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Sample records for activity glutathione peroxidase

  1. Effect of methylmercury on the activity of glutathione peroxidase in rat liver

    SciTech Connect

    Hirota, Y.

    1986-09-01

    The effect of methylmercury on the activity of glutathione peroxidase in rat liver was studied in vivo. A daily dose of 10mg methylmercuric chloride/kg body weight was administered subcutaneously to 15 male Wistar rats for 10 days, and the glutathione peroxidase activity in the liver was measured to compare with the control activity. A marked decrease was observed in the glutathione peroxidase activity in the experimental animals, which measured as low as 40% in comparison to that in the control animals. It can be speculated that the inhibition of glutathione peroxidase activity plays a significant role in the development of mercury toxicity and that the protective effect of selenium and vitamin E on the mercury intoxication might be partly due to preserving the glutathione peroxidase activity in the antioxidative defense mechanisms.

  2. Storage of Heparinised Canine Whole Blood for the Measurement of Glutathione Peroxidase Activity.

    PubMed

    van Zelst, Mariëlle; Hesta, Myriam; Gray, Kerry; Janssens, Geert P J

    2016-08-01

    Glutathione peroxidase activity is used as a biomarker of selenium status in dogs. Freshly collected blood samples are usually measured, due to the lack of knowledge on the effect of storing the samples. This study investigated if the analysis of glutathione peroxidase activity in whole blood collected from dogs was affected by storage of between 5 and 164 days. Results indicated that glutathione peroxidase activity was more variable in the freshly analysed samples compared to the stored samples. Although the mean differences between fresh and stored samples were not always equal to zero, this is thought to be caused by the variability of reagent preparation rather than by storage, as no consistent increase or decrease in glutathione peroxidase activity was found. Therefore, it can be concluded that heparinised dog blood samples can be successfully stored up to 164 days before analysis of glutathione peroxidase activity. PMID:26701335

  3. A supramolecular microgel glutathione peroxidase mimic with temperature responsive activity.

    PubMed

    Yin, Yanzhen; Jiao, Shufei; Lang, Chao; Liu, Junqiu

    2014-05-21

    Glutathione peroxidase (GPx) protects cells from oxidative damage by scavenging surplus reactive oxygen species (ROS). Commonly, an appropriate amount of ROS acts as a signal molecule in the metabolism. A smart artificial GPx exhibits adjustable catalytic activity, which can potentially reduce the amount of ROS to an appropriate degree and maintain its important physiological functions in metabolism. To construct an optimum and excellent smart artificial GPx, a novel supramolecular microgel artificial GPx (SM-Te) was prepared based on the supramolecular host-guest interaction employing the tellurium-containing guest molecule (ADA-Te-ADA) and the cyclodextrin-containing host block copolymer (poly(N-isopropylacrylamide)-b-[polyacrylamides-co-poly(6-o-(triethylene glycol monoacrylate ether)-β-cyclodextrin)], PPAM-CD) as building blocks. Subsequently, based on these building blocks, SM-Te was constructed and the formation of its self-assembled structure was confirmed by dynamic light scattering, NMR, SEM, TEM, etc. Typically, benefitting from the temperature responsive properties of the PNIPAM scaffold, SM-Te also exhibited similar temperature responsive behaviour. Importantly, the GPx catalytic rates of SM-Te displayed a noticeable temperature responsive characteristic. Moreover, SM-Te exhibited the typical saturation kinetics behaviour of a real enzyme catalyst. It was proved that the changes of the hydrophobic microenvironment and the pore size in the supramolecular microgel network of SM-Te played significant roles in altering the temperature responsive catalytic behaviour. The successful construction of SM-Te not only overcomes the insurmountable disadvantages existing in previous covalent bond crosslinked microgel artificial GPx but also bodes well for the development of novel intelligent antioxidant drugs. PMID:24652520

  4. The effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities.

    PubMed

    Yazar, E; Altunok, V; Elmas, M; Traş, B; Baş, A L; Ozdemir, V

    2002-05-01

    In this study, the effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities was investigated. Forty male BALB/c mice were used as material. Ten mice served as a control group, and 30 mice were injected with tilmicosin (25 mg/kg body weight, subcutaneously, with a single injection). After drug administration, they were monitored for 3 days. Tilmicosin caused decreases in cardiac superoxide dismutase and glutathione peroxidase activities.

  5. Glutathione and glutathione peroxidase activities in blood of patients in early stages following kidney transplantation.

    PubMed

    Zachara, Bronislaw A; Wlodarczyk, Zbigniew; Andruszkiewicz, Jacek; Gromadzinska, Jolanta; Wasowicz, Wojciech

    2005-01-01

    This study focuses on glutathione (GSH) level in red blood cells, as well as on glutathione peroxidases (GSH-Px) activities in red blood cells and in plasma of chronic renal failure (CRF) patients following renal transplantation. We want to focus our main attention on plasma GSH-Px, the selenoenzyme that is synthesized primarily in the kidney. In CRF patients, activity of this enzyme is significantly reduced, and the reduction decreases with the progress of the disease, reaching in the end-stage 20% to 30% of the activity of healthy patients. We have shown that following renal transplantation the activity of plasma GSH-Px is restored very rapidly, and 2 weeks after surgery it reached the value of the control group. Red blood cell GSH level is significantly higher in CRF patients, and following transplantation, no significant changes were observed. Red blood cell GSH-Px activity before transplantation was the same as in healthy patients and did not change significantly after surgery. PMID:16350829

  6. Functional mimicry of the active site of glutathione peroxidase by glutathione imprinted selenium-containing protein.

    PubMed

    Liu, Lei; Mao, Shi-zhong; Liu, Xiao-man; Huang, Xin; Xu, Jia-yun; Liu, Jun-qiu; Luo, Gui-min; Shen, Jia-cong

    2008-01-01

    For imitating the active site of antioxidant selenoenzyme glutathione peroxidase (GPx), an artificial enzyme selenosubtilisin was employed as a scaffold for reconstructing substrate glutathione (GSH) specific binding sites by a bioimprinting strategy. GSH was first covalently linked to selenosubtilisin to form a covalent complex GSH-selenosubtilisin through a Se-S bond, then the GSH molecule was used as a template to cast a complementary binding site for substrate GSH recognition. The bioimprinting procedure consists of unfolding the conformation of selenosubtilisin and fixing the new conformation of the complex GSH-selenosubtilisin. Thus a new specificity for naturally occurring GPx substrate GSH was obtained. This bioimprinting procedure facilitates the catalytic selenium moiety of the imprinted selenosubtilisin to match the reactive thiol group of GSH in the GSH binding site, which contributes to acceleration of the intramolecular catalysis. These imprinted selenium-containing proteins exhibited remarkable rate enhancement for the reduction of H2O2 by GSH. The average GPx activity was found to be 462 U/micromol, and it was approximately 100 times that for unimprinted selenosubtilisin. Compared with ebselen, a well-known GPx mimic, an activity enhancement of 500-fold was observed. Detailed steady-state kinetic studies demonstrated that the novel selenoenzyme followed a ping-pong mechanism similar to the naturally occurring GPx. PMID:18163571

  7. Activation of glutathione peroxidase via Nrf1 mediates genistein's protection against oxidative endothelial cell injury

    SciTech Connect

    Hernandez-Montes, Eva; Pollard, Susan E.; Vauzour, David; Jofre-Montseny, Laia; Rota, Cristina; Rimbach, Gerald; Weinberg, Peter D.; Spencer, Jeremy P.E. . E-mail: j.p.e.spencer@reading.ac.uk

    2006-08-04

    Cellular actions of isoflavones may mediate the beneficial health effects associated with high soy consumption. We have investigated protection by genistein and daidzein against oxidative stress-induced endothelial injury. Genistein but not daidzein protected endothelial cells from damage induced by oxidative stress. This protection was accompanied by decreases in intracellular glutathione levels that could be explained by the generation of glutathionyl conjugates of the oxidised genistein metabolite, 5,7,3',4'-tetrahydroxyisoflavone. Both isoflavones evoked increased protein expression of {gamma}-glutamylcysteine synthetase-heavy subunit ({gamma}-GCS-HS) and increased cytosolic accumulation and nuclear translocation of Nrf2. However, only genistein led to increases in the cytosolic accumulation and nuclear translocation of Nrf1 and the increased expression of and activity of glutathione peroxidase. These results suggest that genistein-induced protective effects depend primarily on the activation of glutathione peroxidase mediated by Nrf1 activation, and not on Nrf2 activation or increases in glutathione synthesis.

  8. Effects of commercial selenium products on glutathione peroxidase activity and semen quality in stud boars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to determine how dietary supplementation of inorganic and organic selenium affects selenium concentration and glutathione peroxidase activity in blood and sperm of sexually mature stud boars. Twenty-four boars of the Large White, Landrace, Pietrain, and Duroc breeds of opt...

  9. Correlation between Glutathione Peroxidase Activity and Anthropometrical Parameters in Adolescents with Down Syndrome

    ERIC Educational Resources Information Center

    Ordonez, F. J.; Rosety-Rodriguez, M.

    2007-01-01

    Since we have recently found that regular exercise increased erythrocyte antioxidant enzyme activities such as glutathione peroxidase (GPX) in adolescents with Down syndrome, these programs may be recommended. This study was designed to assess the role of anthropometrical parameters as easy, economic and non-invasive biomarkers of GPX. Thirty-one…

  10. Serum Malondialdehyde Concentration and Glutathione Peroxidase Activity in a Longitudinal Study of Gestational Diabetes

    PubMed Central

    Miranda, María; Muriach, María; Romero, Francisco J.; Villar, Vincent M.

    2016-01-01

    Aims The main goal of this study was to evaluate the presence of oxidative damage and to quantify its level in gestational diabetes. Methods Thirty-six healthy women and thirty-six women with gestational diabetes were studied in the three trimesters of pregnancy regarding their levels of oxidative stress markers. These women were diagnosed with diabetes in the second trimester of pregnancy. Blood glucose levels after 100g glucose tolerance test were higher than 190, 165 or 145 mg/dl, 1, 2 or 3 hours after glucose intake. Results The group of women with gestational diabetes had higher serum malondialdehyde levels, with significant differences between groups in the first and second trimester. The mean values of serum glutathione peroxidase activity in the diabetic women were significantly lower in the first trimester. In the group of women with gestational diabetes there was a negative linear correlation between serum malondialdehyde concentration and glutathione peroxidase activity in the second and third trimester. Conclusions In this observational and longitudinal study in pregnant women, the alterations attributable to oxidative stress were present before the biochemical detection of the HbA1c increase. Usual recommendations once GD is detected (adequate metabolic control, as well as any other normally proposed to these patients) lowered the concentration of malondialdehyde at the end of pregnancy to the same levels of the healthy controls. Serum glutathione peroxidase activity in women with gestational diabetes increased during the gestational period. PMID:27228087

  11. Direct assay of glutathione peroxidase activity using high-performance capillary electrophoresis.

    PubMed

    Pascual, P; Martinez-Lara, E; Bárcena, J A; López-Barea, J; Toribio, F

    1992-10-01

    A fast, sensitive and direct method has been developed for the determination of glutathione peroxidase activity (both selenium- and non-selenium-dependent) in cell-free preparations. The assay is based on the separation and quantitation of reduced and oxidized glutathione by capillary electrophoresis. The electrophoretic separation buffer was 100 mM sodium tetraborate (pH 8.2) containing 100 mM sodium dodecylsulphate. A micellar electrokinetic mechanism took place under these conditions, and a total mass recovery was observed for both peptides. The reproducibility of migration times was excellent (less than 3% variability). A linear detector response range was observed in the range 5-50 U/ml, and both the reproducibility and accuracy were satisfied. Samples out of this linear range could be analysed by either increasing the reaction time or diluting the enzyme preparation. The results obtained with the new direct capillary electrophoresis assay were compared with those derived from a reversed phase high-performance liquid chromatographic and spectrophotometric coupled assay. A very good agreement was found between the two direct assay methods in all samples. Capillary electrophoresis is a versatile technique that allows the automation of the glutathione peroxidase assay in a reproducible manner and within a relatively short time with sufficient accuracy and precision. PMID:1430007

  12. The content of glutathione and glutathione S-transferases and the glutathione peroxidase activity in rat liver nuclei determined by a non-aqueous technique of cell fractionation.

    PubMed Central

    Soboll, S; Gründel, S; Harris, J; Kolb-Bachofen, V; Ketterer, B; Sies, H

    1995-01-01

    Hepatocellular nuclei require glutathione, glutathione S-transferases (GSTs) and Se-dependent glutathione peroxidase (GPx) for intranuclear protection against damage from electrophiles or products of active oxygen. Data so far available from the literature on nuclei isolated in aqueous systems range from glutathione, GSTs and GPx either being absent altogether to being present in quantities in excess of those in the cytoplasm. This paper describes a small-scale preparation of a nuclear fraction from rat liver by a non-aqueous technique, designed to retain nuclear water-soluble molecules in situ, since low-molecular-mass compounds can diffuse freely into other compartments during aqueous separation. This non-aqueous procedure shows the nucleus to contain glutathione at 8.4 mM and soluble GSTs at 38 micrograms/mg of protein, the enrichment over the homogenate being 1.2-1.4-fold. Se-dependent GPx activity was also present in the nucleus (56 m-units/mg), although with slightly lower activity than in the homogenate (0.7-fold). Images Figure 1 PMID:7487946

  13. Salicylic acid modulates oxidative stress and glutathione peroxidase activity in the rat colon.

    PubMed

    Drew, Janice E; Arthur, John R; Farquharson, Andrew J; Russell, Wendy R; Morrice, Philip C; Duthie, Garry G

    2005-09-15

    Oxidative stress is a characteristic of cancerous colon tissue and inflammatory bowel diseases that increase colon cancer risk. Epidemiological evidence supports a protective effect of plant-derived compounds. Aspirin is also protective against colon cancer. The mechanism of action is unclear although salicylic acid, the main metabolite of aspirin, has been shown to decrease the synthesis of pro-inflammatory and potentially neo-plastic prostaglandins. Salicylic acid is found in significant quantities in a plant-based diet. However, in plants salicylic acid is also reported to modulate the expression of numerous enzymes with antioxidant activity. The aim of this study was to assess whether salicylic acid can modulate pro-cancerous biological pathways in the colon. Oxidative stress, prostaglandins and cytosolic glutathione peroxidase (cyGPX) were analysed in proximal, transverse and distal colon from a rat model of diet-induced oxidative stress. Elevated plasma pyruvate kinase activity (1293+/-206 U/ml) and increased indices of lipid peroxidation in colon (proximal 6.4+/-0.84 nM MDA/mg protein; transverse 6.9+/-0.97 nM MDA/mg protein; distal 5.2+/-0.62 nM MDA/mg protein) from rats fed a Vitamin E deficient diet were significantly decreased on supplementation with salicylic acid (plasma pyruvate 546+/-43 U/ml; salicylic acid proximal 3.6+/-0.39 nM MDA/mg protein; transverse 4.5+/-0.61 nM MDA/mg protein; distal 4.4+/-0.27 nM MDA/mg protein). Reductions in oxidative stress and prostaglandin production on supplementation with salicylic acid were associated with an elevation in glutathione peroxidase activity (Vitamin E deficient proximal 0.056+/-0.013 U/mg protein; transverse 0.073+/-0.008 U/mg protein; distal 0.088+/-0.010 U/mg protein; Vitamin E deficient with salicylic acid proximal 0.17+/-0.01 U/mg protein; transverse 0.23+/-0.016 U/mg protein; distal 0.16+/-0.020 U/mg protein). Gpx1 and Gpx2 gene transcripts were not elevated in association with increased activity

  14. Selenium-enriched Agaricus bisporus increases expression and activity of glutathione peroxidase-1 and expression of glutathione peroxidase-2 in rat colon.

    PubMed

    Maseko, Tebo; Howell, Kate; Dunshea, Frank R; Ng, Ken

    2014-03-01

    The effect of dietary supplementation with Se-enriched Agaricus bisporus on cytosolic gluthathione peroxidase-1 (GPx-1), gastrointestinal specific glutathione peroxidase-2 (GPx-2), thioredoxin reductase-1 (TrxR-1) and selenoprotein P (SeP) mRNA expression and GPx-1 enzyme activity in rat colon was examined. Rats were fed for 5weeks with control diet (0.15μg Se/g feed) or Se-enriched diet fortified with selenised mushroom (1μg Se/g feed). The mRNA expression levels were found to be significantly (P<0.01) up-regulated by 1.65-fold and 2.3-fold for GPx-1 and GPx-2, respectively, but were not significantly different for TrxR-1 and SeP between the 2 diet treatments. The up-regulation of GPx-1 mRNA expression was consistent with GPX-1 activity level, which was significantly (P<0.05) increased by 1.77-fold in rats fed with the Se-enriched diet compared to the control diet. The results showed that selenised A. bisporus can positively increase GPx-1 and GPx-2 gene expression and GPx-1 enzyme activity in rat colon.

  15. Effect of chemical form of selenium on tissue glutathione peroxidase activity in developing rats

    NASA Technical Reports Server (NTRS)

    Lane, Helen W.; Strength, Ralph; Johnson, Janet; White, Marguerite T.

    1991-01-01

    The hypothesis that the stage of development of rats may affect the availability of various forms of selenium for the activity of glutathione peroxidase (GSHPx) in the rat was experimentally investigated. One experiment evaluated the availability of selenium as selenite or selenomethionine for GSPHx activity during three developmental states in rats: fetus and 7-day old and 14-day old nursing pups. In all tissues studied, GSHPx activity was highest in the 14-day-old pups whose dams were in the selenomethionine group. Rat pups given intraperitoneal selenite had higher liver and kidney GSHPx activity than pups given the same amount of selenium as intraperitoneal selenomethionine. In a second experiment, all dams were fed the same basal diet and pups were weaned to diets containing one of two levels of selenium and one of three forms of selenium (selenite, selenomethionine, or selenocystine). The results also supported the hypothesis these dietary forms of selenium are differentially available for GSHPx activity.

  16. Peroxiredoxin 6: A Bifunctional Enzyme with Glutathione Peroxidase and Phospholipase A2 Activities

    PubMed Central

    2011-01-01

    Abstract Peroxiredoxin 6 (Prdx6) is the prototype and the only mammalian 1-Cys member of the Prdx family. Major differences from 2-Cys Prdxs include the use of glutathione (GSH) instead of thioredoxin as the physiological reductant, heterodimerization with πGSH S-transferase as part of the catalytic cycle, and the ability either to reduce the oxidized sn-2 fatty acyl group of phospholipids (peroxidase activity) or to hydrolyze the sn-2 ester (alkyl) bond of phospholipids (phospholipase A2 [PLA2] activity). The bifunctional protein has separate active sites for peroxidase (C47, R132, H39) and PLA2 (S32, D140, H26) activities. These activities are dependent on binding of the protein to phospholipids at acidic pH and to oxidized phospholipids at cytosolic pH. Prdx6 can be phosphorylated by MAP kinases at T177, which markedly increases its PLA2 activity and broadens its pH-activity spectrum. Prdx6 is primarily cytosolic but also is targeted to acidic organelles (lysosomes, lamellar bodies) by a specific targeting sequence (amino acids 31–40). Oxidant stress and keratinocyte growth factor are potent regulators of Prdx6 gene expression. Prdx6 has important roles in both antioxidant defense based on its ability to reduce peroxidized membrane phospholipids and in phospholipid homeostasis based on its ability to generate lysophospholipid substrate for the remodeling pathway of phospholipid synthesis. Antioxid. Redox Signal. 15, 831–844. PMID:20919932

  17. Inactivation of glutathione peroxidase activity contributes to UV-induced squamous cell carcinoma formation.

    PubMed

    Walshe, Jennifer; Serewko-Auret, Magdalena M; Teakle, Ngari; Cameron, Sarina; Minto, Kelly; Smith, Louise; Burcham, Philip C; Russell, Terry; Strutton, Geoffrey; Griffin, Anthony; Chu, Fong-Fong; Esworthy, Stephen; Reeve, Vivienne; Saunders, Nicholas A

    2007-05-15

    Cutaneous squamous cell carcinomas (CSCC) are a common malignancy of keratinocytes that arise in sites of the skin exposed to excessive UV radiation. In the present study, we show that human SCC cell lines, preneoplastic solar keratoses (SK), and CSCC are associated with perturbations in glutathione peroxidase (GPX) activity and peroxide levels. Specifically, we found that two of three SKs and four of five CSCCs, in vivo, were associated with decreased GPX activity and all SKs and CSCCs were associated with an elevated peroxide burden. Given the association of decreased GPX activity with CSCC, we examined the basis for the GPX deficiency in the CSCCs. Our data indicated that GPX was inactivated by a post-translational mechanism and that GPX could be inactivated by increases in intracellular peroxide levels. We next tested whether the decreased peroxidase activity coupled with an elevated peroxidative burden might contribute to CSCC formation in vivo. This was tested in Gpx1(-/-) and Gpx2(-/-) mice exposed to solar-simulated UV radiation. These studies showed that Gpx2 deficiency predisposed mice to UV-induced CSCC formation. These results suggest that inactivation of GPX2 in human skin may be an early event in UV-induced SCC formation.

  18. A redox-dependent dimerization switch regulates activity and tolerance for reactive oxygen species of barley seed glutathione peroxidase.

    PubMed

    Navrot, Nicolas; Skjoldager, Nicklas; Bunkenborg, Jakob; Svensson, Birte; Hägglund, Per

    2015-05-01

    Monomeric and dimeric forms of recombinant barley (Hordeum vulgare subsp. vulgare) glutathione peroxidase 2 (HvGpx2) are demonstrated to display distinctly different functional properties in vitro. Monomeric HvGpx2 thus has five fold higher catalytic efficiency than the dimer towards tert-butyl hydroperoxide, but is more sensitive to inactivation by hydrogen peroxide. Treatment of the monomer with hydrogen peroxide results in dimer formation. This observed new behavior of a plant glutathione peroxidase suggests a mechanism involving a switch from a highly catalytically competent monomer to a less active, but more oxidation-resistant dimer. PMID:25796076

  19. NEW STRATEGIES FOR THE ISOLATION AND ACTIVITY DETERMINATION OF NATURALLY OCCURRING TYPE-4 GLUTATHIONE PEROXIDASE

    PubMed Central

    Kernstock, Robert M.; Girotti, Albert W.

    2008-01-01

    Type 4 glutathione peroxidase (GPx4) is a widely expressed mammalian selenoenzyme known to play a vital role in cytoprotection against lipid hydroperoxide (LOOH)-mediated oxidative stress and regulation of oxidative signaling cascades. Since prokaryotes are not equipped to express mammalian selenoproteins, preparation of recombinant GPx4 via commonly used bacterial transformation is not feasible. A published procedure for isolating the enzyme from rat testis employs affinity chromatography on bromosulfophthalein-glutathione-linked agarose as the penultimate step in purification. Since this resin is no longer commercially available and preparing it in satisfactory operational form is tedious, we have developed an alternative purification approach based on sequential anion exchange, size exclusion, and cation exchange chromatography. Final preparations were found to be essentially homogeneous in GPx4 (Mr ∼20 kDa), as demonstrated by SDS-PAGE with protein staining and immunoblotting. Specific enzymatic activity was determined using a novel thin layer chromatographic approach in which the kinetics of phosphatidylcholine hydroperoxide loss or cholesterol-7α-hydroperoxide loss were monitored. A >400-fold purification of active enzyme has been attained. The relatively straightforward isolation procedure described should prove valuable for further functional studies on GPx4, e.g. how its ability to catalyze LOOH reduction compares with that of other LOOH detoxifying enzymes. PMID:18723092

  20. The effects of selenium on glutathione peroxidase activity and radioprotection in mammalian cells

    SciTech Connect

    Diamond, A.M.; Murray, J.L.; Dale, P.; Tritz, R.; Grdina, D.J.

    1995-09-05

    The media of representative mammalian cell lines were supplemented with low levels of selenium in the form of sodium selenite in order to investigate the effects of selenium on mammalian cells. Following incubation in 30 nM sodium selenite, these cells were assayed for changes in glutathione peroxidase (GPx) activity. The cells examined included NIH 3T3 mouse fibroblasts, PC12 rat sympathetic precursor cells, SupT-1 human lymphocytes, MCF-7{sup adr} human breast carcinoma cells and AA8 Chinese hamster ovary cells. Selenium supplementation resulted in a marginal increase in GPx activity for the NIH 3T3, MCF-7{sup adr} and Supt-1 cells but stimulated GPx activity approximately 5-fold in PC12 and AA8 cells. AA8 cells were selected to evaluate whether selenium supplementation was radioprotective against {sup 60}cobalt gamma irradiation. Protection against radiation-induced mutation was measured by evaluating mutation frequency at the hprt locus. In this assay, preincubation of AA8 CHO cells significantly protected these cells from exposure to 8 Gy.

  1. The ocular inflammatory response to endotoxin is not altered when glutathione peroxidase activity is decreased

    SciTech Connect

    Grimes, A.M.; McGahan, M.C.; Smith, M.G. )

    1991-03-11

    Selenium (Se) is an essential trace element and an integral part of the enzyme glutathione peroxidase (GPx). GPx is an antioxidant which scavenges both hydroperoxide and lipid peroxides. The purpose of the current study was to determine if decreased GPx activity affects the ocular inflammatory response. New Zealand White rabbits were fed either a purified Se deficient or Se adequate diet for 9 weeks. After 9 weeks, plasma Se levels were 0.151 {plus minus} 0.0130 {mu}g/ml in the deficient diet group compared to 0.217 {plus minus} 0.015 {plus minus} 0.87 U compared with 25.43 {plus minus} 1.77 U in the basal diet group. At this point, ocular inflammation was induced by intravitreal injection of endotoxin. Twenty-four hours later, despite a 40% decrease in plasma and a 30% decrease in intraocular fluid GPx activity, there was no significant difference in inflammatory parameters between the groups. However, it is possible that a further decrease in GPx activity could have some effect on the inflammatory response.

