modalities and absence of severe deficiency in our study suggests that there is little barrier to the use of single-dose primaquine in this region.

  20. Prevalence of glucose-6-phosphate dehydrogenase deficiency and diagnostic challenges in 1500 immigrants in Denmark examined for haemoglobinopathies.

    PubMed

    Warny, Marie; Klausen, Tobias Wirenfeldt; Petersen, Jesper; Birgens, Henrik

    2015-09-01

    Similar to the thalassaemia syndromes, glucose-6-phosphate dehydrogenase (G6PD) deficiency is highly prevalent in areas historically exposed to malaria. In the present study, we used quantitative and molecular methods to determine the prevalence of G6PD deficiency in a population of 1508 immigrants in Denmark. We found the allele frequency to be between 2.4 and 2.9% in the female immigrants. Furthermore, the mutation pattern in the studied population showed a high prevalence of the G6PD A-(202A) variant in African and African-American immigrants, a high prevalence of the G6PD Mediterranean variant in Mediterranean European and Western Asian immigrants, and substantial heterogeneity in the variants found in the Eastern Asian/Pacific immigrants. Inasmuch as many of the patients included in this investigation had various thalassaemic syndromes, we were able to evaluate the effects of the interaction between a low mean corpuscular haemoglobin (MCH) value and G6PD activity, particularly in heterozygous females. The activity level was markedly influenced by the MCH value in females with normal G6PD activity, but not in heterozygous and homozygous females. Comparison of patients with normal G6PD activity and heterozygous females indicated considerable overlap in activity levels. To help separating heterozygous females from females with wild-type genes, a DNA analysis is necessary when the female activity level is between 4.0 and 4.9 U/g hgb corresponding to 50-60% of the median activity of unaffected males.

  1. Endothelial inflammation induced by excess glucose is associated with cytosolic glucose-6-phosphate but not increased mitochondrial respiration

    PubMed Central

    Sweet, Ian R; Gilbert, Merle; Maloney, Ezekiel; Hockenbery, David M.; Schwartz, Michael W.; Kim, Francis

    2009-01-01

    Aims/hypothesis Exposure of endothelial cells to high glucose levels suppresses responses to insulin, including induction of endothelial nitric oxide synthetase activity, through pro-inflammatory signaling via the IKKβ-NF-κB pathway. In the current study, we aimed to identify metabolic responses to glucose excess that mediate endothelial cell inflammation and insulin resistance. Since endothelial cells decrease their rate of oxygen consumption (OCR) in response to glucose, we hypothesized that increased mitochondrial function would not mediate these cell’s response to excess substrate. Methods The effects of glycolytic and mitochondrial fuels on metabolic intermediates and end products of glycolytic and oxidative metabolism, including glucose-6 phosphate (G6P), lactate, CO2, NAD(P)H, and OCR, were measured in cultured human microvascular endothelial cells and correlated with IKKβ activation. Results In response to increases in glucose concentration from low to physiological levels (0 to 5 mM), production of G6P, lactate, NAD(P)H and CO2 each increased as expected, while OCR was sharply reduced. IKKβ activation was detected at glucose concentrations above 5 mM, which was associated with parallel increases of G6P levels, whereas downstream metabolic pathways were insensitive to excess substrate. Conclusions/interpretation Activation of IKKβ by excess glucose correlates with increased levels of the glycolytic intermediate G6P, but not with lactate generation or OCR, which are inhibited well below saturation levels at physiologic glucose concentrations. These findings suggest that oxidative stress due to increased mitochondrial respiration is unlikely to mediate endothelial inflammation induced by excess glucose and suggests instead the involvement of G6P accumulation in the adverse effects of hyperglycemia on endothelial cells. PMID:19219423

  2. Knockdown of glucose-6-phosphate dehydrogenase (G6PD) following cerebral ischemic reperfusion: the pros and cons.

    PubMed

    Zhao, Gang; Zhao, Yanxin; Wang, Xingyu; Xu, Ying

    2012-07-01

    NADPH derived from glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, has been implicated not only to promote reduced glutathione (GSH) but also enhance oxidative stress in specific cellular conditions. In this study, the effects of G6PD antisense oligodeoxynucleotides (AS-ODNs) was examined on the CA1 pyramidal neurons following transient cerebral ischemia. Specifically knockdown of G6PD protein expression in hippocampus CA1 subregion at early reperfusion period (1-24 h) with a strategy to pre-treated G6PD AS-ODNs significantly reduced G6PD activity and NADPH level, an effect correlated with attenuation of NADPH oxidase activation and superoxide anion production. Concomitantly, pre-treatment of G6PD AS-ODNs markedly reduced oxidative DNA damage and the delayed neuronal cell death in rat hippocampal CA1 region induced by global cerebral ischemia. By contrast, knockdown of G6PD protein at late reperfusion period (48-96 h) increased oxidative DNA damage and exacerbated the ischemia-induced neuronal cell death in hippocampal CA1 region, an effect associated with reduced NADPH level and GSH/GSSG ratio. These findings indicate that G6PD not only plays a role in oxidative neuronal damage but also a neuroprotective role during different ischemic reperfusion period. Therefore, G6PD mediated oxidative response and redox regulation in the hippocampal CA1 act as the two sides of the same coin and may represent two potential applications of G6PD during different stage of cerebral ischemic reperfusion. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Free fatty acid inhibition of the insulin induction of glucose-6-phosphate dehydrogenase in rat hepatocyte monolayers.

    PubMed

    Salati, L M; Adkins-Finke, B; Clarke, S D

    1988-01-01

    Rat hepatocytes in monolayer culture were utilized to determine if the decrease in glucose-6-phosphate dehydrogenase (G6PD) activity resulting from the ingestion of fat can be mimicked by the addition of fatty acids to a chemically, hormonally defined medium. G6PD activity in cultured hepatocytes was induced several-fold by insulin. Dexamethasone or T3 did not amplify the insulin induction of G6PD. Glucose alone increased G6PD activity in cultured hepatocytes from fasted donors by nearly 500%. Insulin in combination with glucose induced G6PD an additional two-fold. The increase in G6PD activity caused by glucose was greater in hepatocytes isolated from 72 hr-fasted rats as compared to fed donor rats. Such a response was reminiscent of the "overshoot" phenomenon in which G6PD activity is induced well above the normal level by fasting-refeeding rats a high glucose diet. Addition of linoleate to the medium resulted in a significant suppression of insulin's ability to induce G6PD, but linoleate had no effect on the induction of G6PD activity by glucose alone. A shift to the right in the insulin-response curve for the induction of G6PD also was detected for the induction of malic enzyme and acetyl-CoA carboxylase. Arachidonate (0.25 mM) was a significantly more effective inhibitor of the insulin action than linoleate was. Apparently rat hepatocytes in monolayer culture can be utilized as a model to investigate the molecular mechanism by which fatty acids inhibit the production of lipogenic enzymes. In part, this mechanism of fatty acid inhibition involves desensitization of hepatocytes to the lipogenic action of insulin.

  4. The mannose-6-phosphate analogue, PXS64, inhibits fibrosis via TGF-β1 pathway in human lung fibroblasts.

    PubMed

    Schilter, Heidi; Cantemir-Stone, Carmen Z; Leksa, Vladimir; Ohradanova-Repic, Anna; Findlay, Alison D; Deodhar, Mandar; Stockinger, Hannes; Song, Xiaomin; Molloy, Mark; Marsh, Clay B; Jarolimek, Wolfgang

    2015-06-01

    Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterised by a progressive decline in lung function which can be attributed to excessive scarring, inflammation and airway remodelling. Mannose-6-phosphate (M6P) is a strong inhibitor of fibrosis and its administration has been associated with beneficial effects in tendon repair surgery as well as nerve repair after injury. Given this promising therapeutic approach we developed an improved analogue of M6P, namely PXS64, and explored its anti-fibrotic effects in vitro. Normal human lung fibroblasts (NHLF) and human lung fibroblast 19 cells (HF19) were exposed to active recombinant human TGF-β1 to induce increases in fibrotic markers. rhTGF-β1 increased constitutive protein levels of fibronectin and collagen in the NHLF cells, whereas HF19 cells showed increased levels of fibronectin, collagen as well as αSMA (alpha smooth muscle actin). PXS64 demonstrated a robust inhibitory effect on all proteins analysed. IPF patient fibroblasts treated with PXS64 presented an improved phenotype in terms of their morphological appearance, as well as a decrease in fibrotic markers (collagen, CTGF, TGF-β3, tenascin C, αSMA and THBS1). To explore the cell signalling pathways involved in the anti-fibrotic effects of PXS64, proteomics analysis with iTRAQ labelling was performed and the data demonstrated a specific antagonistic effect on the TGF-β1 pathway. This study shows that PXS64 effectively inhibits the production of extracellular matrix, as well as myofibroblast differentiation during fibrosis. These results suggest that PXS64 influences tissue remodelling by inhibiting TGF-β1 signalling in NHLF and HF19 cell lines, as well as in IPF patient fibroblasts. Thus PXS64 is a potential candidate for preclinical application in pulmonary fibrosis.

  5. The effects of chemical and radioactive properties of Tl-201 on human erythrocyte glucose 6-phosphate dehydrogenase activity.

    PubMed

    Sahin, Ali; Senturk, Murat; Ciftci, Mehmet; Varoglu, Erhan; Kufrevioglu, Omer Irfan

    2010-04-01

    The inhibitory effects of thallium-201 ((201)Tl) solution on human erythrocyte glucose 6-phosphate dehydrogenase (G6PD) activity were investigated. For this purpose, erythrocyte G6PD was initially purified 835-fold at a yield of 41.7% using 2',5'-Adenosine diphosphate sepharose 4B affinity gel chromatography. The purification was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed a single band for the final enzyme preparation. The in vitro and in vivo effects of the (201)Tl solution including Tl(+), Fe(+3) and Cu(+2) metals and the in vitro effects of the radiation effect of the (201)Tl solution and non-radioactive Tl(+), Fe(+3) and Cu(+2) metals on human erythrocyte G6PD enzyme were studied. Enzyme activity was determined with the Beutler method at 340 nm using a spectrophotometer. All purification procedures were carried out at +4 degrees C. (201)Tl solution and radiation exposure had inhibitory effects on the enzyme activity. IC(50) value of (201)Tl solution was 36.86 microl ([Tl(+)]: 0.0036 microM, [Cu(+2)]: 0.0116 microM, [Fe(+3)]: 0.0132 microM), of human erythrocytes G6PD. Seven human patients were also used for in vivo studies of (201)Tl solution. Furthermore, non-radioactive Tl(+), Fe(+3) and Cu(+2) were found not to have influenced the enzyme in vitro. Human erythrocyte G6PD activity was inhibited by exposure for up to 10 minutes to 0.057 mCi/kg (201)Tl solution. It was detected in in vitro and in vivo studies that the human erythrocyte G6PD enzyme is inhibited due to the radiation effect of (201)Tl solution. Copyright 2010 Elsevier Inc. All rights reserved.

  6. Prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in southeast Iran: implications for malaria elimination.

    PubMed

    Tabatabaei, Seyed Mehdi; Salimi Khorashad, Alireza; Sakeni, Mohammad; Raeisi, Ahmad; Metanat, Zahra

    2015-03-15

    Glucose-6-phosphate dehydrogenase deficiency (G6PD) is an X-linked genetic disorder with a relatively high frequency in malaria-endemic regions. It is an obstacle to malaria elimination, as primaquine administered in the treatment of malaria can cause hemolysis in G6PD-deficient individuals. This study presents information on the prevalence of G6PD deficiency in Sistan and Balouchetsan province, which hosts more than 90% of Plasmodium vivax malaria cases in Iran. This type of information is needed for a successful malaria elimination program. A total of 526 students were randomly recruited through schools located in southeast Iran. Information was collected by interviewing the students using a structured questionnaire. Blood samples taken on filter papers were examined for G6PD deficiency using the fluorescent spot test. Overall, 72.8% (383/526) of the subjects showed normal G6PD enzyme function. Mild and severe G6PD deficiency was observed in 14.8% (78) and 12.2% (64) of subjects, respectively. A total 193/261 males (73.9%) and 190/265 (72%) females had normal enzyme activity. Mild G6PD deficiency was observed in 10.8% (28) and 18.9% (50) of male and female subjects, respectively. However, in comparison with females, a greater proportion of males showed severe enzyme deficiency (15.3% versus 9.1%). All these differences were statistically significant (p < 0.006). G6PD deficiency is highly prevalent in southeast Iran. G6PD-deficient individuals are susceptible to potentially severe and life-threatening hemolytic reactions after primaquine treatment. In order to achieve malaria elimination goals in the province, G6PD testing needs to be made routinely available within the health system.

  7. Trehalose-6-phosphate and SNF1-related protein kinase 1 are involved in the first-fruit inhibition of cucumber.

    PubMed

    Zhang, ZhiPing; Deng, Yukun; Song, Xingxing; Miao, Minmin

    2015-04-01

    In cucumber (Cucumis sativus L.), the preexisting fruits inhibit the growth of subsequent fruits. To study the mechanism underlying this phenomenon, we examined the sink activity, the level of free sugars, and the activity of SNF1-related protein kinase 1 (SnRK1) in the peduncles of two types of fruits. In the two-fruit cucumber plants, the growth rate and sink activity [evaluated by alkaline alpha-galactosidase (CsAGA) activity in the peduncle] of the first fruit were greater than those of the second fruit. The (14)C-labeling experiment revealed that assimilates produced by the leaves closer to the second fruit tended to move to the first fruit. Sucrose and trehalose-6-phosphate (T6P) levels in the peduncle of the first fruit were higher than those in the peduncle of the second fruit. The SnRK1 activity was lower in the peduncle of the first fruit than in that of the second fruit at 0-8 days after anthesis. The growth rate and sink activity of the second fruit were enhanced after the removal of the first fruit or after treatment with 6-benzyl aminopurine, as determined by comparison with an increase in the sucrose and T6P levels and a decrease in the SnRK1 activity in its peduncle. The SnRK1 activity was inhibited by T6P in an in vitro kinase assay, and the mRNA level of CsAGA1 in cucumber calli was up-regulated by exogenous trehalose treatment, confirming that the SnRK1 activity and CsAGA1 expression can be regulated by T6P levels. Our results suggest that the T6P- and SnRK1-mediated signaling functions are involved in the regulation of first-fruit inhibition in cucumber plants. Copyright © 2015. Published by Elsevier GmbH.

  8. One-step purification and immobilization of thermophilic polyphosphate glucokinase from Thermobifida fusca YX: glucose-6-phosphate generation without ATP.

    PubMed

    Liao, Hehuan; Myung, Suwan; Zhang, Y-H Percival

    2012-02-01

    The discovery of stable and active polyphosphate glucokinase (PPGK, EC 2.7.1.63) would be vital to cascade enzyme biocatalysis that does not require a costly ATP input. An open reading frame Tfu_1811 from Thermobifida fusca YX encoding a putative PPGK was cloned and the recombinant protein fused with a family 3 cellulose-binding module (CBM-PPGK) was overexpressed in Escherichia coli. Mg²⁺ was an indispensible activator. This enzyme exhibited the highest activity in the presence of 4 mM Mg²⁺ at 55°C and pH 9.0. Under its suboptimal conditions (pH 7.5), the k (cat) and K(m) values of CBM-PPGK on glucose were 96.9 and 39.7 s⁻¹ as well as 0.77 and 0.45 mM at 37°C and 50°C respectively. The thermoinactivation of CBM-PPGK was independent of its mass concentration. Through one-step enzyme purification and immobilization on a high-capacity regenerated amorphous cellulose, immobilized CBM-PPGK had an approximately eightfold half lifetime enhancement (i.e., t(1/2) = 120 min) as compared to free enzyme at 50°C. To our limited knowledge, this enzyme was the first thermostable PPGK reported. Free PPGK and immobilized CBM-PPGK had total turnover number values of 126,000 and 961,000 mol product per mol enzyme, respectively, suggesting their great potential in glucose-6-phosphate generation based on low-cost polyphosphate.

  9. Impact of glucose-6-phosphate dehydrogenase deficiency on sickle cell anaemia expression in infancy and early childhood: a prospective study.

    PubMed

    Benkerrou, Malika; Alberti, Corinne; Couque, Nathalie; Haouari, Zinedine; Ba, Aissatou; Missud, Florence; Boizeau, Priscilla; Holvoet, Laurent; Ithier, Ghislaine; Elion, Jacques; Baruchel, André; Ducrocq, Rolande

    2013-12-01

    In patients with sickle cell anaemia (SCA), concomitant glucose-6-phosphate dehydrogenase (G6PD) deficiency is usually described as having no effect and only occasionally as increasing severity. We analysed sequential clinical and biological data for the first 42 months of life in SCA patients diagnosed by neonatal screening, including 27 G6PD-deficient patients, who were matched on sex, age and parents' geographic origin to 81 randomly selected patients with normal G6PD activity. In the G6PD-deficient group, steady-state haemoglobin was lower (-6·2 g/l, 95% confidence interval (CI), [-10·1; -2·3]) and reticulocyte count higher (247 × 10(9) /l, 95%CI, [97; 397]). The acute anaemic event rate was 3 times higher in the G6PD-deficient group (P < 10(-3) ). A higher proportion of G6PD-deficient patients required blood transfusion (20/27 [74%] vs. 37/81 [46%], P < 10(-3) ), for acute anaemic events, and also vaso-occlusive and infectious events. No significant between-group differences were found regarding the rates of vaso-occlusive, infectious, or cerebrovascular events. G6PD deficiency in babies with SCA worsens anaemia and increases blood transfusion requirements in the first years of life. These effects decrease after 2 years of age, presumably as the decline in fetal haemoglobin levels leads to increased sickle cell haemolysis and younger red blood cells with higher G6PD activity. © 2013 John Wiley & Sons Ltd.

  10. The level of glucose-6-phosphate dehydrogenase activity strongly influences xylose fermentation and inhibitor sensitivity in recombinant Saccharomyces cerevisiae strains.

    PubMed

    Jeppsson, Marie; Johansson, Björn; Jensen, Peter Ruhdal; Hahn-Hägerdal, Bärbel; Gorwa-Grauslund, Marie F

    2003-11-01

    Disruption of the ZWF1 gene encoding glucose-6-phosphate dehydrogenase (G6PDH) has been shown to reduce the xylitol yield and the xylose consumption in the xylose-utilizing recombinant Saccharomyces cerevisiae strain TMB3255. In the present investigation we have studied the influence of different production levels of G6PDH on xylose fermentation. We used a synthetic promoter library and the copper-regulated CUP1 promoter to generate G6PDH-activities between 0% and 179% of the wild-type level. G6PDH-activities of 1% and 6% of the wild-type level resulted in 2.8- and 5.1-fold increase in specific xylose consumption, respectively, compared with the ZWF1-disrupted strain. Both strains exhibited decreased xylitol yields (0.13 and 0.19 g/g xylose) and enhanced ethanol yields (0.36 and 0.34 g/g xylose) compared with the control strain TMB3001 (0.29 g xylitol/g xylose, 0.31 g ethanol/g xylose). Cytoplasmic transhydrogenase (TH) from Azotobacter vinelandii has previously been shown to transfer NADPH and NAD(+) into NADP(+) and NADH, and TH-overproduction resulted in lower xylitol yield and enhanced glycerol yield during xylose utilization. Strains with low G6PDH-activity grew slower in a lignocellulose hydrolysate than the strain with wild-type G6PDH-activity, which suggested that the availability of intracellular NADPH correlated with tolerance towards lignocellulose-derived inhibitors. Low G6PDH-activity strains were also more sensitive to H(2)O(2) than the control strain TMB3001.

  11. Time course of radiolabeled 2-deoxy-D-glucose 6-phosphate turnover in cerebral cortex of goats

    SciTech Connect

    Pelligrino, D.A.; Miletich, D.J.; Albrecht, R.F.

    1987-02-01

    The vivo dephosphorylation rate of 2-deoxy-D-glucose 6-phosphate (DGP) in the cerebral cortex of goats injected intravenously with radiolabeled 2-deoxy-D-glucose (DG) was investigated. Serial rapidly frozen samples of parietal cortical gray tissue were obtained at regular intervals over time periods from 45 min to 3 h in awake goats or in paralyzed and artificially ventilated goats maintained under 70% N/sub 2/O or pentobarbital sodium anesthesia. The samples were analyzed for glucose content and separate DG and DGP activities. The rate parameters for phosphorylation (k/sup *//sub 4/) and dephosphorylation (k/sup *//sub 4/) were estimated in each animal. The glucose phosphorylation rate (PR) was calculated over the intervals 3-5 (or 6), 3-10, 3-20, 3-30, and 3-45 min, assuming k/sup *//sub 4/ = O. As the evaluation period was extended beyond 10 min, the calculated PR became increasingly less when compared with that calculated over the 3- to 5- (or 6) min interval (PR/sub i/). Furthermore, as metabolic activity decreased, the magnitude of the error increased such that at 45 min pentobarbital-anesthetize goats underestimated the PR/sub i/ by 46.5% compared with only 23.1 in N/sub 2/O-anesthetized goats. This was also reflected in the >twofold higher k/sup *//sub 4//k/sup *//sub 3/ ratio in the pentobarbital vs. N/sub 2/O-anesthetized group. It is concluded that when using the DG method in the goat, DGP dephosphorylation cannot be ignored when employing >10-min evaluation periods.

  12. Should blood donors be routinely screened for glucose-6-phosphate dehydrogenase deficiency? A systematic review of clinical studies focusing on patients transfused with glucose-6-phosphate dehydrogenase-deficient red cells.