  2. Selenium levels and Glutathione peroxidase activity in the plasma of patients with type II diabetes mellitus.

    PubMed

    González de Vega, Raquel; Fernández-Sánchez, María Luisa; Fernández, Juan Carlos; Álvarez Menéndez, Francisco Vicente; Sanz-Medel, Alfredo

    2016-09-01

    Selenium, an essential trace element, is involved in the complex system of defense against oxidative stress through selenium-dependent glutathione peroxidases (GPx) and other selenoproteins. Because of its antioxidant properties, selenium or its selenospecies at appropriate levels could hinder oxidative stress and so development of diabetes. In this vein, quantitative speciation of selenium in human plasma samples from healthy and diabetic patients (controlled and non-controlled) was carried out by affinity chromatography (AF) coupled on-line to inductively coupled plasma mass spectrometry (ICP-MS) and isotope dilution analysis (IDA). Similarly, it is well known that patients with diabetes who exhibit poor control of blood glucose show a decreased total antioxidant activity. Thus, we evaluated the enzymatic activity of GPx in diabetic and healthy individuals, using the Paglia and Valentine enzymatic method, observing a significant difference (p<0.05) between the three groups of assayed patients (healthy (n=24): 0.61±0.11U/ml, controlled diabetic (n=38): 0.40±0.12U/ml and non-controlled diabetic patients (n=40): 0.32±0.09U/ml). Our results show that hyperglycemia induces oxidative stress in diabetic patients compared with healthy controls. What is more, glycation of GPx experiments demonstrated that it is the degree of glycation of the selenoenzyme (another species of the Se protein) what actually modulates its eventual activity against ROS in type II diabetes mellitus patients. PMID:27473831

  3. Unglycosylated recombinant human glutathione peroxidase 3 mutant from Escherichia coli is active as a monomer.

    PubMed

    Song, Jian; Yu, Yang; Xing, Ruiqing; Guo, Xiao; Liu, Dali; Wei, Jingyan; Song, Hongwei

    2014-01-01

    Glutathione peroxidase 3 (GPx3) is a glycosylated member of GPx family and can catalyze the reaction of different types of peroxides with GSH to form their corresponding alcohols in vitro. The active center of GPx3 is selenocysteine (Sec), which is incorporated into proteins by a specific mechanism. In this study, we prepared a recombinant human GPx3 (rhGPx3) mutant with all Cys changed to Ser from a Cys auxotrophic strain of E. coli, BL21(DE3)cys. Although lacking post-translational modification, rhGPx3 mutant still retained the ability to reduce H2O2 and PLPC-OOH. Study on the quaternary structure suggested that rhGPx3 mutant existed as a monomer in solution, which is different from native tetrameric GPx3. Loss of the catalytic activity was considered to be attributed to both the absence of glycosylation and the failure of the tetramer. Further analysis was performed to compare the structures of rhGPx3 and GPx4 mutant, which were quite similar except for oligomerization loop. The differences of amino acid composition and electrostatic potentials on the oligomerization loop may affect the binding of large substrates to rhGPx3 mutant. This research provides an important foundation for biosynthesis of functionally selenium-containing GPx3 mutant in E.coli. PMID:25331785

  4. Measurement of malondialdehyde, glutathione, and glutathione peroxidase in SLE patients.

    PubMed

    Gheita, Tamer A; Kenawy, Sanaa A

    2014-01-01

    Oxidative stress contributes to chronic inflammation of tissues and plays a central role in immunomodulation, which may lead to autoimmune diseases such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome. Markers of oxidative damage include malondialdehyde (MDA), antioxidant scavengers as glutathione (GSH), and glutathione peroxidase (GSH Px), which all correlate well with SLE disease activity. Amelioration of some clinical manifestations of SLE may be expected by targeting lipid peroxidation with dietary or pharmacological antioxidants. Here, we describe the detection of the key players of oxidant/antioxidant imbalance in SLE.

  5. Selenium concentrations and glutathione peroxidase activities in blood of patients before and after allogenic kidney transplantation.

    PubMed

    Zachara, Bronisław A; Włodarczyk, Zbigniew; Masztalerz, Marek; Adamowicz, Andrzej; Gromadzinska, Jolanta; Wasowicz, Wojciech

    2004-01-01

    In animals and humans, the highest level of selenium (Se) occurs in the kidney. This organ is also the major site of the synthesis of the selenoenzyme glutathione peroxidase (GSH-Px). Decreased Se levels and GSH-Px activities in blood are common symptoms in the advanced stage of chronic renal failure (CRF). Blood samples for Se levels and GSH-Px activities measurements from patients were collected just before transplantation and 3, 7, 14, 30, and 90 d posttransplant. The Se levels in whole blood and plasma of patients before transplantation (79.5 and 64.5 ng/mL, respectively) were lower by 23% and 21%, respectively, as compared with controls (p < 0.0001), and 7 d after operation, it further decreased in both components (p < 0.01). Fourteen days after surgery, the levels reached the initial values and increased slowly in the later period. Red blood cell GSHPx activity in patients in the entire period of the study did not differ from the control group. Plasma GSH-Px of patients before the surgery was extremely low (76 U/L) as compared with controls (243 U/L; p < 0.0001) but increased rapidly to 115 U/L after 3 d, to 164 U/L after 14 d, and to 208 U/L after 3 mo posttransplant. In CRF patients, after kidney transplantation, plasma GSH-Px activity increased rapidly, approaching, after 3 mo, the values that were close to the normal levels. A negative correlation between creatinine level and plasma GSH-Px activity is observed in patients after kidney transplantation. Monitoring of plasma GSH-Px activity may be a useful additional marker of the transplanted kidney function. PMID:14742896

  6. Glutathione peroxidase activity, selenium, and lipid peroxide concentrations in blood from a healthy Polish population : I. Maternal and cord blood.

    PubMed

    Zachara, B A; Wąsowicz, W; Gromadzińska, J; Skłodowska, M; Krasomski, G

    1986-09-01

    Selenium (Se) concentrations in whole blood and plasma of 19 nonpregnant women. 14 mothers at delivery, 14 neonates, and 13 infants, aged 2-12 mo, were evaluated. The activity of glutathione peroxidase (GSH-Px) in erythrocytes and plasma and the level of lipid peroxides in plasma were also analyzed. Selenium concentrations in whole blood and plasma in mothers at delivery were significantly lower compared to nonpregnant women. Selenium concentrations in cord blood components were lower compared to mothers, but the differences were not significant. The concentration of the element decreased in the first few months of life. Glutathione peroxidase activity in erythrocytes differed only slightly in the examined groups. In plasma, however, the enzyme activity was significantly lower in pregnant compared to nonpregnant women and in neonates compared to their mothers. Lipid peroxide concentrations in plasma differed only slightly in the examined groups. The results obtained are discussed in terms of the observations of other investigators. PMID:24254392

  7. Effect of N-methyl-D-aspartic acid on activity of superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione level in selected organs of the mouse.

    PubMed

    Szaroma, Waldemar; Dziubek, K; Kapusta, E

    2014-09-01

    One of the major classes of ionotropic glutamate receptors is the class of N-methyl-D-aspartate receptors (NMDARs). Receptor activation recruits, via calcium signal transduction mechanisms which play important roles in oxidative metabolism, mitochondrial free radical production and occurrence of other mitochondrial factors which potentially contribute to excitotoxicity and neuronal death. In the present study, the effects of stimulation of NMDARs by applying N-methyl-D-aspartic acid (NMDA) in the brain, liver, kidneys and pancreas on change of the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx) and in the amount of reduced glutathione (GSH) in blood, brain, liver and kidneys has been investigated. Statistically significant decrease of the activity of SOD, CAT and GSHPx and in the amount of reduced glutathione (GSH) was found in the examined organs after administration of NMDA, an agonist of NMDA receptors, demonstrating that NMDA administration compromises the antioxidant status in the investigated organs of the mouse.

  8. Selenium status, lipid peroxides concentration, and glutathione peroxidase activity in the blood of power station and rubber factory workers.

    PubMed

    Zachara, B A; Wasowicz, W; Sklodowska, M; Gromadzinska, J

    1987-01-01

    Concentration of selenium in whole blood and plasma, lipid peroxides in plasma, and glutathione peroxidase activities in red blood cell hemolysates and plasma were determined in 49 coal power plant workers and in 50 rubber factory workers. The results were compared with those obtained for 58 nonindustrial controls. Whole blood selenium was significantly lower and plasma lipid peroxides were significantly higher in power plant workers when compared to the nonindustrial group. In the rubber factory workers, whole blood selenium and red blood cells and plasma glutathione peroxidase activities were significantly lower than in the control group. Urinary output of selenium was also significantly decreased in rubber factory workers. Slightly elevated lipid peroxides were also observed in that group. It seems reasonable to conclude that the lower blood selenium and decreased urinary output of this element may result from increased loss of selenium with perspiration. No correlation has been observed between selenium concentration and glutathione peroxidase activity and between enzyme activity and lipid peroxides concentration in the industrial group.

  9. Glutathione peroxidase activity and chemical forms of selenium in tissues of rats given selenite or selenomethionine

    SciTech Connect

    Beilstein, M.A.; Whanger, P.D.

    1988-05-01

    Glutathione peroxidase (GPx) activity and deposition of selenium (Se) were examined in tissues of rats given dietary Se for 7 wk as either selenite or selenomethionine (SeMet) with 75Se radiotracer of the same chemical form. On the basis of Se:75Se ratio, all tissues of the rats fed selenite were equilibrated with the dietary source, but tissues of the SeMet fed animals maintained a ratio of Se:75Se greater than the dietary ratio. Deposition of dietary Se and 75Se was higher in most tissues of rats fed SeMet. Muscle 75Se was the largest single tissue pool of 75Se in both groups accounting for one-third of recovered 75Se in the rats fed selenite, and one-half of recovered 75Se in the rats fed SeMet. Tissue GPx activities were not different between the two dietary groups. The proportion of Se as GPx in tissues was highest in erythrocytes of the rats fed selenite (.81) and lowest in testes and epididymides of the rats fed SeMet (.009). The proportion of Se present in cytosolic GPx was consistently higher in tissues of rats fed selenite. Erythrocytes of the rats fed SeMet had more 75Se associated with hemoglobin, and muscle cytosols of the rats fed selenite had more 75Se associated with the G-protein. The proportion of 75Se as SeMet determined by ion exchange chromatography of tissue hydrolysates was higher in tissues of rats fed SeMet (highest in muscle and hemoglobin, 70%, and lowest in testes, 16%). In contrast, selenocysteine was the predominant form of Se present in tissues of rats given selenite. These results indicate that the form of Se administered will influence the form in the tissues, the percentage of Se with GPx and the body burden of Se.

  10. Lack of glutathione peroxidase-1 facilitates a pro-inflammatory and activated vascular endothelium.

    PubMed

    Sharma, Arpeeta; Yuen, Derek; Huet, Olivier; Pickering, Raelene; Stefanovic, Nada; Bernatchez, Pascal; de Haan, Judy B

    2016-04-01

    A critical early event in the pathogenesis of atherosclerosis is vascular inflammation leading to endothelial dysfunction (ED). Reactive oxygen species and inflammation are inextricably linked and declining antioxidant defense is implicated in ED. We have previously shown that Glutathione peroxidase-1 (GPx1) is a crucial antioxidant enzyme in the protection against diabetes-associated atherosclerosis. In this study we aimed to investigate mechanisms by which lack of GPx1 affects pro-inflammatory mediators in primary aortic endothelial cells (PAECs) isolated from GPx1 knockout (GPx1 KO) mice. Herein, we demonstrate that lack of GPx1 prolonged TNF-α induced phosphorylation of P38, ERK and JNK, all of which was reversed upon treatment with the GPx1 mimetic, ebselen. In addition, Akt phosphorylation was reduced in GPx1 KO PAECs, which correlated with decreased nitric oxide (NO) bioavailability as compared to WT PAECs. Furthermore, IκB degradation was prolonged in GPx1 KO PAECS suggesting an augmentation of NF-κB activity. In addition, the expression of vascular cell adhesion molecule (VCAM-1) was significantly increased in GPx1 KO PAECs and aortas. Static and dynamic flow adhesion assays showed significantly increased adhesion of fluorescently labeled leukocytes to GPx1 KO PAECS and aortas respectively, which were significantly reduced by ebselen treatment. Our results suggest that GPx1 plays a critical role in regulating pro-inflammatory pathways, including MAPK and NF-κB, and down-stream mediators such as VCAM-1, in vascular endothelial cells. Lack of GPx1, via effects on p-AKT also affects signaling to eNOS-derived NO. We speculate based on these results that declining antioxidant defenses as seen in cardiovascular diseases, by failing to regulate these pro-inflammatory pathways, facilitates an inflammatory and activated endothelium leading to ED and atherogenesis. PMID:26569096

  11. Arsenic trioxide and reduced glutathione act synergistically to augment inhibition of thyroid peroxidase activity in vitro.

    PubMed

    Palazzolo, Dominic L; Ely, Emily A

    2015-05-01

    Thyroid peroxidase (TPO) is the enzyme involved in thyroid hormone synthesis. Arsenic trioxide (As2O3) is known to inhibit TPO activity in vitro. This inhibition is believed to occur when As2O3 binds to TPO's free sulfhydryl groups. Reduced glutathione (GSH) is also known to inhibit TPO activity in vitro. This inhibition may occur because GSH acts as a competitive substrate for hydrogen peroxide, or possibly reduce the oxidized form of iodide, requirements for TPO action. On the other hand, one could speculate that GSH reduces arsenic-induced TPO inhibition by interacting directly with arsenic or TPO, consequently limiting arsenic's ability to inhibit TPO activity. Since GSH is known to inhibit thyroid hormone synthesis while at the same time it is also known to be an important antioxidant preventing cellular damage induced by oxidative stress and protecting the thyroid gland from oxidative damage induced by arsenic, we wanted to determine if a combination of As2O3 and reduced GSH would either attenuate or augment the As2O3-induced inhibition on TPO activity. Using an in vitro system, TPO was assayed spectrophotometrically in the presence of As2O3 (0.01, 0.1, 1, and 10 ppm), GSH (0.1, 1, 5, and 10 ppm), and As2O3 (0.1 ppm) and GSH (0.01, 0.1, 1, or 10 ppm) combinations. Our results show that 0.1, 1.0, and 10 ppm As2O3 inhibit TPO activity. Similarly, 5 and 10 ppm GSH also inhibit TPO activity. When 0.1 ppm As2O3 (i.e., the lowest dose of arsenic able to partially inhibit TPO activity) is combined with 0.01, 0.1, 1.0, or 10 ppm GSH inhibition of in vitro TPO activity is augmented as indicated by complete inhibition of TPO. The mechanism of this augmentation and whether it translates to living systems remains unclear.

  12. Selenium supplementation on plasma glutathione peroxidase activity in patients with end-stage chronic renal failure.

    PubMed

    Zachara, Bronisław A; Koterska, Dominika; Manitius, Jacek; Sadowski, Leszek; Dziedziczko, Andrzej; Salak, Anna; Wasowicz, Wojciech

    2004-01-01

    Patients with chronic renal failure (CRF) usually have a lower than healthy level of selenium (Se) in whole blood and plasma. Plasma glutathione peroxidase (GSH-Px) is synthesized mostly in the kidney. In CRF patients, activity of this enzyme is significantly reduced and its reduction increases with the progress of the disease. The aim of the study was to evaluate the effect of Se supplementation to CRF patients at various stages of the disease on Se concentration in blood components and on plasma GSHPx activity. The study group comprised 53 CRF patients at various stages of the disease supplemented with Se (200 microg/d for 3 mo as Se-enriched yeast, containing about 70% L-selenomethionine [SeMet]). The control group consisted of 20 healthy subjects. The Se concentration in blood components was measured spectrofluorometrically with 2,3-diaminonaphthalene as a complexing reagent. GSH-Px activity in red cell hemolysates and plasma was assayed by the coupled method with tert-butyl hydroperoxide as a substrate. The Se concentration in whole blood and plasma of CRF patients is significantly lower as compared with healthy subjects, but similar at all stages of the disease. In the patients' plasma, total protein and albumin levels are also significantly lower than in healthy subjects. Plasma GSH-Px activity in patients is extremely low, and contrary to Se concentration, it decreases linearly with the increasing stage of the illness. Se-supplied patients show an increased Se concentration in all blood components and at all disease stages, whereas plasma GSH-Px activity is enhanced only at the incipient stage of the disease. Se supply has no effect on plasma GSHPx activity in uremic patients at the end stage of the disease. Total plasma protein and albumin levels did not change after Se supplementation. Our data seem to show that in patients with CRF lower total protein and albumin levels in plasma may be the chief cause of the low blood and plasma Se concentrations. GSH

  13. Selenium, glutathione peroxidase and other selenoproteins

    SciTech Connect

    Wilhelmsen, E.C.

    1983-01-01

    Selenium, as essential trace element, has long been associated with protein. The essentiality of selenium is partially understood as glutathione peroxidase contains an essential selenocysteine. Glutathione peroxidase has been purified from many tissues including rat liver. An estimated molecular weight of 105,000 was obtained for glutathione peroxidase by comparison to standards. A subunit size of 26,000 was obtained by SDS-gel electrophoresis. Glutathione peroxidase is not the only selenoprotein in the rat. In seven rat tissues examined, there were many different subunit sizes and change groups representing between 9 and 23 selenoproteins. Selenocysteine in glutathione peroxidase accounts for ca. 36% of the selenium in the rat. The mode of synthesis of glutathione peroxidase and the other selenoproteins is not understood. Glutathione peroxidase is strongly and reversibly inhibited by mercaptocarboxylic acids and other mercaptans, including some used as slow-acting drugs for the symtomatic treatment of rheumatoid arthritis. The mechanism and chemistry of this inhibition is discussed. This inhibition may provide a link between selenium and arthritis.

  14. Catalase and glutathione peroxidase are equally active in detoxification of hydrogen peroxide in human erythrocytes

    SciTech Connect

    Gaetani, G.F.; Galiano, S.; Canepa, L.; Ferraris, A.M.; Kirkman, H.N.

    1989-01-01

    Genetic deficiencies of glucose-6-phosphate dehydrogenase (G6PD) and NADPH predispose affected erythrocytes to destruction from peroxides. Conversely, genetic deficiencies of catalase do not predispose affected erythrocytes to peroxide-induced destruction. These observations have served to strengthen the assumption that the NADPH/glutathione/glutathione peroxidase pathway is the principal means for disposal of H/sub 2/O/sub 2/ in human erythrocytes. Recently, however, mammalian catalase was found to have tightly bound NADPH and to require NADPH for the prevention and reversal of inactivation by its toxic substrate (H/sub 2/O/sub 2/). Since both catalase and the glutathione pathway are dependent on NADPH for function, this finding raises the possibility that both mechanisms destroy H/sub 2/O/sub 2/ in human erythrocytes. A comparison of normal and acatalasemic erythrocytes in the present study indicated that catalase accounts for more than half of the destruction of H/sub 2/O/sub 2/ when H/sub 2/O/sub 2/ is generated at a rate comparable to that which leads to hemolysis in G6PD- deficient erythrocytes.

  15. Glutathione peroxidase and catalase modulate the genotoxicity of arsenite.

    PubMed

    Wang, T S; Shu, Y F; Liu, Y C; Jan, K Y; Huang, H

    1997-09-01

    The X-ray hypersensitive Chinese hamster ovary (CHO) cells, xrs-5, are also more sensitive to sodium arsenite in terms of cell growth and micronucleus induction than CHO-K1 cells. Since reactive oxygen species are suggested to be involved in arsenic toxicity, we have measured antioxidant mechanisms in xrs-5 as well as CHO-K1 cells. There were no apparent differences in the activities of superoxide dismutase, glutathione S-transferase, glutathione reductase, and the levels of glutathione between xrs-5 and CHO-K1 cells. However, the activities of glutathione peroxidase and catalase were 5.4- and 5.8-fold lower, respectively, in xrs-5 cells. The addition of catalase or glutathione peroxidase to cultures reduced the arsenite-induced micronuclei in xrs-5 cells. Whereas, simultaneous treatment with mercaptosuccinate, an inhibitor of glutathione peroxidase, and 3-aminotriazole, an inhibitor of catalase, synergistically increased the arsenite-induced micronuclei. These results suggest that both catalase and glutathione peroxidase are involved in defense against arsenite genotoxicity. The xrs-6 cells, another line of x-ray hypersensitive CHO cells, which had 1.6-fold higher catalase activity and 2.5-fold higher glutathione peroxidase activity than xrs-5 cells, were also more sensitive than CHO-K1 cells but were less sensitive than xrs-5 cells to cell growth inhibition of arsenite. Moreover, a 1.6-fold increase of glutathione peroxidase activity by selenite adaptation effectively removed the arsenite-induced micronuclei in CHO-K1 cells. These results suggest that glutathione peroxidase is more important than catalase in defending against arsenite toxicity. Our results also suggest that increasing the intracellular antioxidant level may have preventive or therapeutic effects in arsenic poisoning.

  16. Chemical form of selenium affects its uptake, transport, and glutathione peroxidase activity in the human intestinal Caco-2 cell model.

    PubMed

    Zeng, Huawei; Jackson, Matthew I; Cheng, Wen-Hsing; Combs, Gerald F

    2011-11-01

    Determining the effect of selenium (Se) chemical form on uptake, transport, and glutathione peroxidase activity in human intestinal cells is critical to assess Se bioavailability at nutritional doses. In this study, we found that two sources of L-selenomethionine (SeMet) and Se-enriched yeast each increased intracellular Se content more effectively than selenite or methylselenocysteine (SeMSC) in the human intestinal Caco-2 cell model. Interestingly, SeMSC, SeMet, and digested Se-enriched yeast were transported at comparable efficacy from the apical to basolateral sides, each being about 3-fold that of selenite. In addition, these forms of Se, whether before or after traversing from apical side to basolateral side, did not change the potential to support glutathione peroxidase (GPx) activity. Although selenoprotein P has been postulated to be a key Se transport protein, its intracellular expression did not differ when selenite, SeMSC, SeMet, or digested Se-enriched yeast was added to serum-contained media. Taken together, our data show, for the first time, that the chemical form of Se at nutritional doses can affect the absorptive (apical to basolateral side) efficacy and retention of Se by intestinal cells; but that, these effects are not directly correlated to the potential to support GPx activity.

  17. Enhanced Glutathione Peroxidase Activity of Water-Soluble and Polyethylene Glycol-Supported Selenides, Related Spirodioxyselenuranes, and Pincer Selenuranes.

    PubMed

    McNeil, Nicole M R; Press, David J; Mayder, Don M; Garnica, Pablo; Doyle, Lisa M; Back, Thomas G

    2016-09-01

    Diaryl selenides containing o-hydroxymethylene substituents function as peroxide-destroying mimetics of the antioxidant selenoenzyme glutathione peroxidase (GPx), via oxidation to the corresponding spirodioxyselenuranes with hydrogen peroxide and subsequent reduction back to the original selenides with glutathione. Parent selenides with 3-hydroxypropyl or 2,3-dihydroxypropyl groups produced the novel compounds 10 and 11, respectively, with greatly improved aqueous solubility and catalytic activity. The phenolic derivative 28 displayed similarly ameliorated properties and also modest radical-inhibiting antioxidant activity, as evidenced by an assay based on phenolic hydrogen atom transfer to the stable free radical DPPH. In contrast, several selenides that afford pincer selenuranes (e.g., 20 and 21) instead of spiroselenuranes upon oxidation showed inferior catalytic activity. Several selenide analogues were attached to polyethylene glycol (PEG) oligomers, as PEG substituents can improve water solubility and bioavailability, while retarding clearance. Again, the PEG derivatives afforded remarkable activity when oxidation generated spirodioxyselenuranes and diminished activity when pincer compounds were produced. Several such compounds proved to be ca. 10- to 100-fold catalytically superior to the diaryl selenides and their spirodioxyselenurane counterparts investigated previously. Finally, an NMR-based assay employing glutathione in D2O was designed to accommodate the faster reacting water-soluble mimetics and to more closely duplicate in vivo conditions. PMID:27525346

  18. Brazilian nut consumption improves selenium status and glutathione peroxidase activity and reduces atherogenic risk in obese women.

    PubMed

    Cominetti, Cristiane; de Bortoli, Maritsa C; Garrido, Arthur B; Cozzolino, Silvia M F

    2012-06-01

    Studies have shown that there are inverse relationships between nut consumption and the reduction of cardiovascular risk. This study tested the hypothesis that daily consumption of Brazilian nuts would have a positive effect upon selenium (Se) status, erythrocyte glutathione peroxidase activity, lipid profile, and atherogenic risk in severely obese women. Thirty-seven severely obese women each consumed 1 Brazilian nut a day (290 μg of Se a day) for 8 weeks. Blood Se concentrations, total erythrocyte glutathione peroxidase activity, lipid profile, and Castelli I and II indexes were evaluated before and after the nuts consumption. All the patients were Se deficient at baseline; this deficiency was remedied by the consumption of the Brazilian nut (P < .0001). The intake of Brazilian nuts promoted a significant increase in high-density lipoprotein cholesterol concentrations (P < .00001), which then resulted in a significant improvement of the Castelli I (P < .0002) and II (P < .0004) indexes. This study shows that obese people who implement daily consumption of Brazilian nuts can improve both Se status and lipid profile, especially high-density lipoprotein cholesterol levels, thereby reducing cardiovascular risks.

  19. Glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase in tissues of Balb/C mice

    SciTech Connect

    Spallholz, J.E.; Roveri, A.; Yan, L.; Boylan, L.M.; Kang, C.R.; Ursini, F. Univ. of Padua )

    1991-03-11

    The two selenium (Se) enzymes glutathione peroxidase (GPx) and phospholipid hydroperoxide glutathione peroxide (PHGPx) were assayed in tissues and organ homogenates of female Balb/C mice fed torula yeast diets containing 0.008, 0.2 and 1.0 ug/g Se as selenite for nine months. GPx activity was detected in all tissues and organs whereas PHGPx activity was not detectable in lung, large intestine, eye or thymus tissue. GPx activity nearly always exceeded PHGPx activity when tissues or organs contained both enzymes irrespective of dietary Se treatment. GPx activity in tissues was generally more susceptible to the dietary Se deficiency than was PHGPx activity when expressed as a percentage of the activity found in tissues and organs of mice fed supplemented Se diets. This limited study suggests that dietary Se may be more valued in supporting PHGPx activity than GPx activity in the course of a protracted dietary Se deficiency.

  20. Selenite-induced variation in glutathione peroxidase activity of three mammalian cell lines: no effect on radiation-induced cell killing or DNA strand breakage

    SciTech Connect

    Sandstroem, B.E.C.; Carlsson, J.; Marklund, S.L.

    1989-02-01

    The selenium-dependent glutathione peroxidase activities of three mammalian cell lines, HT29, P31, and N-18, cultured in medium with low serum content, increased about 2-, 5-, and 40-fold, respectively, after supplementation with 100 nM selenite. Catalase, CuZn superoxide dismutase, and Mn superoxide dismutase activities were not generally influenced by selenite supplementation, and there was only a minor nonselenium-dependent glutathione peroxidase activity in the investigated cell lines. Gamma-irradiated control and selenite-supplemented cells showed no changes in the surviving fractions, as estimated by clonogenic survival or (/sup 3/H)-thymidine uptake, nor were there any significant differences between the two groups in the induction of DNA strand breaks after gamma irradiation under repairing (37 degrees C) or nonrepairing (0 degrees C) conditions. The results suggest that selenium-dependent glutathione peroxidase does not contribute significantly to the radiation resistance of cultured mammalian cells.

  1. Catalase and glutathione peroxidase mimics

    PubMed Central

    Day, Brian J.

    2009-01-01

    Overproduction of the reactive oxygen species (ROS) superoxide (O2−) and hydrogen peroxide (H2O2) are increasingly implicated in human disease and aging. ROS are also being explored as important modulating agents in a number of cell signaling pathways. Earlier work has focused on development of small catalytic scavengers of O2−, commonly referred to as superoxide dismutase (SOD) mimetics. Many of these compounds also have substantial abilities to catalytically scavenge H2O2 and peroxynitrite (ONOO−). Peroxides have been increasingly shown to disrupt cell signaling cascades associated with excessive inflammation associated with a wide variety of human diseases. Early studies with enzymatic scavengers like SOD frequently reported little or no beneficial effect in biologic models unless SOD was combined with catalase or a peroxidase. Increasing attention has been devoted to developing catalase or peroxidase mimetics as a way to treat overt inflammation associated with the pathophysiology of many human disorders. This review will focus on recent development of catalytic scavengers of peroxides and their potential use as therapeutic agents for pulmonary, cardiovascular, neurodegenerative and inflammatory disorders. PMID:18948086

  2. Effect of Selenium Supplementation on Glutathione Peroxidase Enzyme Activity in Patients With Chronic Kidney Disease: A Randomized Clinical Trial

    PubMed Central

    Sedighi, Omid; Zargari, Mehryar; Varshi, Gharmohammad

    2014-01-01

    Background: Plasma selenium (Se) concentration and glutathione peroxidase (GSH-Pxs) enzyme activity of the patients with chronic kidney disease (CKD) are usually lower than healthy individuals; however, the effect of Se supplementation on the GSH-Pxs activity in those patients remains unclear. Objectives: This study aimed to assess the effect of Se supplementation on plasma Se concentration and red blood cell (RBC) GSH-Pxs activity in patients with different stages of CKD. Patients and Methods: In this randomized clinical trial, forty-five patients with CKD who attended in a nephrology clinic were recruited. The patients were randomly allocated into three groups according to their creatinine clearance rate and were supplemented with daily Se 200 mcg for three months. Plasma Se concentration and RBC GSH-Pxs activity were measured in each patient at the beginning and at the end of the study. This clinical trial was registered in the Iranian Registry of Clinical Trials (www.irct.ir) with registration number ID of IRCT201305318501N2. Results: Plasma Se concentration and RBC GSH-Pxs activity increased significantly in all three groups of patients with CKD (P < 0.05). There were no significant differences between three groups regarding baseline plasma Se (P = 0.268) and RBC GSH-Pxs activity (P = 0.741). Conclusions: Se supplementation can increase plasma Se concentration and RBC GSH-Pxs activity in patients with different stages of CKD. PMID:25032143

  3. Selenium-Enriched Foods Are More Effective at Increasing Glutathione Peroxidase (GPx) Activity Compared with Selenomethionine: A Meta-Analysis

    PubMed Central

    Bermingham, Emma N.; Hesketh, John E.; Sinclair, Bruce R.; Koolaard, John P.; Roy, Nicole C.

    2014-01-01

    Selenium may play a beneficial role in multi-factorial illnesses with genetic and environmental linkages via epigenetic regulation in part via glutathione peroxidase (GPx) activity. A meta-analysis was undertaken to quantify the effects of dietary selenium supplementation on the activity of overall GPx activity in different tissues and animal species and to compare the effectiveness of different forms of dietary selenium. GPx activity response was affected by both the dose and form of selenium (p < 0.001). There were differences between tissues on the effects of selenium supplementation on GPx activity (p < 0.001); however, there was no evidence in the data of differences between animal species (p = 0.95). The interactions between dose and tissue, animal species and form were significant (p < 0.001). Tissues particularly sensitive to changes in selenium supply include red blood cells, kidney and muscle. The meta-analysis identified that for animal species selenium-enriched foods were more effective than selenomethionine at increasing GPx activity. PMID:25268836

  4. Blood and tissue selenium concentrations and glutathione peroxidase activities in patients with prostate cancer and benign prostate hyperplasia.

    PubMed

    Zachara, B A; Szewczyk-Golec, K; Tyloch, J; Wolski, Z; Szylberg, T; Stepien, S; Kwiatkowski, S; Bloch-Boguslawska, E; Wasowicz, W

    2005-01-01

    Prostate cancer (PC) is the most common cancer in men and a leading cause of cancer death. Prostatic gland accumulates reasonably high amount of selenium (Se), the element that prevents the development of PC. It is hypothesized that some selenoproteins inhibit the transformation of normal prostate epithelium into neoplasm. We studied Se levels in whole blood, plasma and prostate of 32 PC and 40 benign prostate hyperplasia (BPH) patients and in the control group composed of 39 healthy subjects. The selenoenzyme glutathione peroxidase (GSH-Px) was also measured in the patients' red cells, plasma and prostate tissue. Se concentration in whole blood and plasma in both groups of patients was lower as compared with controls, while in prostate gland it was significantly higher in PC than in BPH patients and controls. Red cell GSH-Px activity was the same in PC patients and controls but significantly lower in BPH patients. Plasma GSH-Px activity was significantly lower in PC patients than in the control group, and prostate GSH-Px activity was significantly lower in PC patients as compared with BPH patients. Since Se has anticancer properties, it is very likely that its low level in blood may facilitate the development of cancer. A higher level of Se in prostate of PC patients has no influence on GSH-Px activity in the gland. PMID:15875088

  5. Glutathione peroxidase activity in a healthy Canadian population. Effects of age, smoking and drinking habits, exercise and oral contraceptive use.

    PubMed

    L'abbe, M R; Collins, M W; Trick, K D; Laffey, P J

    1992-01-01

    The activity of the enzyme glutathione peroxidase (SeGSHPx) has been suggested as an indicator of selenium status. The purpose of this study was to measure the activity of this enzyme in a large sample of healthy, free-living Canadians to determine normal distributions and the effects of age, smoking, and drinking habits, exercise, and the use of oral contraceptives (OCs) or estrogen replacement therapy. The population consisted of 386 self-selected subjects between the ages of 24 and 75. Erythrocyte SeGSHPx activity was 21.5 +or- 7 (Mean +or- SD) and 33.6 +or- 8U/g Hb and plasma activity was 226 +or- 31 and 214 +or- 38 U/L for males (n=239) and females (n=147), respectively. Erythrocyte activity was significantly higher in females and males (p0.01). The Se form of GSHPx accounted for 76% and 54% of total activity in plasma and erythrocytes, respectively. No differences due to age were seen in males, although plasma SeGSHPx, non-SeGSHPx, and total GSHPx activities were elevated in females 65 years of age and older. Cigarette smoking significantly elevated erythrocyte SeGSHPx and total activity in male subjects. This elevation did not vary with the amount smoked and was not seen in ex-smokers. Drinking elevated erythrocyte non-SeGSHPx and total activity in male subjects with the highest activity seen in drinkers who also smoked. No significant differences were seen with level of exercise except for a slight elevation with vigorous exercise. Estrogen use significantly elevated erythrocyte SeGSHPx, non-SeGSHPx, and total activities in both pre- and postmenopausal women. These data suggest that some lifestyle factors can have small but significant effects of GSHPx activity and must be controlled for when population-based surveys are being conducted.

  6. Oxidative status, in vitro iron-induced lipid oxidation and superoxide dismutase, catalase and glutathione peroxidase activities in rhea meat.

    PubMed

    Terevinto, A; Ramos, A; Castroman, G; Cabrera, M C; Saadoun, A

    2010-04-01

    Rhea (Rhea americana) muscles Obturatorius medialis (OM) Iliotibialis lateralis (IL) and Iliofibularis (I), obtained from farmed animals, were evaluated regarding their oxidative/antioxidant status. The mean level of thiobarbituric acid reactive substances (TBARS) expressed as malonaldehyde (MDA) content was of 0.84 mg MDA/kg wet tissue for the three muscles. TBARS level was significantly higher in IL than OM and I, with the two latter showing similar levels. The mean level of carbonyl proteins expressed as dinitrophenylhydrazine (DNPH) was 1.59 nmol DNPH mg(-1). Carbonyl protein levels were significantly different (P<0.05) between the three muscles (IL>OM>I). Iron-induced TBARS generation was not significantly different between the three muscles at any time, nor for each muscle during the 5 h of the experiment. Superoxide dismutase activity in IL muscle was significantly higher (P<0.05) than in I muscle. However, the difference between IL and OM muscles was not significant. The differences between the three muscles became not significant when the results were expressed by mg of protein contained in the extract, instead by g of wet tissue. No differences were found for catalase (micromol of discomposed H(2)O(2) min(-1) g(-1) wet tissue or by mg of protein contained in the extract) and glutathione peroxidase (micromol ol of oxidized NADPH min(-1) g(-1) of wet tissue or by mg of protein contained in the extract) activities between the three muscles.

  7. Relationships between silicon content and glutathione peroxidase activity in tissues of rats receiving lithium in drinking water.

    PubMed

    Kiełczykowska, Małgorzata; Musik, Irena; Pasternak, Kazimierz

    2008-02-01

    Lithium salts are widely used in psychiatry, but their presence in organism can result in both beneficial and adverse effects. Silicon, the third most abundant trace element in humans as well as antioxidant enzyme glutathione peroxidase (GPx) play important roles in organism. The disturbance of their level can cause severe disorders. The aim of our work was to evaluate the influence of Li2CO3 administration in drinking water for a period of 4 weeks on Si content and GPx activity in the tissues of liver, kidney, brain and femoral muscle in rats. The concentrations of provided solutions were 0.7, 1.4, 2.6, 3.6, 7.1 and 10.7 mmol Li+ x dm-3. GPx activity was decreased versus control as a consequence of Li treatment, particularly in kidney and brain. This effect could be suggested to contribute to renal abnormalities which could occur during Li therapy. Si tissue level was significantly enhanced versus control in liver and femoral muscle in groups receiving high Li doses. In brain no well-marked changes were observed, whereas in kidney we observed the depletion in low-Li-groups, restoration of Si level in higher-Li-groups and unexpected decrease in the highest-Li-group. Positive correlations between Si content and GPx activity in the tissues of kidney (r = 0.677) and brain (r = 0.790) as well as negative correlation (r = -0.819) in femoral muscle were found. We consider that our results give some reason for suggesting that monitoring of silicon level in patients undergoing Li therapy could be recommended. However, more investigations should be performed, particularly regarding the relationships between Si and GPx in blood and urine Si excretion during lithium administration.

  8. Selenium dependent glutathione-peroxidase (GSH-Px) activity in the retina of preterm human infants

    SciTech Connect

    Lane, H.; Hittner, H.; Barron, S.; Mehta, R.; Kretzer, F.

    1986-03-01

    GSH-Px activity was determined in the retina of 15 preterm human neonates with gestational ages of 17-28 weeks and birth weights of 120 to 960 g. GSH-Px activity was measured using the coupled assay. The infants survived from 0.5 to 9 hours after parturition. The retinas were removed within 3 hours of autopsy. Through electronmicroscopy, there was verification that the entire retina was removed and no contamination of other eye tissues occurred. After removal, the retinas were immediately dissolved in phosphate buffered pH 7.0 saline for assay of GSH-Px activity. The mean GSH-Px activity was 19.44 +/- 6.44 with a range of 11.1 to 32.8 units NAPH/sub 2/ oxidized/min/g protein. There was a negative correlation between birth weight and GSH-Px activity (r = -0.86) and between week of gestation and GSH-Px activity (r = -0.91). The neonatal retina GSH-Px activity was 2 to 15 times higher than found in adult retinas. Thus, this research demonstrates that selenium dependent GSH-Px activity is elevated in the preterm neonate's retina which indicates that retina GSH-Px activity may be an important antioxidation system in the premature neonate.

  9. The influence of atmospheric chromium on selenium content and glutathione peroxidase activity in blood of tannery workers.

    PubMed

    Gromadzińska, J; Wasowicz, W; Sklodowska, M; Bulikowski, W; Rydzyński, K

    1996-12-01

    The concentration of selenium and thiobarbituric acid reactive substances (TBARS) and activity of glutathione peroxidase (GSH-Px) were determined in blood of 34 workers of a tannery in Gniezno, Poland, who worked in an area containing chromium compounds. Fourteen workers were exposed to chromium compounds at concentrations of 0.11 +/- 0.07 mg Cr/m3 (mean +/- SD) and 20 at concentrations 5-10 times lower i.e., 0.022 +/- 0.009 mg Cr/m3. Excretion of Se in urine was measured in all of the investigated workers. Decreased Se concentration in whole blood and blood plasma and elevated TBARS concentration in blood plasma were found in the whole group of investigated tanners as compared to controls. Tanners working in areas with high chromium concentrations had a statistically significant decrease in Se concentration in blood and plasma and decreased urinary excretion of the microelement as compared with other tanners. TBARS concentration was 2.5 times lower in workers exposed to higher chromium concentrations (p < 0.005) than in other workers. Positive linear correlations were found between the concentration of Se in blood and the amount of the element excreted in urine (r = 0.48; p < 0.005), the concentration of Se in blood plasma and in urine (r = 0.46; p < 0.01), and the concentration of Se in blood and erythrocyte GSH-Px activity (r = 0.42; p < 0.02). The observed differences between Se concentration in blood and urine of tannery workers and people who are not employed in the industry may indicate a kind of specific adaptation of the body to the working environment containing chromium compounds.

  10. Probucol increases striatal glutathione peroxidase activity and protects against 3-nitropropionic acid-induced pro-oxidative damage in rats.

    PubMed

    Colle, Dirleise; Santos, Danúbia Bonfanti; Moreira, Eduardo Luiz Gasnhar; Hartwig, Juliana Montagna; dos Santos, Alessandra Antunes; Zimmermann, Luciana Teixeira; Hort, Mariana Appel; Farina, Marcelo

    2013-01-01

    Huntington's disease (HD) is an autosomal dominantly inherited neurodegenerative disease characterized by symptoms attributable to the death of striatal and cortical neurons. The molecular mechanisms mediating neuronal death in HD involve oxidative stress and mitochondrial dysfunction. Administration of 3-nitropropionic acid (3-NP), an irreversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, in rodents has been proposed as a useful experimental model of HD. This study evaluated the effects of probucol, a lipid-lowering agent with anti-inflammatory and antioxidant properties, on the biochemical parameters related to oxidative stress, as well as on the behavioral parameters related to motor function in an in vivo HD model based on 3-NP intoxication in rats. Animals were treated with 3.5 mg/kg of probucol in drinking water daily for 2 months and, subsequently, received 3-NP (25 mg/kg i.p.) once a day for 6 days. At the end of the treatments, 3-NP-treated animals showed a significant decrease in body weight, which corresponded with impairment on motor ability, inhibition of mitochondrial complex II activity and oxidative stress in the striatum. Probucol, which did not rescue complex II inhibition, protected against behavioral and striatal biochemical changes induced by 3-NP, attenuating 3-NP-induced motor impairments and striatal oxidative stress. Importantly, probucol was able to increase activity of glutathione peroxidase (GPx), an enzyme important in mediating the detoxification of peroxides in the central nervous system. The major finding of this study was that probucol protected against 3-NP-induced behavioral and striatal biochemical changes without affecting 3-NP-induced mitochondrial complex II inhibition, indicating that long-term probucol treatment resulted in an increased resistance against neurotoxic events (i.e., increased oxidative damage) secondary to mitochondrial dysfunction. These data appeared to be of great relevance when

  11. The influence of atmospheric chromium on selenium content and glutathione peroxidase activity in blood of tannery workers.

    PubMed Central

    Gromadzińska, J; Wasowicz, W; Sklodowska, M; Bulikowski, W; Rydzyński, K

    1996-01-01

    The concentration of selenium and thiobarbituric acid reactive substances (TBARS) and activity of glutathione peroxidase (GSH-Px) were determined in blood of 34 workers of a tannery in Gniezno, Poland, who worked in an area containing chromium compounds. Fourteen workers were exposed to chromium compounds at concentrations of 0.11 +/- 0.07 mg Cr/m3 (mean +/- SD) and 20 at concentrations 5-10 times lower i.e., 0.022 +/- 0.009 mg Cr/m3. Excretion of Se in urine was measured in all of the investigated workers. Decreased Se concentration in whole blood and blood plasma and elevated TBARS concentration in blood plasma were found in the whole group of investigated tanners as compared to controls. Tanners working in areas with high chromium concentrations had a statistically significant decrease in Se concentration in blood and plasma and decreased urinary excretion of the microelement as compared with other tanners. TBARS concentration was 2.5 times lower in workers exposed to higher chromium concentrations (p < 0.005) than in other workers. Positive linear correlations were found between the concentration of Se in blood and the amount of the element excreted in urine (r = 0.48; p < 0.005), the concentration of Se in blood plasma and in urine (r = 0.46; p < 0.01), and the concentration of Se in blood and erythrocyte GSH-Px activity (r = 0.42; p < 0.02). The observed differences between Se concentration in blood and urine of tannery workers and people who are not employed in the industry may indicate a kind of specific adaptation of the body to the working environment containing chromium compounds. Images Figure 1. Figure 2. PMID:9118872

  12. Red blood cell and plasma glutathione peroxidase activities and selenium concentration in patients with chronic kidney disease: a review.

    PubMed

    Zachara, Bronisław A; Gromadzińska, Jolanta; Wasowicz, Wojciech; Zbróg, Zbigniew

    2006-01-01

    The metabolism of oxygen in aerobic organisms leads to generation of reactive oxygen species (ROS). These entities are able to oxidize almost all classes of macromolecules, including proteins, lipids and nucleic acids. The physiological level of ROS is usually regulated by antioxidant defense mechanisms. There are at least three groups of antioxidant enzymes: superoxide dismutases, catalases and glutathione peroxidases (GSH-Pxs) which neutralize ROS. The trace elements (copper, zinc and selenium) bound to the active sites of the above listed enzymes play an important role in the antioxidant defense system. In mammals, a major function of selenium (Se) and Se-dependent GSH-Pxs is to protect cells from oxidative stress. Selenium concentrations and GSH-Px activities are altered in blood components of chronic kidney disease (CKD) patients. The Se level is frequently lower than in healthy subjects and the concentration very often decreases gradually with advancing stage of the disease. Studies on red cell GSH-Px activity in CKD patients reported its values significantly lower, significantly higher and lower or higher, but not significantly as compared with healthy subjects. On the other hand, all authors who studied plasma GSH-Px activity have shown significantly lower values than in healthy subjects. The degree of the reduction decreases gradually with the progression of the disease. High inverse correlations were seen between plasma GSH-Px activity and creatinine level. A gradual decrease in plasma GSH-Px activity in CKD patients is due to the fact that this enzyme is synthesized predominantly in the kidney and thus the impairment of this organ is the cause of the enzyme's lower activity. Se supplementation to CKD patients has a slightly positive effect in the incipient stage of the disease, but usually no effect was observed in end-stage CKD. Presently, kidney transplantation is the only treatment that may restore plasma Se level and GSH-Px activity in patients

  13. Glutathione-induced radical formation on lactoperoxidase does not correlate with the enzyme's peroxidase activity.

    PubMed

    Bonini, Marcelo G; Siraki, Arno G; Bhattacharjee, Suchandra; Mason, Ronald P

    2007-04-01

    Lactoperoxidase (LPO) is believed to serve as a mediator of host defense against invading pathogens. The protein is more abundant in body fluids such as milk, saliva, and tears. Lactoperoxidase is known to mediate the oxidation of halides and (pseudo)halides in the presence of hydrogen peroxide to reactive intermediates presumably involved in pathogen killing. More recently, LPO has been shown to oxidize a wide diversity of thiol compounds to thiyl free radicals, which ultimately lead to the formation of a protein radical characterized by DMPO-immunospin trapping. In the same study by our group the authors claimed that a consequence of this protein radical formation was the inactivation of LPO (Guo et al., J. Biol. Chem.279:13272-13283; 2004). Here we demonstrate that although thiyl radical formation does lead to LPO radical production, the formation of this radical is unrelated to the enzyme's activity. We suggest the source of this misleading interpretation to be the binding of GSH to ELISA plates, which interferes with ABTS and guaiacol oxidation. In addition, DMPO-GSH-nitrone adducts bind to ELISA plates, leading to ambiguities of interpretation since we have demonstrated that DMPO-GSH nitrone does not bind to LPO, and only LPO-protein-DMPO-nitrone adducts can be detected by Western blot.

  14. Comparison of age-related differences in expression of phospholipid hydroperoxide glutathione peroxidase mRNA and activity in various tissues of pigs.

    PubMed

    Lei, X G; Ross, D A; Roneker, K R

    1997-05-01

    Phospholipid hydroperoxide glutathione peroxidase (PHGPX) is the second identified Se-dependent intracellular glutathione peroxidase (PHGPX) that reduces phospholipid hydroperoxides. The objective of this study was to determine the developmental regulation of PHGPX expression in tissues of neonatal, weanling and finishing pigs (Sus scrofa) compared with the expression of the classic Se-dependent cellular glutathione peroxidase (GPX) and the Se-independent enzyme, glutathione S-transferase (GST). Eight different tissues were collected from Se-adequate male pigs aged 1, 28 and 180 days, and supernatant of the tissue homogenate was assayed for PHGPX, GPX and GST activities by using phosphatidylcholine hydroperoxide, hydrogen peroxide and 1-chloro-2,4-dinitrobenzene as substrate, respectively. Total RNA was isolated from four tissues and assayed for PHGPX mRNA expression. Both mRNA and activity expression of PHGPX in most assayed tissues was increased as pigs became older (P < 0.05), but increases in PHGPX mRNA levels between ages did not fully account for all changes in activity. Expression of GPX activity was increased more than that of PHGPX between day 1 and day 28 (P < 0.0001). Expression of GST activity in various tissues was also affected by age (P < 0.01) but lacked a consistent relationship with the changes in GPX and PHGPX activity. Tissue-specific patterns of developmental expression of these enzymes may be related to the susceptibility of organs to pro-oxidant injuries. In conclusion, expression of PHGPX mRNA and activity in various tissues of pigs is developmentally increased over ages, and the pattern is somewhat different from that of GPX.

  15. Effect of selenium-enriched probiotics on laying performance, egg quality, egg selenium content, and egg glutathione peroxidase activity.

    PubMed

    Pan, Cuiling; Zhao, Yuxin; Liao, Shengfa F; Chen, Fu; Qin, Shunyi; Wu, Xianshi; Zhou, Hong; Huang, Kehe

    2011-11-01

    A 35-day experiment was conducted to evaluate the effect of selenium-enriched probiotics (SP) on laying performance, egg quality, egg selenium (Se) content, and egg glutathione peroxidase (GPX) activity. Five hundred 58-week-old Rohman laying hens were randomly allotted to 5 dietary treatments of 100 each. Each treatment had 5 replicates, and each replicate had 5 cages with 4 hens per cage. The SP was supplemented to a corn-soybean-meal basal diet at 3 different levels that supplied total Se at 0.2, 0.5, and 1.0 mg/kg. The basal diet served as a blank control, while the basal diet with supplemental probiotics served as a probiotics control. The results showed that dietary SP supplementation not only increased (p < 0.05) the rate of egg laying, day egg weight, mean egg weight, egg Se content, and egg GPX activity but also decreased (p < 0.05) the feed:egg ratio and egg cholesterol content. The egg Se content was gradually increased (p < 0.05) along with the increasing level of dietary Se. The SP supplementation also slowed down (p < 0.05) the drop of Haugh units (HU) of eggs stored at room temperature. The egg GPX activity had a positive correlation (p < 0.01) with egg Se content and a negative correlation (p < 0.01) with egg HU drop. These results suggested that Se contents, GPX activity, and HU of eggs were affected by the dietary Se level, whereas the egg-laying performance and egg cholesterol content were affected by the dietary probiotics. It was concluded that this SP is an effective feed additive that combines the organic Se benefit for hen and human health with the probiotics benefit for laying hen production performance. It was also suggested that the eggs from hens fed this SP can serve as a nutraceutical food with high Se and low cholesterol contents for both healthy people and patients with hyperlipidemia, fatty liver, or cardiovascular disease. PMID:21942342

  16. Serine incorporation into the selenocysteine moiety of glutathione peroxidase

    SciTech Connect

    Sunde, R.A.; Evenson, J.K.

    1987-01-15

    The selenium in mammalian glutathione peroxidase is present as a selenocysteine ((Se)Cys) moiety incorporated into the peptide backbone 41-47 residues from the N-terminal end. To study the origin of the skeleton of the (Se)Cys moiety, we perfused isolated rat liver with /sup 14/C- or /sup 3/H-labeled amino acids for 4 h, purified the GSH peroxidase, derivatized the (Se)Cys in GSH peroxidase to carboxymethylselenocysteine ((Se)Cys(Cm)), and determined the amino acid specific activity. Perfusion with (/sup 14/C)cystine resulted in (/sup 14/C)cystine incorporation into GSH peroxidase without labeling (Se)Cys(Cm), indicating that cysteine is not a direct precursor for (Se)Cys. (/sup 14/C)Serine perfusion labeled serine, glycine (the serine hydroxymethyltransferase product), and (Se)Cys(Cm) in purified GSH peroxidase, whereas (3-3H)serine perfusion only labeled serine and (Se)Cys(Cm), thus demonstrating that the (Se)Cys in GSH peroxidase is derived from serine. The similar specific activities of serine and (Se)Cys(Cm) strongly suggest that the precursor pool of serine used for (Se) Cys synthesis is the same or similar to the serine pool used for acylation of seryl-tRNAs.

  17. Probucol Increases Striatal Glutathione Peroxidase Activity and Protects against 3-Nitropropionic Acid-Induced Pro-Oxidative Damage in Rats

    PubMed Central

    Colle, Dirleise; Santos, Danúbia Bonfanti; Moreira, Eduardo Luiz Gasnhar; Hartwig, Juliana Montagna; dos Santos, Alessandra Antunes; Zimmermann, Luciana Teixeira; Hort, Mariana Appel; Farina, Marcelo

    2013-01-01

    Huntington’s disease (HD) is an autosomal dominantly inherited neurodegenerative disease characterized by symptoms attributable to the death of striatal and cortical neurons. The molecular mechanisms mediating neuronal death in HD involve oxidative stress and mitochondrial dysfunction. Administration of 3-nitropropionic acid (3-NP), an irreversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, in rodents has been proposed as a useful experimental model of HD. This study evaluated the effects of probucol, a lipid-lowering agent with anti-inflammatory and antioxidant properties, on the biochemical parameters related to oxidative stress, as well as on the behavioral parameters related to motor function in an in vivo HD model based on 3-NP intoxication in rats. Animals were treated with 3.5 mg/kg of probucol in drinking water daily for 2 months and, subsequently, received 3-NP (25 mg/kg i.p.) once a day for 6 days. At the end of the treatments, 3-NP-treated animals showed a significant decrease in body weight, which corresponded with impairment on motor ability, inhibition of mitochondrial complex II activity and oxidative stress in the striatum. Probucol, which did not rescue complex II inhibition, protected against behavioral and striatal biochemical changes induced by 3-NP, attenuating 3-NP-induced motor impairments and striatal oxidative stress. Importantly, probucol was able to increase activity of glutathione peroxidase (GPx), an enzyme important in mediating the detoxification of peroxides in the central nervous system. The major finding of this study was that probucol protected against 3-NP-induced behavioral and striatal biochemical changes without affecting 3-NP-induced mitochondrial complex II inhibition, indicating that long-term probucol treatment resulted in an increased resistance against neurotoxic events (i.e., increased oxidative damage) secondary to mitochondrial dysfunction. These data appeared to be of great relevance when

  18. Temperature-driven switching of the catalytic activity of artificial glutathione peroxidase by the shape transition between the nanotubes and vesicle-like structures.

    PubMed

    Wang, Liang; Zou, Huixin; Dong, Zeyuan; Zhou, Lipeng; Li, Jiaxi; Luo, Quan; Zhu, Junyan; Xu, Jiayun; Liu, Junqiu

    2014-04-15

    Smart supramolecular nanoenzymes with temperature-driven switching property have been successfully constructed by the self-assembly of supra-amphiphiles formed by the cyclodextrin-based host-guest chemistry. The self-assembled nanostructures were catalyst-functionalized and thermosensitively-functionalized through conveniently linking the catalytic center of glutathione peroxidase and thermosensitive polymer to the host cyclodextrin molecules.The ON-OFF switches for the peroxidase activity by reversible transformation of nanostructures from tube to sphere have been achieved through changing the temperature. We anticipate that such intelligent enzyme mimics could be developed to use in an antioxidant medicine with controlled catalytic efficiency according to the needs of the human body in the future. PMID:24654792

  19. Selenium levels, thiobarbituric acid-reactive substance concentrations and glutathione peroxidase activity in the blood of women with gestosis and imminent premature labour.