    PubMed

    Renzaho, Andre M N; Husser, Eliette; Polonsky, Michael

    2014-01-01

    The risk factors associated with the use of glucose-6-phosphate dehydrogenase (G6PD)-deficient blood in transfusion have not yet been well established. Therefore, the aim of this review was to evaluate whether whole blood from healthy G6PD-deficient donors is safe to use for transfusion. The study undertook a systematic review of English articles indexed in COCHRANE, MEDLINE, EMBASE, and CINHAL, with no date restriction up to March 2013, as well as those included in articles' reference lists and those included in Google Scholar. Inclusion criteria required that studies be randomized controlled trials, case controls, case reports, or prospective clinical series. Data were extracted following the Preferred Reporting Items for Systematic Reviews using a previously piloted form, which included fields for study design, population under study, sample size, study results, limitations, conclusions, and recommendations. The initial search identified 663 potentially relevant articles, of which only 13 studies met the inclusion criteria. The reported effects of G6PD-deficient transfused blood on neonates and children appear to be more deleterious than effects reported on adult patients. In most cases, the rise of total serum bilirubin was abnormal in infants transfused with G6PD-deficient blood from 6 hours up to 60 hours after transfusion. All studies on neonates and children, except one, recommended a routine screening for G6PD deficiency for this at-risk subpopulation because their immature hepatic function potentially makes them less able to handle any excess bilirubin load. It is difficult to make firm clinical conclusions and recommendations given the equivocal results, the lack of standardized evaluation methods to categorize red blood cell units as G6PD deficient (some of which are questionable), and the limited methodological quality and low quality of evidence. Notwithstanding these limitations, based on our review of the available literature, there is little to

  13. Sub-Saharan red cell antigen phenotypes and glucose-6-phosphate dehydrogenase deficiency variants in French Guiana.

    PubMed

    Petit, Florence; Bailly, Pascal; Chiaroni, Jacques; Mazières, Stéphane

    2016-06-07

    The treatment of Plasmodium vivax infections requires the use of primaquine, which can lead to severe haemolysis in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. However, most of the Latin American countries, which are still endemic for vivax malaria, lack information on the distribution of G6PD deficiency (G6PDd). No survey has been performed so far in French Guiana. Herein, 80 individuals of the French Guianan Noir Marron population were scrutinized for red cell surface antigens of six blood group systems (ABO, Rh, Kell, Kidd, Duffy and MNS) and G6PD genetic polymorphisms. First, the sub-Saharan origin of the red cell phenotypes was assessed in relation with the literature. Then, given that the main sub-Saharan G6PDd variants are expected to be encountered, only the G6PD sequences of exons 4, 5, 6 and 9 were screened. This work aims at appraising the G6PD gene variation in this population, and thus, contributing to the G6PD piecemeal information in Latin America. Ninety-seven percent (97 %) of the red cells are Fy(a- b-), either D+ C- E- c+ e+ or D+ C+ E- c+ e+ and 44 % exhibited the Fya-/Jkb-/S- combined phenotype. Noteworthy is the detection of the G6PD(Val68Met) variant characterized by c.202G > A transition, G6PD(Asn126Asp) variant characterized by c.376A>G transition and G6PD(Asp181Val) variant characterized by c.542A>T transversion of the G6PD gene in 22.5 % of the sample, characteristic of the A(-(202)), A and Santamaria G6PDd variants, respectively. French Guianan Noir Marron population represents a pool of Rh-D antigen positive, Duffy-negative and G6PD-deficient erythrocytes, the latter accounting for one in every eight persons. The present study provides the first community-based estimation of the frequency of G6PDd polymorphisms in French Guiana. These results contribute to the G6PD genetic background information puzzle in Latin America.

  14. Glucose-6-phosphate dehydrogenase deficiency among children attending the Emergency Paediatric Unit of Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria.

    PubMed

    Isaac, Iz; Mainasara, As; Erhabor, Osaro; Omojuyigbe, St; Dallatu, Mk; Bilbis, Ls; Adias, Tc

    2013-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human enzyme deficiencies in the world. It is particularly common in populations living in malaria-endemic areas, affecting more than 400 million people worldwide. This present study was conducted with the aim of determining the prevalence of G6PD deficiency among children visiting the Emergency Paediatric Unit of Usmanu Danfodiyo University Teaching Hospital for pediatric-related care. The study included 118 children, made up of 77 (65.3%) males and 41 (34.7%) females aged ≤5 years with mean age of 3.26 ± 1.90 years. Randox G6PD quantitative in vitro test screening was used for the diagnosis of G6PD deficiency. Of the 118 children tested, 17 (14.4%) were G6PD-deficient. Prevalence of G6PD deficiency was concentrated predominantly among male children (22.1%). Male sex was significantly correlated with G6PD deficiency among the children studied (r = 7.85, P = 0.01). The highest prevalence occurred among children in the 2- to 5-year age-group. Of the 17 G6PD-deficient children, twelve (70.2%) were moderately deficient, while five (29.4%) were severely deficient. Blood film from G6PD-deficient children indicated the following morphological changes; Heinz bodies, schistocytes, target cells, nucleated red cells, spherocytes, and polychromasia. This present study has shown a high prevalence of G6PD deficiency among children residing in Sokoto in the northwestern geopolitical zone of Nigeria. The study indicated a male sex bias in the prevalence of G6PD deficiency among the children studied. There is a need for the routine screening of children for G6PD deficiency in our environment, to allow for evidence-based management of these children and to ensure the avoidance of food, drugs, and infective agents that can potentially predispose these children to oxidative stress as well as diseases that deplete micronutrients that protect against oxidative stress. There is need to build capacity in our

  15. Determinants of Cofactor Specificity for the Glucose-6-Phosphate Dehydrogenase from Escherichia coli: Simulation, Kinetics and Evolutionary Studies

    PubMed Central

    Fuentealba, Matias; Muñoz, Rodrigo; Maturana, Pablo; Krapp, Adriana; Cabrera, Ricardo

    2016-01-01

    Glucose 6-Phosphate Dehydrogenases (G6PDHs) from different sources show varying specificities towards NAD+ and NADP+ as cofactors. However, it is not known to what extent structural determinants of cofactor preference are conserved in the G6PDH family. In this work, molecular simulations, kinetic characterization of site-directed mutants and phylogenetic analyses were used to study the structural basis for the strong preference towards NADP+ shown by the G6PDH from Escherichia coli. Molecular Dynamics trajectories of homology models showed a highly favorable binding energy for residues K18 and R50 when interacting with the 2'-phosphate of NADP+, but the same residues formed no observable interactions in the case of NAD+. Alanine mutants of both residues were kinetically characterized and analyzed with respect to the binding energy of the transition state, according to the kcat/KM value determined for each cofactor. Whereas both residues contribute to the binding energy of NADP+, only R50 makes a contribution (about -1 kcal/mol) to NAD+ binding. In the absence of both positive charges the enzyme was unable to discriminate NADP+ from NAD+. Although kinetic data is sparse, the observed distribution of cofactor preferences within the phylogenetic tree is sufficient to rule out the possibility that the known NADP+-specific G6PDHs form a monophyletic group. While the β1-α1 loop shows no strict conservation of K18, (rather, S and T seem to be more frequent), in the case of the β2-α2 loop, different degrees of conservation are observed for R50. Noteworthy is the fact that a K18T mutant is indistinguishable from K18A in terms of cofactor preference. We conclude that the structural determinants for the strict discrimination against NAD+ in the case of the NADP+-specific enzymes have evolved independently through different means during the evolution of the G6PDH family. We further suggest that other regions in the cofactor binding pocket, besides the β1-α1 and β2-α2

  16. Glucose-6-phosphate dehydrogenase regulation in the hepatopancreas of the anoxia-tolerant marine mollusc, Littorina littorea.

    PubMed

    Lama, Judeh L; Bell, Ryan A V; Storey, Kenneth B

    2013-01-01

    Glucose-6-phosphate dehydrogenase (G6PDH) gates flux through the pentose phosphate pathway and is key to cellular antioxidant defense due to its role in producing NADPH. Good antioxidant defenses are crucial for anoxia-tolerant organisms that experience wide variations in oxygen availability. The marine mollusc, Littorina littorea, is an intertidal snail that experiences daily bouts of anoxia/hypoxia with the tide cycle and shows multiple metabolic and enzymatic adaptations that support anaerobiosis. This study investigated the kinetic, physical and regulatory properties of G6PDH from hepatopancreas of L. littorea to determine if the enzyme is differentially regulated in response to anoxia, thereby providing altered pentose phosphate pathway functionality under oxygen stress conditions. Several kinetic properties of G6PDH differed significantly between aerobic and 24 h anoxic conditions; compared with the aerobic state, anoxic G6PDH (assayed at pH 8) showed a 38% decrease in K m G6P and enhanced inhibition by urea, whereas in pH 6 assays K m NADP and maximal activity changed significantly between the two states. The mechanism underlying anoxia-responsive changes in enzyme properties proved to be a change in the phosphorylation state of G6PDH. This was documented with immunoblotting using an anti-phosphoserine antibody, in vitro incubations that stimulated endogenous protein kinases versus protein phosphatases and significantly changed K m G6P, and phosphorylation of the enzyme with (32)P-ATP. All these data indicated that the aerobic and anoxic forms of G6PDH were the high and low phosphate forms, respectively, and that phosphorylation state was modulated in response to selected endogenous protein kinases (PKA or PKG) and protein phosphatases (PP1 or PP2C). Anoxia-induced changes in the phosphorylation state of G6PDH may facilitate sustained or increased production of NADPH to enhance antioxidant defense during long term anaerobiosis and/or during the transition

  17. Determinants of Cofactor Specificity for the Glucose-6-Phosphate Dehydrogenase from Escherichia coli: Simulation, Kinetics and Evolutionary Studies.

    PubMed

    Fuentealba, Matias; Muñoz, Rodrigo; Maturana, Pablo; Krapp, Adriana; Cabrera, Ricardo

    2016-01-01

    Glucose 6-Phosphate Dehydrogenases (G6PDHs) from different sources show varying specificities towards NAD+ and NADP+ as cofactors. However, it is not known to what extent structural determinants of cofactor preference are conserved in the G6PDH family. In this work, molecular simulations, kinetic characterization of site-directed mutants and phylogenetic analyses were used to study the structural basis for the strong preference towards NADP+ shown by the G6PDH from Escherichia coli. Molecular Dynamics trajectories of homology models showed a highly favorable binding energy for residues K18 and R50 when interacting with the 2'-phosphate of NADP+, but the same residues formed no observable interactions in the case of NAD+. Alanine mutants of both residues were kinetically characterized and analyzed with respect to the binding energy of the transition state, according to the kcat/KM value determined for each cofactor. Whereas both residues contribute to the binding energy of NADP+, only R50 makes a contribution (about -1 kcal/mol) to NAD+ binding. In the absence of both positive charges the enzyme was unable to discriminate NADP+ from NAD+. Although kinetic data is sparse, the observed distribution of cofactor preferences within the phylogenetic tree is sufficient to rule out the possibility that the known NADP+-specific G6PDHs form a monophyletic group. While the β1-α1 loop shows no strict conservation of K18, (rather, S and T seem to be more frequent), in the case of the β2-α2 loop, different degrees of conservation are observed for R50. Noteworthy is the fact that a K18T mutant is indistinguishable from K18A in terms of cofactor preference. We conclude that the structural determinants for the strict discrimination against NAD+ in the case of the NADP+-specific enzymes have evolved independently through different means during the evolution of the G6PDH family. We further suggest that other regions in the cofactor binding pocket, besides the β1-α1 and β2-α2

  18. Evidence for two different mechanisms triggering the change in quaternary structure of the allosteric enzyme, glucosamine-6-phosphate deaminase.

    PubMed

    Bustos-Jaimes, Ismael; Ramírez-Costa, Montserrat; De Anda-Aguilar, Lorena; Hinojosa-Ocaña, Pilar; Calcagno, Mario L

    2005-02-01

    The generation and propagation of conformational changes associated with ligand binding in the allosteric enzyme glucosamine-6-phosphate deaminase (GlcN6P deaminase, EC 3.5.99.6) from Escherichia coli were analyzed by fluorescence measurements. Single-tryptophan mutant forms of the enzyme were constructed on the basis of previous structural and functional evidence and used as structural-change probes. The reporter residues were placed in the active-site lid (position 174) and in the allosteric site (254 and 234); in addition, signals from the natural Trp residues (15 and 224) were also studied as structural probes. The structural changes produced by the occupation of either the allosteric or the active site by site-specific ligands were monitored through changes in the spectral center of mass (SCM) of their steady-state emission fluorescence spectra. Binding of the allosteric activator produces only minimal signals in titration experiments. In contrast, measurable spectral signals were found when the active site was occupied by a dead-end inhibitor. The results reveal that the two binary complexes, enzyme-activator (R(A)) and enzyme-inhibitor (R(S)) complexes, have structural differences and that they also differ from the ternary complex (R(AS)). The mobility of the active-site lid motif is shown to be independent of the allosteric transition. The active-site ligand induces cooperative SCM changes even in the enzyme-activator complex, indicating that the propagation pathway of the conformational relaxation triggered from the active site is different from that involved in the heterotropic activation. Analysis of the complete set of mutants shows that the occupation of the active site generates structural perturbations, which are propagated to the whole of the monomer and extend to the other subunits. The accumulative effect of these propagated changes should be responsible for the change in the sign of the DeltaG degrees ' of the T to R transition associated with

  19. Data on how several physiological parameters of stored red blood cells are similar in glucose 6-phosphate dehydrogenase deficient and sufficient donors.

    PubMed

    Tzounakas, Vassilis L; Kriebardis, Anastasios G; Georgatzakou, Hara T; Foudoulaki-Paparizos, Leontini E; Dzieciatkowska, Monika; Wither, Matthew J; Nemkov, Travis; Hansen, Kirk C; Papassideri, Issidora S; D'Alessandro, Angelo; Antonelou, Marianna H

    2016-09-01

    This article contains data on the variation in several physiological parameters of red blood cells (RBCs) donated by eligible glucose-6-phosphate dehydrogenase (G6PD) deficient donors during storage in standard blood bank conditions compared to control, G6PD sufficient (G6PD(+)) cells. Intracellular reactive oxygen species (ROS) generation, cell fragility and membrane exovesiculation were measured in RBCs throughout the storage period, with or without stimulation by oxidants, supplementation of N-acetylcysteine and energy depletion, following incubation of stored cells for 24 h at 37 °C. Apart from cell characteristics, the total or uric acid-dependent antioxidant capacity of the supernatant in addition to extracellular potassium concentration was determined in RBC units. Finally, procoagulant activity and protein carbonylation levels were measured in the microparticles population. Further information can be found in "Glucose 6-phosphate dehydrogenase deficient subjects may be better "storers" than donors of red blood cells" [1].

  20. Effect of peptides of the insulin superfamily on glucose-6-phosphate dehydrogenase activity in skeletal muscles of river lamprey (Lampetra fluviatilis) during prespawning starvation.

    PubMed

    Chistyakova, O V; Kuznetsova, L A

    2009-07-01

    Glucose-6-phosphate dehydrogenase activity in skeletal muscles of the lamprey (Lampetra fluviatilis) decreased during prespawning starvation (September-May). The observed changes were particularly pronounced in January. Insulin, insulin-like growth factor 1, and relaxin produce an in vitro stimulatory effect on the enzyme. Insulin was most potent in this respect. Inactivation of the enzyme was accompanied by a decrease in its sensitivity to the stimulatory effect of insulin and insulin-like growth factor 1.

  1. Acute viral hepatitis E presenting with haemolytic anaemia and acute renal failure in a patient with glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Tomar, Laxmikant Ramkumarsingh; Aggarwal, Amitesh; Jain, Piyush; Rajpal, Surender; Agarwal, Mukul P

    2015-10-01

    The association of acute hepatitis E viral (HEV) infection with glucose-6-phosphate dehydrogenase (G6PD) deficiency leading to extensive intravascular haemolysis is a very rare clinical entity. Here we discuss such a patient, who presented with acute HEV illness, developed severe intravascular haemolysis and unusually high levels of bilirubin, complicated by acute renal failure (ARF), and was later on found to have a deficiency of G6PD. The patient recovered completely with haemodialysis and supportive management.

  2. Against All Odds: Trehalose-6-Phosphate Synthase and Trehalase Genes in the Bdelloid Rotifer Adineta vaga Were Acquired by Horizontal Gene Transfer and Are Upregulated during Desiccation

    PubMed Central

    Hespeels, Boris; Li, Xiang; Flot, Jean-François; Pigneur, Lise-Marie; Malaisse, Jeremy; Da Silva, Corinne; Van Doninck, Karine

    2015-01-01

    The disaccharide sugar trehalose is essential for desiccation resistance in most metazoans that survive dryness; however, neither trehalose nor the enzymes involved in its metabolism have ever been detected in bdelloid rotifers despite their extreme resistance to desiccation. Here we screened the genome of the bdelloid rotifer Adineta vaga for genes involved in trehalose metabolism. We discovered a total of four putative trehalose-6-phosphate synthase (TPS) and seven putative trehalase (TRE) gene copies in the genome of this ameiotic organism; however, no trehalose-6-phosphate phosphatase (TPP) gene or domain was detected. The four TPS copies of A. vaga appear more closely related to plant and fungi proteins, as well as to some protists, whereas the seven TRE copies fall in bacterial clades. Therefore, A. vaga likely acquired its trehalose biosynthesis and hydrolysis genes by horizontal gene transfers. Nearly all residues important for substrate binding in the predicted TPS domains are highly conserved, supporting the hypothesis that several copies of the genes might be functional. Besides, RNAseq library screening showed that trehalase genes were highly expressed compared to TPS genes, explaining probably why trehalose had not been detected in previous studies of bdelloids. A strong overexpression of their TPS genes was observed when bdelloids enter desiccation, suggesting a possible signaling role of trehalose-6-phosphate or trehalose in this process. PMID:26161530

  3. Glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides is a reliable internal standard for radiation-inactivation studies of membranes in the frozen state

    SciTech Connect

    McIntyre, J.O.; Churchill, P.

    1985-06-01

    The target size of four soluble enzymes (beta-galactosidase, pyruvate kinase, alcohol dehydrogenase, and glucose-6-phosphate dehydrogenase) in the presence or absence of subcellular membrane fractions has been determined by the radiation-inactivation method using samples in the frozen state. For each of the four enzymes, full activity was recovered after freezing and thawing in the absence of radiation. The authors found minimal (less than 20%) binding of the enzymes to either submitochondrial vesicles or sarcoplasmic reticulum vesicles. Under the conditions tested, beta-galactosidase, pyruvate kinase, and alcohol dehydrogenase exhibited target sizes which varied according to the experimental conditions, i.e., the buffer selected and also the presence or absence of membrane preparations. For these tetrameric enzymes, the target sizes were generally comparable to either a monomer or a dimer. By contrast, the target size of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides was found to be essentially invariant when frozen in a variety of buffers and in the presence or absence of either cryoprotectant (sucrose or glycerol) or different membrane preparations. The target size from 19 separate determinations gave an average value of 104 +/- 16 kDa, which is comparable to the molecular weight of the enzyme (104 kDa). The authors conclude that glucose-6-phosphate dehydrogenase from L. mesenteroides is a reliable internal standard for radiation-inactivation studies of membrane preparations in the frozen state.

  4. Alterations in Energy/Redox Metabolism Induced by Mitochondrial and Environmental Toxins: A Specific Role for Glucose-6-Phosphate-Dehydrogenase and the Pentose Phosphate Pathway in Paraquat Toxicity

    PubMed Central

    2015-01-01

    Parkinson’s disease (PD) is a multifactorial disorder with a complex etiology including genetic risk factors, environmental exposures, and aging. While energy failure and oxidative stress have largely been associated with the loss of dopaminergic cells in PD and the toxicity induced by mitochondrial/environmental toxins, very little is known regarding the alterations in energy metabolism associated with mitochondrial dysfunction and their causative role in cell death progression. In this study, we investigated the alterations in the energy/redox-metabolome in dopaminergic cells exposed to environmental/mitochondrial toxins (paraquat, rotenone, 1-methyl-4-phenylpyridinium [MPP+], and 6-hydroxydopamine [6-OHDA]) in order to identify common and/or different mechanisms of toxicity. A combined metabolomics approach using nuclear magnetic resonance (NMR) and direct-infusion electrospray ionization mass spectrometry (DI-ESI-MS) was used to identify unique metabolic profile changes in response to these neurotoxins. Paraquat exposure induced the most profound alterations in the pentose phosphate pathway (PPP) metabolome. 13C-glucose flux analysis corroborated that PPP metabolites such as glucose-6-phosphate, fructose-6-phosphate, glucono-1,5-lactone, and erythrose-4-phosphate were increased by paraquat treatment, which was paralleled by inhibition of glycolysis and the TCA cycle. Proteomic analysis also found an increase in the expression of glucose-6-phosphate dehydrogenase (G6PD), which supplies reducing equivalents by regenerating nicotinamide adenine dinucleotide phosphate (NADPH) levels. Overexpression of G6PD selectively increased paraquat toxicity, while its inhibition with 6-aminonicotinamide inhibited paraquat-induced oxidative stress and cell death. These results suggest that paraquat “hijacks” the PPP to increase NADPH reducing equivalents and stimulate paraquat redox cycling, oxidative stress, and cell death. Our study clearly demonstrates that alterations

  5. Alterations in energy/redox metabolism induced by mitochondrial and environmental toxins: a specific role for glucose-6-phosphate-dehydrogenase and the pentose phosphate pathway in paraquat toxicity.

    PubMed

    Lei, Shulei; Zavala-Flores, Laura; Garcia-Garcia, Aracely; Nandakumar, Renu; Huang, Yuting; Madayiputhiya, Nandakumar; Stanton, Robert C; Dodds, Eric D; Powers, Robert; Franco, Rodrigo

    2014-09-19

    Parkinson's disease (PD) is a multifactorial disorder with a complex etiology including genetic risk factors, environmental exposures, and aging. While energy failure and oxidative stress have largely been associated with the loss of dopaminergic cells in PD and the toxicity induced by mitochondrial/environmental toxins, very little is known regarding the alterations in energy metabolism associated with mitochondrial dysfunction and their causative role in cell death progression. In this study, we investigated the alterations in the energy/redox-metabolome in dopaminergic cells exposed to environmental/mitochondrial toxins (paraquat, rotenone, 1-methyl-4-phenylpyridinium [MPP+], and 6-hydroxydopamine [6-OHDA]) in order to identify common and/or different mechanisms of toxicity. A combined metabolomics approach using nuclear magnetic resonance (NMR) and direct-infusion electrospray ionization mass spectrometry (DI-ESI-MS) was used to identify unique metabolic profile changes in response to these neurotoxins. Paraquat exposure induced the most profound alterations in the pentose phosphate pathway (PPP) metabolome. 13C-glucose flux analysis corroborated that PPP metabolites such as glucose-6-phosphate, fructose-6-phosphate, glucono-1,5-lactone, and erythrose-4-phosphate were increased by paraquat treatment, which was paralleled by inhibition of glycolysis and the TCA cycle. Proteomic analysis also found an increase in the expression of glucose-6-phosphate dehydrogenase (G6PD), which supplies reducing equivalents by regenerating nicotinamide adenine dinucleotide phosphate (NADPH) levels. Overexpression of G6PD selectively increased paraquat toxicity, while its inhibition with 6-aminonicotinamide inhibited paraquat-induced oxidative stress and cell death. These results suggest that paraquat "hijacks" the PPP to increase NADPH reducing equivalents and stimulate paraquat redox cycling, oxidative stress, and cell death. Our study clearly demonstrates that alterations in

  6. Effects of yeast trehalose-6-phosphate synthase 1 on gene expression and carbohydrate contents of potato leaves under drought stress conditions

    PubMed Central

    2012-01-01

    Background The development of drought-tolerant, elite varieties of potato (Solanum tuberosum L.) is a challenging task, which might be achieved by introducing transgenic lines into breeding. We previously demonstrated that strains of the White Lady potato cultivar that express the yeast trehalose-6-phosphate synthase ( TPS1) gene exhibit improved drought tolerance. Results We investigated the responses of the drought-sensitive potato cultivar White Lady and the drought-tolerant TPS1 transgenic variant to prolonged drought stress at both the transcriptional and metabolic levels. Leaf mRNA expression profiles were compared using the POCI microarray, which contains 42,034 potato unigene probes. We identified 379 genes of known function that showed at least a 2-fold change in expression across genotypes, stress levels or the interaction between these factors. Wild-type leaves had twice as many genes with altered expression in response to stress than TPS1 transgenic leaves, but 112 genes were differentially expressed in both strains. We identified 42 transcription factor genes with altered expression, of which four were uniquely up-regulated in TPS1 transgenic leaves. The majority of the genes with altered expression that have been implicated in photosynthesis and carbohydrate metabolism were down-regulated in both the wild-type and TPS1 transgenic plants. In agreement with this finding, the starch concentration of the stressed leaves was very low. At the metabolic level, the contents of fructose, galactose and glucose were increased and decreased in the wild-type and TPS1 transgenic leaves, respectively, while the amounts of proline, inositol and raffinose were highly increased in both the wild-type and TPS1 transgenic leaves under drought conditions. Conclusions To our knowledge, this study is the most extensive transcriptional and metabolic analysis of a transgenic, drought-tolerant potato line. We identified four genes that were previously reported as drought

  7. Neuroprotective effect of liquiritin as an antioxidant via an increase in glucose-6-phosphate dehydrogenase expression on B65 neuroblastoma cells.

    PubMed

    Nakatani, Yoshihiko; Kobe, Aya; Kuriya, Megumi; Hiroki, Yoko; Yahagi, Tadahiro; Sakakibara, Iwao; Matsuzaki, Keiichi; Amano, Taku

    2017-09-29

    Glycyrrhiza (the roots and rhizomes of licorice) has been used worldwide as both an herbal nutraceutical and herbal medicine. In addition, it is well known that Glycyrrhiza contains various compounds with biological effects, such as anti-viral, anti-inflammatory, immunoregulatory, anti-tumor and neuroprotective effects. Among the various compounds in Glycyrrhiza, the active compounds that show biological activity are thought to include glycyrrhizin, glycyrrhetinic acid, glabridin, licochalcones and liquiritin. In the present study, we investigated the biological effects of three of these compounds (glycyrrhizin, liquiritin and isoliquiritin) on B65 neuroblastoma cells derived from serotonergic neurons. Among these three compounds, only liquiritin enhanced the proliferation of B65 neuroblastoma cells. In contrast, both glycyrrhizin and isoliquiritin, particularly at high concentrations had cytotoxic effects. Cells were treated with various cytotoxic agents and liquiritin could ameliorate the cytotoxicity induced by menadione sodium bisulfate in a dose-dependent manner. We also examined the effect of liquiritin on cell survival by evaluating the expression levels of phospho-p44/42 mitogen-activated protein kinase, cyclin-related proteins and glucose-6-phosphate dehydrogenase, which produces nicotinamide adenine dinucleotide phosphate. Under treatment with liquiritin, the protein expression level of glucose-6-phosphate dehydrogenase increased in a dose-dependent manner. In contrast, the protein expression level of cyclin-related proteins did not change at all under treatment with liquiritin. These results suggest that liquiritin, which is contained in Glycyrrhiza, may enhance cell survival by increasing the protein expression level of glucose-6 phosphate dehydrogenase. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. The N-Acetylmuramic Acid 6-Phosphate Phosphatase MupP Completes the Pseudomonas Peptidoglycan Recycling Pathway Leading to Intrinsic Fosfomycin Resistance

    PubMed Central

    Borisova, Marina; Gisin, Jonathan

    2017-01-01

    ABSTRACT Bacterial cells are encased in and stabilized by a netlike peptidoglycan (PGN) cell wall that undergoes turnover during bacterial growth. PGN turnover fragments are frequently salvaged by the cells via a pathway referred to as PGN recycling. Two different routes for the recycling of the cell wall sugar N-acetylmuramic acid (MurNAc) have been recognized in bacteria. In Escherichia coli and related enterobacteria, as well as in most Gram-positive bacteria, MurNAc is recovered via a catabolic route requiring a MurNAc 6-phosphate etherase (MurQ in E. coli) enzyme. However, many Gram-negative bacteria, including Pseudomonas species, lack a MurQ ortholog and use an alternative, anabolic recycling route that bypasses the de novo biosynthesis of uridyldiphosphate (UDP)-MurNAc, the first committed precursor of PGN. Bacteria featuring the latter pathway become intrinsically resistant to the antibiotic fosfomycin, which targets the de novo biosynthesis of UDP-MurNAc. We report here the identification and characterization of a phosphatase enzyme, named MupP, that had been predicted to complete the anabolic recycling pathway of Pseudomonas species but has remained unknown so far. It belongs to the large haloacid dehalogenase family of phosphatases and specifically converts MurNAc 6-phosphate to MurNAc. A ΔmupP mutant of Pseudomonas putida was highly susceptible to fosfomycin, accumulated large amounts of MurNAc 6-phosphate, and showed lower levels of UDP-MurNAc than wild-type cells, altogether consistent with a role for MupP in the anabolic PGN recycling route and as a determinant of intrinsic resistance to fosfomycin. PMID:28351914

  9. Antibody formation and mannose-6-phosphate receptor expression impact the efficacy of muscle-specific transgene expression in murine Pompe disease.

    PubMed

    Sun, Baodong; Li, Songtao; Bird, Andrew; Yi, Haiqing; Kemper, Alex; Thurberg, Beth L; Koeberl, Dwight D

    2010-11-01

    Lysosomal storage disorders such as Pompe disease can be more effectively treated, if immune tolerance to enzyme or gene replacement therapy can be achieved. Alternatively, immune responses against acid α-glucosidase (GAA) might be evaded in Pompe disease through muscle-specific expression of GAA with adeno-associated virus (AAV) vectors. An AAV vector containing the MHCK7 regulatory cassette to drive muscle-specific GAA expression was administered to GAA knockout (KO) mice, immune tolerant GAA-KO mice and mannose-6-phosphate deficient GAA-KO mice. GAA activity and glycogen content were analyzed in striated muscle to determine biochemical efficacy. The biochemical efficacy from GAA expression was slightly reduced in GAA-KO mice, as demonstrated by higher residual glycogen content in skeletal muscles. Next, immune tolerance to GAA was induced in GAA-KO mice by co-administration of a second AAV vector encoding liver-specific GAA along with the AAV vector encoding muscle-specific GAA. Antibody formation was prevented by liver-specific GAA, and the biochemical efficacy of GAA expression was improved in the absence of antibodies, as demonstrated by significantly reduced glycogen content in the diaphragm. Efficacy was reduced in old GAA-KO mice despite the absence of antibodies. The greatest impact upon gene therapy was observed in GAA-KO mice lacking the mannose-6-phosphate receptor in muscle. The clearance of stored glycogen was markedly impaired despite high GAA expression in receptor-deficient Pompe disease mice. Overall, antibody formation had a subtle effect upon efficacy, whereas the absence of mannose-6-phosphate receptors markedly impaired muscle-targeted gene therapy in murine Pompe disease. Copyright © 2010 John Wiley & Sons, Ltd.

  10. Antibody formation and mannose-6-phosphate receptor expression impact the efficacy of muscle-specific transgene expression in murine Pompe disease

    PubMed Central

    Sun, Baodong; Li, Songtao; Bird, Andrew; Yi, Haiqing; Kemper, Alex; Koeberl, Dwight D.

    2013-01-01

    BACKGROUND Lysosomal storage disorders such as Pompe disease can be more effectively treated, if immune tolerance to enzyme or gene replacement therapy can be achieved. Alternatively, immune responses against acid α-glucosidase (GAA) might be evaded in Pompe disease through muscle-specific expression of GAA with adeno-associated virus (AAV) vectors. METHODS An AAV vector containing the MHCK7 regulatory cassette to drive muscle-specific GAA expression was administered to GAA knockout (KO) mice, immune tolerant GAA-KO mice, and mannose-6-phosphate deficient GAA-KO mice. GAA activity and glycogen content were analyzed in striated muscle to determine biochemical efficacy. RESULTS The biochemical efficacy from GAA expression was slightly reduced in GAA-KO mice, as demonstrated by higher residual glycogen content in skeletal muscles. Next immune tolerance to GAA was induced in GAA-KO mice by co-administration of a second AAV vector encoding liver-specific GAA along with the AAV vector encoding muscle-specific GAA. Antibody formation was prevented by liver-specific GAA, and the biochemical efficacy of GAA expression was improved in absence of antibodies as evidenced by significantly reduced glycogen content in the diaphragm. Efficacy was reduced in old GAA-KO mice despite the absence of antibodies. The greatest impact upon gene therapy was observed in GAA-KO mice lacking the mannose-6-phosphate receptor in muscle. The clearance of stored glycogen was markedly impaired despite high GAA expression in receptor-deficient Pompe disease mice. CONCLUSIONS Overall, antibody formation had a subtle effect upon efficacy, while the absence of mannose-6-phosphate receptors markedly impaired muscle-targeted gene therapy in murine Pompe disease. PMID:20967919

  11. The mouse insulin-like growth factor II/cation-independent mannose 6-phosphate (IGF-II/MPR) receptor gene: Molecular cloning and genomic organization

    SciTech Connect

    Szebenyi, G.; Rotwein, P. )

    1994-01-01

    The mammalian insulin-like growth factor III/cation-independent mannose 6-phosphate receptor (IGF-II/MPR) is a multifunctional protein that binds both IGF-II and ligands containing a mannose 6-phosphate recognition marker through distinct high-affinity sites. This receptor plays an integral part in lysosomal enzyme transport, has a potential role in growth factor maturation and clearance, and may mediate IGF-II-activated signal transduction through a G-protein-coupled mechanism. Recent studies have shown that production of IGF-II/MPR mRNA and protein begins in the mouse embryo soon after fertilization and have demonstrated that the receptor gene is on mouse chromosome 17 and is maternally imprinted. In this paper, the authors report the cloning and characterization of the mouse IGF-II/MPR gene. The gene is 93 kb long, is composed of 48 exons, and codes for a predicted protein of 2482 amino acids. The extracellular part of the receptor is encoded by exons 1-46, with each of 15 related repeating motifs being determined by parts of 3-5 exons. A single fibronectin type II-like element is found in exon 39. The transmembrane portion of the receptor also is encoded by exon 46, and the cytoplasmic region by exons 46-48. The positions of exon-intron splice junctions are conserved between several of the repeats in the IGF-II/MPR and the homologous extracellular region of the gene for the other known lysosomal sorting receptor, the cation-dependent mannose 6-phosphate receptor. The gene duplications that gave rise to the modern IGF-II/MPR probably occurred before the divergence of mammals, since there is more extensive protein sequence conservation between receptors from different species than between any pair of repeating motifs within a single receptor. 55 refs., 7 figs., 1 tab.

  12. Expression, crystallization and preliminary X-ray crystallographic analysis of glucose-6-phosphate dehydrogenase from the human pathogen Trypanosoma cruzi in complex with substrate

    PubMed Central

    Ortíz, Cecilia; Larrieux, Nicole; Medeiros, Andrea; Botti, Horacio; Comini, Marcelo; Buschiazzo, Alejandro

    2011-01-01

    An N-terminally truncated version of the enzyme glucose-6-phosphate dehydrogenase from Trypanosoma cruzi lacking the first 37 residues was crystallized both in its apo form and in a binary complex with glucose 6-­phosphate. The crystals both belonged to space group P21 and diffracted to 2.85 and 3.35 Å resolution, respectively. Self-rotation function maps were consistent with point group 222. The structure was solved by molecular replacement, confirming a tetrameric quaternary structure. PMID:22102256

  13. Unsuspected glucose-6-phosphate dehydrogenase deficiency presenting as symptomatic methemoglobinemia with severe hemolysis after fava bean ingestion in a 6-year-old boy.

    PubMed

    Odièvre, Marie-Hélène; Danékova, Névéna; Mesples, Bettina; Chemouny, Myriam; Couque, Nathalie; Parez, Nathalie; Ducrocq, Rolande; Elion, Jacques

    2011-05-01

    We report the occurrence of symptomatic methemoglobinemia in a previously healthy boy, who presented with severe acute hemolysis after fava bean ingestion. The methemoglobinemia revealed a previously unrecognized glucose-6-phosphate dehydrogenase (G6PD) deficiency. We discuss the pathophysiology of severe methemoglobinemia when associated with acute hemolysis, favism, and the common African G6PD A-variant [G6PD, VAL68MET, ASN126ASP]. In conclusion, screening for G6PD deficiency must be considered in symptomatic methemoglobinemia, especially in young boys, when associated with intravascular hemolysis.

  14. General Linker Diversification Approach to Bivalent Ligand Assembly: Generation of an Array of Ligands for the Cation-Independent Mannose 6-Phosphate Receptor.

    PubMed

    Fei, Xiang; Zavorka, Megan E; Malik, Guillaume; Connelly, Christopher M; MacDonald, Richard G; Berkowitz, David B

    2017-08-18

    A generalized strategy is presented for the rapid assembly of a set of bivalent ligands with a variety of linking functionalities from a common monomer. Herein, an array of phosphatase-inert mannose-6-phosphonate-presenting ligands for the cation-independent-mannose 6-phosphate receptor (CI-MPR) is constructed. Receptor binding affinity varies with linking functionality-the simple amide and 1,5-triazole(tetrazole) being preferred over the 1,4-triazole. This approach is expected to find application across chemical biology, particularly in glycoscience, wherein multivalency often governs molecular recognition.

  15. The N-Acetylmuramic Acid 6-Phosphate Phosphatase MupP Completes the Pseudomonas Peptidoglycan Recycling Pathway Leading to Intrinsic Fosfomycin Resistance.

    PubMed

    Borisova, Marina; Gisin, Jonathan; Mayer, Christoph

    2017-03-28

    Bacterial cells are encased in and stabilized by a netlike peptidoglycan (PGN) cell wall that undergoes turnover during bacterial growth. PGN turnover fragments are frequently salvaged by the cells via a pathway referred to as PGN recycling. Two different routes for the recycling of the cell wall sugar N-acetylmuramic acid (MurNAc) have been recognized in bacteria. In Escherichia coli and related enterobacteria, as well as in most Gram-positive bacteria, MurNAc is recovered via a catabolic route requiring a MurNAc 6-phosphate etherase (MurQ in E. coli) enzyme. However, many Gram-negative bacteria, including Pseudomonas species, lack a MurQ ortholog and use an alternative, anabolic recycling route that bypasses the de novo biosynthesis of uridyldiphosphate (UDP)-MurNAc, the first committed precursor of PGN. Bacteria featuring the latter pathway become intrinsically resistant to the antibiotic fosfomycin, which targets the de novo biosynthesis of UDP-MurNAc. We report here the identification and characterization of a phosphatase enzyme, named MupP, that had been predicted to complete the anabolic recycling pathway of Pseudomonas species but has remained unknown so far. It belongs to the large haloacid dehalogenase family of phosphatases and specifically converts MurNAc 6-phosphate to MurNAc. A ΔmupP mutant of Pseudomonas putida was highly susceptible to fosfomycin, accumulated large amounts of MurNAc 6-phosphate, and showed lower levels of UDP-MurNAc than wild-type cells, altogether consistent with a role for MupP in the anabolic PGN recycling route and as a determinant of intrinsic resistance to fosfomycin.IMPORTANCE Many Gram-negative bacteria, but not E. coli, make use of a cell wall salvage pathway that contributes to the pool of UDP-MurNAc, the first committed precursor of cell wall synthesis in bacteria. This salvage pathway is of particular interest because it confers intrinsic resistance to the antibiotic fosfomycin, which blocks de novo UDP

  16. G6PD (Dublin): chronic non-spherocytic haemolytic anaemia resulting from glucose-6-phosphate dehydrogenase deficiency in an Irish kindred.

    PubMed Central

    McCann, S R; Smithwick, A M; Temperley, I J; Tipton, K

    1980-01-01

    A new variant of G6PD associated with chronic non-spherocytic haemolytic anaemia (CNSHA) in an Irish male is described. This variant is unique in that it has a normal electrophoretic mobility, Michaelis constant for G6P and NADP, and a normal pH optimum, together with a marked increase in utilisation of the substrate 2 deoxy glucose-6-phosphate. It is also relatively heat stable when compared with the normal (B) variant. These characteristics distinguish this variant from previously reported variants associated with CNSHA and we have called it G6PD Dublin. PMID:7401130

  17. Structural and In Vivo Studies on Trehalose-6-Phosphate Synthase from Pathogenic Fungi Provide Insights into Its Catalytic Mechanism, Biological Necessity, and Potential for Novel Antifungal Drug Design.

    PubMed

    Miao, Yi; Tenor, Jennifer L; Toffaletti, Dena L; Maskarinec, Stacey A; Liu, Jiuyu; Lee, Richard E; Perfect, John R; Brennan, Richard G

    2017-07-25

    The disaccharide trehalose is critical to the survival of pathogenic fungi in their human host. Trehalose-6-phosphate synthase (Tps1) catalyzes the first step of trehalose biosynthesis in fungi. Here, we report the first structures of eukaryotic Tps1s in complex with substrates or substrate analogues. The overall structures of Tps1 from Candida albicans and Aspergillus fumigatus are essentially identical and reveal N- and C-terminal Rossmann fold domains that form the glucose-6-phosphate and UDP-glucose substrate binding sites, respectively. These Tps1 structures with substrates or substrate analogues reveal key residues involved in recognition and catalysis. Disruption of these key residues severely impaired Tps1 enzymatic activity. Subsequent cellular analyses also highlight the enzymatic function of Tps1 in thermotolerance, yeast-hypha transition, and biofilm development. These results suggest that Tps1 enzymatic functionality is essential for the fungal stress response and virulence. Furthermore, structures of Tps1 in complex with the nonhydrolyzable inhibitor, validoxylamine A, visualize the transition state and support an internal return-like catalytic mechanism that is generalizable to other GT-B-fold retaining glycosyltransferases. Collectively, our results depict key Tps1-substrate interactions, unveil the enzymatic mechanism of these fungal proteins, and pave the way for high-throughput inhibitor screening buttressed and guided by the current structures and those of high-affinity ligand-Tps1 complexes.IMPORTANCE Invasive fungal diseases have emerged as major threats, resulting in more than 1.5 million deaths annually worldwide. This epidemic has been further complicated by increasing resistance to all major classes of antifungal drugs in the clinic. Trehalose biosynthesis is essential for the fungal stress response and virulence. Critically, this biosynthetic pathway is absent in mammals, and thus, the two enzymes that carry out trehalose biosynthesis

  18. pH-induced bistable dynamic behaviour in the reaction catalysed by glucose-6-phosphate dehydrogenase and conformational hysteresis of the enzyme.

    PubMed Central

    Aon, M A; Cortassa, S; Hervagault, J F; Thomas, D

    1989-01-01

    1. Bistable (multiple stationary states) dynamic behaviour in the activity of glucose-6-phosphate dehydrogenase that was subjected to successive pH change was demonstrated in an open continuously stirred tank reactor. Although the enzyme under study did not exhibit an autocatalytic effect and was homogeneously distributed, bistability was shown to occur. 2. The successive pH changes of the enzyme solution corresponded to a pH transition (8.3 in equilibrium 2), i.e. an acidification (forward direction) and an alkalinization (reverse direction). By use of intrinsic protein fluorescence methods, a glucose-6-phosphate dehydrogenase conformational hysteresis was shown to exist concomitant with the pH transition before and after enzyme injection into the reactor. 3. The results obtained suggest that the enzyme behaves, conformationally, as a memory device that stores information about its pH history (i.e. the enzyme records information in its structure about the environment to which it was previously exposed) and transduces it in a non-linear dynamic fashion, producing the bistable behaviour observed in the open reactor. PMID:2590166

  19. Glycogen Metabolic Genes Are Involved in Trehalose-6-Phosphate Synthase-Mediated Regulation of Pathogenicity by the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Wilson, Richard A.; Wang, Zheng-Yi; Kershaw, Michael J.; Talbot, Nicholas J.

    2013-01-01

    The filamentous fungus Magnaporthe oryzae is the causal agent of rice blast disease. Here we show that glycogen metabolic genes play an important role in plant infection by M. oryzae. Targeted deletion of AGL1 and GPH1, which encode amyloglucosidase and glycogen phosphorylase, respectively, prevented mobilisation of glycogen stores during appressorium development and caused a significant reduction in the ability of M. oryzae to cause rice blast disease. By contrast, targeted mutation of GSN1, which encodes glycogen synthase, significantly reduced the synthesis of intracellular glycogen, but had no effect on fungal pathogenicity. We found that loss of AGL1 and GPH1 led to a reduction in expression of TPS1 and TPS3, which encode components of the trehalose-6-phosphate synthase complex, that acts as a genetic switch in M. oryzae. Tps1 responds to glucose-6-phosphate levels and the balance of NADP/NADPH to regulate virulence-associated gene expression, in association with Nmr transcriptional inhibitors. We show that deletion of the NMR3 transcriptional inhibitor gene partially restores virulence to a Δagl1Δgph1 mutant, suggesting that glycogen metabolic genes are necessary for operation of the NADPH-dependent genetic switch in M. oryzae. PMID:24098112

  20. Cloning and characterization of an alternative transcript of ovine glucose 6-phosphate dehydrogenase gene: comparative approach between ruminant and non-ruminant species.

    PubMed

    Laliotis, George P; Argyrokastritis, Alexandros; Bizelis, Iosif; Rogdakis, Emmanuel

    2007-02-15

    Glucose 6-phosphate dehydrogenase (G6PD) plays an important role in ruminant's lipogenesis, as it provides necessary compounds of NADPH for the synthesis of fatty acids catalyzing the first committed reaction in the pentose phosphate pathway. In this work the full length ovine glucose 6-phosphate dehydrogenase cDNA was isolated using a polymerase chain reaction based strategy. Two isoforms (OG6PDA and OG6PDB) were detected encoding a protein of 515 and 524 amino acids, respectively. Both deduced amino acid sequences reveal a well conserved protein containing all the important residues for its catalytic role. The extra nine amino acids encoded by OG6PDB cause a frameshift in the polypeptide chain resulting in changes around the area of the potential substrate binding site. A three-dimensional model of ovine G6PD protein shows that this frameshift cause structural changes in the catalytic binding "pocket" of the molecule. Southern blot and RT analysis revealed that ovine G6PD appears as a single copy gene while it is expressed, with slight variability, in all tissues analyzed. Moreover, expression analysis of the ovine G6PD isoforms showed that OG6PDB is expressed only in tissues where lipogenesis is high in ruminants. Thus, we hypothesize that in ruminants G6PD may be regulated by the ratio of the two transcripts, according to the existence stimulus.

  1. Purification and characterization of glucose 6-phosphate dehydrogenase enzyme from rainbow trout (Oncorhynchus mykiss) liver and investigation of the effects of some metal ions on enzyme activity.