    PubMed

    Gromadzinska, J; Wasowicz, W; Krasomski, G; Broniarczyk, D; Andrijewski, M; Rydzynski, K; Wolkanin, P

    1998-01-01

    The aim of the study was to investigate antioxidant status, monitored by selenium and thiobarbituric acid-reactive substance concentrations in blood plasma, and glutathione peroxidase activity in erythrocytes and blood plasma in women with gestosis (n = 26), imminent premature labour (n = 48) and normal pregnancy (n = 23) during 19-38 weeks of pregnancy. Selenium concentrations in blood plasma were significantly higher in women with pathological pregnancies than in normal (45.5 +/- 10.5 micrograms l-1, p < 0.01 and 44.1 +/- 11.6 micrograms l-1, p < 0.05 vs. 38.6 +/- 8.3 micrograms l-1, respectively). In all groups of pregnant women Se concentrations were extremely low as compared with non-pregnant females. Glutathione peroxidase (GSH-Px) activity in blood plasma was significantly higher in complicated pregnancies than in healthy ones. There were no significant differences in thiobarbituric acid-reactive substance concentrations between all groups of pregnant women. Statistically significant correlations were found between blood plasma Se concentrations and GSH-Px activity in healthy pregnant (r = 0.53, p < 0.01), imminent premature labour (r = 0.39, p < 0.01), and non-pregnant females (r = 0.56, p < 0.001). PMID:9581018

  20. Activities of Antioxidant Scavenger Enzymes (Superoxide Dismutase and Glutathione Peroxidase) in Erythrocytes in Adult Women With and Without Type II Diabetes

    PubMed Central

    Coleman, Raymond; Berner, Yitshal N.

    2004-01-01

    It is widely believed that oxidative stress plays an important role in the pathogenesis of type II diabetes. The present study was undertaken to examine the functioning of two antioxidant scavenger enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), in erythrocytes in a population of healthy aging adult women compared with a similar population with type II diabetes. Blood samples were examined from 42 female adult healthy subjects at different ages and from 59 female patients with type II diabetes. A significant increase in SOD activities was correlated with aging in erythrocytes of the healthy control subjects (r = .550, P = .001); however, this correlation was not found in subjects with type II diabetes (r = .250, P < .07). A trend showing a reduction in glutathione peroxidase activities was demonstrated with aging (r = −.331, P = .228); however, this trend was not found in diabetic subjects (r = .031, P < .820). The results indicate a possible imbalance in the antioxidant system in erythrocytes of aging adult women, which is even more pronounced in cases of type II diabetes. This study may indicate possible therapeutic treatment or preventive measures to limit oxidative damage and reduce complications of diabetes. PMID:15203888

  1. Dietary fish oil replacement with palm or poultry oil increases fillet oxidative stability and decreases liver glutathione peroxidase activity in barramundi (Lates calcarifer).

    PubMed

    Wan Ahmad, Wan A R; Stone, David A J; Schuller, Kathryn A

    2013-12-01

    Complete dietary fish oil replacement with palm or poultry oil in barramundi (Lates calcarifer) had no detrimental effects on growth or hepatosomatic index of juvenile fish up to an average size of ~50 g. However, it significantly decreased the omega-3 (n-3) long-chain polyunsaturated fatty acid content of the fish muscle (fillet) lipids. This was particularly true for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which are recognised for their health beneficial effects in the human diet. As a result of their decreased EPA and DHA content, the peroxidation index of the muscle lipids was also decreased. This was associated with increased simulated retail storage shelf life as indicated by decreased thiobarbituric acid reactive substances in muscle samples from fish fed the palm or poultry oil-based diets. Concomitantly, glutathione peroxidase (GPx) activity, but not glutathione S-transferase (GST) activity or reduced glutathione concentration, was significantly reduced in the liver of barramundi fed the palm or poultry oil-based diets as compared with the fish fed the fish oil-based diet. Furthermore, GPx and GST activity were very low in muscle, much lower than in gastrointestinal tract, liver or swim bladder. Therefore, we propose that liver GPx activity may be a good predictor of fillet shelf life in barramundi and other fish species.

  2. N-acetyl cysteine, L-cysteine, and beta-mercaptoethanol augment selenium-glutathione peroxidase activity in glucose-6-phosphate dehydrogenase-deficient human erythrocytes.

    PubMed

    Alicigüzel, Y; Aslan, M

    2004-09-01

    In glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes, failure to maintain normal levels of reduced glutathione (GSH) due to decreased NADPH regeneration in the hexose monophosphate pathway results in acute hemolytic anemia following exposure to oxidative insults, such as ingestion of Vicia fava beans or use of certain drugs. GSH is a source of protection against oxidative attack, used by the selenium-dependent glutathione peroxidase (Se-GSH-Px)/reductase (GR) system to detoxify hydrogen peroxide and organic peroxides, provided that sufficient GSH is made available. In this study, Se-GSH-Px activity was analyzed in G6PD-deficient patients in the presence of reducing agents such as N-Acetyl cysteine, L-cysteine, and beta-mercaptoethanol. Se-GSH-Px activity was decreased in G6PD-deficient red blood cells (RBCs). N-Acetyl cysteine, L-cysteine, and beta-mercaptoethanol increased Se-GSH-Px activity in G6PD-deficient human erythrocytes, indicating that other reducing agents can be utilized to complement Se-GSH-Px activity in G6PD deficiency. Based on the increased susceptibility of G6PD-deficient patients to oxidative stress, the reported increase in Se-GSH-Px activity can facilitate the detoxification of reactive oxygen species. PMID:15598086

  3. Glutathione peroxidase and iron-thiol dependent lipid peroxidation.

    PubMed

    Punekar, N S; Lardy, H A

    1989-12-01

    Role of glutathione peroxidase in iron-thiol-mediated lipid peroxidation was examined. The enzyme was unable to prevent peroxidation of extracted rat liver microsomal lipids. In contrast, when arachidonic acid was the substrate, glutathione peroxidase did decrease the formation of thiobarbituric acid-reactive material. Superoxide dismutase produced a consistent but partial inhibition of peroxidation and catalase was without effect. Our results suggest that iron-thiol-dependent lipid peroxidation cannot be completely blocked by protective enzymes that are effective in other systems. PMID:2635868

  4. Glutathione peroxidase 4 prevents necroptosis in mouse erythroid precursors

    PubMed Central

    Canli, Özge; Alankuş, Yasemin B.; Grootjans, Sasker; Vegi, Naidu; Hültner, Lothar; Hoppe, Philipp S.; Schroeder, Timm; Vandenabeele, Peter; Bornkamm, Georg W.

    2016-01-01

    Maintaining cellular redox balance is vital for cell survival and tissue homoeostasis because imbalanced production of reactive oxygen species (ROS) may lead to oxidative stress and cell death. The antioxidant enzyme glutathione peroxidase 4 (Gpx4) is a key regulator of oxidative stress–induced cell death. We show that mice with deletion of Gpx4 in hematopoietic cells develop anemia and that Gpx4 is essential for preventing receptor-interacting protein 3 (RIP3)-dependent necroptosis in erythroid precursor cells. Absence of Gpx4 leads to functional inactivation of caspase 8 by glutathionylation, resulting in necroptosis, which occurs independently of tumor necrosis factor α activation. Although genetic ablation of Rip3 normalizes reticulocyte maturation and prevents anemia, ROS accumulation and lipid peroxidation in Gpx4-deficient cells remain high. Our results demonstrate that ROS and lipid hydroperoxides function as not-yet-recognized unconventional upstream signaling activators of RIP3-dependent necroptosis. PMID:26463424

  5. Tuning the activity of glutathione peroxidase mimics through intramolecular Se···N,O interactions: a DFT study incorporating solvent-assisted proton exchange (SAPE).

    PubMed

    Bayse, Craig A; Pavlou, Andrea

    2011-12-01

    Diaryl diselenide mimics of the antioxidant selenoprotein glutathione peroxidase (GPx) often incorporate intramolecular Se···N,O interactions to enhance their GPx-like activity. Although the strength of the interaction is defined by the Lewis basicity of the donating group and the strength of the Se-X bond, there is not a clear relationship between the interaction and the GPx-like activity. Density-functional theory and natural bond orbital (NBO) calculations are used to show the range of Se···N,O interactions for various functional groups. The strongest interactions are found for groups which stabilize the donor-acceptor interaction through aromatic stabilization. The activation barriers for the GPx-like mechanism of activity of several substituted areneselenols are calculated using DFT and solvent-assisted proton exchange (SAPE), a technique that incorporates networks of solvent molecules into the theoretical model to facilitate proton transfer between sites in the reactant and product. DFT-SAPE models show that, in addition to decreasing the barrier to oxidation of the selenol, Se···N,O interactions generally increase the barriers for selenenic acid reduction and selenol regeneration because the Se···N,O interaction must be broken for the reaction to proceed. Calculated activation barriers for the rate-determining step are consistent with the relative experimental GPx-like activities of a series of diaryl diselenides.

  6. Selenium regulation of glutathione peroxidase in human hepatoma cell line Hep3B.

    PubMed

    Baker, R D; Baker, S S; LaRosa, K; Whitney, C; Newburger, P E

    1993-07-01

    Glutathione peroxidase is an important enzyme in cellular antioxidant defense systems, detoxifying peroxides and hydroperoxides. As a component of the glutathione cycle, it protects the liver from reactive oxygen metabolites. Selenocysteine is present at the catalytic site of glutathione peroxidase, and selenium availability regulates glutathione peroxidase enzyme activity. Hep3B cells, a well-differentiated human hepatoma-derived cell line, exhibited time-dependent decrease in glutathione peroxidase activity (nmol NADPH oxidized/min/mg protein, mean +/- SE) when incubated in selenium-free medium for 10 days (Day 0, 21.8 +/- 7.3; Day 2, 10.9 +/- 1.2; Day 4, 7.9 +/- 0.8; Day 6, 4.0 +/- 0.7; Day 8, 4.5 +/- 0.6; Day 10, 1.6 +/- 0.4). With the reintroduction of selenium, glutathione peroxidase activity returned. A second human hepatoma cell line, HepG2, demonstrated a similar pattern when depleted of and then repleted with selenium. To assess protein synthesis, glutathione peroxidase activity was measured in deficient and replete Hep3B cells incubated with and without selenium and with and without cycloheximide. Deficient cells (mean +/- SE) (4.9 +/- 0.2) showed an increase in glutathione peroxidase activity after 24 h in selenium-containing medium (11.6 +/- 0.2), but not when cycloheximide was included in the medium (6.9 +/- 0.5) or when cycloheximide and no selenium was included (5.3 +/- 0.8). Replete Hep3B cells (40.1 +/- 1.1) demonstrated decreased glutathione peroxidase after 24 h in medium without selenium (34.0 +/- 1.4), medium with both cycloheximide and selenium (34.0 +/- 2.6), and medium without selenium and containing cycloheximide (37.6 +/- 1.3). These data suggest that protein synthesis is needed for selenium repletion to exert control on glutathione peroxidase activity. Using a cDNA for human glutathione peroxidase (GPx1), selenium-deficient and replete Hep3B cell RNA was analyzed by Northern blot. mRNA for GPx was quantified by densitometry. The steady

  7. Modulation of the Activities of Catalase, Cu-Zn, Mn Superoxide Dismutase, and Glutathione Peroxidase in Adipocyte from Ovariectomised Female Rats with Metabolic Syndrome

    PubMed Central

    Guerra, Rebeca Cambray; Zuñiga-Muñoz, Alejandra; Guarner Lans, Verónica; Díaz-Díaz, Eulises; Tena Betancourt, Carlos Alberto; Pérez-Torres, Israel

    2014-01-01

    The aim of this study was to evaluate the association between estrogen removal, antioxidant enzymes, and oxidative stress generated by obesity in a MS female rat model. Thirty two female Wistar rats were divided into 4 groups: Control (C), MS, MS ovariectomized (Ovx), and MS Ovx plus estradiol (E2). MS was induced by administering 30% sucrose to drinking water for 24 weeks. After sacrifice, intra-abdominal fat was dissected; adipocytes were isolated and lipid peroxidation, non-enzymatic antioxidant capacity, and the activities of Cu-Zn and Mn superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined. There were no significant differences in the activities of Cu-Zn, Mn SOD, CAT, and GPx between the C and MS groups, but in the MS Ovx group there was a statistically significant decrease in the activities of these enzymes when compared to MS and MS Ovx+E2. The increased lipid peroxidation and nonenzymatic antioxidant capacity found in MS Ovx was significantly decreased when compared to MS and MS Ovx+E2. In conclusion, the removal of E2 by ovariectomy decreases the activity of the antioxidant enzymes in the intra-abdominal tissue of MS female rats; this is reflected by increased lipid peroxidation and decreased nonenzymatic antioxidant capacity. PMID:24987414

  8. Differential effects of sodium selenite and nano-Se on growth performance, tissue se distribution, and glutathione peroxidase activity of avian broiler.

    PubMed

    Wang, Yanbo

    2009-05-01

    The present research evaluated differential effects of sodium selenite and nano-Se on growth performance, tissue Se distribution, and glutathione peroxidase (GSH-Px) activity of avian broiler. Broilers were randomly segregated into 12 groups so that three replicates were available for each of the three treatments (T-1, T-2, and T-3) and control groups. The control groups were fed basal diets without Se addition. T-1, T-2, and T-3 were fed with diets containing 0.2 mg kg(-1) sodium selenite, 0.2 mg kg(-1) nano-Se, and 0.5 mg kg(-1) nano-Se, respectively. Compared with the control, Se supplementation remarkably improved daily weight gain and survival rate and decreased feed conversion ratio (P < 0.05). However, no significant difference was observed between T-1, T-2, and T-3. The tissue Se content was significantly higher (P < 0.05) in Se-supplemented groups than the control, and T-3 showed the highest. Furthermore, higher Se content was observed in liver, and there was a significant difference (P < 0.05) compared with that in muscle. As for serum and hepatic GSH-Px activities, Se supplementation remarkably improved GSH-Px activity (P < 0.05), and there was no significant difference (P > 0.05) between treatments (T-1, T-2, and T-3). PMID:18972070

  9. Glutathione peroxidase mimics as novel antioxidants from vegetables.

    PubMed

    Terao, Junji; Hiwada, Mio; Taguchi, Keiko; Takahara, Keigo; Mohri, Satoshi

    2005-01-01

    Vegetables are generally recognized as rich sources of dietary antioxidants for inhibiting lipid peroxidation. Here we investigated lipid hydroperoxide (LOOH)-reducing activity of several vegetables to estimate their role on the prevention of lipid peroxidation in food and the digestive tract. By using HPLC analysis, we screened vegetables possessing the ability to convert 13-hydroperoxyoctadecadienoic acid (13-HPODE) to its reduced derivative, 13-hydroxyoctadecadienoic acid (13-HODE). Welsh onion (Allium fistulosum L.) was found to be highly active in the reduction of 13-HPODE among tested vegetables. There was no relationship between 13-HPODE reducing activity and GSH peroxidase (GPX) activity in the tested vegetables. 13-HPODE-reducing activity of welsh onion was enhanced by the addition of sulfhydryl compounds including glutathione (GSH). Neither GPX inhibitor nor heat treatment suppressed 13-HPODE-reducing activity effectively. These results suggest that welsh onion and other vegetables contain GPX mimics responsible for the reduction of LOOH. GPX mimics may be helpful in the attenuation of harmful effect of LOOH from food. PMID:15817993

  10. Expression of glutathione, glutathione peroxidase and glutathione S-transferase pi in canine mammary tumors

    PubMed Central

    2014-01-01

    Background Glutathione (GSH) is one of the most important agents of the antioxidant defense system of the cell because, in conjunction with the enzymes glutathione peroxidase (GSH-Px) and glutathione S transferase pi (GSTpi), it plays a central role in the detoxification and biotransformation of chemotherapeutic drugs. This study evaluated the expression of GSH and the GSH-Px and GSTpi enzymes by immunohistochemistry in 30 canine mammary tumors, relating the clinicopathological parameters, clinical outcome and survival of the bitches. In an in vitro study, the expression of the genes glutamate cysteine ligase (GCLC) and glutathione synthetase (GSS) that synthesize GSH and GSH-Px gene were verified by qPCR and subjected to treatment with doxorubicin, to check the resistance of cancer cells to chemotherapy. Results The immunohistochemical expression of GSH, GSH-Px and GSTpi was compared with the clinical and pathological characteristics and the clinical outcome in the bitches, including metastasis and death. The results showed that high immunoexpression of GSH was correlated to the absence of tumor ulceration and was present in dogs without metastasis (P < 0.05). There was significant correlation of survival with the increase of GSH (P < 0.05). The expression of the GSH-Px and GSTpi enzymes showed no statistically significant correlation with the analyzed variables (p > 0.05). The analysis of the relative expression of genes responsible for the synthesis of GSH (GCLC and GSS) and GSH-Px by quantitative PCR was done with cultured cells of 10 tumor fragments from dogs with mammary tumors. The culture cells showed a decrease in GCLC and GSS expression when compared with no treated cells (P < 0.05). High GSH immunoexpression was associated with better clinical outcomes. Conclusion Therefore, high expression of the GSH seems to play an important role in the clinical outcome of patients with mammary tumors and suggest its use as prognostic marker. The in

  11. Redox regulation of antioxidant enzymes: post-translational modulation of catalase and glutathione peroxidase activity by resveratrol in diabetic rat liver.

    PubMed

    Sadi, Gökhan; Bozan, Davut; Yildiz, Huseyin Bekir

    2014-08-01

    Resveratrol is a strong antioxidant that exhibits blood glucose-lowering effects, which might contribute to its usefulness in preventing complications associated with diabetes. The present study aimed to investigate resveratrol effects on catalase (CAT) and glutathione peroxidase (GPx) gene and protein expression, their phosphorylation states and activities in rat liver of STZ-induced diabetes. Diabetes increased the levels of total protein phosphorylation and p-CAT, while mRNA expression, protein levels, and activity were reduced. Although diabetes induced transcriptional repression over GPx, it did not affect the protein levels and activity. When resveratrol was administered to diabetic rats, an increase in activity was associated with an increase in p-GPx levels. Decrease in Sirtuin1 (SIRT1) and nuclear factor erythroid 2-related factor (Nrf2) and increase in nuclear factor kappa B (NFκB) gene expression in diabetes were associated with a decrease in CAT and GPx mRNA expression. A possible compensatory mechanism for reduced gene expression of antioxidant enzymes is proved to be nuclear translocation of redox-sensitive Nrf2 and NFκB in diabetes which is confirmed by the increase in nuclear and decrease in cytoplasmic protein levels of Nrf2 and NFκB. Taken together, these findings revealed that an increase in the oxidized state in diabetes intricately modified the cellular phosphorylation status and regulation of antioxidant enzymes. Gene regulation of antioxidant enzymes was accompanied by nuclear translocation of Nrf2 and NFκB. Resveratrol administration also activated a coordinated cytoprotective response against diabetes-induced changes in liver tissues.

  12. Influence of dietary nano elemental selenium on growth performance, tissue selenium distribution, meat quality, and glutathione peroxidase activity in Guangxi Yellow chicken.

    PubMed

    Zhou, X; Wang, Y

    2011-03-01

    This experiment was designed to investigate the effect of feed supplementation with nano elemental Se (Nano-Se) on growth performance, tissue Se distribution, meat quality, and glutathione peroxidase (GSH-Px) activity in Guangxi Yellow chicken. Four treatments (control, T-1, T-2, and T-3 treatment groups) with 3 replicates of 30 chickens each were carried out. Diets for the control, T-1, T-2, and T-3 groups consisted of the basal diet supplemented with, respectively, 0.00, 0.10, 0.30, and 0.50 mg/kg of Nano-Se. Improved final BW, daily BW gain (DWG), feed conversion ratios, and survival rate (P < 0.05) were observed in the groups supplemented with Nano-Se as compared with the control groups after 90 d of feeding. The groups that received Nano-Se showed higher (P < 0.05) hepatic and muscle Se contents, drip loss percentage, inosine 5'-monophosphate content, and GSH-Px activities in the serum and liver than that did the control groups. For the T-2 and T-3 groups, a significant difference (P < 0.05) was observed in final BW, DWG, muscle Se content, breast drip loss, and GSH-Px activities in the serum and liver compared with the T-1 group. However, no significant differences were observed in final BW, DWG, and GSH-Px activities in the serum and liver between the T-2 and T-3 groups. It could be concluded from this study that supplementing diets with 0.30 mg/kg of Nano-Se for was effective in increasing the growth performance and feed conversion ratios of chickens, the Se content of tissues, and the quality of the meat. PMID:21325242

  13. Sex- and age-dependent activity of glutathione peroxidase in reproductive organs in pre- and post-pubertal cattle in relation to total antioxidant capacity.

    PubMed

    Kankofer, M; Wawrzykowski, J; Giergiel, M

    2013-08-01

    Antioxidative/oxidative balance is crucial for proper functioning of cells and tissues. It is suggested that this balance can be partly controlled by sex steroid hormones and in consequence can exhibit age- and sex-related dependency. The aim of present study was to describe sex- and age-related changes in the activity of glutathione peroxidase (GSH-Px) with respect to total antioxidant activity (TAC) in reproductive organs of cattle. Biological samples were collected from slaughterhouse and comprised of ovaries, uterus, testes as well as livers as reference tissue. Animals were divided into group of bulls (aged between 13 and 24 months; n = 12), cows (aged between 14 and 27 months; n = 12) and female calves (aged between 2 weeks and 2 months; n = 12). Examined parameters were determined spectrophotometrically and the presence of GSH-Px isoform was confirmed by Western blotting technique. Activity of GSH-Px in genital tissues regardless of sex was significantly higher than in livers, while TAC showed opposite relationship. The differences in antioxidative parameters between testes and mature ovaries (e.g. GSH-Px-1.42 ± 0.47 nkat/mg prot vs. 1.08 ± 0.24 and 1.15 ± 0.23) were noticed as well as in chosen values between cows and female calves. Western blotting allowed the detection of cytosolic GSH-Px in all examined tissues with molecular weight around 21 kDa as monomer and around 84 kDa as tetramer depending on conditions of electrophoresis. The results may confirm the influence and regulatory role of sex steroid hormones on GSH-Px activity because the alterations were sex and age dependent. PMID:23740597

  14. Sex- and age-dependent activity of glutathione peroxidase in reproductive organs in pre- and post-pubertal cattle in relation to total antioxidant capacity.

    PubMed

    Kankofer, M; Wawrzykowski, J; Giergiel, M

    2013-08-01

    Antioxidative/oxidative balance is crucial for proper functioning of cells and tissues. It is suggested that this balance can be partly controlled by sex steroid hormones and in consequence can exhibit age- and sex-related dependency. The aim of present study was to describe sex- and age-related changes in the activity of glutathione peroxidase (GSH-Px) with respect to total antioxidant activity (TAC) in reproductive organs of cattle. Biological samples were collected from slaughterhouse and comprised of ovaries, uterus, testes as well as livers as reference tissue. Animals were divided into group of bulls (aged between 13 and 24 months; n = 12), cows (aged between 14 and 27 months; n = 12) and female calves (aged between 2 weeks and 2 months; n = 12). Examined parameters were determined spectrophotometrically and the presence of GSH-Px isoform was confirmed by Western blotting technique. Activity of GSH-Px in genital tissues regardless of sex was significantly higher than in livers, while TAC showed opposite relationship. The differences in antioxidative parameters between testes and mature ovaries (e.g. GSH-Px-1.42 ± 0.47 nkat/mg prot vs. 1.08 ± 0.24 and 1.15 ± 0.23) were noticed as well as in chosen values between cows and female calves. Western blotting allowed the detection of cytosolic GSH-Px in all examined tissues with molecular weight around 21 kDa as monomer and around 84 kDa as tetramer depending on conditions of electrophoresis. The results may confirm the influence and regulatory role of sex steroid hormones on GSH-Px activity because the alterations were sex and age dependent.

  15. Effect of polyphenols extracted from tamarind (Tamarindus indica L.) seed coat on pathophysiological changes and red blood cell glutathione peroxidase activity in heat-stressed broilers.

    PubMed

    Aengwanich, Worapol; Suttajit, Maitree

    2013-01-01

    The purpose of this study was to determine the effect of polyphenols extracted from the tamarind seed coat (PETSC) on glutathione peroxidase (GPx) activity, red blood cell parameters and bilirubin in heat-stressed broilers. One hundred forty-seven broilers, 18-days old were divided into two groups. In group 1, broilers were maintained at an environmental temperature of 26 ± 2 °C throughout the experimental period. In group 2, the broilers were maintained at 38 ± 2 °C (cyclic temperature: 26 ± 2 °C; -38 ± 2 °C; and -26 ± 2 °C, and broilers were maintained at 38 ± 2 °C for 6 h/ day) and received PETSC at a concentration of 0, 100, 200, 300, 400 or 500 mg/kg in their diet ad libitum. Parameters were investigated on days 1, 7, 14 and 21 of the experimental period. Results showed that GPx activity of heat-stressed broilers that received 100 mg/kg of PETSC in their diet was lower (P < 0.05) than that in broilers fed the other concentrations. The mean total red blood cell count and hemoglobin concentration of heat-stressed broilers that received 100 mg/kg PETSC was higher (P < 0.05) than those in broilers in group 1 and those fed the other concentrations. The mean bilirubin level in the excreta of heat-stressed broilers that received 100 mg/kg of PETSC was lower (P < 0.05) than that in broilers that received 0, 300, 400 and 500 mg/kg of PETSC. This showed that PETSC could reduce GPx activity and bilirubin in feces, and increase red blood cell parameters in heat-stressed broilers.

  16. Effect of polyphenols extracted from tamarind ( Tamarindus indica L.) seed coat on pathophysiological changes and red blood cell glutathione peroxidase activity in heat-stressed broilers

    NASA Astrophysics Data System (ADS)

    Aengwanich, Worapol; Suttajit, Maitree

    2013-01-01

    The purpose of this study was to determine the effect of polyphenols extracted from the tamarind seed coat (PETSC) on glutathione peroxidase (GPx) activity, red blood cell parameters and bilirubin in heat-stressed broilers. One hundred forty-seven broilers, 18-days old were divided into two groups. In group 1, broilers were maintained at an environmental temperature of 26 ± 2 °C throughout the experimental period. In group 2, the broilers were maintained at 38 ± 2 °C (cyclic temperature: 26 ± 2 °C; -38 ± 2 °C; and -26 ± 2 °C, and broilers were maintained at 38 ± 2 °C for 6 h/ day) and received PETSC at a concentration of 0, 100, 200, 300, 400 or 500 mg/kg in their diet ad libitum. Parameters were investigated on days 1, 7, 14 and 21 of the experimental period. Results showed that GPx activity of heat-stressed broilers that received 100 mg/kg of PETSC in their diet was lower ( P < 0.05) than that in broilers fed the other concentrations. The mean total red blood cell count and hemoglobin concentration of heat-stressed broilers that received 100 mg/kg PETSC was higher ( P < 0.05) than those in broilers in group 1 and those fed the other concentrations. The mean bilirubin level in the excreta of heat-stressed broilers that received 100 mg/kg of PETSC was lower ( P < 0.05) than that in broilers that received 0, 300, 400 and 500 mg/kg of PETSC. This showed that PETSC could reduce GPx activity and bilirubin in feces, and increase red blood cell parameters in heat-stressed broilers.

  17. Effect of polyphenols extracted from tamarind (Tamarindus indica L.) seed coat on pathophysiological changes and red blood cell glutathione peroxidase activity in heat-stressed broilers.