    PubMed

    Comakli, Veysel; Akkemik, Ebru; Ciftci, Mehmet; Kufrevioglu, Omer Irfan

    2015-05-01

    Glucose 6-phosphate dehydrogenase (d-glucose 6-phosphate: NADP(+) oxidoreductase, EC 1.1.1.49; G6PD) is a key enzyme that is localized in all mammal tissues, especially in cytoplasmic sections and that catalyzes the first step of pentose phosphate metabolic pathway. In this study, G6PD enzyme was purified 1444-fold with a yield of 77% from rainbow trout liver using 2',5'-ADP-sepharose-4B affinity chromatography. Moreover, a purity check of the enzyme was performed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Some characteristic features like optimal pH, stable pH, optimal temperature and optimal ionic strength were determined for the purified enzyme. In addition to this, in vitro effects of ions like silver nitrate (Ag(+)), thallium sulphate (TI(+)), cobalt (II) nitrate (Co(2+)) and arsenic (V) oxide (As(5+)) on enzyme activity were researched. Half-maximal inhibitory concentration (IC50) values of Ag(+), Co(2+) and As(5+) metal ions, which showed an inhibitory effect, were found to be 0.0044, 0.084 and 4.058 mM, respectively; and their inhibition constants (K i) were found to be 0.0052 ± 0.00042, 0.087 ± 0.015700 and 4.833 ± 1.753207 mM, respectively. Tl(+) not exhibited inhibitory effect on the enzyme activity. © The Author(s) 2013.

  2. Overproduction, crystallization and preliminary X-ray analysis of the putative l-ascorbate-6-phosphate lactonase UlaG from Escherichia coli

    SciTech Connect

    Garces, Fernando; Fernández, Francisco J.; Pérez-Luque, Rosa; Aguilar, Juan; Baldomà, Laura; Coll, Miquel; Badía, Josefa; Vega, M. Cristina

    2008-01-01

    UlaG, the putative l-ascorbate-6-phosphate lactonase encoded by the ulaG gene from the utilization of l-ascorbate regulon in E. coli, has been cloned, overexpressed, purified using standard chromatographic techniques and crystallized in a monoclinic space group. Crystals were obtained by the sitting-drop vapour-diffusion method at 293 K. A data set diffracting to 3 Å resolution was collected from a single crystal at 100 K. UlaG, the putative l-ascorbate-6-phosphate lactonase encoded by the ulaG gene from the utilization of l-ascorbate regulon in Escherichia coli, has been cloned, overexpressed, purified using standard chromatographic techniques and crystallized. Crystals were obtained by sitting-drop vapour diffusion at 293 K. Preliminary X-ray diffraction analysis revealed that the UlaG crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 104.52, b = 180.69, c = 112.88 Å, β = 103.26°. The asymmetric unit is expected to contain six copies of UlaG, with a corresponding volume per protein weight of 2.16 Å{sup 3} Da{sup −1} and a solvent content of 43%.

  3. Characterization, Localization, Essentiality, and High-Resolution Crystal Structure of Glucosamine 6-Phosphate N-Acetyltransferase from Trypanosoma brucei ▿ ‡ §

    PubMed Central

    Mariño, Karina; Güther, M. Lucia Sampaio; Wernimont, Amy K.; Qiu, Wei; Hui, Raymond; Ferguson, Michael A. J.

    2011-01-01

    A gene predicted to encode Trypanosoma brucei glucosamine 6-phosphate N-acetyltransferase (TbGNA1; EC 2.3.1.4) was cloned and expressed in Escherichia coli. The recombinant protein was enzymatically active, and its high-resolution crystal structure was obtained at 1.86 Å. Endogenous TbGNA1 protein was localized to the peroxisome-like microbody, the glycosome. A bloodstream-form T. brucei GNA1 conditional null mutant was constructed and shown to be unable to sustain growth in vitro under nonpermissive conditions, demonstrating that there are no metabolic or nutritional routes to UDP-GlcNAc other than via GlcNAc-6-phosphate. Analysis of the protein glycosylation phenotype of the TbGNA1 mutant under nonpermissive conditions revealed that poly-N-acetyllactosamine structures were greatly reduced in the parasite and that the glycosylation profile of the principal parasite surface coat component, the variant surface glycoprotein (VSG), was modified. The significance of results and the potential of TbGNA1 as a novel drug target for African sleeping sickness are discussed. PMID:21531872

  4. Redundant and non-redundant roles of the trehalose-6-phosphate phosphatases in leaf growth, root hair specification and energy-responses in Arabidopsis.

    PubMed

    Van Houtte, Hilde; López-Galvis, Lorena; Vandesteene, Lies; Beeckman, Tom; Van Dijck, Patrick

    2013-03-01

    The Arabidopsis trehalose-6-phosphate phosphatase (TPP) gene family arose mainly from whole genome duplication events and consists of 10 genes (TPPA-J). All the members encode active TPP enzymes, possibly regulating the levels of trehalose-6-phosphate, an established signaling metabolite in plants. GUS activity studies revealed tissue-, cell- and stage-specific expression patterns for the different members of the TPP gene family. Here we list additional examples of the remarkable features of the TPP gene family. TPPA-J expression levels seem, in most of the cases, differently regulated in response to light, darkness and externally supplied sucrose. Disruption of the TPPB gene leads to Arabidopsis plants with larger leaves, which is the result of an increased cell number in the leaves. Arabidopsis TPPA and TPPG are preferentially expressed in atrichoblast cells. TPPA and TPPG might fulfill redundant roles during the differentiation process of root epidermal cells, since the tppa tppg double mutant displays a hairy root phenotype, while the respective single knockouts have a distribution of trichoblast and atrichoblast cells similar to the wild type. These new data portray redundant and non-redundant functions of the TPP proteins in regulatory pathways of Arabidopsis.

  5. Source/sink interactions underpin crop yield: the case for trehalose 6-phosphate/SnRK1 in improvement of wheat

    PubMed Central

    Lawlor, David W.; Paul, Matthew J.

    2014-01-01

    Considerable interest has been evoked by the analysis of the regulatory pathway in carbohydrate metabolism and cell growth involving the non-reducing disaccharide trehalose (TRE). TRE is at small concentrations in mesophytes such as Arabidopsis thaliana and Triticum aestivum, excluding a role in osmoregulation once suggested for it. Studies of TRE metabolism, and genetic modification of it, have shown a very wide and more important role of the pathway in regulation of many processes in development, growth, and photosynthesis. It has now been established that rather than TRE, it is trehalose 6-phosphate (T6P) which has such profound effects. T6P is the intermediary in TRE synthesis formed from glucose-6-phosphate and UDP-glucose, derived from sucrose, by the action of trehalose phosphate synthase. The concentration of T6P is determined both by the rate of synthesis, which depends on the sucrose concentration, and also by the rate of breakdown by trehalose-6-phosphate phosphatase which produces TRE. Changing T6P concentrations by genetically modifying the enzymes of synthesis and breakdown has altered photosynthesis, sugar metabolism, growth, and development which affect responses to, and recovery from, environmental factors. Many of the effects of T6P on metabolism and growth occur via the interaction of T6P with the SnRK1 protein kinase system. T6P inhibits the activity of SnRK1, which de-represses genes encoding proteins involved in anabolism. Consequently, a large concentration of sucrose increases T6P and thereby inhibits SnRK1, so stimulating growth of cells and their metabolic activity. The T6P/SnRK1 mechanism offers an important new view of how the distribution of assimilates to organs, such as developing grains in cereal plants, is achieved. This review briefly summarizes the factors determining, and limiting, yield of wheat (particularly mass/grain which is highly conserved) and considers how T6P/SnRK1 might function to determine grain yield and might be

  6. Source/sink interactions underpin crop yield: the case for trehalose 6-phosphate/SnRK1 in improvement of wheat.

    PubMed

    Lawlor, David W; Paul, Matthew J

    2014-01-01

    Considerable interest has been evoked by the analysis of the regulatory pathway in carbohydrate metabolism and cell growth involving the non-reducing disaccharide trehalose (TRE). TRE is at small concentrations in mesophytes such as Arabidopsis thaliana and Triticum aestivum, excluding a role in osmoregulation once suggested for it. Studies of TRE metabolism, and genetic modification of it, have shown a very wide and more important role of the pathway in regulation of many processes in development, growth, and photosynthesis. It has now been established that rather than TRE, it is trehalose 6-phosphate (T6P) which has such profound effects. T6P is the intermediary in TRE synthesis formed from glucose-6-phosphate and UDP-glucose, derived from sucrose, by the action of trehalose phosphate synthase. The concentration of T6P is determined both by the rate of synthesis, which depends on the sucrose concentration, and also by the rate of breakdown by trehalose-6-phosphate phosphatase which produces TRE. Changing T6P concentrations by genetically modifying the enzymes of synthesis and breakdown has altered photosynthesis, sugar metabolism, growth, and development which affect responses to, and recovery from, environmental factors. Many of the effects of T6P on metabolism and growth occur via the interaction of T6P with the SnRK1 protein kinase system. T6P inhibits the activity of SnRK1, which de-represses genes encoding proteins involved in anabolism. Consequently, a large concentration of sucrose increases T6P and thereby inhibits SnRK1, so stimulating growth of cells and their metabolic activity. The T6P/SnRK1 mechanism offers an important new view of how the distribution of assimilates to organs, such as developing grains in cereal plants, is achieved. This review briefly summarizes the factors determining, and limiting, yield of wheat (particularly mass/grain which is highly conserved) and considers how T6P/SnRK1 might function to determine grain yield and might be

  7. Glucose-6-phosphate dehydrogenase Guadalajara--a case of chronic non-spherocytic haemolytic anaemia responding to splenectomy and the role of splenectomy in this disorder.

    PubMed

    Hamilton, J W; Jones, F G C; McMullin, Mary Frances

    2004-08-01

    Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme of the pentose phosphate shunt pathway a major function of which is to prevent cellular oxidative damage. Deficiency in red blood cells is associated with a number of varied clinical manifestations. Chronic non-spherocytic haemolytic anaemia is uncommon but is usually characterized by chronic haemolysis, often with severe anaemia. In the past splenectomy in this condition has been thought to be of questionable benefit. We report a case of G6PD Guadalajara where splenectomy produced transfusion independence and have reviewed the literature. Those cases with exon 10 mutations often have a severe clinical phenotype, which responds to splenectomy. This procedure should be considered in this condition.

  8. Marked differences in drug-induced methemoglobinemia in sheep are not due to RBC glucose-6-phosphate dehydrogenase, reduced glutathione, or methemoglobin reductase activity

    SciTech Connect

    Martin, D.G.; Guertler, A.T.; Lagutchik, M.S.; Woodard, C.L.; Leonard, D.A.

    1993-05-13

    Benzocaine is a commonly used topical anesthetic that is structurally similar to current candidates for cyanide prophylaxis. Benzocaine induces profound methemoglobinemia in some sheep but not others. After topical benzocaine administration certain sheep respond to form MHb (elevated MHb 16-50% after a 56-280 mg dose, a 2-10 second spray with benzocine), while other phenotypically similar sheep fail to significantly form MHb (less than a 2% increase from baseline). Deficiencies in Glucose-6-phosphate dehydrogenase (G-6-PD), reduced glutathione (GSH), and MHb reductase increase the susceptibility to methemoglobinemia in man and animals. Sheep are used as a model for G-6-PD deficiency in man, and differences in this enzyme level could cause the variable response seen in these sheep. Similarly, differences in GSH and MHb reductase could be responsible for the observed differences in MHb formation.

  9. A head-to-head comparison of eneamide and epoxyamide inhibitors of glucosamine-6-phosphate synthase from the dapdiamide biosynthetic pathway.

    PubMed

    Hollenhorst, Marie A; Ntai, Ioanna; Badet, Bernard; Kelleher, Neil L; Walsh, Christopher T

    2011-05-17

    The dapdiamides make up a family of antibiotics that have been presumed to be cleaved in the target cell to enzyme-inhibitory N-acyl-2,3-diaminopropionate (DAP) warheads containing two alternative electrophilic moieties. Our prior biosynthetic studies revealed that an eneamide warhead is made first and converted to an epoxyamide via a three-enzyme branch pathway. Here we provide a rationale for this logic. We report that the R,R-epoxyamide warhead is a more efficient covalent inactivator of glucosamine-6-phosphate synthase by 1 order of magnitude versus the eneamide, and this difference correlates with a >10-fold difference in antibiotic activity for the corresponding acyl-DAP dipeptides.

  10. [Effect of aminotriazole on the activity of catalase and glucose-6-phosphate dehydrogenase in tissues of two frog species--Rana ridibunda and Rana esculenta].

    PubMed

    Lushchak, O V; Bahniukova, T V; Lushchak, V I

    2003-01-01

    Changes of the activity of catalase and glucose-6-phosphate dehydrogenase (G6PDH) during 48 hrs after intraperitoneal injection of 1.0, 0.5 and 0.1 mg aminotriazole per gram of body weight of two frog species as well as catalase inhibition by aminotriazole in vitro were investigated. Both aminotriazole concentration and species affiliation affected the catalase inhibition. The sensitivity of catalase from different tissues was decreased in the order: liver--kidney--lung--muscle--brain. The constant of half inhibition of lung catalase was significantly lower than that of liver and kidney catalase. The activity of G6PDH of AMT-treated frogs R. esculenta was higher comparing to control group. Possible ways of compensation of antioxidant defense under catalase inhibition are discussed.

  11. Prevalence of anemia, iron deficiency, thalassemia and glucose-6-phosphate dehydrogenase deficiency among hill-tribe school children in Omkoi District, Chiang Mai Province, Thailand.

    PubMed

    Yanola, Jintana; Kongpan, Chatpat; Pornprasert, Sakorn

    2014-07-01

    The prevalaence of anemia, iron deficiency, thalassemia and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency were examined among 265 hill-tribe school children, 8-14 years of age, from Omkoi District, Chiang Mai Province, Thailand. Anemia was observed in 20 school children, of whom 3 had iron deficiency anemia. The prevalence of G-6-PD deficiency and β-thalassemia trait [codon 17 (A>T), IVSI-nt1 (G>T) and codons 71/72 (+A) mutations] was 4% and 8%, respectively. There was one Hb E trait, and no α-thalassemia-1 SEA or Thai type deletion. Furthermore, anemia was found to be associated with β-thalassemia trait in 11 children. These data can be useful for providing appropriate prevention and control of anemia in this region of Thailand.

  12. A Novel de novo Mutation in the G6PD Gene in a Korean Boy with Glucose-6-phosphate Dehydrogenase Deficiency: Case Report.

    PubMed

    Jang, Mi-Ae; Kim, Ji-Yoon; Lee, Ki-O; Kim, Sun-Hee; Koo, Hong Hoe; Kim, Hee-Jin

    2015-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive hemolytic anemia caused by a mutation in the G6PD gene on Xq28. Herein, we describe a Korean boy with G6PD deficiency resulting from a novel mutation in G6PD. A 20-month-old boy with hemolytic anemia was referred for molecular diagnosis. He had no relevant family history. The G6PD activity was severely decreased at 0.2 U/g Hb (severe deficiency). Direct sequencing analyses on the G6PD gene revealed that he was hemizygous for a novel missense variant, c.1187C>G (p.Pro396Arg), in exon 10 of G6PD. Family study involving his parents revealed the de novo occurrence of the mutation. This is the first report of genetically confirmed G6PD deficiency in Korea.

  13. [Frequency of color blindness and glucose-6-phosphate dehydrogenase enzyme deficiency in non-industrialized populations in the state of Nuevo León, México].

    PubMed

    Ceda-Flores, R M; Arriaga-Ríos, G; Muñoz-Campos, J; Bautista-Peña, V A; Angeles Rojas-Alvarado, M; González-Quiróga, G; Leal-Garza, C H; Garza-Chapa, R

    1990-01-01

    In order to know if there would be genetic structural differences among non industrial and industrial populations, two genetic markers were studied: color-blindness (CPC) and glucose-6-phosphate dehydrogenase deficiency (G6PD), in students, males and females that were resident in five non industrial populations in the State of Nuevo Leon. The results were compared with the information for industrial zone from the Monterrey Metropolitan area (AMM). It was found that the frequencies of CPC and G6PD in non industrial populations (2.57 and 0.00 per cent), were lower than the ones in the industrial AMM (4.0 and 0.66 per cent), probably as a result that in the first populations, with minor urbanization, the main factors that influence are: natural selection, interacial mixed or genetic drift and the second population is the immigration, since 1940 to present time, of Mexican populations with greater influence from the Indians and Africans.

  14. What is the true enzyme kinetics in the biological system? An investigation of macromolecular crowding effect upon enzyme kinetics of glucose-6-phosphate dehydrogenase.

    PubMed

    Norris, Matthew G S; Malys, Naglis

    2011-02-18

    Enzyme kinetic parameters for rate equations are vital in metabolic network simulation, a major part of systems biology research efforts. Measurements of Michaelis-Menten kinetic parameters Km and Kcat have been performed for enzymes glucose-6-phosphate dehydrogenase (G6P DH) under crowded conditions using molecular crowding agents bovine serum albumin (BSA) and polyethylene glycol (PEG) of 8000 Da molecular weight. An increase in Kcat was observed at very low concentrations of crowding agent, and also at high crowder concentrations when the experiment was performed at 45 °C with PEG. The observed pattern in Kcat for G6P DH at high crowder concentrations has been explained via modelling using excluded volume theory. An increase in rate was observed at 45 °C for G6P DH versus 30 °C; this has been modelled via the Arrhenius equation.

  15. The Two Km's for ATP of Corn-Root H+-ATPase and the Use of Glucose-6-Phosphate and Hexokinase as an ATP-Regenerating System.

    PubMed Central

    Ramos, R. S.; Caldeira, M. T.; Arruda, P.; De Meis, L.

    1994-01-01

    Plasma membrane vesicles derived from corn (Zea mays L.) roots retain a membrane-bound H+-ATPase that is able to form a H+ gradient across the vesicle membranes. The activity of this ATPase is enhanced 2- to 3-fold when Triton X-100 or lysophosphatidylcholine is added to the medium at a protein:detergent ratio of 2:1 (w/w). In the absence of detergent, the ATPase exhibits only one Km for ATP (0.1-0.2 mM), which is the same as for the pumping of H+. After the addition of either Triton X-100 or lysophosphatidylcholine, two Km's for ATP are detected, one in the range of 1 to 3 [mu]M and a second in the range of 0.1 to 0.2 mM. The Vmax of the second Km for ATP increases as the temperature of the assay medium is raised from 15[deg]C to 38[deg]C. The Arrhenius plot reveals a single break at 30[deg]C, both in the absence and in the presence of detergents. In the presence of Triton X-100 the H+-ATPase catalyzes the cleavage of glucose-6-phosphate when both hexokinase and ADP are included in the assay medium. There is no measurable cleavage when the apparent affinity for ATP of the H+-ATPase is not enhanced by Triton X-100 or when 1 mM glucose is included in the assay medium. These data indicate that when the high-affinity Km for ATP is unmasked with the use of detergent, the ATPase can use glucose-6-phosphate and hexokinase as an ATP-regenerating system. PMID:12232248

  16. Enhanced freeze tolerance of baker's yeast by overexpressed trehalose-6-phosphate synthase gene (TPS1) and deleted trehalase genes in frozen dough.

    PubMed

    Tan, Haigang; Dong, Jian; Wang, Guanglu; Xu, Haiyan; Zhang, Cuiying; Xiao, Dongguang

    2014-08-01

    Several recombinant strains with overexpressed trehalose-6-phosphate synthase gene (TPS1) and/or deleted trehalase genes were obtained to elucidate the relationships between TPS1, trehalase genes, content of intracellular trehalose and freeze tolerance of baker's yeast, as well as improve the fermentation properties of lean dough after freezing. In this study, strain TL301(TPS1) overexpressing TPS1 showed 62.92 % higher trehalose-6-phosphate synthase (Tps1) activity and enhanced the content of intracellular trehalose than the parental strain. Deleting ATH1 exerted a significant effect on trehalase activities and the degradation amount of intracellular trehalose during the first 30 min of prefermentation. This finding indicates that acid trehalase (Ath1) plays a role in intracellular trehalose degradation. NTH2 encodes a functional neutral trehalase (Nth2) that was significantly involved in intracellular trehalose degradation in the absence of the NTH1 and/or ATH1 gene. The survival ratio, freeze-tolerance ratio and relative fermentation ability of strain TL301(TPS1) were approximately twice as high as those of the parental strain (BY6-9α). The increase in freeze tolerance of strain TL301(TPS1) was accompanied by relatively low trehalase activity, high Tps1 activity and high residual content of intracellular trehalose. Our results suggest that overexpressing TPS1 and deleting trehalase genes are sufficient to improve the freeze tolerance of baker's yeast in frozen dough. The present study provides guidance for the commercial baking industry as well as the research on the intracellular trehalose mobilization and freeze tolerance of baker's yeast.

  17. Structural Insights into the Mechanism of pH-dependent Ligand Binding and Release by the Cation-dependent Mannose 6-Phosphate Receptor

    SciTech Connect

    Olson, Linda J.; Hindsgaul, Ole; Dahms, Nancy M.; Kim, Jung-Ja P.

    2008-04-29

    The cation-dependent mannose 6-phosphate receptor (CD-MPR) is a key component of the lysosomal enzyme targeting system that binds newly synthesized mannose 6-phosphate (Man-6-P)-containing acid hydrolases and transports them to endosomal compartments. The interaction between the MPRs and its ligands is pH-dependent; the homodimeric CD-MPR binds lysosomal enzymes optimally in the pH environment of the trans Golgi network (pH {approx} 6.5) and releases its cargo in acidic endosomal compartments (

  18. High-Affinity Ligand Binding by Wild-Type:Mutant Heteromeric Complexes of the Mannose 6-Phosphate/Insulin-like Growth Factor II Receptors

    PubMed Central

    Hartman, Michelle A.; Kreiling, Jodi L.; Byrd, James C.; MacDonald, Richard G.

    2009-01-01

    Summary The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) has diverse ligand-binding properties contributing to its roles in lysosome biogenesis and growth suppression. Optimal receptor binding and internalization of mannose 6-phosphate (Man-6-P)-bearing ligands requires a dimeric structure leading to bivalent high-affinity binding, presumably mediated by cooperation between sites on both subunits. Insulin-like growth factor II (IGF-II) binds to a single site on each monomer. It is hypothesized that IGF-II binding to cognate sites on each monomer occurs independently, but bivalent Man-6-P ligand binding requires cooperative contributions from sites on both monomers. To test this hypothesis, we co-immunoprecipitated differentially epitope-tagged soluble mini-receptors and assessed ligand binding. Pairing of wild-type and point-mutated IGF-II binding sites between two dimerized mini-receptors had no effect on the function of the contralateral binding site, indicating IGF-II binding to each side of the dimer is independent and manifests no intersubunit effects. As expected, heterodimeric receptors composed of a wild-type monomer and a mutant bearing two Man-6-P-binding knockout mutations form functional IGF-II binding sites. In contrast to prediction, such heterodimeric receptors also bind Man-6-P–based ligands with high affinity, and the amount of binding can be attributed entirely to the immunoprecipitated wild-type receptors. Anchoring of both C-terminal ends of the heterodimer produces optimal binding of both IGF-II and Man-6-P ligands. Thus, IGF-II binds independently to both subunits of the dimeric M6P/IGF2R. Although wild-type/mutant heterooligomers from readily when mixed, it appears that multivalent Man-6-P ligands bind preferentially to wild-type sites, possibly by cross-bridging receptors within clusters of immobilized receptors. PMID:19236480

  19. Discovery and characterization of an F420-dependent glucose-6-phosphate dehydrogenase (Rh-FGD1) from Rhodococcus jostii RHA1.

    PubMed

    Nguyen, Quoc-Thai; Trinco, Gianluca; Binda, Claudia; Mattevi, Andrea; Fraaije, Marco W

    2017-04-01

    Cofactor F420, a 5-deazaflavin involved in obligatory hydride transfer, is widely distributed among archaeal methanogens and actinomycetes. Owing to the low redox potential of the cofactor, F420-dependent enzymes play a pivotal role in central catabolic pathways and xenobiotic degradation processes in these organisms. A physiologically essential deazaflavoenzyme is the F420-dependent glucose-6-phosphate dehydrogenase (FGD), which catalyzes the reaction F420 + glucose-6-phosphate → F420H2 + 6-phospho-gluconolactone. Thereby, FGDs generate the reduced F420 cofactor required for numerous F420H2-dependent reductases, involved e.g., in the bioreductive activation of the antitubercular prodrugs pretomanid and delamanid. We report here the identification, production, and characterization of three FGDs from Rhodococcus jostii RHA1 (Rh-FGDs), being the first experimental evidence of F420-dependent enzymes in this bacterium. The crystal structure of Rh-FGD1 has also been determined at 1.5 Å resolution, showing a high similarity with FGD from Mycobacterium tuberculosis (Mtb) (Mtb-FGD1). The cofactor-binding pocket and active-site catalytic residues are largely conserved in Rh-FGD1 compared with Mtb-FGD1, except for an extremely flexible insertion region capping the active site at the C-terminal end of the TIM-barrel, which also markedly differs from other structurally related proteins. The role of the three positively charged residues (Lys197, Lys258, and Arg282) constituting the binding site of the substrate phosphate moiety was experimentally corroborated by means of mutagenesis study. The biochemical and structural data presented here provide the first step towards tailoring Rh-FGD1 into a more economical biocatalyst, e.g., an F420-dependent glucose dehydrogenase that requires a cheaper cosubstrate and can better match the demands for the growing applications of F420H2-dependent reductases in industry and bioremediation.

  20. Molecular Epidemiological Survey of Glucose-6-Phosphate Dehydrogenase Deficiency and Thalassemia in Uygur and Kazak Ethnic Groups in Xinjiang, Northwest China.

    PubMed

    Han, Luhao; Su, Hai; Wu, Hao; Jiang, Weiying; Chen, Suqin

    2016-06-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency and thalassemia occur frequently in tropical and subtropical regions, while the prevalence of relationship between the two diseases in Xinjiang has not been reported. We aimed to determine the prevalence of these diseases and clarify the relationship between genotypes and phenotypes of the two diseases in the Uygur and Kazak ethnic groups in Xinjiang. We measured G6PD activity by G6PD:6PGD (glucose acid-6-phosphate dehydrogenase) ratio, identified the gene variants of G6PD and α- and β-globin genes by polymerase chain reaction (PCR)-DNA sequencing and gap-PCR and compared these variants in different ethnic groups in Xinjiang with those adjacent to it. Of the 149 subjects with molecular analysis of G6PD deficiency conducted, a higher prevalence of the combined mutations c.1311C > T/IVSXI + 93T > C and IVSXI + 93T > C, both with normal enzymatic activities, were observed in the Uygur and Kazak subjects. A case of rare mutation HBB: c.135delC [codon 44 (-C) in the heterozygous state], a heterozygous case of HBB: c.68A > G [Hb G-Taipei or β22(B4)Glu→Gly] and several common single nucleotide polymorphisms (SNPs) were found on the β-globin gene. In conclusion, G6PD deficiency with pathogenic mutations and three common α-thalassemia (α-thal) [- -(SEA), -α(3.7) (rightward), -α(4.2) (leftward)] deletions and point mutations of the α-globin gene were not detected in the present study. The average incidence of β-thalassemia (β-thal) in Uygurs was 1.45% (2/138) in Xinjiang. The polymorphisms of G6PD and β-globin genes might be useful genetic markers to trace the origin and migration of the Uygur and Kazak in Xinjiang.

  1. Trehalose-6-Phosphate-Mediated Toxicity Determines Essentiality of OtsB2 in Mycobacterium tuberculosis In Vitro and in Mice

    PubMed Central

    Koliwer-Brandl, Hendrik; Hartman, Travis; Jacobs, William R.; Ioerger, Thomas R.; Ehrt, Sabine

    2016-01-01

    Trehalose biosynthesis is considered an attractive target for the development of antimicrobials against fungal, helminthic and bacterial pathogens including Mycobacterium tuberculosis. The most common biosynthetic route involves trehalose-6-phosphate (T6P) synthase OtsA and T6P phosphatase OtsB that generate trehalose from ADP/UDP-glucose and glucose-6-phosphate. In order to assess the drug target potential of T6P phosphatase, we generated a conditional mutant of M. tuberculosis allowing the regulated gene silencing of the T6P phosphatase gene otsB2. We found that otsB2 is essential for growth of M. tuberculosis in vitro as well as for the acute infection phase in mice following aerosol infection. By contrast, otsB2 is not essential for the chronic infection phase in mice, highlighting the substantial remodelling of trehalose metabolism during infection by M. tuberculosis. Blocking OtsB2 resulted in the accumulation of its substrate T6P, which appears to be toxic, leading to the self-poisoning of cells. Accordingly, blocking T6P production in a ΔotsA mutant abrogated otsB2 essentiality. T6P accumulation elicited a global upregulation of more than 800 genes, which might result from an increase in RNA stability implied by the enhanced neutralization of toxins exhibiting ribonuclease activity. Surprisingly, overlap with the stress response caused by the accumulation of another toxic sugar phosphate molecule, maltose-1-phosphate, was minimal. A genome-wide screen for synthetic lethal interactions with otsA identified numerous genes, revealing additional potential drug targets synergistic with OtsB2 suitable for combination therapies that would minimize the emergence of resistance to OtsB2 inhibitors. PMID:27936238

  2. Antisense inhibition of the plastidial glucose-6-phosphate/phosphate translocator in Vicia seeds shifts cellular differentiation and promotes protein storage.

    PubMed

    Rolletschek, Hardy; Nguyen, Thuy H; Häusler, Rainer E; Rutten, Twan; Göbel, Cornelia; Feussner, Ivo; Radchuk, Ruslana; Tewes, Annegret; Claus, Bernhard; Klukas, Christian; Linemann, Ute; Weber, Hans; Wobus, Ulrich; Borisjuk, Ljudmilla

    2007-08-01

    The glucose-6-phosphate/phosphate translocator (GPT) acts as an importer of carbon into the plastid. Despite the potential importance of GPT for storage in crop seeds, its regulatory role in biosynthetic pathways that are active during seed development is poorly understood. We have isolated GPT1 from Vicia narbonensis and studied its role in seed development using a transgenic approach based on the seed-specific legumin promoter LeB4. GPT1 is highly expressed in vegetative sink tissues, flowers and young seeds. In the embryo, localized upregulation of GPT1 at the onset of storage coincides with the onset of starch accumulation. Embryos of transgenic plants expressing antisense GPT1 showed a significant reduction (up to 55%) in the specific transport rate of glucose-6-phosphate as determined using proteoliposomes prepared from embryos. Furthermore, amyloplasts developed later and were smaller in size, while the expression of genes encoding plastid-specific translocators and proteins involved in starch biosynthesis was decreased. Metabolite analysis and stable isotope labelling demonstrated that starch biosynthesis was also reduced, although storage protein biosynthesis increased. This metabolic shift was characterized by upregulation of genes related to nitrogen uptake and protein storage, morphological variation of the protein-storing vacuoles, and a crude protein content of mature seeds of transgenics that was up to 30% higher than in wild-type. These findings provide evidence that (1) the prevailing level of GPT1 abundance/activity is rate-limiting for the synthesis of starch in developing seeds, (2) GPT1 exerts a controlling function on assimilate partitioning into storage protein, and (3) GPT1 is essential for the differentiation of embryonic plastids and seed maturation.

  3. Glucose-6-phosphate dehydrogenase deficiency

    MedlinePlus

    ... be available to those who have a family history of the condition. Alternative Names ... PG. Hemolytic anemias. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap ...

  4. Reconstitution of ethanolic fermentation in permeabilized spheroplasts of wild-type and trehalose-6-phosphate synthase mutants of the yeast Saccharomyces cerevisiae.

    PubMed

    Noubhani, A; Bunoust, O; Rigoulet, M; Thevelein, J M

    2000-07-01

    In the yeast Saccharomyces cerevisiae, TPS1-encoded trehalose-6-phosphate synthase (TPS) exerts an essential control on the influx of glucose into glycolysis, presumably by restricting hexokinase activity. Deletion of TPS1 results in severe hyperaccumulation of sugar phosphates and near absence of ethanol formation. To investigate whether trehalose 6-phosphate (Tre6P) is the sole mediator of hexokinase inhibition, we have reconstituted ethanolic fermentation from glucose in permeabilized spheroplasts of the wild-type, tps1Delta and tps2Delta (Tre6P phosphatase) strains. For the tps1Delta strain, ethanol production was significantly lower and was associated with hyperaccumulation of Glu6P and Fru6P. A tps2Delta strain shows reduced accumulation of Glu6P and Fru6P both in intact cells and in permeabilized spheroplasts. These results are not consistent with Tre6P being the sole mediator of hexokinase inhibition. Reconstitution of ethanolic fermentation in permeabilized spheroplasts with glycolytic intermediates indicates additional target site(s) for the Tps1 control. Addition of Tre6P partially shifts the ethanol production rate and the metabolite pattern in permeabilized tps1Delta spheroplasts to those of the wild-type strain, but only with glucose as substrate. This is observed at a very high ratio of glucose to Tre6P. Inhibition of hexokinase activity by Tre6P is less efficiently counteracted by glucose in permeabilized spheroplasts compared to cell extracts, and this effect is largely abolished by deletion of TPS2 but not TPS1. In permeabilized spheroplasts, hexokinase activity is significantly lower in a tps2Delta strain compared to a wild-type strain and this difference is strongly reduced by additional deletion of TPS1. These results indicate that Tps1-mediated protein-protein interactions are important for control of glucose influx into yeast glycolysis, that Tre6P inhibition of hexokinase might not be competitive with respect to glucose in vivo and that also

  5. Glucose-6-phosphate dehydrogenase plays a central role in the response of tomato (Solanum lycopersicum) plants to short and long-term drought.

    PubMed

    Landi, Simone; Nurcato, Roberta; De Lillo, Alessia; Lentini, Marco; Grillo, Stefania; Esposito, Sergio

    2016-08-01

    The present study was undertaken to investigate the expression, occurrence and activity of glucose 6 phosphate dehydrogenase (G6PDH - EC 1.1.1.49), the key-enzyme of the Oxidative Pentose Phosphate Pathway (OPPP), in tomato plants (Solanum lycopersicum cv. Red Setter) exposed to short- and long-term drought stress. For the first time, drought effects have been evaluated in plants under different growth conditions: in hydroponic laboratory system, and in greenhouse pots under controlled conditions; and in open field, in order to evaluate drought response in a representative agricultural environment. Interestingly, changes observed appear strictly associated to the induction of well known stress response mechanisms, such as the increase of proline synthesis, accumulation of chaperone Hsp70, and ascorbate peroxidase. Results show significant increase in total activity of G6PDH, and specifically in expression and occurrence of cytosolic isoform (cy-G6PDH) in plants grown in any cultivation system upon drought. Intriguingly, the results clearly suggest that abscissic acid (ABA) pathway and signaling cascade (protein phosphatase 2C PP2C) could be strictly related to increased G6PDH expression, occurrence and activities. We hypothesized for G6PDH a specific role as one of the main reductants' suppliers to counteract the effects of drought stress, in the light of converging evidences given by young and adult tomato plants under stress of different duration and intensity.

  6. Avoiding Buffer Interference in ITC Experiments: A Case Study from the Analysis of Entropy-Driven Reactions of Glucose-6-Phosphate Dehydrogenase.

    PubMed

    Bianconi, M Lucia

    2016-01-01

    Isothermal titration calorimetry (ITC) is a label-free technique that allows the direct determination of the heat absorbed or released in a reaction. Frequently used to determining binding parameters in biomolecular interactions, it is very useful to address enzyme-catalyzed reactions as both kinetic and thermodynamic parameters can be obtained. Since calorimetry measures the total heat effects of a reaction, it is important to consider the contribution of the heat of protonation/deprotonation that is possibly taking place. Here, we show a case study of the reaction catalyzed by the glucose-6-phosphate dehydrogenase (G6PD) from Leuconostoc mesenteroides. This enzyme is able to use either NAD(+) or NADP(+) as a cofactor. The reactions were done in five buffers of different enthalpy of protonation. Depending on the buffer used, the observed calorimetric enthalpy (ΔH(cal)) of the reaction varied from -22.93 kJ/mol (Tris) to 19.37 kJ/mol (phosphate) for the NADP(+)-linked reaction, and -11.67 kJ/mol (Tris) to 7.32 kcal/mol or 30.63 kJ/mol (phosphate) for the NAD(+) reaction. We will use this system as an example of how to extract proton-independent reaction enthalpies from kinetic data to ensure that the reported accurately represent the intrinsic heat of reaction.

  7. Metabolomic profile of glycolysis and the pentose phosphate pathway identifies the central role of glucose-6-phosphate dehydrogenase in clear cell-renal cell carcinoma.

    PubMed

    Lucarelli, Giuseppe; Galleggiante, Vanessa; Rutigliano, Monica; Sanguedolce, Francesca; Cagiano, Simona; Bufo, Pantaleo; Lastilla, Gaetano; Maiorano, Eugenio; Ribatti, Domenico; Giglio, Andrea; Serino, Grazia; Vavallo, Antonio; Bettocchi, Carlo; Selvaggi, Francesco Paolo; Battaglia, Michele; Ditonno, Pasquale

    2015-05-30

    The analysis of cancer metabolome has shown that proliferating tumor cells require a large quantities of different nutrients in order to support their high rate of proliferation. In this study we analyzed the metabolic profile of glycolysis and the pentose phosphate pathway (PPP) in human clear cell-renal cell carcinoma (ccRCC) and evaluate the role of these pathways in sustaining cell proliferation, maintenance of NADPH levels, and production of reactive oxygen species (ROS). Metabolomic analysis showed a clear signature of increased glucose uptake and utilization in ccRCC tumor samples. Elevated levels of glucose-6-phosphate dehydrogenase (G6PDH) in association with higher levels of PPP-derived metabolites, suggested a prominent role of this pathway in RCC-associated metabolic alterations. G6PDH inhibition, caused a significant decrease in cancer cell survival, a decrease in NADPH levels, and an increased production of ROS, suggesting that the PPP plays an important role in the regulation of ccRCC redox homeostasis. Patients with high levels of glycolytic enzymes had reduced progression-free and cancer-specific survivals as compared to subjects with low levels. Our data suggest that oncogenic signaling pathways may promote ccRCC through rerouting the sugar metabolism. Blocking the flux through this pathway may serve as a novel therapeutic target.

  8. Resistance of glucose-6-phosphate dehydrogenase deficiency to malaria: effects of fava bean hydroxypyrimidine glucosides on Plasmodium falciparum growth in culture and on the phagocytosis of infected cells.

    PubMed

    Ginsburg, H; Atamna, H; Shalmiev, G; Kanaani, J; Krugliak, M

    1996-07-01

    The balanced polymorphism of glucose-6-phosphate dehydrogenase deficiency (G6PD-) is believed to have evolved through the selective pressure of malarial combined with consumption of fava beans. The implicated fava bean constituents are the hydroxypyrimidine glucosides vicine and convicine, which upon hydrolysis of their beta-O-glucosidic bond, became protein pro-oxidants. In this work we show that the glucosides inhibit the growth of Plasmodium falciparum, increase the hexose-monophosphate shunt activity and the phagocytosis of malaria-infected erythrocytes. These activities are exacerbated in the presence of beta-glucosidase, implicating their pro-oxidant aglycones in the toxic effect, and are more pronounced in infected G6PD- erythrocytes. These results suggest that G6PD- infected erythrocytes are more susceptible to phagocytic cells, and that fava bean pro-oxidants are more efficiently suppressing parasite propagation in G6PD- erythrocytes, either by directly affecting parasite growth, or by means of enhanced phagocytic elimination of infected cells. The present findings could account for the relative resistance of G6PD- bearers to falciparum malaria, and establish a link between dietary habits and malaria in the selection of the G6PD- genotype.

  9. Increased red cell calcium, decreased calcium adenosine triphosphatase, and altered membrane proteins during fava bean hemolysis in glucose-6-phosphate dehydrogenase-deficient (Mediterranean variant) individuals.

    PubMed

    Turrini, F; Naitana, A; Mannuzzu, L; Pescarmona, G; Arese, P

    1985-08-01

    RBCs from four glucose-6-phosphate dehydrogenase (G6PD)-deficient (Mediterranean variant) subjects were studied during fava bean hemolysis. In the density-fractionated RBC calcium level, Ca2+-ATPase activity, reduced glutathione level, and ghost protein pattern were studied. In the bottom fraction, containing most heavily damaged RBCs, calcium level ranged from 143 to 244 mumol/L RBCs (healthy G6PD-deficient controls: 17 +/- 5 mumol/L RBCs). The Ca2+-ATPase activity ranged from 0.87 to 1.84 mumol ATP consumed/g Hb/min (healthy G6PD-deficient controls: 2.27 +/- 0.4). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of ghosts showed: (1) the presence of high mol wt aggregates (in three cases they were reduced by dithioerythritol; in one case, only partial reduction was possible); (2) the presence of multiple, scattered new bands; and (3) the reduction of band 3. Oxidant-mediated damage to active calcium extrusion, hypothetically associated with increased calcium permeability, may explain the large increase in calcium levels. They, in turn, could activate calcium-dependent protease activity, giving rise to the profound changes in the ghost protein pattern.

  10. Mutations of Glucose-6-Phosphate Dehydrogenase Durham, Santa-Maria and A+ Variants Are Associated with Loss Functional and Structural Stability of the Protein.

    PubMed

    Gómez-Manzo, Saúl; Marcial-Quino, Jaime; Vanoye-Carlo, America; Enríquez-Flores, Sergio; De la Mora-De la Mora, Ignacio; González-Valdez, Abigail; García-Torres, Itzhel; Martínez-Rosas, Víctor; Sierra-Palacios, Edgar; Lazcano-Pérez, Fernando; Rodríguez-Bustamante, Eduardo; Arreguin-Espinosa, Roberto

    2015-12-02

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy in the world. More than 160 mutations causing the disease have been identified, but only 10% of these variants have been studied at biochemical and biophysical levels. In this study we report on the functional and structural characterization of three naturally occurring variants corresponding to different classes of disease severity: Class I G6PD Durham, Class II G6PD Santa Maria, and Class III G6PD A+. The results showed that the G6PD Durham (severe deficiency), and the G6PD Santa Maria and A+ (less severe deficiency) (Class I, II and III, respectively) affect the catalytic efficiency of these enzymes, are more sensitive to temperature denaturing, and affect the stability of the overall protein when compared to the wild type WT-G6PD. In the variants, the exposure of more and buried hydrophobic pockets was induced and monitored with 8-Anilinonaphthalene-1-sulfonic acid (ANS) fluorescence, directly affecting the compaction of structure at different levels and probably reducing the stability of the protein. The degree of functional and structural perturbation by each variant correlates with the clinical severity reported in different patients.

  11. The use of primaquine in malaria infected patients with red cell glucose-6-phosphate dehydrogenase (G6PD) deficiency in Myanmar.

    PubMed

    Myat-Phone-Kyaw; Myint-Oo; Aung-Naing; Aye-Lwin-Htwe

    1994-12-01

    32 subjects with Plasmodium falciparum gametocytes, and 31 cases with Plasmodium vivax infection from two military hospitals (Lashio, Mandalay) were treated with quinine 600 mg three times a day for 7 days followed by primaquine 45 mg single dose for gametocytes and 45 mg weekly x 8 weeks for vivax malaria. Although screening of red cell glucose-6-phosphate dehydrogenase (G6PD) was done prior to primaquine treatment, G6PD deficient subjects were not excluded from the trial. 20 patients hemizygous for mild G6PD deficiency (GdB- variant), 2 patients hemizygous for severe deficiency (Gd-Myanmar variant) completed the trial. No case of acute hemolysis was observed in all 22 patients with two genotypes of red cell G6PD deficiency status. Therefore, a single dose of primaquine 45 mg and/or weekly for 8 weeks is adequate for the treatment of patients with P. falciparum gametocytes and/or P. vivax malaria ignoring these red cell G6PD enzyme deficient variants in Myanmar.

  12. Increased activity of 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase in purified cell suspensions and single cells from the uterine cervix in cervical intraepithelial neoplasia.

    PubMed Central

    Jonas, S. K.; Benedetto, C.; Flatman, A.; Hammond, R. H.; Micheletti, L.; Riley, C.; Riley, P. A.; Spargo, D. J.; Zonca, M.; Slater, T. F.

    1992-01-01

    The activities of 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase have been measured in squamous epithelial cells of the uterine cervix from normal patients and cases of cervical intraepithelial neoplasia (CIN). A biochemical cycling method, which uses only simple equipment and is suited to routine use and to automation, was applied to cells separated by gradient centrifugation. In addition, cells were examined cytochemically, and the intensity of staining in the cytoplasm of single whole cells was measured using computerised microcytospectrophotometry. Twenty per cent of cells in samples from normal patients (n=61) showed staining intensities above an extinction of 0.15 at 540 nm, compared to 71% of cases of CIN 1 (n=14), 91% of cases of CIN 2 (n=11) and 67% of cases of CIN 3 (n=15). The cytochemical data do not allow definitive distinctions to be made between different grades of CIN whereas the biochemical assay applied to cell lysates shows convincing differences between normal samples and cases of CIN. There are no false negatives for CIN 3 (n=14) and CIN 2 (n=10) and 11% false negatives for CIN 1 (n=9) and 14% of false positives for normal cases (n=21). The results of this preliminary study with reference to automation are discussed [corrected]. Images Figure 1 PMID:1637668

  13. A role of Rab29 in the integrity of the trans-Golgi network and retrograde trafficking of mannose-6-phosphate receptor.

    PubMed

    Wang, Shicong; Ma, Zexu; Xu, Xiaohui; Wang, Zhen; Sun, Lixiang; Zhou, Yunhe; Lin, Xiaosi; Hong, Wanjin; Wang, Tuanlao

    2014-01-01

    Rab29 (also referred as Rab7L1) is a novel Rab protein, and is recently demonstrated to regulate phagocytosis and traffic from the Golgi to the lysosome. However, its roles in membrane trafficking have not been investigated extensively. Our results in this study revealed that Rab29 is associated with the trans-Golgi network (TGN), and is essential for maintaining the integrity of the TGN, because inhibition of the activity of Rab29 or depletion of Rab29 resulted in fragmentation of the TGN marked by TGN46. Expression of the dominant negative form Rab29T21N or shRNA-Rab29 also altered the distribution of mannose-6-phosphate receptor (M6PR), and interrupted the retrograde trafficking of M6PR through monitoring the endocytosis of CD8-tagged calcium dependent M6PR (cdM6PR) or calcium independent M6PR (ciM6PR), but without significant effects on the anterograde trafficking of vesicular stomatitis virus G protein (VSV-G). Our results suggest that Rab29 is essential for the integrity of the TGN and participates in the retrograde trafficking of M6PRs.