    PubMed

    Aengwanich, Worapol; Suttajit, Maitree

    2013-01-01

    The purpose of this study was to determine the effect of polyphenols extracted from the tamarind seed coat (PETSC) on glutathione peroxidase (GPx) activity, red blood cell parameters and bilirubin in heat-stressed broilers. One hundred forty-seven broilers, 18-days old were divided into two groups. In group 1, broilers were maintained at an environmental temperature of 26 ± 2 °C throughout the experimental period. In group 2, the broilers were maintained at 38 ± 2 °C (cyclic temperature: 26 ± 2 °C; -38 ± 2 °C; and -26 ± 2 °C, and broilers were maintained at 38 ± 2 °C for 6 h/ day) and received PETSC at a concentration of 0, 100, 200, 300, 400 or 500 mg/kg in their diet ad libitum. Parameters were investigated on days 1, 7, 14 and 21 of the experimental period. Results showed that GPx activity of heat-stressed broilers that received 100 mg/kg of PETSC in their diet was lower (P < 0.05) than that in broilers fed the other concentrations. The mean total red blood cell count and hemoglobin concentration of heat-stressed broilers that received 100 mg/kg PETSC was higher (P < 0.05) than those in broilers in group 1 and those fed the other concentrations. The mean bilirubin level in the excreta of heat-stressed broilers that received 100 mg/kg of PETSC was lower (P < 0.05) than that in broilers that received 0, 300, 400 and 500 mg/kg of PETSC. This showed that PETSC could reduce GPx activity and bilirubin in feces, and increase red blood cell parameters in heat-stressed broilers. PMID:22434485

  18. Effect of selenium supplementation on the level of glutathione-peroxidase (GSH-Px) activity in the nursing rat

    SciTech Connect

    Barron, S.P.; Hittner, H.M.; Strength, D.R.; Kretzer, F.; Lane, H.W.

    1986-03-01

    Prevention of retinopathy of prematurity using vitamin E as an antioxidant has been demonstrated. The purpose of this experiment was to study the antioxidant system, GSH-Px, (a selenoenzyme), in the retina. The effect of i.p. administration and dietary Se as selenite or selenomethionine (selmet) on tissue GSH-Px activity was determined in nursing pups. Dams were randomized into 3 dietary treatments (Basal, 0.15 ppm selenite, and 0.15 ppm selmet) and mated. Pups were sacrificed at 0, 7, and 14 days after delivery and GSH-Px was measured in pup eyes, hearts, livers, and kidneys, and dam livers. The pups of the dams consuming the Basal diet were divided into 4 i.p. groups: none, saline, selenite, and selmet (3 ..mu..g Se/kg body wt). The i.p. Se had no effect on GSH-Px activity in eye or heart, but significantly increased GSH-Px activity in liver and kidney with no difference between selenite and selmet. The pups of the dams consuming selenite and selmet diets showed significantly higher GSH-Px activity in all tissues studied than those consuming the Basal diet. For all tissues GSH-Px activity was higher for pups and dams fed selmet than those fed selenite. This research demonstrates that there was a difference in selenium availability between diet and i.p. administration.

  19. Selenium reduces the proapoptotic signaling associated to NF-kappaB pathway and stimulates glutathione peroxidase activity during excitotoxic damage produced by quinolinate in rat corpus striatum.

    PubMed

    Santamaría, Abel; Vázquez-Román, Beatriz; La Cruz, Verónica Pérez-De; González-Cortés, Carolina; Trejo-Solís, Ma Cristina; Galván-Arzate, Sonia; Jara-Prado, Aurelio; Guevara-Fonseca, Jorge; Ali, Syed F

    2005-12-15

    Quinolinate (QUIN) neurotoxicity has been attributed to degenerative events in nerve tissue produced by sustained activation of N-methyl-D-aspartate receptor (NMDAr) and oxidative stress. We have recently described the protective effects that selenium (Se), an antioxidant, produces on different markers of QUIN-induced neurotoxicity (Santamaría et al., 2003, J Neurochem 86:479-488.). However, the mechanisms by which Se exerts its protective actions remain unclear. Since some of these events are thought to be related with inhibition of deadly molecular cascades through the activation of antioxidant selenoproteins, in this study we investigated the effects of Se on QUIN-induced cell damage elicited by the nuclear factor kappaB (NF-kappaB) pathway, as well as the time-course response of striatal glutathione peroxidase (GPx) activity. Se (sodium selenite, 0.625 mg/kg/day, i.p.) was administered to rats for 5 days, and 120 min after the last administration, animals received a single striatal injection of QUIN (240 nmol/mul). Twenty-four hours later, their striata were tested for the expression of IkappaB-alpha (the NF-kappaB cytosolic binding protein), the immunohistochemical expression of NF-kappaB (evidenced as nuclear expression of P65), caspase-3-like activation, and DNA fragmentation. Additional groups were killed at 2, 6, and 24 h for measurement of GPx activity. Se reduced the QUIN-induced decrease in IkappaB-alpha expression, evidencing a reduction in its cytosolic degradation. Se also prevented the QUIN-induced increase in P65-immunoreactive cells, suggesting a reduction of NF-kappaB nuclear translocation. Caspase-3-like activation and DNA fragmentation produced by QUIN were also inhibited by Se. Striatal GPx activity was stimulated by Se at 2 and 6 h, but not at 24 h postlesion. Altogether, these data suggest that the protective effects exerted by Se on QUIN-induced neurotoxicity are partially mediated by the inhibition of proapoptotic events underlying Ikappa

  20. Identification and characterization of a selenium-dependent glutathione peroxidase in Setaria cervi

    SciTech Connect

    Singh, Anchal; Rathaur, Sushma . E-mail: sushmarathaur@yahoo.com

    2005-06-17

    Setaria cervi a bovine filarial parasite secretes selenium glutathione peroxidase during in vitro cultivation. A significant amount of enzyme activity was detected in the somatic extract of different developmental stages of the parasite. Among different stages, microfilariae showed a higher level of selenium glutathione peroxidase activity followed by males then females. However, when the activity was compared in excretory secretory products of these stages males showed higher activity than microfilariae and female worms. The enzyme was purified from female somatic extract using a combination of glutathione agarose and gel filtration chromatography, which migrated as a single band of molecular mass {approx}20 kDa. Selenium content of purified enzyme was estimated by atomic absorption spectroscopy and found to be 3.5 ng selenium/{mu}g of protein. Further, inhibition of enzyme activity by potassium cyanide suggested the presence of selenium at the active site of enzyme. This is the first report of identification of selenium glutathione peroxidase from any filarial parasite.

  1. Plant glutathione peroxidases: emerging role of the antioxidant enzymes in plant development and stress responses.

    PubMed

    Bela, Krisztina; Horváth, Edit; Gallé, Ágnes; Szabados, László; Tari, Irma; Csiszár, Jolán

    2015-03-15

    The plant glutathione peroxidase (GPX) family consists of multiple isoenzymes with distinct subcellular locations which exhibit different tissue-specific expression patterns and environmental stress responses. Contrary to most of their counterparts in animal cells, plant GPXs contain cysteine instead of selenocysteine in their active site and while some of them have both glutathione peroxidase and thioredoxin peroxidase functions, the thioredoxin regenerating system is much more efficient in vitro than the glutathione system. At present, the function of these enzymes in plants is not completely understood. The occurrence of thiol-dependent activities of plant GPX isoenzymes suggests that - besides detoxification of H2O2 and organic hydroperoxides - they may be involved in regulation of the cellular redox homeostasis by maintaining the thiol/disulfide or NADPH/NADP(+) balance. GPXs may represent a link existing between the glutathione- and the thioredoxin-based system. The various thiol buffers, including Trx, can affect a number of redox reactions in the cells most probably via modulation of thiol status. It is still required to identify the in vivo reductant for particular GPX isoenzymes and partners that GPXs interact with specifically. Recent evidence suggests that plant GPXs does not only protect cells from stress induced oxidative damage but they can be implicated in plant growth and development. Following a more general introduction, this study summarizes present knowledge on plant GPXs, highlighting the results on gene expression analysis, regulation and signaling of Arabidopsis thaliana GPXs and also suggests some perspectives for future research.

  2. The Roles of Glutathione Peroxidases during Embryo Development.

    PubMed

    Ufer, Christoph; Wang, Chi Chiu

    2011-01-01

    Embryo development relies on the complex interplay of the basic cellular processes including proliferation, differentiation, and apoptotic cell death. Precise regulation of these events is the basis for the establishment of embryonic structures and the organ development. Beginning with fertilization of the oocyte until delivery the developing embryo encounters changing environmental conditions such as varying levels of oxygen, which can give rise to reactive oxygen species (ROS). These challenges are met by the embryo with metabolic adaptations and by an array of anti-oxidative mechanisms. ROS can be deleterious by modifying biological molecules including lipids, proteins, and nucleic acids and may induce abnormal development or even embryonic lethality. On the other hand ROS are vital players of various signaling cascades that affect the balance between cell growth, differentiation, and death. An imbalance or dysregulation of these biological processes may generate cells with abnormal growth and is therefore potentially teratogenic and tumorigenic. Thus, a precise balance between processes generating ROS and those decomposing ROS is critical for normal embryo development. One tier of the cellular protective system against ROS constitutes the family of selenium-dependent glutathione peroxidases (GPx). These enzymes reduce hydroperoxides to the corresponding alcohols at the expense of reduced glutathione. Of special interest within this protein family is the moonlighting enzyme glutathione peroxidase 4 (Gpx4). This enzyme is a scavenger of lipophilic hydroperoxides on one hand, but on the other hand can be transformed into an enzymatically inactive cellular structural component. GPx4 deficiency - in contrast to all other GPx family members - leads to abnormal embryo development and finally produces a lethal phenotype in mice. This review is aimed at summarizing the current knowledge on GPx isoforms during embryo development and tumor development with an emphasis on

  3. Insights into the catalytic mechanism of synthetic glutathione peroxidase mimetics.

    PubMed

    Bhowmick, Debasish; Mugesh, Govindasamy

    2015-11-01

    Glutathione Peroxidase (GPx) is a key selenoenzyme that protects biomolecules from oxidative damage. Extensive research has been carried out to design and synthesize small organoselenium compounds as functional mimics of GPx. While the catalytic mechanism of the native enzyme itself is poorly understood, the synthetic mimics follow different catalytic pathways depending upon the structures and reactivities of various intermediates formed in the catalytic cycle. The steric as well as electronic environments around the selenium atom not only modulate the reactivity of these synthetic mimics towards peroxides and thiols, but also the catalytic mechanisms. The catalytic cycle of small GPx mimics is also dependent on the nature of peroxides and thiols used in the study. In this review, we discuss how the catalytic mechanism varies with the substituents attached to the selenium atom.

  4. Interplay between Superoxide Dismutase, Glutathione Peroxidase, and Peroxisome Proliferator Activated Receptor Gamma Polymorphisms on the Risk of End-Stage Renal Disease among Han Chinese Patients

    PubMed Central

    Chao, Chia-Ter; Chen, Yen-Ching; Chiang, Chih-Kang; Huang, Jenq-Wen; Fang, Cheng-Chung; Chang, Chen-Chih; Yen, Chung-Jen

    2016-01-01

    Background. Single nucleotide polymorphisms (SNPs) of antioxidants, including superoxide dismutase 2 (SOD2) and glutathione peroxidase 1 (GPX1), play an important role in the risk for cancer and metabolic disorders. However, little is known regarding the effect of antioxidant SNPs on renal events. Methods. We prospectively enrolled multicenter patients with end-stage renal disease (ESRD) and those without chronic kidney disease (CKD) of Han Chinese origin, with SOD2 (Val16Ala), GPX1 (Pro197Leu), and PPAR-γ (Pro12Ala, C161T) genotyped. Multiple regression analyses were conducted to evaluate the significant risk determinants for ESRD. Results. Compared to ESRD patients, non-CKD subjects were more likely to have T allele at SOD2 Val16Ala (p = 0.036) and CC genotype at PPAR-γ Pro12Ala (p = 0.028). Regression analysis showed that TT genotype of SOD2 Val16Ala conferred significantly lower ESRD risk among patients without diabetes (odds ratio 0.699; p = 0.018). GPX1 SNP alone did not alter the risk. We detected significant interactions between SNPs including PPAR-γ Pro12Ala, C161T, and GPX1 regarding the risk of ESRD. Conclusion. This is the first and largest study on the association between adverse renal outcomes and antioxidant SNPs among Han Chinese population. Determination of SOD2 and PPAR-γ SNPs status might assist in ESRD risk estimation. PMID:26881045

  5. Evaluation of Glutathione Peroxidase 4 role in Preeclampsia.

    PubMed

    Peng, Xinguo; Lin, Yan; Li, Jinling; Liu, Mengchun; Wang, Jingli; Li, Xueying; Liu, Jingjing; Jia, Xuewen; Jing, Zhongcui; Huang, Zuzhou; Chu, Kaiqiu; Liu, Shiguo

    2016-01-01

    Preeclampsia (PE) is a pregnancy-specific syndrome that may be lifethreatening to pregnancies and fetus. Glutathione Peroxidase 4 (GPx4) is a powerful antioxidant enzyme that can provide protection from oxidative stress damage which plays a pivotal role in the pathology of PE. Therefore, this study aims to investigate the association between Gpx4 polymorphisms and the susceptibility to PE in Chinese Han women. TaqMan allelic discrimination real-time PCR was used to perform the genotyping of rs713041 and rs4807542 in 1008 PE patients and 1386 normotensive pregnancies. Obviously statistical difference of genotypic and allelic frequencies were found of rs713041 in GPx4 between PE patients and controls and the C allele has the higher risk for pathogenesis of PE (χ(2) = 12.292, P = 0.002 by genotype; χ(2) = 11.035, P = 0.001, OR = 1.216, 95% CI 1.084-1.365 by allele). Additionally, when subdividing these samples into CC + CT and TT groups, we found a significant difference between the two groups (χ(2) = 11.241, P = 0.001, OR = 1.417, 95% CI 1.155-1.738). Furthermore, the genotype of rs713041 was found to be associated with the mild, severe and early-onset PE. Our results suggest that rs713041 in GPx4 may play a key role in the pathogenesis of PE. PMID:27641822

  6. Function of glutathione peroxidases in legume root nodules

    PubMed Central

    Matamoros, Manuel A.; Saiz, Ana; Peñuelas, Maria; Bustos-Sanmamed, Pilar; Mulet, Jose M.; Barja, Maria V.; Rouhier, Nicolas; Moore, Marten; James, Euan K.; Dietz, Karl-Josef; Becana, Manuel

    2015-01-01

    Glutathione peroxidases (Gpxs) are antioxidant enzymes not studied so far in legume nodules, despite the fact that reactive oxygen species are produced at different steps of the symbiosis. The function of two Gpxs that are highly expressed in nodules of the model legume Lotus japonicus was examined. Gene expression analysis, enzymatic and nitrosylation assays, yeast cell complementation, in situ mRNA hybridization, immunoelectron microscopy, and LjGpx-green fluorescent protein (GFP) fusions were used to characterize the enzymes and to localize each transcript and isoform in nodules. The LjGpx1 and LjGpx3 genes encode thioredoxin-dependent phospholipid hydroperoxidases and are differentially regulated in response to nitric oxide (NO) and hormones. LjGpx1 and LjGpx3 are nitrosylated in vitro or in plants treated with S-nitrosoglutathione (GSNO). Consistent with the modification of the peroxidatic cysteine of LjGpx3, in vitro assays demonstrated that this modification results in enzyme inhibition. The enzymes are highly expressed in the infected zone, but the LjGpx3 mRNA is also detected in the cortex and vascular bundles. LjGpx1 is localized to the plastids and nuclei, and LjGpx3 to the cytosol and endoplasmic reticulum. Based on yeast complementation experiments, both enzymes protect against oxidative stress, salt stress, and membrane damage. It is concluded that both LjGpxs perform major antioxidative functions in nodules, preventing lipid peroxidation and other oxidative processes at different subcellular sites of vascular and infected cells. The enzymes are probably involved in hormone and NO signalling, and may be regulated through nitrosylation of the peroxidatic cysteine essential for catalytic function. PMID:25740929

  7. Evaluation of Glutathione Peroxidase 4 role in Preeclampsia

    PubMed Central

    Peng, Xinguo; Lin, Yan; Li, Jinling; Liu, Mengchun; Wang, Jingli; Li, Xueying; Liu, Jingjing; Jia, Xuewen; Jing, Zhongcui; Huang, Zuzhou; Chu, Kaiqiu; Liu, Shiguo

    2016-01-01

    Preeclampsia (PE) is a pregnancy-specific syndrome that may be lifethreatening to pregnancies and fetus. Glutathione Peroxidase 4 (GPx4) is a powerful antioxidant enzyme that can provide protection from oxidative stress damage which plays a pivotal role in the pathology of PE. Therefore, this study aims to investigate the association between Gpx4 polymorphisms and the susceptibility to PE in Chinese Han women. TaqMan allelic discrimination real-time PCR was used to perform the genotyping of rs713041 and rs4807542 in 1008 PE patients and 1386 normotensive pregnancies. Obviously statistical difference of genotypic and allelic frequencies were found of rs713041 in GPx4 between PE patients and controls and the C allele has the higher risk for pathogenesis of PE (χ2 = 12.292, P = 0.002 by genotype; χ2 = 11.035, P = 0.001, OR = 1.216, 95% CI 1.084–1.365 by allele). Additionally, when subdividing these samples into CC + CT and TT groups, we found a significant difference between the two groups (χ2 = 11.241, P = 0.001, OR = 1.417, 95% CI 1.155–1.738). Furthermore, the genotype of rs713041 was found to be associated with the mild, severe and early-onset PE. Our results suggest that rs713041 in GPx4 may play a key role in the pathogenesis of PE. PMID:27641822

  8. Erythrocyte glutathione peroxidase in subjects of Mediterranean origin. A family study.

    PubMed

    Gerli, G C; Mongiat, R; Gualandri, V; Orsini, G B; Porta, E

    1984-01-01

    Erythrocyte glutathione peroxidase (GSH-Px) was assayed in subjects of Mediterranean origin and the distribution of the data obtained seems to confirm the existence of two alleles coding for low and high enzyme activity. In order to define the limits of expected genotypes less arbitrarily we studied families where parents' genotypes could allow us to define that of the children. Gene frequencies were calculated from genotype frequencies of an unrelated population and from crossings distribution by the Hardy-Weinberg equation. We observed a good agreement between gene frequencies obtained by these two different methods. PMID:6469259

  9. The role of mitochondrial phospholipid hydroperoxide glutathione peroxidase in cancer therapy

    NASA Astrophysics Data System (ADS)

    Wang, Hong

    Phospholipid hydroperoxide glutathione peroxidase (PhGPx) is a unique selenoenzyme that directly detoxifies lipid hydroperoxides in situ . It therefore plays an important role in the protection of cellular membranes. PhGPx is expressed in most mammalian tissues. It is present as a mitochondrial form (L-PhGPx) and a cytosolic form (S-PhGPx). Overexpression of PhGPx has been shown to significantly protect cells from oxidative damage. The hypothesis of this thesis is that mitochondrial PhGPx (L-PhGPx) may play an important role in the resistance of cells to certain oxidative stress- mediated cancer therapies. A human breast carcinoma MCF-7 cell line was used as a cell model system in this research. It was stably transfected with human L-PhGPx sense cDNA. Four clones (P-1, P-2, P-3, and P-4) with 3- to 7-fold increases in PhGPx activity were selected for study. Overexpression of L-PhGPx did not significantly influence other cellular antioxidants, including superoxide dismutases, cytosolic glutathione peroxidase, catalase, glutathione reductase, and glutathione. However, L-PhGPx did decrease the rate of cell growth. Cell plating efficiency was inversely correlated with effective PhGPx activity, which is defined as the product of cellular PhGPx activity and total glutathione. The biological functions of L-PhGPx have been investigated in cancer treatment, including photodynamic therapy (PDT) and hyperthermia (HT). Both PDT and HT can induce oxidative stress. Overexpression of L-PhGPx in MCF-7 cells significantly increased the resistance of cells to PDT- and HT-mediated cytotoxicity. The effective PhGPx activity had a remarkable inverse linear correlation (r = -0.80) to the rate of removal of lipid hydroperoxides in living cells, and correlated positively with cell survival after photooxidation (r = 0.91). L-PhGPx protected mitochondrial function by preserving the mitochondrial membrane potential. These data demonstrate that L-PhGPx provides significant protection against

  10. The biological importance of glutathione peroxidase and peroxiredoxin backup systems in bivalves during peroxide exposure.

    PubMed

    Trevisan, Rafael; Mello, Danielle Ferraz; Uliano-Silva, Marcela; Delapedra, Gabriel; Arl, Miriam; Dafre, Alcir Luiz

    2014-10-01

    Organic peroxide elimination in eukaryotes essentially depends on glutathione peroxidase (GPx) and peroxiredoxin (Prx) enzymes, which are supported by their respective electron donors, glutathione (GSH) and thioredoxin (Trx). This system depends on the ancillary enzymes glutathione reductase (GR) and thioredoxin reductase (TrxR) to maintain GSH and Trx in their reduced state. This study discusses the biological importance of GR and TrxR in supporting GPx and Prx during cumene hydroperoxide (CHP) exposure in brown mussel Perna perna. ZnCl2 or 1-chloro-2,4-dinitrobenze (CDNB) was used to decrease GR and TrxR activities in gills, as already reported with mammals and bivalves. ZnCl2 exposure lowered GR activity (28%), impaired the in vivo CHP decomposition and decreased the survival rates under CHP exposure. CDNB decreased GR (54%) and TrxR (73%) activities and induced glutathione depletion (99%), promoting diminished peroxide elimination and survival rates at a greater extent than ZnCl2. CDNB also increased the susceptibility of hemocytes to CHP toxicity. Despite being toxic and causing mortality at longer exposures, short (2 h) exposure to CHP promoted an up regulation of GSH (50 and 100 μM CHP) and protein-thiol (100 μM CHP) levels, which was blocked by ZnCl2 or CDNB pre-exposure. Results highlight the biological importance of GSH, GR and TrxR in supporting GPx and Prx activities, contributing to organic peroxides elimination and mussel survival under oxidative challenges. To our knowledge, this is the first work that demonstrates, albeit indirectly, the biological importance of GPx/GR/GSH and Prx/TrxR/Trx systems on in vivo organic peroxide elimination in bivalves.

  11. Crystal and solution structural studies of mouse phospholipid hydroperoxide glutathione peroxidase 4

    PubMed Central

    Janowski, Robert; Scanu, Sandra; Niessing, Dierk; Madl, Tobias

    2016-01-01

    The mammalian glutathione peroxidase (GPx) family is a key component of the cellular antioxidative defence system. Within this family, GPx4 has unique features as it accepts a large class of hydroperoxy lipid substrates and has a plethora of biological functions, including sperm maturation, regulation of apoptosis and cerebral embryogenesis. In this paper, the structure of the cytoplasmic isoform of mouse phospholipid hydroperoxide glutathione peroxidase (O70325-2 GPx4) with selenocysteine 46 mutated to cysteine is reported solved at 1.8 Å resolution using X-ray crystallography. Furthermore, solution data of an isotope-labelled GPx protein are presented. PMID:27710939

  12. Fully-branched hyperbranched polymers with a diselenide core as glutathione peroxidase mimics.

    PubMed

    Fu, Yu; Chen, Junyi; Xu, Huaping; Van Oosterwijck, Chantal; Zhang, Xi; Dehaen, Wim; Smet, Mario

    2012-05-14

    A novel glutathione peroxidase (GPx) mimic has been prepared by incorporation of a selenium-based catalytic unit into the focal point of a fully-branched hyperbranched polymer. First, an AB(2) monomer consisting of isatin and an electron rich aromatic moiety was polycondensed in the presence of 5-nitroisatin as a core reagent, resulting in a polymer with 100% degree of branching. The latter was coupled to the catalytically active moiety, Br(CH(2))(5) SeSe(CH(2))(5) Br, by nucleophilic substitution of the bromides by the residual amide groups of the incorporated nitroisatin core. The obtained polymer has demonstrated prominent GPx activity as desired, which could be attributed to the hydrophobic, densely branched and core-shell structure of the polymer surrounding the catalytic center. PMID:22434542

  13. E6* oncoprotein expression of human papillomavirus type-16 determines different ultraviolet sensitivity related to glutathione and glutathione peroxidase antioxidant defence.

    PubMed

    Mouret, Stéphane; Sauvaigo, Sylvie; Peinnequin, André; Favier, Alain; Beani, Jean-Claude; Leccia, Marie-Thérèse

    2005-06-01

    Clinical observations of non-melanoma skin cancer in immunocompromised patients, such as organ transplant recipients, suggest co-operative effects of human papillomavirus (HPV) and ultraviolet (UV) radiation. The aim of the present study is to evaluate UV sensitivity and DNA damage formation according to antioxidant status in HPV16-infected keratinocytes. We used SKv cell lines, infected with HPV16 and well characterized for their proliferative and tumorigenic capacities. We showed that SKv cell lines presented various E6* (a truncated form of E6) RNA levels. We demonstrated that the higher oncoprotein RNA expression level was associated with a higher resistance to solar-simulated radiation, more specifically to UVB radiation and to hydrogen peroxide. Moreover, this high resistance was associated with a low oxidative DNA damage formation after UV radiation and was related to high glutathione content and glutathione peroxidase activities. Therefore, the results of our study suggest that E6* levels could modulate the glutathione/glutathione peroxidase pathway providing a mechanism to protect HPV-infected keratinocytes against an environmental oxidative stress, such as UV radiation.

  14. Selenocysteine oxidation in glutathione peroxidase catalysis: an MS-supported quantum mechanics study.

    PubMed

    Orian, Laura; Mauri, Pierluigi; Roveri, Antonella; Toppo, Stefano; Benazzi, Louise; Bosello-Travain, Valentina; De Palma, Antonella; Maiorino, Matilde; Miotto, Giovanni; Zaccarin, Mattia; Polimeno, Antonino; Flohé, Leopold; Ursini, Fulvio

    2015-10-01

    Glutathione peroxidases (GPxs) are enzymes working with either selenium or sulfur catalysis. They adopted diverse functions ranging from detoxification of H(2)O(2) to redox signaling and differentiation. The relative stability of the selenoenzymes, however, remained enigmatic in view of the postulated involvement of a highly unstable selenenic acid form during catalysis. Nevertheless, density functional theory calculations obtained with a representative active site model verify the mechanistic concept of GPx catalysis and underscore its efficiency. However, they also allow that the selenenic acid, in the absence of the reducing substrate, reacts with a nitrogen in the active site. MS/MS analysis of oxidized rat GPx4 complies with the predicted structure, an 8-membered ring, in which selenium is bound as selenenylamide to the protein backbone. The intermediate can be re-integrated into the canonical GPx cycle by glutathione, whereas, under denaturing conditions, its selenium moiety undergoes β-cleavage with formation of a dehydro-alanine residue. The selenenylamide bypass prevents destruction of the redox center due to over-oxidation of the selenium or its elimination and likely allows fine-tuning of GPx activity or alternate substrate reactions for regulatory purposes.

  15. Evidences for a role of glutathione peroxidase 4 (GPx4) in methylmercury induced neurotoxicity in vivo.

    PubMed

    Zemolin, A P P; Meinerz, D F; de Paula, M T; Mariano, D O C; Rocha, J B T; Pereira, A B; Posser, T; Franco, J L

    2012-12-01

    We evaluated the activity and expression of antioxidant enzymes in the cerebellum and cortex of Swiss adult male mice exposed to methylmercury (MeHg) in drinking water (40mg/L) during 21 days. The activity of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD) and thioredoxin reductase (TrxR) were determined spectrophotometrically. The expression (protein levels) of GPx1 and GPx4 isoforms, TrxR1 as well as heat shock protein 70 (HSP70) were evaluated using specific antibodies and normalized by actin levels. The exposure of mice to MeHg caused a significant impairment in locomotors performance in the open field test (crossings and rearing). This result was followed by a significant reduction of GPx and TrxR activities in the cerebellum and cortex when compared to untreated animals. We also observed a substantial decrease in GPx1, GPx4 and TrxR1 protein levels in the cerebellum, while in the cerebral cortex, only GPx4 and TrxR1 were decreased after MeHg treatment. The activities of the antioxidant enzymes GR, GST, CAT and SOD were increased in the cerebellum after MeHg administration to mice. In contrast, only CAT was increased in the cerebral cortex of MeHg-treated animals. The expression of HSP70 was up-regulated only in the cerebellum where MeHg-exposed mice showed a significant increase in the immunocontent of HSP70 when compared to controls. This is the first report showing a role for GPx4 in the neurotoxicity induced by MeHg in vivo. In addition, our data indicates that the selenoproteins GPx and TrxR as main targets during MeHg exposure, which may be considered in biomarker studies.