  14. Exposure to chrysotile asbestos causes carbonylation of glucose 6-phosphate dehydrogenase through a reaction with lipid peroxidation products in human lung epithelial cells.

    PubMed

    Ogasawara, Yuki; Ishii, Kazuyuki

    2010-05-19

    Exposure to asbestos is known to lead to a reduction in glucose 6-phosphate dehydrogenase (G6PDH) activity and to cause oxidative damage to cells. In the present study, we exposed the human lung carcinoma cell line A549 to chrysotile. We observed an increase in the production of thiobarbituric acid-reactive substances (TBARS, the breakdown products of lipid peroxide) along with a significant decrease in G6PDH activity. Alternatively, when chrysotile was added directly to the cell extract obtained by removing the cell membrane, no loss of G6PDH activity was observed. To elucidate the mechanism of G6PDH inactivation due to exposure to chrysotile, we focused on the TBARS responsible for protein modification via carbonylation. When malondialdehyde or 4-hydroxy-2-nonenal was added to a membrane-free A549 cell extract, G6PDH activity was reduced markedly. However, when t-butylhydroperoxide was added to the extract, there was no significant decrease in G6PDH activity. Western blot analysis and immunoprecipitation of the carbonylated proteins in the A549 cell lysate that was prepared after exposure to chrysotile demonstrated that G6PDH had been carbonylated. Our findings indicate that the decrease in G6PDH activity that occurs after exposure of the cultured cells to chrysotile results from the carbonylation of G6PDH by TBARS.

  15. DNA damage and apoptosis in mononuclear cells from glucose-6-phosphate dehydrogenase-deficient patients (G6PD Aachen variant) after UV irradiation.

    PubMed

    Efferth, T; Fabry, U; Osieka, R

    2001-03-01

    Patients affected with X chromosome-linked, hereditary glucose-6-phosphate dehydrogenase (G6PD) deficiency suffer from life-threatening hemolytic crises after intake of certain drugs or foods. G6PD deficiency is associated with low levels of reduced glutathione. We analyzed mononuclear white blood cells (MNC) of three males suffering from the German G6PD Aachen variant, four heterozygote females of this family, one G6PD-deficient male from another family coming from Iran, and six healthy male volunteers with respect to their DNA damage in two different genes (G6PD and T-cell receptor-delta) and their propensity to enter apoptosis after UV illumination (0.08-5.28 J/cm2). As determined by PCR stop assays, there was more UV-induced DNA damage in MNC of G6PD-deficient male patients than in those of healthy subjects. MNC of G6PD-deficient patients showed a higher rate of apoptosis after UV irradiation than MNC of healthy donors. MNC of heterozygote females showed intermediate rates of DNA damage and apoptosis. It is concluded that increased DNA damage may be a result of deficient detoxification of reactive oxygen species by glutathione and may ultimately account for the higher rate of apoptosis in G6PD-deficient MNC.

  16. Recombinant trehalose-6-phosphate phosphatase of Brugia malayi cross-reacts with human Wuchereria bancrofti immune sera and engenders a robust protective outcome in mice.

    PubMed

    Kushwaha, Susheela; Singh, Prashant Kumar; Gupta, Jyoti; Soni, Vishal Kumar; Misra-Bhattacharya, Shailja

    2012-11-01

    Trehalose-6-phosphate phosphatase of Brugia malayi (Bm-TPP) represents an attractive vaccine candidate because it is present in all the major life stages of parasite, but is absent in mammals. We have previously cloned, purified and biochemically characterized Bm-TPP. In the present study, we investigated the cross-reactivity of recombinant Bm-TPP (r-Bm-TPP) with the sera of human bancroftian patients belonging to different disease categories. In silico study using bioinformatics tool demonstrated that Bm-TPP is highly immunogenic in nature. BALB/c mice administered with r-Bm-TPP alone or in combination with Freund's complete adjuvant (FCA) generated a strong IgG response. Further investigations on the antibody isotypes showed generation of a mixed T helper cell response which was marginally biased towards Th1 phenotype. r-Bm-TPP with or without adjuvant lead to significantly increased accumulation of CD4+ and CD8+ T cells in the spleen of infected mice and increased the activation of peritoneal macrophages. Additionally, r-Bm-TPP enhanced the production of both proinflammatory (IL-2, IFN-γ) and anti-inflammatory (IL-4, IL-10) cytokines and mice immunized with r-Bm-TPP alone or in combination with FCA showed 54.5% and 67% protection respectively against B. malayi infective larvae challenge. Taken together, our findings suggest that Bm-TPP is protective in nature and might be a potential candidate for development of vaccine against lymphatic filarial infections.

  17. Effects of dehydroepiandrosterone on obesity and glucose-6-phosphate dehydrogenase activity in the lethal yellow mouse (strain 129/Sv-Ay/Aw).

    PubMed

    Granholm, N H; Staber, L D; Wilkin, P J

    1987-04-01

    We investigated the anti-obesity effects of the adrenal androgen, dehydroepiandrosterone (DHEA), on genetically predisposed obese lethal yellow mice (Ay/Aw). Secondly, we tested the hypothesis that DHEA promotes its anti-obesity effects by decreasing the activity of glucose-6-phosphate dehydrogenase (G6PDH). We subjected four genotype-sex combinations of yellow and agouti (control) mice to four dietary treatments and determined weight changes, food consumption, and G6PDH activity. Although G6PDH activities of yellow mice were considerably decreased in the 0.4% DHEA treatment group, they were elevated in the 0.0 and 0.1% DHEA treatment groups. In contrast, G6PDH activities of DHEA-treated control agouti mice remained relatively constant. These studies confirm that DHEA prevents the Ay gene from promoting excess fat deposition via some mechanism(s) other than reduced dietary intake. However, the overall absence of agreement between weight change (gain or loss) and G6PDH activity suggests that the anti-obesity activity of DHEA is not mediated via G6PDH. Since yellow obese (Ay/Aw) mice were found to be more susceptible to DHEA's effects than their agouti (Aw/Aw) littermates, Ay appears to induce an altered metabolism in Ay/Aw mice which is more susceptible to the effects of DHEA than the normal metabolism of Aw/Aw mice.

  18. Accumulation of Trehalose by Overexpression of tps1, Coding for Trehalose-6-Phosphate Synthase, Causes Increased Resistance to Multiple Stresses in the Fission Yeast Schizosaccharomyces pombe

    PubMed Central

    Soto, Teresa; Fernández, Juana; Vicente-Soler, Jero; Cansado, Jose; Gacto, Mariano

    1999-01-01

    Recent studies have shown that heat shock proteins and trehalose synthesis are important factors in the thermotolerance of the fission yeast Schizosaccharomyces pombe. We examined the effects of trehalose-6-phosphate (trehalose-6P) synthase overexpression on resistance to several stresses in cells of S. pombe transformed with a plasmid bearing the tps1 gene, which codes for trehalose-6P synthase, under the control of the strong thiamine-repressible promoter. Upon induction of trehalose-6P synthase, the elevated levels of intracellular trehalose correlated not only with increased tolerance to heat shock but also with resistance to freezing and thawing, dehydration, osmostress, and toxic levels of ethanol, indicating that trehalose may be the stress metabolite underlying the overlap in induced tolerance to these stresses. Among the isogenic strains transformed with this construct, one in which the gene coding for the trehalose-hydrolyzing enzyme, neutral trehalase, was disrupted accumulated trehalose to a greater extent and was more resistant to the above stresses. Increased trehalose concentration is thus a major determinant of the general stress protection response in S. pombe. PMID:10223994

  19. Accumulation of trehalose by overexpression of tps1, coding for trehalose-6-phosphate synthase, causes increased resistance to multiple stresses in the fission yeast schizosaccharomyces pombe

    PubMed

    Soto; Fernandez; Vicente-Soler; Cansado; Gacto

    1999-05-01

    Recent studies have shown that heat shock proteins and trehalose synthesis are important factors in the thermotolerance of the fission yeast Schizosaccharomyces pombe. We examined the effects of trehalose-6-phosphate (trehalose-6P) synthase overexpression on resistance to several stresses in cells of S. pombe transformed with a plasmid bearing the tps1 gene, which codes for trehalose-6P synthase, under the control of the strong thiamine-repressible promoter. Upon induction of trehalose-6P synthase, the elevated levels of intracellular trehalose correlated not only with increased tolerance to heat shock but also with resistance to freezing and thawing, dehydration, osmostress, and toxic levels of ethanol, indicating that trehalose may be the stress metabolite underlying the overlap in induced tolerance to these stresses. Among the isogenic strains transformed with this construct, one in which the gene coding for the trehalose-hydrolyzing enzyme, neutral trehalase, was disrupted accumulated trehalose to a greater extent and was more resistant to the above stresses. Increased trehalose concentration is thus a major determinant of the general stress protection response in S. pombe.

  20. Somatic-cell selection is a major determinant of the blood-cell phenotype in heterozygotes for glucose-6-phosphate dehydrogenase mutations causing severe enzyme deficiency.

    PubMed Central

    Filosa, S.; Giacometti, N.; Wangwei, C.; De Mattia, D.; Pagnini, D.; Alfinito, F.; Schettini, F.; Luzzatto, L.; Martini, G.

    1996-01-01

    X-chromosome inactivation in mammals is regarded as an essentially random process, but the resulting somatic-cell mosaicism creates the opportunity for cell selection. In most people with red-blood-cell glucose-6-phosphate dehydrogenase (G6PD) deficiency, the enzyme-deficient phenotype is only moderately expressed in nucleated cells. However, in a small subset of hemizygous males who suffer from chronic nonspherocytic hemolytic anemia, the underlying mutations (designated class I) cause more-severe G6PD deficiency, and this might provide an opportunity for selection in heterozygous females during development. In order to test this possibility we have analyzed four heterozygotes for class I G6PD mutations: two with G6PD Portici (1178G-->A) and two with G6PD Bari (1187C-->T). We found that in fractionated blood cell types (including erythroid, myeloid, and lymphoid cell lineages) there was a significant excess of G6PD-normal cells. The significant concordance that we have observed in the degree of imbalance in the different blood-cell lineages indicates that a selective mechanism is likely to operate at the level of pluripotent blood stem cells. Thus, it appears that severe G6PD deficiency affects adversely the proliferation or the survival of nucleated blood cells and that this phenotypic characteristic is critical during hematopoiesis. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 PMID:8808605

  1. The potential of species-specific tagatose-6-phosphate (T6P) pathway in Lactobacillus casei group for galactose reduction in fermented dairy foods.

    PubMed

    Wu, Qinglong; Shah, Nagendra P

    2017-04-01

    Residual lactose and galactose in fermented dairy foods leads to several industrial and health concerns. There is very little information pertaining to manufacture of fermented dairy foods that are low in lactose and galactose. In the present study, comparative genomic survey demonstrated the constant presence of chromosome-encoded tagatose-6-phosphate (T6P) pathway in Lactobacillus casei group. Lactose/galactose utilization tests and β-galactosidase assay suggest that PTS(Gal) system, PTS(Lac) system and T6P pathway are major contributors for lactose/galactose catabolism in this group of organisms. In addition, it was found than lactose catabolism by Lb. casei group accumulated very limited galactose in the MRS-lactose medium and in reconstituted skim milk, whereas Streptococcus thermophilus and Lb. delbrueckii subsp. bulgaricus (Lb. bulgaricus) strains secreted high amount of galactose extracellularly. Moreover, co-culturing Lb. casei group with Str. thermophilus showed significant reduction in galactose content, while co-culturing Lb. casei group with Lb. bulgaricus showed significant reduction in lactose content but significant increase in galactose content in milk. Overall, the present study highlighted the potential of Lb. casei group for reducing galactose accumulation in fermented milks due to its species-specific T6P pathway.

  2. Magnetic resonance angiography-defined intracranial vasculopathy is associated with silent cerebral infarcts and glucose-6-phosphate dehydrogenase mutation in children with sickle cell anaemia.

    PubMed

    Thangarajh, Mathula; Yang, Genyan; Fuchs, Dana; Ponisio, Maria R; McKinstry, Robert C; Jaju, Alok; Noetzel, Michael J; Casella, James F; Barron-Casella, Emily; Hooper, W Craig; Boulet, Sheree L; Bean, Christopher J; Pyle, Meredith E; Payne, Amanda B; Driggers, Jennifer; Trau, Heidi A; Vendt, Bruce A; Rodeghier, Mark; DeBaun, Michael R

    2012-11-01

    Silent cerebral infarct (SCI) is the most commonly recognized cause of neurological injury in sickle cell anaemia (SCA). We tested the hypothesis that magnetic resonance angiography (MRA)-defined vasculopathy is associated with SCI. Furthermore, we examined genetic variations in glucose-6-phosphate dehydrogenase (G6PD) and HBA (α-globin) genes to determine their association with intracranial vasculopathy in children with SCA. Magnetic resonance imaging (MRI) of the brain and MRA of the cerebral vasculature were available in 516 paediatric patients with SCA, enrolled in the Silent Infarct Transfusion (SIT) Trial. All patients were screened for G6PD mutations and HBA deletions. SCI were present in 41·5% (214 of 516) of SIT Trial children. The frequency of intracranial vasculopathy with and without SCI was 15·9% and 6·3%, respectively (P < 0·001). Using a multivariable logistic regression model, only the presence of a SCI was associated with increased odds of vasculopathy (P = 0·0007, odds ratio (OR) 2·84; 95% Confidence Interval (CI) = 1·55-5·21). Among male children with SCA, G6PD status was associated with vasculopathy (P = 0·04, OR 2·78; 95% CI = 1·04-7·42), while no significant association was noted for HBA deletions. Intracranial vasculopathy was observed in a minority of children with SCA, and when present, was associated with G6PD status in males and SCI.

  3. Rapid epidemiologic assessment of glucose-6-phosphate dehydrogenase deficiency in malaria-endemic areas in Southeast Asia using a novel diagnostic kit.

    PubMed

    Jalloh, A; Tantular, I S; Pusarawati, S; Kawilarang, A P; Kerong, H; Lin, K; Ferreira, M U; Matsuoka, H; Arai, M; Kita, K; Kawamoto, F

    2004-05-01

    We recently reported a new rapid screening method for glucose-6-phosphate dehydrogenase (G6PD) deficiency. This method incorporates a new formazan substrate (WST-8) and is capable of detecting heterozygous females both qualitatively and quantitatively. Here, we report its evaluation during field surveys at three malaria centres and in malaria-endemic villages of Myanmar and Indonesia, either alone or in combination with a rapid on-site diagnosis of malaria. A total of 57 severe (45 males and 12 females) and 34 mild (five males and 29 females) cases of G6PD deficiency were detected among 855 subjects in Myanmar whilst 30 severe (25 males and five females) and 23 mild (six males and 17 females) cases were found among 1286 subjects in Indonesia. In all cases, severe deficiency was confirmed with another formazan method but due to limitations in its detection threshold, mild cases were misdiagnosed as G6PD-normal by this latter method. Our results indicate that the novel method can qualitatively detect both severely deficient subjects as well as heterozygous females in the field. The antimalarial drug, primaquine, was safely prescribed to Plasmodium vivax-infected patients in Myanmar. Our new, rapid screening method may be essential for the diagnosis of G6PD deficiency particularly in rural areas without electricity, and can be recommended for use in malaria control programmes.

  4. Escherichia coli arabinose isomerase and Staphylococcus aureus tagatose-6-phosphate isomerase: which is a better template for directed evolution of non-natural substrate isomerization?

    PubMed

    Kim, Hye Jung; Uhm, Tae Guk; Kim, Seong Bo; Kim, Pil

    2010-06-01

    Metallic and non-metallic isomerases can be used to produce commercially important monosaccharides. To determine which category of isomerase is more suitable as a template for directed evolution to improve enzymes for galactose isomerization, L-arabinose isomerase from Escherichia coli (ECAI; E.C. 5.3.1.4) and tagatose-6-phosphate isomerase from Staphylococcus aureus (SATI; E.C. 5.3.1.26) were chosen as models of a metallic and non-metallic isomerase, respectively. Random mutations were introduced into the genes encoding ECAI and SATI at the same rate, resulting in the generation of 515 mutants of each isomerase. The isomerization activity of each of the mutants toward a non-natural substrate (galactose) was then measured. With an average mutation rate of 0.2 mutations/kb, 47.5% of the mutated ECAIs showed an increase in activity compared with wild-type ECAI, and the remaining 52.5% showed a decrease in activity. Among the mutated SATIs, 58.6% showed an increase in activity, whereas 41.4% showed a decrease in activity. Mutant clones showing a significant change in relative activity were sequenced and specific increases in activity were measured. The maximum increase in activity achieved by mutation of ECAI was 130%, and that for SATI was 190%. Based on these results, the characteristics of the different isomerases are discussed in terms of their usefulness for directed evolution of non-natural substrate isomerization.

  5. Impact of temperature stress and validamycin A on compatible solutes and fumonisin production in F. verticillioides: role of trehalose-6-phosphate synthase.

    PubMed

    Boudreau, Beth A; Larson, Troy M; Brown, Daren W; Busman, Mark; Roberts, Ethan S; Kendra, David F; McQuade, Kristi L

    2013-08-01

    Fusarium verticillioides is a pathogen of maize that causes root, stalk and ear rot and produces fumonisins, toxic secondary metabolites associated with disease in livestock and humans. Environmental stresses such as heat and drought influence disease severity and toxin production, but the effects of abiotic stress on compatible solute production by F. verticillioides have not been fully characterized. We found that decreasing the growth temperature leads to a long-term reduction in polyol levels, whereas increasing the temperature leads to a transient increase in polyols. The effects of temperature shifts on trehalose levels are opposite the effects on polyols and more dramatic. Treatment with validamycin A, a trehalose analog with antifungal activity, leads to a rapid reduction in trehalose levels, despite its known role as a trehalase inhibitor. Mutant strains lacking TPS1, which encodes a putative trehalose-6-phosphate synthase, have altered growth characteristics, do not produce detectable amounts of trehalose under any condition tested, and accumulate glycogen at levels significantly higher than wild-type F. verticillioides. TPS1 mutants also produce significantly less fumonisin than wild type and are also less pathogenic than wild type on maize. These data link trehalose biosynthesis, secondary metabolism, and disease, and suggest that trehalose metabolic pathways may be a viable target for the control of Fusarium diseases and fumonisin contamination of maize. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Somatic-cell selection is a major determinant of the blood-cell phenotype in heterozygotes for glucose-6-phosphate dehydrogenase mutations causing severe enzyme deficiency

    SciTech Connect

    Filosa, S.; Giacometti, N.; Wangwei, C.; Martini, G.

    1996-10-01

    X-chromosome inactivation in mammals is regarded as an essentially random process, but the resulting somatic-cell mosaicism creates the opportunity for cell selection. In most people with red-blood-cell glucose-6-phosphate dehydrogenase (G6PD) deficiency, the enzyme-deficient phenotype is only moderately expressed in nucleated cells. However, in a small subset of hemizygous males who suffer from chronic nonspherocytic hemolytic anemia, the underlying mutations (designated class I) cause more-severe G6PD deficiency, and this might provide an opportunity for selection in heterozygous females during development. In order to test this possibility we have analyzed four heterozygotes for class I G6PD mutations: two with G6PD Portici (1178G{r_arrow}A) and two with G6PD Bari (1187C{r_arrow}T). We found that in fractionated blood cell types (including erythroid, myeloid, and lymphoid cell lineages) there was a significant excess of G6PD-normal cells. The significant concordance that we have observed in the degree of imbalance in the different blood-cell lineages indicates that a selective mechanism is likely to operate at the level of pluripotent blood stem cells. Thus, it appears that severe G6PD deficiency affects adversely the proliferation or the survival of nucleated blood cells and that this phenotypic characteristic is critical during hematopoiesis. 65 refs., 6 figs., 3 tabs.

  7. Overcompensation in Response to Herbivory in Arabidopsis thaliana: The Role of Glucose-6-Phosphate Dehydrogenase and the Oxidative Pentose-Phosphate Pathway

    PubMed Central

    Siddappaji, Madhura H.; Scholes, Daniel R.; Bohn, Martin; Paige, Ken N.

    2013-01-01

    That some plants benefit from being eaten is counterintuitive, yet there is now considerable evidence demonstrating enhanced fitness following herbivory (i.e., plants can overcompensate). Although there is evidence that genetic variation for compensation exists, little is known about the genetic mechanisms leading to enhanced growth and reproduction following herbivory. We took advantage of the compensatory variation in recombinant inbred lines of Arabidopsis thaliana, combined with microarray and QTL analyses to assess the molecular basis of overcompensation. We found three QTL explaining 11.4, 10.1, and 26.7% of the variation in fitness compensation, respectively, and 109 differentially expressed genes between clipped and unclipped plants of the overcompensating ecotype Columbia. From the QTL/microarray screen we uncovered one gene that plays a significant role in overcompensation: glucose-6-phosphate-1-dehydrogenase (G6PDH1). Knockout studies of Transfer-DNA (T-DNA) insertion lines and complementation studies of G6PDH1 verify its role in compensation. G6PDH1 is a key enzyme in the oxidative pentose-phosphate pathway that plays a central role in plant metabolism. We propose that plants capable of overcompensating reprogram their transcriptional activity by up-regulating defensive genes and genes involved in energy metabolism and by increasing DNA content (via endoreduplication) with the increase in DNA content feeding back on pathways involved in defense and metabolism through increased gene expression. PMID:23934891

  8. Mutations of Glucose-6-Phosphate Dehydrogenase Durham, Santa-Maria and A+ Variants Are Associated with Loss Functional and Structural Stability of the Protein

    PubMed Central

    Gómez-Manzo, Saúl; Marcial-Quino, Jaime; Vanoye-Carlo, America; Enríquez-Flores, Sergio; De la Mora-De la Mora, Ignacio; González-Valdez, Abigail; García-Torres, Itzhel; Martínez-Rosas, Víctor; Sierra-Palacios, Edgar; Lazcano-Pérez, Fernando; Rodríguez-Bustamante, Eduardo; Arreguin-Espinosa, Roberto

    2015-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy in the world. More than 160 mutations causing the disease have been identified, but only 10% of these variants have been studied at biochemical and biophysical levels. In this study we report on the functional and structural characterization of three naturally occurring variants corresponding to different classes of disease severity: Class I G6PD Durham, Class II G6PD Santa Maria, and Class III G6PD A+. The results showed that the G6PD Durham (severe deficiency), and the G6PD Santa Maria and A+ (less severe deficiency) (Class I, II and III, respectively) affect the catalytic efficiency of these enzymes, are more sensitive to temperature denaturing, and affect the stability of the overall protein when compared to the wild type WT-G6PD. In the variants, the exposure of more and buried hydrophobic pockets was induced and monitored with 8-Anilinonaphthalene-1-sulfonic acid (ANS) fluorescence, directly affecting the compaction of structure at different levels and probably reducing the stability of the protein. The degree of functional and structural perturbation by each variant correlates with the clinical severity reported in different patients. PMID:26633385

  9. Enhanced production of epsilon-caprolactone by overexpression of NADPH-regenerating glucose 6-phosphate dehydrogenase in recombinant Escherichia coli harboring cyclohexanone monooxygenase gene.