  16. Effects of supplementation with two sources and two levels of copper on meat lipid oxidation, meat colour and superoxide dismutase and glutathione peroxidase enzyme activities in Nellore beef cattle.

    PubMed

    Correa, Lísia Bertonha; Zanetti, Marcus Antonio; Del Claro, Gustavo Ribeiro; de Paiva, Fernanda Alves; da Luz e Silva, Saulo; Netto, Arlindo Saran

    2014-10-28

    In the present study, thirty-five Nellore bulls were used to determine the effects of two levels and two sources (organic and inorganic) of Cu supplementation on the oxidative stability of lipids, measured by the thiobarbituric acid-reactive substance (TBARS) test, meat colour and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities. The following treatments were used: (1) control (C) - basal diet without supplementation of Cu (7 mg Cu/kg DM); (2) I10 - basal diet supplemented with 10 mg Cu/kg DM in the form of copper sulphate (inorganic form); (3) I40 - basal diet supplemented with 40 mg Cu/kg DM in the form of copper sulphate; (4) O10 - basal diet supplemented with 10 mg Cu/kg DM in the form of copper proteinate (organic form); (5) O40 - basal diet supplemented with 40 mg Cu/kg DM in the form of copper proteinate. Lipid oxidation was determined in meat samples exposed to display, modified atmosphere (MA) and vacuum packaging (VC) conditions and in liver samples using the TBARS test. These samples were also evaluated for meat discolouration after exposure to air. The activities of SOD and GSH-Px enzymes were determined in liver samples. In display, MA and VC conditions, the TBARS values of samples from animals supplemented with 40 mg Cu/kg DM were lower than those of samples from control animals. There was no effect of treatment on the colour variables (L*, a*, b*). There was also no significant effect of treatment on hepatic TBARS concentrations and GSH-Px activity. Supplementation with Cu at 40 mg/kg, regardless of the source, induced higher hepatic SOD activity compared with the control treatment. In conclusion, Cu supplementation improved the oxidative stability of lipids in samples exposed to display, MA and VC conditions, demonstrating the antioxidant effect of this mineral.

  17. Bioaccumulation of PCB-153 and effects on molecular biomarkers acetylcholinesterase, glutathione-S-transferase and glutathione peroxidase in Mytilus galloprovincialis mussels.

    PubMed

    Vidal-Liñán, Leticia; Bellas, Juan; Soriano, José Antonio; Concha-Graña, Estefanía; Muniategui, Soledad; Beiras, Ricardo

    2016-07-01

    In this study, PCB-153 bioaccumulation kinetics and concentration-response experiments were performed employing wild Mytilus galloprovincialis mussels. In addition, the activity of three enzymatic biomarkers: glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE), were measured in the mussel gills. The experimental data fitted well to an asymptotic accumulation model with a high bioconcentration factor (BCF) of 9324 L kg(-1) and a very limited depuration capacity, described by a low excretion rate coefficient (Kd = 0.083 d(-1)). This study reports by first time in mussels significant inhibition of GST activity and significant induction of GPx activity as a result of exposure to dissolved PCB-153. In contrast, AChE activity was unaffected at all concentrations and exposure times tested. The effects on both enzymes are time-dependent, which stresses the difficulties inherent to the use of these biomarkers in chemical pollution monitoring programs.

  18. Bioaccumulation of PCB-153 and effects on molecular biomarkers acetylcholinesterase, glutathione-S-transferase and glutathione peroxidase in Mytilus galloprovincialis mussels.

    PubMed

    Vidal-Liñán, Leticia; Bellas, Juan; Soriano, José Antonio; Concha-Graña, Estefanía; Muniategui, Soledad; Beiras, Ricardo

    2016-07-01

    In this study, PCB-153 bioaccumulation kinetics and concentration-response experiments were performed employing wild Mytilus galloprovincialis mussels. In addition, the activity of three enzymatic biomarkers: glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE), were measured in the mussel gills. The experimental data fitted well to an asymptotic accumulation model with a high bioconcentration factor (BCF) of 9324 L kg(-1) and a very limited depuration capacity, described by a low excretion rate coefficient (Kd = 0.083 d(-1)). This study reports by first time in mussels significant inhibition of GST activity and significant induction of GPx activity as a result of exposure to dissolved PCB-153. In contrast, AChE activity was unaffected at all concentrations and exposure times tested. The effects on both enzymes are time-dependent, which stresses the difficulties inherent to the use of these biomarkers in chemical pollution monitoring programs. PMID:27176625

  19. Bioaccumulation of 4-nonylphenol and effects on biomarkers, acetylcholinesterase, glutathione-S-transferase and glutathione peroxidase, in Mytilus galloprovincialis mussel gilla.

    PubMed

    Vidal-Liñán, Leticia; Bellas, Juan; Salgueiro-González, Noelia; Muniategui, Soledad; Beiras, Ricardo

    2015-05-01

    Wild marine mussels, Mytilus galloprovincialis showed a moderate bioaccumulation ability when exposed to waterborne 4-nonylphenol (4-NP), with a bioconcentration factor (BCF) of 6850 L Kg(-1) (dry weight). Kinetic and concentration-response experiments were performed and three enzymatic biomarkers in mussel gills were measured: Glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE). Exposure of mussels to environmentally relevant concentrations (25-100 μg L(-1)) of 4-nonylphenol significantly inhibited the AChE activity and induced the GST and GPx activities. GST induction was dose dependent whilst GPx activity showed a less consistent pattern, but in both cases the induction remained after a 10 d depuration period. Mussels seem capable of eliminating 4-NP from their tissues through a mechanism involving GST induction.

  20. Bioaccumulation of BDE-47 and effects on molecular biomarkers acetylcholinesterase, glutathione-S-transferase and glutathione peroxidase in Mytilus galloprovincialis mussels.

    PubMed

    Vidal-Liñán, Leticia; Bellas, Juan; Fumega, José; Beiras, Ricardo

    2015-03-01

    Mussels, Mytilus galloprovincialis, showed a high bioaccumulation ability when exposed to waterborne tetrabromodiphenyl ether (BDE-47), with a bioconcentration factor of 10,900 L Kg(-1) wet weight, and slow depuration rates in clean seawater. Kinetic and concentration-response experiments were performed measuring in the exposed mussel the activities of three molecular biomarkers: glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE). The long term (30 days) exposure of mussels to all concentrations (2-15 µg L(-1)) of BDE-47 significantly inhibited the AChE and GST activities, a result that supports the suitability of these biomarkers in marine pollution monitoring programs. However, GPx activity showed a less consistent pattern of response depending on the concentration and the duration of exposure.

  1. Glutathione Peroxidase 7 Utilizes Hydrogen Peroxide Generated by Ero1α to Promote Oxidative Protein Folding

    PubMed Central

    Zhang, Lihui; Niu, Yingbo; Sitia, Roberto

    2014-01-01

    Abstract Aims: Ero1 flavoproteins catalyze oxidative folding in the endoplasmic reticulum (ER), consuming oxygen and generating hydrogen peroxide (H2O2). The ER-localized glutathione peroxidase 7 (GPx7) shows protein disulfide isomerase (PDI)-dependent peroxidase activity in vitro. Our work aims at identifying the physiological role of GPx7 in the Ero1α/PDI oxidative folding pathway and at dissecting the reaction mechanisms of GPx7. Results: Our data show that GPx7 can utilize Ero1α-produced H2O2 to accelerate oxidative folding of substrates both in vitro and in vivo. H2O2 oxidizes Cys57 of GPx7 to sulfenic acid, which can be resolved by Cys86 to form an intramolecular disulfide bond. Both the disulfide form and sulfenic acid form of GPx7 can oxidize PDI for catalyzing oxidative folding. GPx7 prefers to interact with the a domain of PDI, and intramolecular cooperation between the two redox-active sites of PDI increases the activity of the Ero1α/GPx7/PDI triad. Innovation: Our in vitro and in vivo evidence provides mechanistic insights into how cells consume potentially harmful H2O2 while optimizing oxidative protein folding via the Ero1α/GPx7/PDI triad. Cys57 can promote PDI oxidation in two ways, and Cys86 emerges as a novel noncanonical resolving cysteine. Conclusion: GPx7 promotes oxidative protein folding, directly utilizing Ero1α-generated H2O2 in the early secretory compartment. Thus, the Ero1α/GPx7/PDI triad generates two disulfide bonds and two H2O molecules at the expense of a single O2 molecule. Antioxid. Redox Signal. 20, 545–556. PMID:23919619

  2. Purification, crystallization and preliminary X-ray analysis of glutathione peroxidase Gpx3 from Saccharomyces cerevisiae

    SciTech Connect

    Yang, Zhu; Zhou, Cong-Zhao

    2006-06-01

    The glutathione peroxidase Gpx3 from the yeast S. cerevisiae has been overexpressed, purified, crystallized and diffracted to 2.6 Å resolution. Gpx3 is a monomer in solution which is different from its counterparts in mammals. The glutathione peroxidase Gpx3 from the yeast Saccharomyces cerevisiae has been overexpressed, purified and crystallized. Both gel-filtration and dynamic light-scattering (DLS) results indicate that Gpx3 is a monomer in solution at a concentration of about 2 mg ml{sup −1}, whereas glutathione peroxidases are normally tetrameric or dimeric. X-ray diffraction data from a single crystal of Gpx3 have been collected to 2.6 Å resolution. The crystals are triclinic and belong to space group P1, with unit-cell parameters a = 38.187, b = 43.372, c = 56.870 Å, α = 71.405, β = 73.376, γ = 89.633°. There are two Gpx3 monomers in a crystallographic asymmetric unit. Preliminary analyses show that the yeast Gpx3 is quite different from those of mammals.

  3. Construction of a smart microgel glutathione peroxidase mimic based on supramolecular self-assembly.

    PubMed

    Yin, Yanzhen; Jiao, Shufei; Zhang, Ruirui; Hu, Xiaoxi; Shi, Zhongfeng; Huang, Zuqiang

    2015-07-14

    In an effort to construct smart artificial glutathione peroxidase (GPx) featuring high catalytic activity in an efficient preparation process, an artificial microgel GPx (PPAM-ADA-Te) has been prepared using a supramolecular host-guest self-assembly technique. Herein, 6,6'-telluro-bis(6-deoxy-β-cyclodextrin) (CD-Te-CD) was selected as a tellurium-containing host molecule, which also served as the crosslinker for the scaffold of the supramolecular microgel. And an adamantane-containing block copolymer (PPAM-ADA) was designed and synthesized as a guest building block copolymer. Subsequently, PPAM-ADA-Te was constructed through the self-assembly of CD-Te-CD and PPAM-ADA. The formation of this self-assembled construct was confirmed by dynamic light scattering, NMR, SEM and TEM. Notably, PPAM-ADA-Te not only exhibits a significant temperature responsive catalytic activity, but also features the characteristic saturation kinetics behaviour similar to that of a natural enzyme catalyst. We demonstrate in this paper that both the hydrophobic microenvironment and the crosslinker in this supramolecular microgel network played significant roles in enhancing and altering the temperature responsive catalytic behaviour. The successful construction of PPAM-ADA-Te not only provides a novel method for the preparation of microgel artificial GPx with high catalytic activity but also provides properties suitable for the future development of intelligent antioxidant drugs. PMID:26053236

  4. Expression and characterization of a phospholipid hydroperoxide glutathione peroxidase gene in Schistosoma japonicum.

    PubMed

    Zhang, Ying; He, Yuan; He, L I; Zong, Hongying; Cai, Guobin

    2015-11-01

    Phospholipid hydroperoxide glutathione peroxidase (PHGPx, GPx4) is a major antioxidant enzyme, which plays unique roles in the protection of cells against oxidative stress by catalysing reduction of lipid hydroperoxides. We isolated and characterized a full-length cDNA sequence encoding GPx gene from a blood fluke, Schistosoma japonicum (designated SjGPx), which contained an in-frame TGA codon for selenocysteine (Sec) and a concurrent Sec insertion sequence in its 3'-untranslated region. Protein encoded by SjGPx demonstrated a primary structure characteristic to the PHGPx family, including preservation of catalytic domains and absence of the subunit interaction domains. Semi-quantitative reverse transcription PCR and Western blotting showed that the SjGPx was mainly expressed in the female adults and eggs. RNA interference approach was employed to investigate the effects of knockdown of SjGPx. SjGPx expression level was significantly reduced on the 5th day post-RNAi. Significantly reduction in GPx enzyme activities, as well as obvious changes in morphology of intrauterine eggs followed the reduction in SjGPx transcript level. We observed a 63·04% reduction in GPx activity and the eggs severely deformed. Our results revealed that SjGPx protein might be involved in the provision of enzyme activity during egg production. PMID:26283515

  5. Dopamine quinone modifies and decreases the abundance of the mitochondrial selenoprotein glutathione peroxidase 4.

    PubMed

    Hauser, David N; Dukes, April A; Mortimer, Amanda D; Hastings, Teresa G

    2013-12-01

    Oxidative stress and mitochondrial dysfunction are known to contribute to the pathogenesis of Parkinson's disease. Dopaminergic neurons may be more sensitive to these stressors because they contain dopamine (DA), a molecule that oxidizes to the electrophilic dopamine quinone (DAQ) which can covalently bind nucleophilic amino acid residues such as cysteine. The identification of proteins that are sensitive to covalent modification and functional alteration by DAQ is of great interest. We have hypothesized that selenoproteins, which contain a highly nucleophilic selenocysteine residue and often play vital roles in the maintenance of neuronal viability, are likely targets for the DAQ. Here we report the findings of our studies on the effect of DA oxidation and DAQ on the mitochondrial antioxidant selenoprotein glutathione peroxidase 4 (GPx4). Purified GPx4 could be covalently modified by DAQ, and the addition of DAQ to rat testes lysate resulted in dose-dependent decreases in GPx4 activity and monomeric protein levels. Exposing intact rat brain mitochondria to DAQ resulted in similar decreases in GPx4 activity and monomeric protein levels as well as detection of multiple forms of DA-conjugated GPx4 protein. Evidence of both GPx4 degradation and polymerization was observed following DAQ exposure. Finally, we observed a dose-dependent loss of mitochondrial GPx4 in differentiated PC12 cells treated with dopamine. Our findings suggest that a decrease in mitochondrial GPx4 monomer and a functional loss of activity may be a contributing factor to the vulnerability of dopaminergic neurons in Parkinson's disease. PMID:23816523

  6. Construction of a highly stable artificial glutathione peroxidase on a protein nanoring.

    PubMed

    Miao, Lu; Zhang, Xiyu; Si, Chengye; Gao, Yuzhou; Zhao, Linlu; Hou, Chunxi; Shoseyov, Oded; Luo, Quan; Liu, Junqiu

    2014-01-14

    Stable Protein One (SP1) is a boiling-stable oligomeric protein. The unique characteristics of SP1 offer a scaffold to design artificial enzymes against extreme temperature. Here, an efficient antioxidase is successfully constructed on the ring-shaped SP1 homododecamer. By means of computational design and genetic engineering, the active center of glutathione peroxidase (GPx), selenocysteine (Sec), is introduced to the SP1 monomer surface, and the self-assembly properties of the protein monomer lead to a ring-shaped SP1 with homododecamer catalytic selenium centers. This artificial selenoenzyme exhibits high GPx catalytic activity and shows a typical ping-pong kinetic mechanism. Moreover, it has a significantly broader temperature range and high thermostability. Owing to having multi-GPx active centers on a SP1 oligomer, this selenium-containing biomacromolecule exerts an excellent capability to protect cells from oxidative damage at the mitochondrial level. This strategy represents a new way to develop thermostable artificial nanoenzymes for some specific applications. PMID:24264596

  7. Electrotypes and formal genetics of red cell glutathione peroxidase (GPX1) in the Djuka of Surinam.

    PubMed Central

    Meera Khan, P; Verma, C; Wijnen, L M; Wijnen, J T; Prins, H K; Nijenhuis, L E

    1986-01-01

    Samples of venous blood from 239 male and 476 female adults including 41 pairs of parents and 123 of their children belonging to a Surinam population called the Djuka or Bush Negroes of West African origin were screened for electrophoretic variants of red cell glutathione peroxidase (GPX1) in Cellogel. The results confirmed an earlier hypothesis that at least a part of the GPX1 variation mainly, if not exclusively, observed in the Africans and people of African origin living elsewhere, is determined by two codominant alleles (called GPX1*1 and GPX1*2), at an autosomal locus. The frequency of GPX1*2 allele in the Djuka was estimated to be .054. A rare variant provisionally designed as GPX1 Djuka (thought to be a heterozygote due to a third allele called GPX1*3 and the GPX1*1) was found in two apparently unrelated individuals. Catalytically, the product of GPX1*2 appears to be about twice more active than that of GPX1*1. For heuristic purposes, it was proposed and discussed that GPX1*2 is a South-Saharan African allele and is amenable for natural selection. Images Fig. 1 PMID:3717160

  8. Glutathione peroxidase inhibitory assay for electrophilic pollutants in diesel exhaust and tobacco smoke.

    PubMed

    Staimer, Norbert; Nguyen, Tran B; Nizkorodov, Sergey A; Delfino, Ralph J

    2012-04-01

    We developed a rapid kinetic bioassay demonstrating the inhibition of glutathione peroxidase 1 (GPx-1) by organic electrophilic pollutants, such as acrolein, crotonaldehyde, and p-benzoquinone, that are frequently found as components of tobacco smoke, diesel exhaust, and other combustion sources. In a complementary approach, we applied a high-resolution proton-transfer reaction time-of-flight mass spectrometer to monitor in real-time the generation of electrophilic volatile carbonyls in cigarette smoke. The new bioassay uses the important antioxidant selenoenzyme GPx-1, immobilized to 96-well microtiter plates, as a probe. The selenocysteine bearing subunits of the enzyme's catalytic site are viewed as cysteine analogues and are vulnerable to electrophilic attack by compounds with conjugated carbonyl systems. The immobilization of GPx-1 to microtiter plate wells enabled facile removal of excess reactive inhibitory compounds after incubation with electrophilic chemicals or aqueous extracts of air samples derived from different sources. The inhibitory response of cigarette smoke and diesel exhaust particle extracts were compared with chemical standards of a group of electrophilic carbonyls and the arylating p-benzoquinone. GPx-1 activity was directly inactivated by millimolar concentrations of highly reactive electrophilic chemicals (including acrolein, glyoxal, methylglyoxal, and p-benzoquinone) and extracts of diesel and cigarette smoke. We conclude that the potential of air pollutant components to generate oxidative stress may be, in part, a result of electrophile-derived covalent modifications of enzymes involved in the cytosolic antioxidant defense.

  9. Association of Catalase and Glutathione Peroxidase 1 Polymorphisms with Chronic Hepatitis C Outcome.

    PubMed

    Sousa, Vanessa C S D; Carmo, Rodrigo F; Vasconcelos, Luydson R S; Aroucha, Dayse C B L; Pereira, Leila M M B; Moura, Patrícia; Cavalcanti, Maria S M

    2016-05-01

    The hepatic damage caused by hepatitis C virus (HCV) infection is associated with the host immune response and viral regulatory factors. Catalase (CAT) and glutathione peroxidase 1 (GPX1) are antioxidant enzymes located in the peroxisomes and mitochondria, respectively, and are responsible for the control of intracellular hydrogen peroxide levels. Polymorphisms in CAT (C-262T) and GPX1 (Pro198Leu) are correlated with serum levels and enzyme activity. This study aimed to investigate the association of genetic polymorphisms of CAT C-262T (rs1001179) and GPX1 Pro198Leu (rs1050450) with different stages of liver fibrosis and development of hepatocellular carcinoma (HCC). This study included 445 patients with chronic hepatitis C, of whom 139 patients had mild fibrosis (F0-F1), 200 had moderate/severe fibrosis (F2-F4), and 106 had HCC. Genotyping of SNPs was performed by real-time PCR using TaqMan probes. The Pro/Pro genotype of GPX1 was significantly associated with fibrosis severity, HCC, Child Pugh score, and BCLC staging. Additionally, patients carrying both CT+TT genotypes in the CAT gene and the Pro/Pro genotype in the GPX1 gene had higher risk for developing moderate/severe fibrosis or HCC (p = 0.009, OR 2.40 and p = 0.002, OR 3.56, respectively). CAT and GPX1 polymorphisms may be implicated in the severity of liver fibrosis and HCC caused by HCV.

  10. Regulation of the Extracellular Antioxidant Selenoprotein Plasma Glutathione Peroxidase (GPx-3) in Mammalian Cells

    PubMed Central

    Ottaviano, Filomena G.; Tang, Shiow-Shih; Handy, Diane E.; Loscalzo, Joseph

    2009-01-01

    Plasma glutathione peroxidase (GPx-3) is a selenocysteine-containing extracellular antioxidant protein that catalyzes the reduction of hydrogen peroxide and lipid hydroperoxides. Selenoprotein expression involves the alternate recognition of a UGA codon as a selenocysteine codon and requires signals in the 3′-untranslated region (UTR), including a selenocysteine insertion sequence (SECIS), as well as specific translational cofactors. To ascertain regulatory determinants of GPx-3 expression and function, we generated recombinant GPx-3 (rGPX-3) constructs with various 3′-UTR, as well as a Sec73Cys mutant. In transfected Cos7 cells, the Sec73Cys mutant was expressed at higher levels than the wild type rGPx-3, although the wild type rGPx-3 had higher specific activity, similar to plasma purified GPx-3. A 3′-UTR with only the SECIS was insufficient for wild type rGPx-3 protein expression. Selenocompound supplementation and co-transfection with SECIS binding protein 2, increased wild type rGPx-3 expression. These results demonstrate the importance of translational mechanisms in GPx-3 expression. PMID:19219623

  11. Cloning a glutathione peroxidase gene from Nelumbo nucifera and enhanced salt tolerance by overexpressing in rice.

    PubMed

    Diao, Ying; Xu, Huaxue; Li, Guolin; Yu, Aiqing; Yu, Xia; Hu, Wanling; Zheng, Xingfei; Li, Shaoqing; Wang, Youwei; Hu, Zhongli

    2014-08-01

    A full-length cDNA clone encoding an 866 bp-length glutathione peroxidase protein (NnGPX) was isolated from lotus (Nelumbo nucifera L.). The deduced amino acid sequence of the NnGPX gene had significant homology with ATGPX6. A 3D structural model of the NnGPX was constructed by homology modeling. The cloned NnGPX gene was expressed in Escherichia coli, and a fusion protein of about 40 kDa was detected after isopropyl thiogalactoside induction. Under different concentrations of Na2SeO3 treatments, NnGPX was found to be an enzyme that does not contain selenium. Real-time PCR analysis showed that the NnGPX gene was expressed in all organs of lotus, and its high expression mainly occurred in organs with active metabolisms. NnGPX transcript increased remarkably in response to cold, heat, mechanical damage, and salt treatment. Subsequently, the NnGPX gene was introduced in Oryza sativa cv. Yuetai B. PCR results verified the integration of this gene into the genome of rice and reverse transcription-PCR verified that this gene had been expressed in transgenic rice. The transgenic plants were significantly more tolerant to salt stress compared with the wild-type. PMID:24715609

  12. TcGPXII, a glutathione-dependent Trypanosoma cruzi peroxidase with substrate specificity restricted to fatty acid and phospholipid hydroperoxides, is localized to the endoplasmic reticulum.

    PubMed Central

    Wilkinson, Shane R; Taylor, Martin C; Touitha, Said; Mauricio, Isabel L; Meyer, David J; Kelly, John M

    2002-01-01

    Until recently, it had been thought that trypanosomes lack glutathione peroxidase activity. Here we report the subcellular localization and biochemical properties of a second glutathione-dependent peroxidase from Trypanosoma cruzi (TcGPXII). TcGPXII is a single-copy gene which encodes a 16 kDa protein that appears to be specifically dependent on glutathione as the source of reducing equivalents. Recombinant TcGPXII was purified and shown to have peroxidase activity towards a narrow substrate range, restricted to hydroperoxides of fatty acids and phospholipids. Analysis of the pathway revealed that TcGPXII activity could be readily saturated by glutathione and that the peroxidase functioned by a Ping Pong mechanism. Enzyme reduction was shown to be the rate-limiting step in this pathway. Using immunofluorescence, TcGPXII was shown to co-localize with a homologue of immunoglobulin heavy-chain binding protein (BiP), a protein restricted to the endoplasmic reticulum and Golgi. As the smooth endoplasmic reticulum is the site of phospholipid and fatty acid biosynthesis, this suggests that TcGPXII may play a specific role in the T. cruzi oxidative defence system by protecting newly synthesized lipids from peroxidation. PMID:12049643

  13. Screening Actinomycetes for Extracellular Peroxidase Activity

    PubMed Central

    Mercer, D. K.; Iqbal, M.; Miller, P.; McCarthy, A. J.

    1996-01-01

    A diverse collection of actinomycete strains were screened for production of extracellular peroxidase activity by adapting a chemiluminescence analysis system developed for horseradish peroxidase-based enzyme-linked immunosorbent assay. Extracellular peroxidase activity was found to be common but quantitatively variable, and this rapid and sensitive screening system permitted identification of a small group of high-producing strains. A range of spectrophotometric assays were compared for the measurement of peroxidase activity in concentrated culture supernatants of two selected thermophilic streptomycetes. Of these, the peroxide-dependent oxidation of 2,4-dichlorophenol was identified as the most robust and reproducible assay for quantitative studies. PMID:16535344

  14. Evidence for peroxidase activity in Caralluma umbellata.

    PubMed

    Achar, Raghu Ram; Venkatesh, B K; Sharanappa, P; Priya, B S; Swamy, S Nanjunda

    2014-08-01

    Vast applications of peroxidases create an increasing demand to characterize peroxidases from new sources with more applicability potential. The aim of the present study was to check the presence of peroxidase activity from Caralluma umbellata. This is the first report on the C. umbellata peroxidase (CUP). The presence of peroxidase was revealed by the histochemical analysis of the stem sections, zymographic studies, and in vitro peroxidase activity assay using various reducing substrates viz., 2, 2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), guaiacol, o-dianisidine, and ferulic acid. The band pattern in zymogram confirms that CUP has a molecular weight less than that of horseradish peroxidase (44 kDa). Comparative evaluation of peroxidase activity of CUP with respect to horseradish peroxidase (HRP) indicates that CUP catalyzes ABTS and ferulic acid in a similar pattern as HRP but with guaiacol, the extent of catalysis shown by CUP over HRP is high. The standard inhibitors sodium azide and sodium meta bisulphite inhibited CUP activity in a dose dependent manner.

  15. Identification of methionine as a possible precursor to the selenocysteine catalytic site of glutathione peroxidase

    SciTech Connect

    Chung, C.K.

    1985-01-01

    The selenium (Se) moiety of glutathione peroxidase (GSHPx) occurs as selenocysteine and is present at the catalytic active site of the enzyme which catalyzes the reduction of hydrogen peroxides and lipid peroxides. The presence of this unusual amino acid at the active site raises the question as to the origin of the carbon skeleton of Se-cysteine. ICR Swiss mice were fed a Se deficient diet for 50 days and then were fed a Se adequate diet (1 ppm Se as SeO/sub 3/). Mice were i.p. injected with either (U-/sup 14/C) methionine, serine, or alanine (0.5 ..mu..Ci/0.1 ml/mouse/day) for 25 days. Recovered GSHPx activity in liver and blood was carboxymethylated (CM) with iodoacetic acid. CM-GSHPx was partially purified by column chromatography. /sup 14/C-GSHPx fractions were collected, lyophilized, and hydrolyzed. /sup 14/C-amino acids were separated by TLC and ion-exchange chromatography. TLC (phenol, cyclohexane, acetic acid, and water (90;6.5;3.5;8)) revealed a GSHPx /sup 14/C-amino acid derived from U-/sup 14/C-methionine, but not from serine or alanine corresponding to CM-selenocysteine (R/sub f/; 0.16). Ion-exchange chromatography of U-/sup 14/C-methionine labeled GSHPx hydrolyzate revealed two radio carbon ninhydrin positive peaks corresponding to /sup 14/C-CM-selenocysteine and /sup 14/C-methionine. No corresponding /sup 14/C-labeled peaks were observed for CM-selenocysteine derived from U-/sup 14/C serine or alanine. The results suggest that methionine may contribute a portion of the carbon skeleton to selenocysteine which may include an alternative metabolic pathway. Animal studies demonstrated that GSHPx activity is increased by methionine supplementation may be due to its contribution of carbon source to the catalytic site of the enzyme.

  16. Selenium concentrations and enzyme activities of glutathione metabolism in wild long-tailed ducks and common eiders

    USGS Publications Warehouse

    Franson, J. Christian; Hoffman, David J.; Flint, Paul L.

    2011-01-01

    The relationships of selenium (Se) concentrations in whole blood with plasma activities of total glutathione peroxidase, Se-dependent glutathione peroxidase, and glutathione reductase were studied in long-tailed ducks (Clangula hyemalis) and common eiders (Somateria mollissima) sampled along the Beaufort Sea coast of Alaska, USA. Blood Se concentrations were >8 μg/g wet weight in both species. Linear regression revealed that the activities of total and Se-dependent glutathione peroxidase were significantly related to Se concentrations only in long-tailed ducks, raising the possibility that these birds were experiencing early oxidative stress.

  17. Identification of a selenium-dependent glutathione peroxidase in the blood-sucking insect Rhodnius prolixus.

    PubMed

    Dias, Felipe A; Gandara, Ana C P; Perdomo, Hugo D; Gonçalves, Renata S; Oliveira, Carolina R; Oliveira, Raquel L L; Citelli, Marta; Polycarpo, Carla R; Santesmasses, Didac; Mariotti, Marco; Guigó, Roderic; Braz, Gloria R; Missirlis, Fanis; Oliveira, Pedro L

    2016-02-01

    The selenium-dependent glutathione peroxidase (SeGPx) is a well-studied enzyme that detoxifies organic and hydrogen peroxides and provides cells or extracellular fluids with a key antioxidant function. The presence of a SeGPx has not been unequivocally demonstrated in insects. In the present work, we identified the gene and studied the function of a Rhodnius prolixus SeGPx (RpSeGPx). The RpSeGPx mRNA presents the UGA codon that encodes the active site selenocysteine (Sec) and a corresponding Sec insertion sequence (SECIS) in the 3' UTR region. The encoded protein includes a signal peptide, which is consistent with the high levels of GPx enzymatic activity in the insect's hemolymph, and clusters phylogenetically with the extracellular mammalian GPx03. This result contrasts with all other known insect GPxs, which use a cysteine residue instead of Sec and cluster with the mammalian phospholipid hydroperoxide GPx04. RpSeGPx is widely expressed in insect organs, with higher expression levels in the fat body. RNA interference (RNAi) was used to reduce RpSeGPx gene expression and GPx activity in the hemolymph. Adult females were apparently unaffected by RpSeGPx RNAi, whereas first instar nymphs showed a three-day delay in ecdysis. Silencing of RpSeGPx did not alter the gene expression of the antioxidant enzymes catalase, xanthine dehydrogenase and a cysteine-GPx, but it reduced the levels of the dual oxidase and NADPH oxidase 5 transcripts that encode for enzymes releasing extracellular hydrogen peroxide/superoxide. Collectively, our data suggest that RpSeGPx functions in the regulation of extracellular (hemolymph) redox homeostasis of R. prolixus. PMID:26392061

  18. Identification of a selenium-dependent glutathione peroxidase in the blood-sucking insect Rhodnius prolixus.

    PubMed

    Dias, Felipe A; Gandara, Ana C P; Perdomo, Hugo D; Gonçalves, Renata S; Oliveira, Carolina R; Oliveira, Raquel L L; Citelli, Marta; Polycarpo, Carla R; Santesmasses, Didac; Mariotti, Marco; Guigó, Roderic; Braz, Gloria R; Missirlis, Fanis; Oliveira, Pedro L

    2016-02-01

    The selenium-dependent glutathione peroxidase (SeGPx) is a well-studied enzyme that detoxifies organic and hydrogen peroxides and provides cells or extracellular fluids with a key antioxidant function. The presence of a SeGPx has not been unequivocally demonstrated in insects. In the present work, we identified the gene and studied the function of a Rhodnius prolixus SeGPx (RpSeGPx). The RpSeGPx mRNA presents the UGA codon that encodes the active site selenocysteine (Sec) and a corresponding Sec insertion sequence (SECIS) in the 3' UTR region. The encoded protein includes a signal peptide, which is consistent with the high levels of GPx enzymatic activity in the insect's hemolymph, and clusters phylogenetically with the extracellular mammalian GPx03. This result contrasts with all other known insect GPxs, which use a cysteine residue instead of Sec and cluster with the mammalian phospholipid hydroperoxide GPx04. RpSeGPx is widely expressed in insect organs, with higher expression levels in the fat body. RNA interference (RNAi) was used to reduce RpSeGPx gene expression and GPx activity in the hemolymph. Adult females were apparently unaffected by RpSeGPx RNAi, whereas first instar nymphs showed a three-day delay in ecdysis. Silencing of RpSeGPx did not alter the gene expression of the antioxidant enzymes catalase, xanthine dehydrogenase and a cysteine-GPx, but it reduced the levels of the dual oxidase and NADPH oxidase 5 transcripts that encode for enzymes releasing extracellular hydrogen peroxide/superoxide. Collectively, our data suggest that RpSeGPx functions in the regulation of extracellular (hemolymph) redox homeostasis of R. prolixus.

  19. Phospholipid hydroperoxide glutathione peroxidase induces a delay in G1 of the cell cycle.

    PubMed

    Wang, Hong P; Schafer, Freya Q; Goswami, Prabhat C; Oberley, Larry W; Buettner, Garry R

    2003-06-01

    Phospholipid hydroperoxide glutathione peroxidase (PhGPx) is an antioxidant enzyme that reduces cellular phospholipid hydroperoxides (PLOOHs) to alcohols. Cellular peroxide tone has been implicated in cell growth and differentiation. By reducing the PLOOH level in the cell membrane, PhGPx regulates the peroxide tone and thereby might be involved in cell growth. We hypothesized that overexpression of PhGPx in human breast cancer cells would decrease their growth rate. We stably transfected MCF-7 cells (Wt) with L-PhGPx and measured cell doubling time, plating efficiency, and cell cycle phase transit times. P-4 cells (8-fold increase in PhGPx activity) showed a 2-fold increase in doubling time; doubling time increased directly with PhGPx activity (r = 0.95). The higher the PhGPx activity, the lower the plating efficiency (r = -0.86). The profile of other antioxidant enzymes was unchanged. Overexpression of PhGPx lowered the steady-state level of PLOOH (by > 60%). Results from bromodeoxyuridine pulse-chase experiments and flow cytometry indicate that PhGPx induced a delay in MCF-7 proliferation that was primarily due to a slower progression from G1 to S. These results support the hypothesis that PhGPx plays a regulatory role in the progression of MCF-7 cells from G1 to S possibly by regulating the steady-state levels of PLOOH. These data suggest that PhGPx can lower the peroxide tone, which might change the cellular redox environment resulting in a delay in G1 transit. Thus, PhGPx could be an important factor in cell growth. PMID:12868489

  20. Tomato Phospholipid Hydroperoxide Glutathione Peroxidase Inhibits Cell Death Induced by Bax and Oxidative Stresses in Yeast and Plants1

    PubMed Central

    Chen, Shaorong; Vaghchhipawala, Zarir; Li, Wei; Asard, Han; Dickman, Martin B.

    2004-01-01

    Using a conditional life or death screen in yeast, we have isolated a tomato (Lycopersicon esculentum) gene encoding a phospholipid hydroperoxide glutathione peroxidase (LePHGPx). The protein displayed reduced glutathione-dependent phospholipid hydroperoxide peroxidase activity, but differs from counterpart mammalian enzymes that instead contain an active seleno-Cys. LePHGPx functioned as a cytoprotector in yeast (Saccharomyces cerevisiae), preventing Bax, hydrogen peroxide, and heat stress induced cell death, while also delaying yeast senescence. When tobacco (Nicotiana tabacum) leaves were exposed to lethal levels of salt and heat stress, features associated with mammalian apoptosis were observed. Importantly, transient expression of LePHGPx protected tobacco leaves from salt and heat stress and suppressed the apoptotic-like features. As has been reported, conditional expression of Bax was lethal in tobacco, resulting in tissue collapse and membrane permeability to Evans blue. When LePHGPx was coexpressed with Bax, little cell death and no vital staining were observed. Moreover, stable expression of LePHGPx in tobacco conferred protection against the fungal phytopathogen Botrytis cinerea. Taken together, our data indicated that LePHGPx can protect plant tissue from a variety of stresses. Moreover, functional screens in yeast are a viable tool for the identification of plant genes that regulate cell death. PMID:15235116

  1. Glutathione Peroxidase Level in Patients with Vitiligo: A Meta-Analysis

    PubMed Central

    Xiao, Bi-huan; Shi, Meihui; Chen, Hongqiang; Cui, Shaoshan; Gao, Xing-Hua; Chen, Hong-Duo

    2016-01-01

    Abnormality of glutathione peroxidase (GPx) is involved in the etiology and pathogenesis of vitiligo. However, the results were controversial. Aim. The purpose of this meta-analysis is to compare the levels of GPx between vitiligo patients and healthy controls. Methods. Relevant published articles were searched according to eligibility criteria. A meta-analysis was conducted to pool estimates of the standardized mean difference (SMD) with 95% confidence interval (CI). Results. Twenty-three studies with a total of 1076 vitiligo patients and 770 healthy controls were included. The pooled meta-analysis showed that patients with vitiligo had equivalent levels of GPx with the healthy controls (SMD = −0.47, 95% CI: −1.03 to 0.08, and p = 0.095). Further subgroup analysis showed that the GPx levels of Asian patients or segmental vitiligo patients were, respectively, lower than those of healthy controls (Asian: SMD = −0.47, 95% CI: −1.08 to 0.14, and p = 0.001; segmental: SMD = −3.59, 95% CI: −6.38 to −0.80, and p = 0.012). Furthermore, the GPx levels in serum/plasma were significantly decreased in either stable or active vitiligo patients, comparing to healthy controls (stable: SMD = −2.01, 95% CI: −3.52 to −0.49, and p = 0.009; active: SMD = −2.34, 95% CI: −4.07 to −0.61, and p = 0.008). Conclusion. This meta-analysis showed a significant association between low GPx level and vitiligo. PMID:27218102

  2. Effect of Zirconium Dioxide Nanoparticles on Glutathione Peroxidase Enzyme in PC12 and N2a Cell Lines

    PubMed Central

    Asadpour, Elham; Sadeghnia, Hamid Reza; Ghorbani, Ahmad; Boroushaki, Mohammad Taher

    2014-01-01

    Today, special attention is paid to the use of zirconium dioxide nanoparticle (nano-ZrO2), a neutral bioceramic metal, particularly for drug and gene delivery in medicine. However, there are some reports implying that use of nano-ZrO2 is associated with cytotoxic effects like inhibiting the cell proliferation, DNA damage and apoptosis. In the present study, we examined whether nano-ZrO2 alters cell viability and glutathione peroxidase (GPx) activity in two neuronal cell lines. The PC12 and N2a cells were cultured in the absence or presence of varying concentrations (31.25-2000 µg/mL) of nano-ZrO2 for 12, 24 or 48 h. The cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and GPx activity was determined by quantifying the rate of oxidation of the reduced glutathione to the oxidized glutathione. Nano-ZrO2 caused a significant reduction in cell viability and GPx activity after 12, 24 and 48 h, as compared with control group. These effects were concentration dependent and started from 250 µg/mL. The present study demonstrated that nano-ZrO2, at concentrations of > 250 µg/mL, has antiproliferative effects via reducing the cell defense mechanism against oxidative stress. PMID:25587301

  3. Epigenetic and Glucocorticoid Receptor-Mediated Regulation of Glutathione Peroxidase 3 in Lung Cancer Cells

    PubMed Central

    An, Byung Chull; Jung, Nak-Kyun; Park, Chun Young; Oh, In-Jae; Choi, Yoo-Duk; Park, Jae-Il; Lee, Seung-won

    2016-01-01

    Glutathione peroxidase 3 (GPx3), an antioxidant enzyme, acts as a modulator of redox signaling, has immunomodulatory function, and catalyzes the detoxification of reactive oxygen species (ROS). GPx3 has been identified as a tumor suppressor in many cancers. Although hyper-methylation of the GPx3 promoter has been shown to down-regulate its expression, other mechanisms by which GPx3 expression is regulated have not been reported. The aim of this study was to further elucidate the mechanisms of GPx3 regulation. GPx3 gene analysis predicted the presence of ten glucocorticoid response elements (GREs) on the GPx3 gene. This result prompted us to investigate whether GPx3 expression is regulated by the glucocorticoid receptor (GR), which is implicated in tumor response to chemotherapy. The corticosteroid dexamethasone (Dex) was used to examine the possible relationship between GR and GPx3 expression. Dex significantly induced GPx3 expression in H1299, H1650, and H1975 cell lines, which exhibit low levels of GPx3 expression under normal conditions. The results of EMSA and ChIP-PCR suggest that GR binds directly to GRE 6 and 7, both of which are located near the GPx3 promoter. Assessment of GPx3 transcription efficiency using a luciferase reporter system showed that blocking formation of the GR-GRE complexes reduced luciferase activity by 7–8-fold. Suppression of GR expression by siRNA transfection also induced down-regulation of GPx3. These data indicate that GPx3 expression can be regulated independently via epigenetic or GR-mediated mechanisms in lung cancer cells, and suggest that GPx3 could potentiate glucocorticoid (GC)-mediated anti-inflammatory signaling in lung cancer cells. PMID:27484907

  4. Epigenetic and Glucocorticoid Receptor-Mediated Regulation of Glutathione Peroxidase 3 in Lung Cancer Cells.

    PubMed

    An, Byung Chull; Jung, Nak-Kyun; Park, Chun Young; Oh, In-Jae; Choi, Yoo-Duk; Park, Jae-Il; Lee, Seung-Won

    2016-08-31

    Glutathione peroxidase 3 (GPx3), an antioxidant enzyme, acts as a modulator of redox signaling, has immunomodulatory function, and catalyzes the detoxification of reactive oxygen species (ROS). GPx3 has been identified as a tumor suppressor in many cancers. Although hyper-methylation of the GPx3 promoter has been shown to down-regulate its expression, other mechanisms by which GPx3 expression is regulated have not been reported. The aim of this study was to further elucidate the mechanisms of GPx3 regulation. GPx3 gene analysis predicted the presence of ten glucocorticoid response elements (GREs) on the GPx3 gene. This result prompted us to investigate whether GPx3 expression is regulated by the glucocorticoid receptor (GR), which is implicated in tumor response to chemotherapy. The corticosteroid dexamethasone (Dex) was used to examine the possible relationship between GR and GPx3 expression. Dex significantly induced GPx3 expression in H1299, H1650, and H1975 cell lines, which exhibit low levels of GPx3 expression under normal conditions. The results of EMSA and ChIP-PCR suggest that GR binds directly to GRE 6 and 7, both of which are located near the GPx3 promoter. Assessment of GPx3 transcription efficiency using a luciferase reporter system showed that blocking formation of the GR-GRE complexes reduced luciferase activity by 7-8-fold. Suppression of GR expression by siRNA transfection also induced down-regulation of GPx3. These data indicate that GPx3 expression can be regulated independently via epigenetic or GR-mediated mechanisms in lung cancer cells, and suggest that GPx3 could potentiate glucocorticoid (GC)-mediated anti-inflammatory signaling in lung cancer cells. PMID:27484907

  5. Overexpression of glutathione peroxidase attenuates myocardial remodeling and preserves diastolic function in diabetic heart.

    PubMed

    Matsushima, Shouji; Kinugawa, Shintaro; Ide, Tomomi; Matsusaka, Hidenori; Inoue, Naoki; Ohta, Yukihiro; Yokota, Takashi; Sunagawa, Kenji; Tsutsui, Hiroyuki

    2006-11-01

    Oxidative stress plays an important role in the structural and functional abnormalities of diabetic heart. Glutathione peroxidase (GSHPx) is a critical antioxidant enzyme that removes H(2)O(2) in both the cytosol and mitochondia. We hypothesized that the overexpression of GSHPx gene could attenuate left ventricular (LV) remodeling in diabetes mellitus (DM). We induced DM by injection of streptozotocin (160 mg/kg ip) in male GSHPx transgenic mice (TG+DM) and nontransgenic wildtype littermates (WT+DM). GSHPx activity was higher in the hearts of TG mice compared with WT mice, with no significant changes in other antioxidant enzymes. LV thiobarbituric acid-reactive substances measured in TG+DM at 8 wk were significantly lower than those in WT+DM (58 +/- 3 vs. 71 +/- 5 nmol/g, P < 0.05). Heart rate and aortic blood pressure were comparable between groups. Systolic function was preserved normal in WT+DM and TG+DM mice. In contrast, diastolic function was impaired in WT+DM and was improved in TG+DM as assessed by the deceleration time of peak velocity of transmitral diastolic flow and the time needed for relaxation of 50% maximal LV pressure to baseline value (tau; 13.5 +/- 1.2 vs. 8.9 +/- 0.7 ms, P < 0.01). The TG+DM values were comparable with those of WT+Control (tau; 7.8 +/- 0.2 ms). Improvement of LV diastolic function was accompanied by the attenuation of myocyte hypertrophy, interstitial fibrosis, and apoptosis. Overexpression of GSHPx gene ameliorated LV remodeling and diastolic dysfunction in DM. Therapies designed to interfere with oxidative stress might be beneficial to prevent cardiac abnormalities in DM. PMID:16844917

  6. Selenium and glutathione peroxidases in blood of patients with different stages of chronic renal failure.

    PubMed

    Zachara, Bronislaw A; Salak, Anna; Koterska, Dominika; Manitius, Jacek; Wasowicz, Wojciech

    2004-01-01

    In patients with chronic renal failure (CRF) Se concentration in blood components is usually lower as compared with healthy controls. One of the five known forms of Se-dependent glutathione peroxidases (GSH-Px), the plasma GSH-Px, is synthesized primarily in the kidney. In CRF patients, plasma GSH-Px activity is reduced and the reduction increases with the progress of the disease. The Se concentration in blood components was measured spectrofluorometrically with 2,3-diaminonaphthalene as complexing reagent. Activities of GSH-Px in red cells and in plasma were assayed by the coupled method with t-butyl hydroperoxide as substrate. The study group consisted of 150 patients in different stages of CRF. The results were compared with the values for 30 healthy subjects. Se concentrations in whole blood and plasma of the entire group of patients were significantly lower (p < 0.01) as compared with the healthy subjects. In the incipient stage, however, the Se levels in all blood components were non-significantly lower. In whole blood and plasma the Se levels gradually decreased, reaching in the end stage values that were lower by 29 to 32% (p < 0.0001) as compared with the control group. Total protein and albumin levels in plasma of patients were significantly lower (p < 0.0001) as compared with healthy subjects and they decreased linearly with the progress of the disease. Positive and highly significant correlations were noted between total plasma protein and plasma Se concentrations (p < 0.0001) as well as between plasma albumin and plasma Se concentrations (p < 0.0001). Red cell GSH-Px activity in the entire group of patients was lower (p < 0.05) than in the control group and did not change significantly with the progress of the disease. In plasma, however, GSH-Px activity of the entire group was lower by 33% (p < 0.0001) as compared with healthy subjects and decreased gradually with increasing renal failure. Highly significant, inverse correlations were seen between

  7. Engineering Ascorbate Peroxidase Activity Into Cytochrome C Peroxidase

    SciTech Connect

    Meharenna, Y.T.; Oertel, P.; Bhaskar, B.; Poulos, T.L.

    2009-05-26

    Cytochrome c peroxidase (CCP) and ascorbate peroxidase (APX) have very similar structures, and yet neither CCP nor APX exhibits each others activities with respect to reducing substrates. APX has a unique substrate binding site near the heme propionates where ascorbate H-bonds with a surface Arg and one heme propionate (Sharp et al. (2003) Nat. Struct. Biol. 10, 303--307). The corresponding region in CCP has a much longer surface loop, and the critical Arg residue that is required for ascorbate binding in APX is Asn in CCP. In order to convert CCP into an APX, the ascorbate-binding loop and critical arginine were engineered into CCP to give the CCP2APX mutant. The mutant crystal structure shows that the engineered site is nearly identical to that found in APX. While wild-type CCP shows no APX activity, CCP2APX catalyzes the peroxidation of ascorbate at a rate of {approx}12 min{sup -1}, indicating that the engineered ascorbate-binding loop can bind ascorbate.

  8. A novel glutathione-S transferase immunosensor based on horseradish peroxidase and double-layer gold nanoparticles.

    PubMed

    Lu, Dingqiang; Lu, Fuping; Pang, Guangchang

    2016-06-01

    GSTs, a biotransformation enzyme group, can perform metabolism, drug transfer and detoxification functions. Rapid detection of the GSTs with more sensitive approaches is of great importance. In the current study, a novel double-layer gold nanoparticles-electrochemical immunosensor electrode (DGN-EIE) immobilized with Glutathione S-Transferase (GST) antibody derived from Balb/c mice was developed. To increase the fixed quantity of antibodies and electrochemical signal, an electrochemical biosensing signal amplification system was utilized with gold nanoparticles-thionine-chitosan absorbing horseradish peroxidase (HRP). In addition, transmission electron microscope (TEM) was used to characterize the nanogold solution. To evaluate the quality of DGN-EIE, the amperometric I-t curve method was applied to determine the GST in PBS. The results showed that the response current had a good linear correlation with the GST concentration ranged from 0.1-10(4) pg/mL. The lowest detection limit was found at 0.03 pg/mL(S/N = 3). The linear equation was deduced as △I/% = 7.386lgC + 22.36 (R(2) = 0.998). Moreover, it was validated with high sensitivity and reproducibility. Apparently, DGN-EIE may be a very useful tool for monitoring the GST. PMID:27220630

  9. Glutathione Peroxidase-3 Deficiency Promotes Platelet-dependent Thrombosis in vivo

    PubMed Central

    Jin, Richard C.; Mahoney, Christopher E.; Anderson, Laura (Coleman); Ottaviano, Filomena; Croce, Kevin; Leopold, Jane A.; Zhang, Yingyi; Tang, Shiow-Shih; Handy, Diane E.; Loscalzo, Joseph

    2011-01-01

    Background Glutathione peroxidase-3 (GPx-3) is a selenocysteine-containing plasma protein that scavenges reactive oxygen species in the extracellular compartment. A deficiency of this enzyme has been associated with platelet-dependent thrombosis, and a promoter haplotype with reduced function has been associated with stroke risk in young individuals. Methods and Results We recently developed a genetic mouse model to assess platelet function in hemostasis and thrombosis in the setting of GPx-3 deficiency. GPx-3(−/−) mice showed an attenuated bleeding time compared with wild-type mice. Platelet aggregation studies revealed an enhanced aggregation response to the agonist ADP in GPx-3(−/−) compared to wild-type mice. We also found an increase in the plasma levels of soluble P-selectin and a decrease in plasma cyclic GMP in GPx-3(−/−) mice compared with wild-type mice. ADP was infused into the right ventricle of mice to induce platelet aggregation in the pulmonary vasculature, and produced a more robust platelet activation response in the GPx-3(−/−) mice than in wild-type mice; histological sections from the pulmonary vasculature of GPx-3(−/−) compared with wild-type mice show increased platelet-rich thrombi and a higher percentage of occluded vessels. Endothelial function studies using a cremaster muscle preparation revealed dysfunction in the GPx-3(−/−) compared to wild-type mice. Using a no-flow ischemia-reperfusion stroke model, GPx-3(−/−) mice had significantly larger cerebral infarctions compared with wild-type mice. To investigate the effect of platelet inhibition on stroke size in GPx-3 deficiency, we found that clopidogrel treatment reduced stroke size significantly in GPx-3(−/−) mice compared with vehicle-treated controls. To assess the neuroprotective role of antioxidants in this model, we found that MnTBAP treatment reduced stroke size in GPx-3(−/−) mice compared with vehicle-treated controls. Conclusions These findings

  10. Effect of EPA and Vitamin C on Superoxide Dismutase, Glutathione Peroxidase, Total Antioxidant Capacity and Malondialdehyde in Type 2 Diabetic Patients

    PubMed Central

    Mahmoudabadi, Mohammad Mehdi Shakouri; Rahbar, Ali Reza

    2014-01-01

    Objectives The aim of this study is to investigate the effect of eicosapentaenoic acid combined with vitamin C in comparison with the pure form of eicosapentaenoic acid on the serum concentration of malondialdehyde, erythrocyte activity of superoxide dismutase, glutathione peroxidase, and the serum level of total antioxidant capacity in patients with type 2 diabetes. Methods Eighty one male diabetic patients, aged 33-63 years, were randomly assigned to one of 4 groups. The subjects consumed 500 mg/d pure eicosapentaenoic acid, 200 mg/d vitamin C, 500 mg eicosapentaenoic acid and 200 mg/d vitamin C or placebo depending on their groups. In fasting blood samples, superoxide dismutase and glutathione peroxidase activities were determined via the enzymatic method (Randox kit) and the serum total antioxidant capacity, malondialdehyde and vitamin C concentrations were estimated by colorimetric methods. Results Administration of pure eicosapentaenoic acid in diabetic patients increased superoxide dismutase by 4%, glutathione peroxidase 53%, total antioxidant capacity 36% and decreased malondialdehyde significantly by 25%. Prescription of eicosapentaenoic acid combined with vitamin C demonstrated a significant increment for superoxide dismutase activity by 3% and for glutathione peroxidase activity by 52% during the study, but no significant change was seen for total antioxidant capacity and malondialdehyde, respectively. There was a significant decrease in FBS and HbA1c following prescription of eicosapentaenoic acid with/without vitamin C along the study, although these changes were not significant between the study groups. Conclusion It is concluded that prescription of eicosapentaenoic acid in the pure form reduces oxidative stress in type 2 diabetic patients; albeit, it does not alleviate hyperglycemia. Combination of vitamin C and eicosapentaenoic acid does not improve antioxidant property of eicosapentaenoic acid. PMID:24498481

  11. Glutathione

    PubMed Central

    Noctor, Graham; Queval, Guillaume; Mhamdi, Amna; Chaouch, Sejir; Foyer, Christine H.