    PubMed

    Lee, Won-Heong; Park, Jin-Byung; Park, Kyungmoon; Kim, Myoung-Dong; Seo, Jin-Ho

    2007-08-01

    Whole-cell conversion of cyclohexanone to epsilon-caprolactone was attempted by recombinant Escherichia coli BL21(DE3) expressing cyclohexanone monooxygenase (CHMO) of Acinetobacter calcoaceticus NCIMB 9871. High concentrations of cyclohexanone and epsilon-caprolactone reduced CHMO-mediated bioconversion of cyclohexanone to epsilon-caprolactone in the resting recombinant E. coli cells. Metabolically active cells were employed by adopting a fed-batch culture to improve the production of epsilon-caprolactone from cyclohexanone. A glucose-limited fed-batch Baeyer-Villiger oxidation where a cyclohexanone level was maintained less than 6 g/l resulted in a maximum epsilon-caprolactone concentration of 11.0 g/l. The maximum epsilon-caprolactone concentration was improved further to 15.3 g/l by coexpression of glucose-6-phosphate dehydrogenase, an NADPH-generating enzyme encoded by the zwf gene which corresponded to a 39% enhancement in epsilon-caprolactone concentration compared with the control experiment performed under the same conditions.

  10. Metabolomic profile of glycolysis and the pentose phosphate pathway identifies the central role of glucose-6-phosphate dehydrogenase in clear cell-renal cell carcinoma

    PubMed Central

    Sanguedolce, Francesca; Cagiano, Simona; Bufo, Pantaleo; Lastilla, Gaetano; Maiorano, Eugenio; Ribatti, Domenico; Giglio, Andrea; Serino, Grazia; Vavallo, Antonio; Bettocchi, Carlo; Selvaggi, Francesco Paolo; Battaglia, Michele; Ditonno, Pasquale

    2015-01-01

    The analysis of cancer metabolome has shown that proliferating tumor cells require a large quantities of different nutrients in order to support their high rate of proliferation. In this study we analyzed the metabolic profile of glycolysis and the pentose phosphate pathway (PPP) in human clear cell-renal cell carcinoma (ccRCC) and evaluate the role of these pathways in sustaining cell proliferation, maintenance of NADPH levels, and production of reactive oxygen species (ROS). Metabolomic analysis showed a clear signature of increased glucose uptake and utilization in ccRCC tumor samples. Elevated levels of glucose-6-phosphate dehydrogenase (G6PDH) in association with higher levels of PPP-derived metabolites, suggested a prominent role of this pathway in RCC-associated metabolic alterations. G6PDH inhibition, caused a significant decrease in cancer cell survival, a decrease in NADPH levels, and an increased production of ROS, suggesting that the PPP plays an important role in the regulation of ccRCC redox homeostasis. Patients with high levels of glycolytic enzymes had reduced progression-free and cancer-specific survivals as compared to subjects with low levels. Our data suggest that oncogenic signaling pathways may promote ccRCC through rerouting the sugar metabolism. Blocking the flux through this pathway may serve as a novel therapeutic target. PMID:25945836

  11. Nanoparticle abraxane possesses impaired proliferation in A549 cells due to the underexpression of glucosamine 6-phosphate N-acetyltransferase 1 (GNPNAT1/GNA1)

    PubMed Central

    Zhao, Minzhi; Li, Haiyun; Ma, Yan; Gong, He; Yang, Shu; Fang, Qiaojun; Hu, Zhiyuan

    2017-01-01

    Abraxane (Abr), a US Food and Drug Administration-approved albumin-bound nanoparticle applied for the treatment of non-small-cell lung cancer, has been reported to be more effective than paclitaxel (PTX). To further understand the molecular mechanisms that produce this superior drug efficacy of Abr, a quantitative proteomic approach has been applied to investigate the global protein expression profiles of lung cancer cell A549 treated with Abr and PTX. Only one protein, namely, glucosamine 6-phosphate N-acetyltransferase 1 (GNA1), showed significant differential expression (P<0.05) in the cutoff of 2.0 fold, suggesting that Abr can be used safely as a substitute for PTX. GNA1 is a key enzyme in the biosynthesis of uridine diphosphate-N-acetylglucosamine, which is an important donor substrate for N-linked glycosylation and has several important functions such as embryonic development and growth. Albumin plays a major role in the regulation of this protein. In summary, this study first shows that the superior drug effect of Abr is mainly due to the downregulation of GNA1, which causes proliferative delay and cell adhesion defect. It is also noteworthy that the deficiency of GNA1 might reduce insulin secretion which correlates with type 2 diabetes. PMID:28280335

  12. Increasing crop yield and resilience with trehalose 6-phosphate: targeting a feast-famine mechanism in cereals for better source-sink optimization.

    PubMed

    Paul, Matthew J; Oszvald, Maria; Jesus, Claudia; Rajulu, Charukesi; Griffiths, Cara A; Raines, Christine

    2017-07-20

    Food security is a pressing global issue. New approaches are required to break through a yield ceiling that has developed in recent years for the major crops. As important as increasing yield potential is the protection of yield from abiotic stresses in an increasingly variable and unpredictable climate. Current strategies to improve yield include conventional breeding, marker-assisted breeding, quantitative trait loci (QTLs), mutagenesis, creation of hybrids, genetic modification (GM), emerging genome-editing technologies, and chemical approaches. A regulatory mechanism amenable to three of these approaches has great promise for large yield improvements. Trehalose 6-phosphate (T6P) synthesized in the low-flux trehalose biosynthetic pathway signals the availability of sucrose in plant cells as part of a whole-plant sucrose homeostatic mechanism. Modifying T6P content by GM, marker-assisted selection, and novel chemistry has improved yield in three major cereals under a range of water availabilities from severe drought through to flooding. Yield improvements have been achieved by altering carbon allocation and how carbon is used. Targeting T6P both temporally and spatially offers great promise for large yield improvements in productive (up to 20%) and marginal environments (up to 120%). This opinion paper highlights this important breakthrough in fundamental science for crop improvement. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  13. Prevalence of thalassaemia, iron-deficiency anaemia and glucose-6-phosphate dehydrogenase deficiency among Arab migrating nomad children, southern Islamic Republic of Iran.

    PubMed

    Pasalar, M; Mehrabani, D; Afrasiabi, A; Mehravar, Z; Reyhani, I; Hamidi, R; Karimi, M

    2014-12-17

    This study investigated the prevalence of iron-deficiency anaemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency and β-thalassaemia trait among Arab migrating nomad children in southern Islamic Republic of Iran. Blood samples were analysed from 134 schoolchildren aged < 18 years (51 males, 83 females). Low serum ferritin (< 12 ng/dL) was present in 17.9% of children (21.7% in females and 11.8% in males). Low haemoglobin (Hb) correlated significantly with a low serum ferritin. Only 1 child had G6PD deficiency. A total of 9.7% of children had HbA2 ≥ 3.5 g/dL, indicating β-thalassaemia trait (10.8% in females and 7.8% in males). Mean serum iron, serum ferritin and total iron binding capacity were similar in males and females. Serum ferritin index was as accurate as Hb index in the diagnosis of iron-deficiency anaemia. A high prevalence of β-thalassaemia trait was the major potential risk factor in this population.

  14. Nanoparticle abraxane possesses impaired proliferation in A549 cells due to the underexpression of glucosamine 6-phosphate N-acetyltransferase 1 (GNPNAT1/GNA1).

    PubMed

    Zhao, Minzhi; Li, Haiyun; Ma, Yan; Gong, He; Yang, Shu; Fang, Qiaojun; Hu, Zhiyuan

    2017-01-01

    Abraxane (Abr), a US Food and Drug Administration-approved albumin-bound nanoparticle applied for the treatment of non-small-cell lung cancer, has been reported to be more effective than paclitaxel (PTX). To further understand the molecular mechanisms that produce this superior drug efficacy of Abr, a quantitative proteomic approach has been applied to investigate the global protein expression profiles of lung cancer cell A549 treated with Abr and PTX. Only one protein, namely, glucosamine 6-phosphate N-acetyltransferase 1 (GNA1), showed significant differential expression (P<0.05) in the cutoff of 2.0 fold, suggesting that Abr can be used safely as a substitute for PTX. GNA1 is a key enzyme in the biosynthesis of uridine diphosphate-N-acetylglucosamine, which is an important donor substrate for N-linked glycosylation and has several important functions such as embryonic development and growth. Albumin plays a major role in the regulation of this protein. In summary, this study first shows that the superior drug effect of Abr is mainly due to the downregulation of GNA1, which causes proliferative delay and cell adhesion defect. It is also noteworthy that the deficiency of GNA1 might reduce insulin secretion which correlates with type 2 diabetes.

  15. Cysteine34 of the cytoplasmic tail of the cation-dependent mannose 6- phosphate receptor is reversibly palmitoylated and required for normal trafficking and lysosomal enzyme sorting

    PubMed Central

    1996-01-01

    We have examined whether the two cysteine residues (Cys30 and Cys34) in the cytoplasmic tail of the cation-dependent mannose 6-phosphate receptor are palmitoylated via thioesters and whether these residues influence the biologic function of the receptor. To do this, mouse L cells expressing wild-type and mutant receptors were analyzed by metabolic labeling with [3H]palmitate, immunoprecipitation, and SDS- PAGE. Both Cys30 and Cys34 were found to be sites of palmitoylation and together they accounted for the total palmitoylation of the receptor. The palmitate rapidly turned over with a half-life of approximately 2 h compared to a half-life of greater than 40 h for the protein. Mutation of Cys34 to Ala resulted in the gradual accumulation of the receptor in dense lysosomes and the total loss of cathepsin D sorting function in the Golgi. A Cys30 to Ala mutation had no biologic consequences, showing the importance of Cys34. Mutation of amino acids 35-39 to alanines impaired palmitoylation of Cys30 and Cys34 and resulted in abnormal receptor trafficking to lysosomes and loss of cathepsin D sorting. These data suggest that palmitoylation of Cys30 and Cys34 leads to anchoring of this region of the cytoplasmic tail to the lipid bilayer. Anchoring via Cys34 is essential for the normal trafficking and lysosomal enzyme sorting function of the receptor. PMID:8647889

  16. A Selaginella lepidophylla Trehalose-6-Phosphate Synthase Complements Growth and Stress-Tolerance Defects in a Yeast tps1 Mutant1

    PubMed Central

    Zentella, Rodolfo; Mascorro-Gallardo, José O.; Van Dijck, Patrick; Folch-Mallol, Jorge; Bonini, Beatriz; Van Vaeck, Christophe; Gaxiola, Roberto; Covarrubias, Alejandra A.; Nieto-Sotelo, Jorge; Thevelein, Johan M.; Iturriaga, Gabriel

    1999-01-01

    The accumulation of the disaccharide trehalose in anhydrobiotic organisms allows them to survive severe environmental stress. A plant cDNA, SlTPS1, encoding a 109-kD protein, was isolated from the resurrection plant Selaginella lepidophylla, which accumulates high levels of trehalose. Protein-sequence comparison showed that SlTPS1 shares high similarity to trehalose-6-phosphate synthase genes from prokaryotes and eukaryotes. SlTPS1 mRNA was constitutively expressed in S. lepidophylla. DNA gel-blot analysis indicated that SlTPS1 is present as a single-copy gene. Transformation of a Saccharomyces cerevisiae tps1Δ mutant disrupted in the ScTPS1 gene with S. lepidophylla SlTPS1 restored growth on fermentable sugars and the synthesis of trehalose at high levels. Moreover, the SlTPS1 gene introduced into the tps1Δ mutant was able to complement both deficiencies: sensitivity to sublethal heat treatment at 39°C and induced thermotolerance at 50°C. The osmosensitive phenotype of the yeast tps1Δ mutant grown in NaCl and sorbitol was also restored by the SlTPS1 gene. Thus, SlTPS1 protein is a functional plant homolog capable of sustaining trehalose biosynthesis and could play a major role in stress tolerance in S. lepidophylla. PMID:10198107

  17. Testosterone influences the expression and distribution of the cation-dependent mannose-6-phosphate receptor in rat epididymis. Implications in the distribution of enzymes.

    PubMed

    Carvelli, L; Bannoud, N; Aguilera, A C; Sartor, T; Malossi, E; Sosa, M A

    2014-04-01

    The mammalian epididymis plays a role in sperm maturation through its secretory activity. Among the proteins secreted by the epithelium, there are significant amounts of acid hydrolases. In most cell types, the normal distribution of lysosomal enzymes is mediated by mannose-6-phosphate receptors (MPRs). In this study, we analysed the expression and distribution of the cation-dependent MPR (CD-MPR) in epididymis from control, castrated or castrated rats with testosterone replacement. It was observed that expression of CD-MPR increased due to castration in all regions of the epididymis, which was reversed by injection of testosterone. We also measured the activity of α-mannosidase and observed that the castration tends to increase the retention of this enzyme in the tissue, which is reversed by the hormone replacement. In corpus, this resulted in a reduced secretion of the enzyme. Immunohistochemistry showed that CD-MPR has a supranuclear location (different from the cation-independent MPR), most likely in principal cells, and low reactivity in other cell types. The signal in castrated animals was more intense and tended to redistribute towards the apical cytoplasm. Thus, we concluded that expression and distribution of CD-MPR is affected by decrease of testosterone in rat epididymis, and this could change the distribution of lysosomal enzymes.

  18. A highly phosphorylated subpopulation of insulin-like growth factor II/mannose 6-phosphate receptors is concentrated in a clathrin-enriched plasma membrane fraction

    SciTech Connect

    Corvera, S.; Folander, K.; Clairmont, K.B.; Czech, M.P. )

    1988-10-01

    Insulin-like growth factor II (IGF-II)/mannose 6-phosphate (Man-6-P) receptors immunoprecipitated from purified plasma membranes of {sup 32}P-labeled rat adipocytes are markedly heterogenous in their phosphorylation state. Approximately 80% of the plasma membrane receptors are solubilized in 1% (vol/vol) Triton X-100 and are phosphorylated on serine residues at a stoichiometry of {approx} 0.1-0.2 mol of phosphate per mol of receptor. In contrast, 15-20% of the receptors are Triton X-100-insoluble and are phosphorylated on serine and threonine residues at {approx} 4 or 5 mol of phosphate per mol of receptor. This Triton X-100-insoluble membrane subfraction contains only 5% of the total plasma membrane protein and yet contains all of the clathrin heavy chain associated with plasma membrane. Based on the relative yields of protein in the detergent-insoluble material, IGF-II/Man-6-P receptors are concentrated {approx} 3-fold in this clathrin-enriched subfraction. Taken together, these results indicate that insulin decreases the phosphorylation state of a highly phosphorylated subpopulation of IGF-II/Man-6-P receptors on the plasma membrane. In addition, insulin action may prevent the concentration of these receptors in a clathrin-enriched membrane subfraction.

  19. A new glucose-6-phosphate dehydrogenase variant, G6PD Orissa (44 Ala{yields}Gly), is the major polymorphic variant in tribal populations in India

    SciTech Connect

    Kaeda, J.S.; Bautista, J.M.; Stevens, D.

    1995-12-01

    Deficiency of glucose-6-phosphate dehydrogenase (G6PD) is usually found at high frequencies in areas of the world where malaria has been epidemic. The frequency and genetic basis of G6PD deficiency have been studied in Africa, around the Mediterranean, and in the Far East, but little such information is available about the situation in India. To determine the extent of heterogeneity of G6PD, we have studied several different Indian populations by screening for G6PD deficiency, followed by molecular analysis of deficient alleles. The frequency of G6PD deficiency varies between 3% and 15% in different tribal and urban groups. Remarkably, a previously unreported deficient variant, G6PD Orissa (44 Ala{yields}Gly), is responsible for most of the G6PD deficiency in tribal Indian populations but is not found in urban populations, where most of the G6PD deficiency is due to the G6PD Mediterranean (188 Ser{yields}Phe) variant. The K{sup NADP}{sub m} of G6PD Orissa is fivefold higher than that of the normal enzyme. This may be due to the fact that the alanine residue that is replaced by glycine is part of a putative coenzyme-binding site. 37 refs., 2 figs., 3 tabs.

  20. A trehalose 6-phosphate synthase gene of the hemocytes of the blue crab, Callinectes sapidus: cloning, the expression, its enzyme activity and relationship to hemolymph trehalose levels.

    PubMed

    Chung, J Sook

    2008-12-12

    Trehalose in ectoderms functions in energy metabolism and protection in extreme environmental conditions. We structurally characterized trehalose 6-phosphate synthase (TPS) from hemocytes of the blue crab, Callinectes sapidus. C. sapidus Hemo TPS (CasHemoTPS), like insect TPS, encodes both TPS and trehalose phosphate phosphatase domains. Trehalose seems to be a major sugar, as it shows higher levels than does glucose in hemocytes and hemolymph. Increases in HemoTPS expression, TPS enzyme activity in hemocytes, and hemolymph trehalose levels were determined 24 h after lipopolysaccharide challenge, suggesting that both TPS and TPP domains of CasHemoTPS are active and functional. The TPS gene has a wide tissue distribution in C. sapidus, suggesting multiple biosynthetic sites. A correlation between TPS activity in hemocytes and hemolymph trehalose levels was found during the molt cycle. The current study provides the first evidence of presence of trehalose in hemocytes and TPS in tissues of C. sapidus and implicates its functional role in energy metabolism and physiological adaptation.

  1. A trehalose 6-phosphate synthase gene of the hemocytes of the blue crab, Callinectes sapidus: cloning, the expression, its enzyme activity and relationship to hemolymph trehalose levels

    PubMed Central

    Chung, J Sook

    2008-01-01

    Trehalose in ectoderms functions in energy metabolism and protection in extreme environmental conditions. We structurally characterized trehalose 6-phosphate synthase (TPS) from hemocytes of the blue crab, Callinectes sapidus. C. sapidus Hemo TPS (CasHemoTPS), like insect TPS, encodes both TPS and trehalose phosphate phosphatase domains. Trehalose seems to be a major sugar, as it shows higher levels than does glucose in hemocytes and hemolymph. Increases in HemoTPS expression, TPS enzyme activity in hemocytes, and hemolymph trehalose levels were determined 24 h after lipopolysaccharide challenge, suggesting that both TPS and TPP domains of CasHemoTPS are active and functional. The TPS gene has a wide tissue distribution in C. sapidus, suggesting multiple biosynthetic sites. A correlation between TPS activity in hemocytes and hemolymph trehalose levels was found during the molt cycle. The current study provides the first evidence of presence of trehalose in hemocytes and TPS in tissues of C. sapidus and implicates its functional role in energy metabolism and physiological adaptation. PMID:19077285

  2. The role of reduced glutathione during the course of acute haemolysis in glucose-6-phosphate dehydrogenase deficient patients: clinical and pharmacodynamic aspects.

    PubMed

    Corbucci, G G

    1990-01-01

    Tissue hypoperfusion leads to cellular oxidative and peroxidative damage due to biochemical disorders in the oxygen and substrate metabolism. The metabolic turnover of glutathione (GSH) represents one the main cytoprotective systems against the peroxide attack and the depletion or defect in resynthesis of this compound is accompanied by pathological consequences. In the present study the clinical effects of glutathione depletion were investigated in conditions of acute tissue hypoxia due to marked haemolysis in glucose-6-phosphate dehydrogenase deficient patients (favism syndrome). In these subjects a significant marker of the tissue oxidative damage was represented by the uric acid blood levels, presumably linked to xanthine-hypoxanthine altered metabolism. To antagonize the effects of oxyradical pathology, reduced glutathione was administered to a group of patients and the results confirmed the cytoprotective role played by the GSH supplementation. The GSH action was evident on the tissue metabolism and this supports the opinion that reduced glutathione could represent a new and interesting therapeutic approach in marked and acute hypoxic conditions.

  3. Ethanol-induced yeast flocculation directed by the promoter of TPS1 encoding trehalose-6-phosphate synthase 1 for efficient ethanol production.

    PubMed

    Li, Qian; Zhao, Xin-Qing; Chang, Alan K; Zhang, Qiu-Mei; Bai, Feng-Wu

    2012-01-01

    Yeast flocculation is an important trait in the brewing industry as well as in ethanol production, through which biomass can be recovered by cost-effective sedimentation. However, mass transfer limitation may affect yeast growth and ethanol fermentation if the flocculation occurs earlier before fermentation is completed. In this article, a novel type of cell-cell flocculation induced by trehalose-6-phosphate synthase 1 (TPS1) promoter was presented. The linear cassette HO-P(TPS1)-FLO1(SPSC01)-KanMX4-HO was constructed to transform the non-flocculating industrial yeast S. cerevisiae 4126 by chromosome integration to obtain a new flocculating yeast strain, ZLH01, whose flocculation was induced by ethanol produced during fermentation. The experimental results illustrated that flocculation of ZLH01 was triggered by 3% (v/v) ethanol and enhanced as ethanol concentration increased till complete flocculation was achieved at ethanol concentration of 8% (v/v). Real time PCR analysis confirmed that the expression of FLO1(SPSC01) was dependent on ethanol concentration. The growth and ethanol fermentation of ZLH01 were improved significantly, compared with the constitutive flocculating yeast BHL01 engineered with the same FLO gene but directed by the constitutive 3-phosphoglycerate kinase promoter PGK1, particularly under high temperature conditions. These characteristics make the engineered yeast more suitable for ethanol production from industrial substrates under high gravity and temperature conditions. In addition, this strategy offers advantage in inducing differential expression of other genes for metabolic engineering applications of S. cerevisiae.

  4. [Adaptogenic effect of the vitamin D3 containing supplement "videchol" on glucose-6-phosphate dehydrogenase activity in erythrone of irradiated rats].

    PubMed

    Becerril Aragon, G A; Starykovych, L S; Kolodkin, A; Horot', I V; Velykyĭ, M M

    2007-01-01

    Two fast migrating, major, multiple molecular forms (MMF) of glucose-6-phosphate dehydrogenase [EC:1.1.1.49]: G-6-PDH-1 and G-6-PDH-2, and two minor forms: G-6-PDH-3 and G-6-PDH-4 were revealed in the electrophoregrams of both erythrocytes haemolisates as well in the homogenates of bone marrow cellular lines of rats at control conditions. Daily 1 cGy irradiation of rats up to a cumulative dose of 20 cGy led to a drop of G-6-PDH total activity and it caused a redistribution of the MMF of the enzyme in bone marrow cellular populations. However, G-6-PDH activity in erythrocytes exceeded the control means in all the experimental terms. The calculation of the local redistribution coefficient (l(G-6-FDH-i)) showed that these changes are mainly determined by the increase of the activity of the isoform G-6-PDH-3. Vitamin D3 administration to rats generated a correction of G-6-PDH activity in all studied cellular populations. Meanwhile, the MMF profiles were characterized by multidirectional rearrangements in the bone marrow erythroid and granulocyte-monocyte cells and in erythrocytes. The specificity of changes in the distribution of the MMF of G-6-PDH in the three studied cellular populations depends on the particularities of their energetic metabolism at irradiation conditions and on the modifying action of the natural adaptogen 1,25-dihydroxicholecalciferol.

  5. Red blood cell indices and prevalence of hemoglobinopathies and glucose 6 phosphate dehydrogenase deficiencies in male Tanzanian residents of Dar es Salaam.

    PubMed

    Mwakasungula, Solomon; Schindler, Tobias; Jongo, Said; Moreno, Elena; Kamaka, Kasimu; Mohammed, Mgeni; Joseph, Selina; Rashid, Ramla; Athuman, Thabit; Tumbo, Anneth Mwasi; Hamad, Ali; Lweno, Omar; Tanner, Marcel; Shekalaghe, Seif; Daubenberger, Claudia A

    2014-01-01

    Hemoglobinopathies, disorders of hemoglobin structure and production, are one of the most common monogenic disorders in humans. Glucose 6 phosphate dehydrogenase deficiency (G6PD) is an inherited enzymopathy resulting in increased oxygen stress susceptibility of red blood cells. The distributions of these genetic traits in populations living in tropical and subtropical regions where malaria has been or is still present are thought to result from survival advantage against severe life threatening malaria disease. 384 male Tanzanian volunteers residing in Dar es Salaam were typed for G6PD, sickle cell disease and α-thalassemia. The most prominent red blood cell polymorphism was heterozygous α(+)-thalassemia (37.8%), followed by the G6PD(A) deficiency (16.4%), heterozygous sickle cell trait (15.9%), G6PD(A-) deficiency (13.5%) and homozygous α(+)-thalassemia (5.2%). 35%, 45%, 17% and 3% of these volunteers were carriers of wild type gene loci, one, two or three of these hemoglobinopathies, respectively. We find that using a cut off value of 28.6 pg. for mean corpuscular hemoglobin (MCH), heterozygous α(+)-thalassemia can be predicted with a sensitivity of 84% and specificity of 72% in this male population. All subjects carrying homozygous α(+)-thalassemia were identified based on their MCH value < 28.6 pg.

  6. The phosphorylation pattern of oligosaccharides in secreted procathepsin D is glycosylation site-specific and independent of the expression of mannose 6-phosphate receptors.

    PubMed

    Dittmer, F; Pohlmann, R; von Figura, K

    1997-01-10

    Mammalian cells contain two types of mannose 6-phosphate receptors (MPR), MPRs 46 and 300, that contribute with variable efficiency to the sorting of individual lysosomal proteins. To evaluate the role of phosphorylated oligosaccharides for the sorting efficiency by either of the two receptors, the structure of phosphorylated oligosaccharides on lysosomal proteins escaping sorting in cells lacking MPR 46 and/or MPR 300 was analyzed. Procathepsin D was chosen as a model because it is sorted efficiently via MPR 300 and poorly via MPR 46 and contains a distinct and highly heterogenous mixture of phosphorylated oligosaccharides at either of its two N-glycosylation sites. Both MPRs 46 and 300 were found to have a minor but distinct preference for forms of procathepsin D and other lysosomal proteins containing oligosaccharides with two phosphomonoesters. However, the phosphorylation of oligosaccharides in procathepsin D and other lysosomal proteins that escape sorting in control cells or in cells lacking MPR 46 and/or MPR 300 was strikingly similar, and oligosaccharides with two phosphomonoesters represented the major oligosaccharide species. We conclude from these results that the position of the position of the phosphate groups, the structure of the underlying oligosaccharide, and/or the polypeptide backbone of lysosomal proteins have major roles in determining the affinity to MPRs.

  7. Serum factors alter the extent of dephosphorylation of ligands endocytosed via the mannose 6-phosphate/insulin-like growth factor II receptor

    PubMed Central

    1989-01-01

    Mouse L-cells that contain the cation-independent (CI) mannose 6- phosphate (Man 6-P)/insulin-like growth factor (IGF) II receptor endocytose acid hydrolases and deliver these enzymes to lysosomes. The postendocytic loss of the Man 6-P recognition marker from the cell- associated acid hydrolases was assessed by CI-Man 6-P receptor affinity chromatography. 125I-labeled acid hydrolases internalized by L-cells grown at high density were delivered to lysosomes but were not dephosphorylated. In contrast, the same 125I-labeled hydrolases internalized by L-cells maintained at low density were delivered to lysosomes and were extensively dephosphorylated. The dephosphorylation at low density required 5 h for completion suggesting that the phosphatase responsible for the dephosphorylation is located within the lysosomal compartment. Transition from the high to low density state was rapid and was not inhibited by cycloheximide. Medium substitution experiments indicated that serum factors were necessary to maintain the L-cells in the dephosphorylation-competent (low density) state, and that serum-free conditions led to a dephosphorylation-incompetent (high density) state. Addition of IGF II to cells in serum-free medium allowed acid hydrolases subsequently introduced by endocytosis to be dephosphorylated. The results indicate that the removal of the Man 6-P recognition marker from endocytosed acid hydrolases is regulated by serum factors in the growth medium, including IGF II. PMID:2549075

  8. Involvement of ABA- and H2O2-dependent cytosolic glucose-6-phosphate dehydrogenase in maintaining redox homeostasis in soybean roots under drought stress.

    PubMed

    Wang, Huahua; Yang, Lidan; Li, Yan; Hou, Junjie; Huang, Junjun; Liang, Weihong

    2016-10-01

    The roles of abscisic acid (ABA) and hydrogen peroxide (H2O2) in inducing glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) activity and the possible roles of G6PDH in regulating ascorbate-glutathione (AsA-GSH) cycle were investigated in soybean (Glycine max L.) roots under drought stress. Drought caused a marked increase of the total and cytosolic G6PDH activities and triggered a rapid ABA and H2O2 accumulation in soybean roots. Exogenous ABA or H2O2 treatment elevated the total and cytosolic G6PDH activities, whereas suppressing ABA or H2O2 production inhibited the drought-induced increase in total and cytosolic G6PDH activities, suggesting that ABA and H2O2 are required for drought-induced increase of total G6PDH activity, namely cytosolic G6PDH activity. Furthermore, ABA induced H2O2 production by stimulating NADPH oxidase activity under drought stress. Moreover, drought significantly increased the contents of AsA and GSH and the activities of key enzymes in AsA-GSH cycle, while application of G6PDH inhibitor to seedlings significantly reduced the above effect induced by drought. Taken together, these results indicate that H2O2 acting as a downstream signaling molecule of ABA mediates drought-induced increase in cytosolic G6PDH activity, and that enhanced cytosolic G6PDH activity maintains cellular redox homeostasis by regulating AsA-GSH cycle in soybean roots. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Trehalose metabolism in the blue crab Callinectes sapidus: isolation of multiple structural cDNA isoforms of trehalose-6-phosphate synthase and their expression in muscles.

    PubMed

    Shi, Q; Chung, J Sook

    2014-02-15

    Adult blue crab Callinectes sapidus exhibit behavioral and ecological dimorphisms: females migrating from the low salinity water to the high salinity area vs. males remaining in the same areas. The flesh basal muscle of the swimming paddle shows a dimorphic color pattern in that levator (Lev) and depressor (Dep) of females tend to be much darker than those of males, while both genders have the same light colored remoter (Rem) and promoter (Pro). The full-length cDNA sequence of four structural isoforms of trehalose-6-phosphate synthase (TPS) is isolated from chela muscles of an adult female, C. sapidus. Two isoforms of the C. sapidus TPS encode functional domains of TPS and trehalose-6-phosphorylase (TPP) in tandem as a fused gene product of Escherichia coli Ost A and Ost B. The other two isoforms contain only a single TPS domain. In both males and females, the darker (Lev+Dep) muscles exhibit greater amounts of trehalose, TPS and trehalase activities than the light colored (Rem+Pro). The fact that adult females show higher levels of trehalase activity in the basal muscles and of glucose in Lev+Dep than those of adult males suggests that there may be a metabolic dimorphism. Moreover, the involvement of trehalose in energy metabolism that was examined under the condition of strenuous swimming activity mimicked in adult females demonstrates the intrinsic trehalose metabolism in Lev+Dep, which subsequently results in hemolymphatic hyperglycemia and hyperlactemia. Our data support that trehalose serves as an additional carbohydrate source of hemolymphatic hyperglycemia in this species. Behavioral and ecological dimorphisms of C. sapidus adults may be supported by a functional dimorphism in energy metabolism.

  10. Chemical modification of lysozyme, glucose 6-phosphate dehydrogenase, and bovine eye lens proteins induced by peroxyl radicals: role of oxidizable amino acid residues.

    PubMed

    Arenas, Andrea; López-Alarcón, Camilo; Kogan, Marcelo; Lissi, Eduardo; Davies, Michael J; Silva, Eduardo

    2013-01-18

    Chemical and structural alterations to lysozyme (LYSO), glucose 6-phosphate dehydrogenase (G6PD), and bovine eye lens proteins (BLP) promoted by peroxyl radicals generated by the thermal decomposition of 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) under aerobic conditions were investigated. SDS-PAGE analysis of the AAPH-treated proteins revealed the occurrence of protein aggregation, cross-linking, and fragmentation; BLP, which are naturally organized in globular assemblies, were the most affected proteins. Transmission electron microscopy (TEM) analysis of BLP shows the formation of complex protein aggregates after treatment with AAPH. These structural modifications were accompanied by the formation of protein carbonyl groups and protein hydroperoxides. The yield of carbonyls was lower than that for protein hydroperoxide generation and was unrelated to protein fragmentation. The oxidized proteins were also characterized by significant oxidation of Met, Trp, and Tyr (but not other) residues, and low levels of dityrosine. As the dityrosine yield is too low to account for the observed cross-linking, we propose that aggregation is associated with tryptophan oxidation and Trp-derived cross-links. It is also proposed that Trp oxidation products play a fundamental role in nonrandom fragmentation and carbonyl group formation particularly for LYSO and G6PD. These data point to a complex mechanism of peroxyl-radical mediated modification of proteins with monomeric (LYSO), dimeric (G6PD), and multimeric (BLP) structural organization, which not only results in oxidation of protein side chains but also gives rise to radical-mediated protein cross-links and fragmentation, with Trp species being critical intermediates.

  11. Recognition of the 300-kDa mannose 6-phosphate receptor cytoplasmic domain by 47-kDa tail-interacting protein

    PubMed Central

    Orsel, Joke G.; Sincock, Paul M.; Krise, Jeffrey P.; Pfeffer, Suzanne R.

    2000-01-01

    Tail-interacting 47-kDa protein (TIP47) binds the cytoplasmic domains of the cation-dependent (CD) and cation-independent (CI) mannose 6-phosphate receptors (MPRs) and is required for their transport from endosomes to the Golgi complex. TIP47 recognizes a phenylalanine-tryptophan signal in the CD-MPR. We show here that TIP47 interaction with the 163-residue CI-MPR cytoplasmic domain is highly conformation dependent and requires CI-MPR residues that are proximal to the membrane. CI-MPR cytoplasmic domain residues 1–47 are dispensable, whereas residues 48–74 are essential for high-affinity binding. However, residues 48–74 are not sufficient for high-affinity binding; residues 75–163 alone display weak affinity for TIP47, yet they contribute to the presentation of residues 48–74 in the intact protein. Independent competition binding experiments confirm that TIP47 interacts with the membrane-proximal portion of the CI-MPR cytoplasmic domain. TIP47 binding is competed by the binding of the AP-2 clathrin adaptor at (and near) residues 24–29 but not by AP-1 binding at (and near) residues 160–161. Finally, TIP47 appears to recognize a putative loop generated by the sequence PPAPRPG and other hydrophobic residues in the membrane-proximal domain. Although crystallography will be needed to define the precise interaction interface, these data provide an initial structural basis for TIP47–CI-MPR association. PMID:10908666

  12. The chemopreventive properties of chlorogenic acid reveal a potential new role for the microsomal glucose-6-phosphate translocase in brain tumor progression

    PubMed Central

    Belkaid, Anissa; Currie, Jean-Christophe; Desgagnés, Julie; Annabi, Borhane

    2006-01-01

    Background Chlorogenic acid (CHL), the most potent functional inhibitor of the microsomal glucose-6-phosphate translocase (G6PT), is thought to possess cancer chemopreventive properties. It is not known, however, whether any G6PT functions are involved in tumorigenesis. We investigated the effects of CHL and the potential role of G6PT in regulating the invasive phenotype of brain tumor-derived glioma cells. Results RT-PCR was used to show that, among the adult and pediatric brain tumor-derived cells tested, U-87 glioma cells expressed the highest levels of G6PT mRNA. U-87 cells lacked the microsomal catalytic subunit glucose-6-phosphatase (G6Pase)-α but expressed G6Pase-β which, when coupled to G6PT, allows G6P hydrolysis into glucose to occur in non-glyconeogenic tissues such as brain. CHL inhibited U-87 cell migration and matrix metalloproteinase (MMP)-2 secretion, two prerequisites for tumor cell invasion. Moreover, CHL also inhibited cell migration induced by sphingosine-1-phosphate (S1P), a potent mitogen for glioblastoma multiform cells, as well as the rapid, S1P-induced extracellular signal-regulated protein kinase phosphorylation potentially mediated through intracellular calcium mobilization, suggesting that G6PT may also perform crucial functions in regulating intracellular signalling. Overexpression of the recombinant G6PT protein induced U-87 glioma cell migration that was, in turn, antagonized by CHL. MMP-2 secretion was also inhibited by the adenosine triphosphate (ATP)-depleting agents 2-deoxyglucose and 5-thioglucose, a mechanism that may inhibit ATP-mediated calcium sequestration by G6PT. Conclusion We illustrate a new G6PT function in glioma cells that could regulate the intracellular signalling and invasive phenotype of brain tumor cells, and that can be targeted by the anticancer properties of CHL. PMID:16566826

  13. Haptoglobin, alpha-thalassaemia and glucose-6-phosphate dehydrogenase polymorphisms and risk of abnormal transcranial Doppler among patients with sickle cell anaemia in Tanzania.

    PubMed

    Cox, Sharon E; Makani, Julie; Soka, Deogratias; L'Esperence, Veline S; Kija, Edward; Dominguez-Salas, Paula; Newton, Charles R J; Birch, Anthony A; Prentice, Andrew M; Kirkham, Fenella J

    2014-06-01

    Transcranial Doppler ultrasonography measures cerebral blood flow velocity (CBFv) of basal intracranial vessels and is used clinically to detect stroke risk in children with sickle cell anaemia (SCA). Co-inheritance in SCA of alpha-thalassaemia and glucose-6-phosphate dehydrogenase (G6PD) polymorphisms is reported to associate with high CBFv and/or risk of stroke. The effect of a common functional polymorphism of haptoglobin (HP) is unknown. We investigated the effect of co-inheritance of these polymorphisms on CBFv in 601 stroke-free Tanzanian SCA patients aged <24 years. Homozygosity for alpha-thalassaemia 3·7 deletion was significantly associated with reduced mean CBFv compared to wild-type (β-coefficient -16·1 cm/s, P = 0·002) adjusted for age and survey year. Inheritance of 1 or 2 alpha-thalassaemia deletions was associated with decreased risk of abnormally high CBFv, compared to published data from Kenyan healthy control children (Relative risk ratio [RRR] = 0·53 [95% confidence interval (CI):0·35-0·8] & RRR = 0·43 [95% CI:0·23-0·78]), and reduced risk of abnormally low CBFv for 1 deletion only (RRR = 0·38 [95% CI:0·17-0·83]). No effects were observed for G6PD or HP polymorphisms. This is the first report of the effects of co-inheritance of common polymorphisms, including the HP polymorphism, on CBFv in SCA patients resident in Africa and confirms the importance of alpha-thalassaemia in reducing risk of abnormal CBFv.

  14. A trade off between catalytic activity and protein stability determines the clinical manifestations of glucose-6-phosphate dehydrogenase (G6PD) deficiency.

    PubMed

    Boonyuen, Usa; Chamchoy, Kamonwan; Swangsri, Thitiluck; Junkree, Thanyaphorn; Day, Nicholas P J; White, Nicholas J; Imwong, Mallika

    2017-11-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common polymorphism and enzymopathy in humans, affecting approximately 400 million people worldwide. It is responsible for various clinical manifestations, including favism, hemolytic anemia, chronic non-spherocytic hemolytic anemia, spontaneous abortion, and neonatal hyperbilirubinemia. Understanding the molecular mechanisms underlying the severity of G6PD deficiency is of great importance but that of many G6PD variants are still unknown. In this study, we report the construction, expression, purification, and biochemical characterization in terms of kinetic properties and stability of five clinical G6PD variants-G6PD Bangkok, G6PD Bangkok noi, G6PD Songklanagarind, G6PD Canton+Bangkok noi, and G6PD Union+Viangchan. G6PD Bangkok and G6PD Canton+Bangkok noi showed a complete loss of catalytic activity and moderate reduction in thermal stability when compared with the native G6PD. G6PD Bangkok noi and G6PD Union+Viangchan showed a significant reduction in catalytic efficiency, whereas G6PD Songklanagarind showed a catalytic activity comparable to the wild-type enzyme. The Union+Viangchan mutation showed a remarkable effect on the global stability of the enzyme. In addition, our results indicate that the location of mutations in G6PD variants affects their catalytic activity, stability, and structure. Hence, our results provide a molecular explanation for clinical manifestations observed in individuals with G6PD deficiency. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  15. A missense mutation in the glucosamine-6-phosphate N-acetyltransferase-encoding gene causes temperature-dependent growth defects and ectopic lignin deposition in Arabidopsis.

    PubMed

    Nozaki, Mamoru; Sugiyama, Munetaka; Duan, Jun; Uematsu, Hiroshi; Genda, Tatsuya; Sato, Yasushi

    2012-08-01

    To study the regulatory mechanisms underlying lignin biosynthesis, we isolated and characterized lignescens (lig), a previously undescribed temperature-sensitive mutant of Arabidopsis thaliana that exhibits ectopic lignin deposition and growth defects under high-temperature conditions. The lig mutation was identified as a single base transition in GNA1 encoding glucosamine-6-phosphate N-acetyltransferase (GNA), a critical enzyme of UDP-N-acetylglucosamine (UDP-GlcNAc) biosynthesis. lig harbors a glycine-to-serine substitution at residue 68 (G68S) of GNA1. Enzyme activity assays of the mutant protein (GNA1(G68S)) showed its thermolability relative to the wild-type protein. The lig mutant exposed to the restrictive temperature contained a significantly smaller amount of UDP-GlcNAc than did the wild type. The growth defects and ectopic lignification of lig were suppressed by the addition of UDP-GlcNAc. Since UDP-GlcNAc is an initial sugar donor of N-glycan synthesis and impaired N-glycan synthesis is known to induce the unfolded protein response (UPR), we examined possible relationships between N-glycan synthesis, UPR, and the lig phenotype. N-glycans were reduced and LUMINAL BINDING PROTEIN3, a typical UPR gene, was expressed in lig at the restrictive temperature. Furthermore, treatment with UPR-inducing reagents phenocopied the lig mutant. Our data collectively suggest that impairment of N-glycan synthesis due to a shortage of UDP-GlcNAc leads to ectopic lignin accumulation, mostly through the UPR.

  16. Starvation actively inhibits splicing of glucose-6-phosphate dehydrogenase mRNA via a bifunctional ESE/ESS element bound by hnRNP K.

    PubMed

    Cyphert, T J; Suchanek, A L; Griffith, B N; Salati, L M

    2013-09-01

    Regulated expression of glucose-6-phosphate dehydrogenase (G6PD) is due to changes in the rate of pre-mRNA splicing and not changes in its transcription. Starvation alters pre-mRNA splicing by decreasing the rate of intron removal, leading to intron retention and a decrease in the accumulation of mature mRNA. A regulatory element within exon 12 of G6PD pre-mRNA controls splicing efficiency. Starvation caused an increase in the expression of heterogeneous nuclear ribonucleoprotein (hnRNP) K protein and this increase coincided with the increase in the binding of hnRNP K to the regulatory element and a decrease in the expression of G6PD mRNA. HnRNP K bound to two C-rich motifs forming an ESS within exon 12. Overexpression of hnRNP K decreased the splicing and expression of G6PD mRNA, while siRNA-mediated depletion of hnRNP K caused an increase in the splicing and expression of G6PD mRNA. Binding of hnRNP K to the regulatory element was enhanced in vivo by starvation coinciding with a decrease in G6PD mRNA. HnRNP K binding to the C-rich motifs blocked binding of serine-arginine rich, splicing factor 3 (SRSF3), a splicing enhancer. Thus hnRNP K is a nutrient regulated splicing factor responsible for the inhibition of the splicing of G6PD during starvation.

  17. Glucose-6-phosphate dehydrogenase and alternative oxidase are involved in the cross tolerance of highland barley to salt stress and UV-B radiation.

    PubMed

    Zhao, Chengzhou; Wang, Xiaomin; Wang, Xiaoyu; Wu, Kunlun; Li, Ping; Chang, Ning; Wang, Jianfeng; Wang, Feng; Li, Jiaolong; Bi, Yurong

    2015-06-01

    In this study, a new mechanism involving glucose-6-phosphate dehydrogenase (G6PDH) and alternative pathways (AP) in salt pretreatment-induced tolerance of highland barley to UV-B radiation was investigated. When highland barley was exposed to UV-B radiation, the G6PDH activity decreased but the AP capacity increased. In contrast, under UV-B+NaCl treatment, the G6PDH activity was restored to the control level and the maximal AP capacity and antioxidant enzyme activities were reached. Glucosamine (Glucm, an inhibitor of G6PDH) obviously inhibited the G6PDH activity in highland barley under UV-B + NaCl treatment and a similar pattern was observed in reduced glutathione (GSH) and ascorbic acid (Asc) contents. Similarly, salicylhydroxamic acid (SHAM, an inhibitor of AOX) significantly reduced the AP capacity in highland barley under UV-B + NaCl treatment. The UV-B-induced hydrogen peroxide (H2O2) accumulation was also followed. Further studies indicated that non-functioning of G6PDH or AP under UV-B+NaCl + Glucm or UV-B + NaCl + SHAM treatment also caused damages in photosynthesis and stomatal movement. Western blot analysis confirmed that the alternative oxidase (AOX) and G6PDH were dependent each other in cross tolerance to UV-B and salt. The inhibition of AP or G6PDH activity resulted in a significant accumulation or reduction of NADPH content, respectively, under UV-B+NaCl treatment in highland barley leaves. Taken together, our results indicate that AP and G6PDH mutually regulate and maintain photosynthesis and stomata movement in the cross adaptation of highland barley seedlings to UV-B and salt by modulating redox homeostasis and NADPH content.

  18. Elevated glucose-6-phosphate dehydrogenase expression in the cervical cancer cases is associated with the cancerigenic event of high-risk human papillomaviruses

    PubMed Central

    Hu, Tao; Li, Ya-Shan; Chen, Bo; Chang, Ye-Fei; Liu, Guang-Cai; Hong, Ying; Chen, Ho