    2011-01-01

    Glutathione is a simple sulfur compound composed of three amino acids and the major non-protein thiol in many organisms, including plants. The functions of glutathione are manifold but notably include redox-homeostatic buffering. Glutathione status is modulated by oxidants as well as by nutritional and other factors, and can influence protein structure and activity through changes in thiol-disulfide balance. For these reasons, glutathione is a transducer that integrates environmental information into the cellular network. While the mechanistic details of this function remain to be fully elucidated, accumulating evidence points to important roles for glutathione and glutathione-dependent proteins in phytohormone signaling and in defense against biotic stress. Work in Arabidopsis is beginning to identify the processes that govern glutathione status and that link it to signaling pathways. As well as providing an overview of the components that regulate glutathione homeostasis (synthesis, degradation, transport, and redox turnover), the present discussion considers the roles of this metabolite in physiological processes such as light signaling, cell death, and defense against microbial pathogen and herbivores. PMID:22303267

  12. An extracytoplasmic function sigma factor-dependent periplasmic glutathione peroxidase is involved in oxidative stress response of Shewanella oneidensis

    SciTech Connect

    Dai, Jingcheng; Wei, Hehong; Tian, Chunyuan; Damron, Fredrick; Zhou, Jizhong; Qiu, Dongru

    2015-01-01

    Background: Bacteria use alternative sigma factors (σs) to regulate condition-specific gene expression for survival and Shewanella harbors multiple ECF (extracytoplasmic function) σ genes and cognate anti-sigma factor genes. Here we comparatively analyzed two of the rpoE-like operons in the strain MR-1: rpoE-rseA-rseB-rseC and rpoE2-chrR. Results: RpoE was important for bacterial growth at low and high temperatures, in the minimal medium, and high salinity. The degP/htrA orthologue, required for growth of Escherichia coli and Pseudomonas aeruginosa at high temperature, is absent in Shewanella, while the degQ gene is RpoE-regulated and is required for bacterial growth at high temperature. RpoE2 was essential for the optimal growth in oxidative stress conditions because the rpoE2 mutant was sensitive to hydrogen peroxide and paraquat. The operon encoding a ferrochelatase paralogue (HemH2) and a periplasmic glutathione peroxidase (PgpD) was identified as RpoE2-dependent. PgpD exhibited higher activities and played a more important role in the oxidative stress responses than the cytoplasmic glutathione peroxidase CgpD under tested conditions. The rpoE2-chrR operon and the identified regulon genes, including pgpD and hemH2, are coincidently absent in several psychrophilic and/or deep-sea Shewanella strains. Conclusion: In S. oneidensis MR-1, the RpoE-dependent degQ gene is required for optimal growth under high temperature. The rpoE2 and RpoE2-dependent pgpD gene encoding a periplasmic glutathione peroxidase are involved in oxidative stress responses. But rpoE2 is not required for bacterial growth at low temperature and it even affected bacterial growth under salt stress, indicating that there is a tradeoff between the salt resistance and RpoE2-mediated oxidative stress responses.

  13. An extracytoplasmic function sigma factor-dependent periplasmic glutathione peroxidase is involved in oxidative stress response of Shewanella oneidensis

    DOE PAGES

    Dai, Jingcheng; Wei, Hehong; Tian, Chunyuan; Damron, Fredrick; Zhou, Jizhong; Qiu, Dongru

    2015-01-01

    Background: Bacteria use alternative sigma factors (σs) to regulate condition-specific gene expression for survival and Shewanella harbors multiple ECF (extracytoplasmic function) σ genes and cognate anti-sigma factor genes. Here we comparatively analyzed two of the rpoE-like operons in the strain MR-1: rpoE-rseA-rseB-rseC and rpoE2-chrR. Results: RpoE was important for bacterial growth at low and high temperatures, in the minimal medium, and high salinity. The degP/htrA orthologue, required for growth of Escherichia coli and Pseudomonas aeruginosa at high temperature, is absent in Shewanella, while the degQ gene is RpoE-regulated and is required for bacterial growth at high temperature. RpoE2 was essentialmore » for the optimal growth in oxidative stress conditions because the rpoE2 mutant was sensitive to hydrogen peroxide and paraquat. The operon encoding a ferrochelatase paralogue (HemH2) and a periplasmic glutathione peroxidase (PgpD) was identified as RpoE2-dependent. PgpD exhibited higher activities and played a more important role in the oxidative stress responses than the cytoplasmic glutathione peroxidase CgpD under tested conditions. The rpoE2-chrR operon and the identified regulon genes, including pgpD and hemH2, are coincidently absent in several psychrophilic and/or deep-sea Shewanella strains. Conclusion: In S. oneidensis MR-1, the RpoE-dependent degQ gene is required for optimal growth under high temperature. The rpoE2 and RpoE2-dependent pgpD gene encoding a periplasmic glutathione peroxidase are involved in oxidative stress responses. But rpoE2 is not required for bacterial growth at low temperature and it even affected bacterial growth under salt stress, indicating that there is a tradeoff between the salt resistance and RpoE2-mediated oxidative stress responses.« less

  14. Glutathione peroxidase potentiates the inhibition of platelet function by S-nitrosothiols.

    PubMed Central

    Freedman, J E; Frei, B; Welch, G N; Loscalzo, J

    1995-01-01

    GSH peroxidase (Px) catalyzes the reduction of lipid hydroperoxides (LOOH), known metabolic products of platelets and vascular cells. Because interactions between these cells are modulated by nitric oxide (NO) and LOOH inactivate NO, we investigated the effect of GSH-Px on the inhibition of platelet function by the naturally occurring S-nitrosothiol, S-nitroso-glutathione (SNO-Glu). Concentrations of SNO-Glu that alone did not inhibit platelet function (subthreshold inhibitory concentrations) were added to platelet-rich plasma together with GSH-Px (0.2-20 U/ml); this led to a dose-dependent inhibition of platelet aggregation with an IC50 of 0.6 U/ml GSH-Px. In the presence of subthreshold inhibitory concentrations of SNO-Glu, the LOOH, 5-hydroperoxy-6,8,11,14-eicosatetraenoic acid, increased platelet aggregation, an effect reversed by GSH-Px. Glutathione and SNO-Glu were equally effective as cosubstrates for GSH-Px. Incubation of SNO-Glu with GSH-Px for 1 min led to a 48.5% decrease in the concentration of SNO-Glu. Incubation of SNO-Glu with serum albumin led to the formation of S-nitroso-albumin, an effect enhanced by GSH-Px. These observations suggest that GSH-Px has two functions: reduction of LOOH, thereby preventing inactivation of NO, and metabolism of SNO-Glu, thereby liberating NO and/or supporting further transnitrosation reactions. PMID:7615810

  15. Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese

    USGS Publications Warehouse

    Franson, J.C.; Hoffman, D.J.; Schmutz, J.A.

    2002-01-01

    In 1998, we collected blood samples from 63 emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feathera??molting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.

  16. Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese

    USGS Publications Warehouse

    Franson, J.C.; Hoffman, D.J.; Schmutz, J.A.

    2002-01-01

    In 1998, we collected blood samples from 63 emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feathermolting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.

  17. Construction of a subtractive library from hexavalent chromium treated winter flounder (Pseudopleuronectes americanus) reveals alterations in non-selenium glutathione peroxidases.

    PubMed

    Chapman, Laura M; Roling, Jonathan A; Bingham, Lacey K; Herald, Matt R; Baldwin, William S

    2004-04-14

    Chromium is released during several industrial processes and has accumulated in some estuarine areas. Its effects on mammals have been widely studied, but relatively little information is available on its effects on fish. Gene expression changes are useful biomarkers that can provide information about toxicant exposure and effects, as well as the health of an organism and its ability to adapt to its surroundings. Therefore, we investigated the effects of Cr(VI) on gene expression in the sediment dwelling fish, winter flounder (Pseudopleuronectes americanus). Winter flounder ranging from 300 to 360 g were injected i.p. with Cr(VI) as chromium oxide at 25 microg/kg chromium in 0.15N KCl. Twenty-four hours following injections, winter flounder were euthanized with MS-222 and the livers were excised. Half of the livers were used to make cytosol and the other half were used to isolate mRNA for subtractive hybridization. Subtractive clones obtained were spotted onto nylon filters, which revealed several genes with potentially altered expression due to Cr(VI), including an alpha class GST, 1-Cys peroxiredoxin (a non-selenium glutathione peroxidase), a P-450 2X subfamily member, two elongation factors (EF-1 gamma and EF-2), and complement component C3. Semi-quantitative RT-PCR was performed and confirmed that Cr(VI) down-regulated complement component C3, an EST, and two potential glutathione peroxidases, GSTA3 and 1-Cys peroxiredoxin. In addition, cytosolic GSH peroxidase activity was reduced, and silver stained SDS-PAGE gels from glutathione-affinity purified cytosol demonstrated that a 27.1 kDa GSH-binding protein was down-regulated greater than 50%. Taken together, Cr(VI) significantly altered the expression of several genes including two potential glutathione peroxidases in winter flounder. PMID:15003702

  18. Roles of catalase and glutathione peroxidase in the tolerance of a pulmonate gastropod to anoxia and reoxygenation.

    PubMed

    Welker, Alexis F; Moreira, Daniel C; Hermes-Lima, Marcelo

    2016-07-01

    Humans and most mammals suffer severe damage when exposed to ischemia and reperfusion episodes due to an overproduction of reactive oxygen species (ROS). In contrast, several hypoxia/anoxia-tolerant animals survive very similar situations. We evaluated herein the redox metabolism in the anoxia-tolerant land snail Helix aspersa after catalase inhibition by 3-amino-1,2,4-triazole (ATZ) injection during a cycle of wide and abrupt change in oxygen availability. The exposure to anoxia for 5 h caused a change of only one of several parameters related to free radical metabolism: a rise in selenium-dependent glutathione peroxidase (Se-GPX) activity in muscle of both saline- and ATZ-injected animals (by 1.9- and 1.8-fold, respectively). Catalase suppression had no effect in animals under normoxia or anoxia. However, during reoxygenation catalase suppression kept high levels of muscle Se-GPX activity (twofold higher than in saline-injected snails up to 30 min reoxygenation) and induced the increase in hepatopancreas SOD activity (by 22 %), indicating higher levels of ROS in both organs than in saline-injected animals. Additionally, catalase-suppressed snails showed 12 % higher levels of carbonyl protein-a sign of mild oxidative stress-in muscle during reoxygenation than those animals with intact catalase. No changes were observed in glutathione parameters (GSH, GSSG and GSSG:GSH ratio), TBARS, and GST activity in any of the experimental groups, in both organs. These results indicate that catalase inhibition inflicts changes in the free radical metabolism during reoxygenation, prompting a stress-response that is a reorganization in other enzymatic antioxidant defenses to minimize alterations in the redox homeostasis in land snails. PMID:27062029

  19. Variations in the distribution of selenium between erythrocyte glutathione peroxidase and hemoglobin in different human populations

    SciTech Connect

    Whanger, P.D.; Robinson, M.F.; Feldman, E.B.; Beilstein, M.A.; Butler, J.A.

    1986-03-01

    The majority of erythrocyte (RBC) selenium (Se) is associated with glutathione peroxidase (GPx) in animals, but most of it is with hemoglobin (Hb) in human RBCs. Dietary forms of Se may influence this distribution since a rat study showed that selenite promoted the deposition of Se in GPx but selenomethionine (SeMet) resulted in greater amounts with Hb. Three different populations of people were chosen to investigate some possible reasons for the Se distribution in human RBC proteins. An average of 12% of the RBC Se (0.71 ng Se/mg Hb) was associated with GPx in people living in Oregon, but nearly 30% of the Se was associated with GPx in RBC (0.26 ng Se/mg Hb) from New Zealanders. Georgia residents with low RBC Se levels (0.35 ng Se/mg Hb) had 38% of the Se associated with GPx as compared to 29% for those with higher RBC levels (0.56 ng Se/mg Hb). In a third group of people the amount of Se tended to be higher in RBC GPx from non-vegetarian OSU students than from vegetarians. The predominant form of Se in meat appears to be selenocysteine, which is metabolized similarly to selenite, and presumably contributes to this difference since many plant foods contain Se as SeMet. These are examples of many possible factors affecting the relative distribution of Se in human RBC proteins.

  20. Natural allelic variations in glutathione peroxidase-1 affect its subcellular localization and function.

    PubMed

    Bera, Soumen; Weinberg, Frank; Ekoue, Dede N; Ansenberger-Fricano, Kristine; Mao, Mao; Bonini, Marcelo G; Diamond, Alan M

    2014-09-15

    Glutathione peroxidase 1 (GPx-1) has been implicated in the etiology of several common diseases due to the association between specific allelic variations and cancer risk. The most common among these variations are the codon 198 polymorphism that results in either a leucine or proline and the number of alanine repeat codons in the coding sequence. The molecular and biologic consequences of these variations remain to be characterized. Toward achieving this goal, we have examined the cellular location of GPx-1 encoded by allelic variants by ectopically expressing these genes in MCF-7 human breast carcinoma cells that produce undetectable levels of GPx-1, thus achieving exclusive expression in the same cellular environment. A differential distribution between the cytoplasm and mitochondria was observed, with the allele expressing the leucine-198 polymorphism and 7 alanine repeats being more cytoplasmically located than the other alleles examined. To assess whether the distribution of GPx-1 between the cytoplasm and mitochondria had a biologic consequence, we engineered derivative GPx-1 proteins that were targeted to the mitochondria by the addition of a mitochondria targeting sequence and expressed these proteins in MCF-7 cells. These cells were examined for their response to oxidative stress, energy metabolism, and impact on cancer-associated signaling molecules. The results obtained indicated that both primary GPx-1 sequence and cellular location have a profound impact on cellular biology and offer feasible hypotheses about how expression of distinct GPx-1 alleles can affect cancer risk. Cancer Res; 74(18); 5118-26. ©2014 AACR.

  1. Glutathione Peroxidase-1 in Health and Disease: From Molecular Mechanisms to Therapeutic Opportunities

    PubMed Central

    Lubos, Edith; Loscalzo, Joseph

    2011-01-01

    Abstract Reactive oxygen species, such as superoxide and hydrogen peroxide, are generated in all cells by mitochondrial and enzymatic sources. Left unchecked, these reactive species can cause oxidative damage to DNA, proteins, and membrane lipids. Glutathione peroxidase-1 (GPx-1) is an intracellular antioxidant enzyme that enzymatically reduces hydrogen peroxide to water to limit its harmful effects. Certain reactive oxygen species, such as hydrogen peroxide, are also essential for growth factor-mediated signal transduction, mitochondrial function, and maintenance of normal thiol redox-balance. Thus, by limiting hydrogen peroxide accumulation, GPx-1 also modulates these processes. This review explores the molecular mechanisms involved in regulating the expression and function of GPx-1, with an emphasis on the role of GPx-1 in modulating cellular oxidant stress and redox-mediated responses. As a selenocysteine-containing enzyme, GPx-1 expression is subject to unique forms of regulation involving the trace mineral selenium and selenocysteine incorporation during translation. In addition, GPx-1 has been implicated in the development and prevention of many common and complex diseases, including cancer and cardiovascular disease. This review discusses the role of GPx-1 in these diseases and speculates on potential future therapies to harness the beneficial effects of this ubiquitous antioxidant enzyme. Antioxid. Redox Signal. 15, 1957–1997. PMID:21087145

  2. Selenium and its relationship with selenoprotein P and glutathione peroxidase in children and adolescents with Hashimoto's thyroiditis and hypothyroidism.

    PubMed

    Nourbakhsh, Mitra; Ahmadpour, Fatemeh; Chahardoli, Behnam; Malekpour-Dehkordi, Zahra; Nourbakhsh, Mona; Hosseini-Fard, Seyed Reza; Doustimotlagh, Amirhossein; Golestani, Abolfazl; Razzaghy-Azar, Maryam

    2016-03-01

    The essential trace element selenium (Se) is required for thyroid hormone synthesis and metabolism. Selenoproteins contain selenocysteine and are responsible for biological functions of selenium. Glutathione peroxidase (GPx) is one of the major selenoproteins which protects the thyroid cells from oxidative damage. Selenoprotein P (SePP) is considered as the plasma selenium transporter to tissues. The aim of this study was to evaluate serum Se and SePP levels, and GPx activity in erythrocytes of children and adolescents with treated Hashimoto's thyroiditis, hypothyroidism, and normal subjects. Blood samples were collected from 32 patients with Hashimoto's thyroiditis, 20 with hypothyroidism, and 25 matched normal subjects. All the patients were under treatment with levothyroxine and at the time of analysis all of the thyroid function tests were normal. GPx enzyme activity was measured by spectrophotometry at 340 nm. Serum selenium levels were measured by high-resolution continuum source graphite furnace atomic absorption. SePP, TPOAb (anti-thyroid peroxidase antibody), and TgAb (anti-thyroglobulin antibody) were determined by ELISA kits. T4, T3, T3 uptake and TSH were also measured. Neither GPx activity nor SePP levels were significantly different in patients with Hashimoto's thyroiditis or hypothyroidism compared to normal subjects. Although GPx and SePP were both lower in patients with hypothyroidism compared to those with Hashimoto's thyroiditis and normal subjects but the difference was not significant. Serum Se levels also did not differ significantly in patients and normal subjects. We did not find any correlation between GPx or SePP with TPOAb or TgAb but SePP was significantly correlated with Se. Results show that in patients with Hashimoto's thyroiditis or hypothyroidism who have been under treatment with levothyroxine and have normal thyroid function tests, the GPx, SePP and Se levels are not significantly different. PMID:26854239

  3. Copper and resveratrol attenuates serum catalase, glutathione peroxidase, and element values in rats with DMBA-induced mammary carcinogenesis.

    PubMed

    Skrajnowska, Dorota; Bobrowska-Korczak, Barbara; Tokarz, Andrzej; Bialek, Slawomir; Jezierska, Ewelina; Makowska, Justyna

    2013-12-01

    In this paper, a hypothesis was assessed whether or not the intoxication with copper and supplementation with copper plus resveratrol would result in changes in the activities of catalase and glutathione peroxidase and moreover if the characteristic changes would appear in concentrations of copper, iron, calcium, magnesium, and zinc in the serum of rats with chemically induced carcinogenesis. Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet, were treated with copper (42.6 mg Cu/kg food as CuSO4·5H2O) or copper plus resveratrol (0.2 mg/kg body) via gavage for a period from 40 days until 20 weeks of age. In cancer groups, the rats were treated with a dose of 80 mg/body weight of 7,12-dimethyl-1,2-benz[a]anthracene (DMBA) given in rapeseed oil at 50 and 80 days of age to induce mammary carcinogenesis. The control groups included the rats kept in the same conditions and fed with the same diet as the animals from the study groups, but not DMBA-treated. The activity of catalase significantly decreased in groups of rats with mammary carcinogenesis that were supplemented with copper (p < 0.05) or copper plus resveratrol (p < 0.001) in comparison with the control groups that received the same diets. In cancer groups of nonsupplemented rats, the increase of glutathione peroxidase activity was observed. The process of carcinogenesis and the applied supplementation significantly altered the concentrations of trace elements in serum, in particular as concerns iron and copper. The mean serum iron levels in rats with breast cancer were significantly lower than those in the control groups (p < 0.001). The mean serum copper levels significantly decreased in the groups of rats with mammary carcinogenesis that were supplemented with copper or copper plus resveratrol in comparison with the control groups that received the same diets (p < 0.001). The characteristic changes in iron content and the zinc/copper and zinc/iron ratios in blood

  4. Copper and resveratrol attenuates serum catalase, glutathione peroxidase, and element values in rats with DMBA-induced mammary carcinogenesis.

    PubMed

    Skrajnowska, Dorota; Bobrowska-Korczak, Barbara; Tokarz, Andrzej; Bialek, Slawomir; Jezierska, Ewelina; Makowska, Justyna

    2013-12-01

    In this paper, a hypothesis was assessed whether or not the intoxication with copper and supplementation with copper plus resveratrol would result in changes in the activities of catalase and glutathione peroxidase and moreover if the characteristic changes would appear in concentrations of copper, iron, calcium, magnesium, and zinc in the serum of rats with chemically induced carcinogenesis. Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet, were treated with copper (42.6 mg Cu/kg food as CuSO4·5H2O) or copper plus resveratrol (0.2 mg/kg body) via gavage for a period from 40 days until 20 weeks of age. In cancer groups, the rats were treated with a dose of 80 mg/body weight of 7,12-dimethyl-1,2-benz[a]anthracene (DMBA) given in rapeseed oil at 50 and 80 days of age to induce mammary carcinogenesis. The control groups included the rats kept in the same conditions and fed with the same diet as the animals from the study groups, but not DMBA-treated. The activity of catalase significantly decreased in groups of rats with mammary carcinogenesis that were supplemented with copper (p < 0.05) or copper plus resveratrol (p < 0.001) in comparison with the control groups that received the same diets. In cancer groups of nonsupplemented rats, the increase of glutathione peroxidase activity was observed. The process of carcinogenesis and the applied supplementation significantly altered the concentrations of trace elements in serum, in particular as concerns iron and copper. The mean serum iron levels in rats with breast cancer were significantly lower than those in the control groups (p < 0.001). The mean serum copper levels significantly decreased in the groups of rats with mammary carcinogenesis that were supplemented with copper or copper plus resveratrol in comparison with the control groups that received the same diets (p < 0.001). The characteristic changes in iron content and the zinc/copper and zinc/iron ratios in blood

  5. Molecular cloning and characterization of a phospholipid hydroperoxide glutathione peroxidase gene from a blood fluke Schistosoma japonicum.

    PubMed

    Zhang, Ying; He, Yuan; He, Li; Zong, Hong-Ying; Cai, Guo-Bin

    2015-01-01

    Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a major antioxidant enzyme and plays critical roles in the protection of cells against oxidative stress by catalysing reduction of lipid hydroperoxides. A full-length cDNA sequence corresponding to GPx gene from Schistosoma japonicum (designated SjGPx) was isolated and characterized. SjGPx contained an in-frame TGA codon for selenocysteine (Sec) and a concurrent Sec insertion sequence in its 3'-untranslated region. Protein encoded by SjGPx demonstrated a primary structure characteristic to the PHGPx family, including preservation of catalytic domains and absence of the subunit interaction domains. Phylogenetic analysis revealed that the SjGPx was highly related to the other PHGPx-related members, and clustered into the trematode subclade II. Semi-quantitative reverse transcription PCR and western blotting showed that the SjGPx was mainly expressed in the female adults and eggs. RNA interference was employed to investigate the effects of knockdown of SjGPx. SjGPx expression level was significantly reduced on the 5th day post-RNAi. We observed a 53.86% reduction in total GPx activity and the eggs severely deformed. Oxidative stimulation of viable worms with H2O2 or paraquat resulted in 1.6- to 2.1-fold induction of the GPx activity. Our results revealed that the SjGPx protein is selenium-dependent PHGPx, which might actively participate in the detoxification of oxidative damage during egg production. PMID:26484892

  6. In vitro effect of sodium fluoride on malondialdehyde concentration and on superoxide dismutase, catalase, and glutathione peroxidase in human erythrocytes.

    PubMed

    Gutiérrez-Salinas, José; García-Ortíz, Liliana; Morales González, José A; Hernández-Rodríguez, Sergio; Ramírez-García, Sotero; Núñez-Ramos, Norma R; Madrigal-Santillán, Eduardo

    2013-01-01

    The aim of this paper was to describe the in vitro effect of sodium fluoride (NaF) on the specific activity of the major erythrocyte antioxidant enzymes, as well as on the membrane malondialdehyde concentration, as indicators of oxidative stress. For this purpose, human erythrocytes were incubated with NaF (0, 7, 28, 56, and 100 μg/mL) or NaF (100 μg/mL) + vitamin E (1, 2.5, 5 and 10 μg/mL). The malondialdehyde (MDA) concentration on the surface of the erythrocytes was determined, as were the enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GlPx). Our results demonstrated that erythrocytes incubated with increasing NaF concentrations had an increased MDA concentration, along with decreased activity of antioxidant enzymes. The presence of vitamin E partially reversed the toxic effects of NaF on erythrocytes. These findings suggest that NaF induces oxidative stress in erythrocytes in vitro, and this stress is partially reversed by the presence of vitamin E.

  7. Ablation of the Ferroptosis Inhibitor Glutathione Peroxidase 4 in Neurons Results in Rapid Motor Neuron Degeneration and Paralysis.

    PubMed

    Chen, Liuji; Hambright, William Sealy; Na, Ren; Ran, Qitao

    2015-11-20

    Glutathione peroxidase 4 (GPX4), an antioxidant defense enzyme active in repairing oxidative damage to lipids, is a key inhibitor of ferroptosis, a non-apoptotic form of cell death involving lipid reactive oxygen species. Here we show that GPX4 is essential for motor neuron health and survival in vivo. Conditional ablation of Gpx4 in neurons of adult mice resulted in rapid onset and progression of paralysis and death. Pathological inspection revealed that the paralyzed mice had a dramatic degeneration of motor neurons in the spinal cord but had no overt neuron degeneration in the cerebral cortex. Consistent with the role of GPX4 as a ferroptosis inhibitor, spinal motor neuron degeneration induced by Gpx4 ablation exhibited features of ferroptosis, including no caspase-3 activation, no TUNEL staining, activation of ERKs, and elevated spinal inflammation. Supplementation with vitamin E, another inhibitor of ferroptosis, delayed the onset of paralysis and death induced by Gpx4 ablation. Also, lipid peroxidation and mitochondrial dysfunction appeared to be involved in ferroptosis of motor neurons induced by Gpx4 ablation. Taken together, the dramatic motor neuron degeneration and paralysis induced by Gpx4 ablation suggest that ferroptosis inhibition by GPX4 is essential for motor neuron health and survival in vivo.

  8. In Vitro Effect of Sodium Fluoride on Malondialdehyde Concentration and on Superoxide Dismutase, Catalase, and Glutathione Peroxidase in Human Erythrocytes

    PubMed Central

    Gutiérrez-Salinas, José; García-Ortíz, Liliana; Morales González, José A.; Hernández-Rodríguez, Sergio; Ramírez-García, Sotero; Núñez-Ramos, Norma R.; Madrigal-Santillán, Eduardo

    2013-01-01

    The aim of this paper was to describe the in vitro effect of sodium fluoride (NaF) on the specific activity of the major erythrocyte antioxidant enzymes, as well as on the membrane malondialdehyde concentration, as indicators of oxidative stress. For this purpose, human erythrocytes were incubated with NaF (0, 7, 28, 56, and 100 μg/mL) or NaF (100 μg/mL) + vitamin E (1, 2.5, 5 and 10 μg/mL). The malondialdehyde (MDA) concentration on the surface of the erythrocytes was determined, as were the enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GlPx). Our results demonstrated that erythrocytes incubated with increasing NaF concentrations had an increased MDA concentration, along with decreased activity of antioxidant enzymes. The presence of vitamin E partially reversed the toxic effects of NaF on erythrocytes. These findings suggest that NaF induces oxidative stress in erythrocytes in vitro, and this stress is partially reversed by the presence of vitamin E. PMID:24223512

  9. Ablation of the Ferroptosis Inhibitor Glutathione Peroxidase 4 in Neurons Results in Rapid Motor Neuron Degeneration and Paralysis.

    PubMed

    Chen, Liuji; Hambright, William Sealy; Na, Ren; Ran, Qitao

    2015-11-20

    Glutathione peroxidase 4 (GPX4), an antioxidant defense enzyme active in repairing oxidative damage to lipids, is a key inhibitor of ferroptosis, a non-apoptotic form of cell death involving lipid reactive oxygen species. Here we show that GPX4 is essential for motor neuron health and survival in vivo. Conditional ablation of Gpx4 in neurons of adult mice resulted in rapid onset and progression of paralysis and death. Pathological inspection revealed that the paralyzed mice had a dramatic degeneration of motor neurons in the spinal cord but had no overt neuron degeneration in the cerebral cortex. Consistent with the role of GPX4 as a ferroptosis inhibitor, spinal motor neuron degeneration induced by Gpx4 ablation exhibited features of ferroptosis, including no caspase-3 activation, no TUNEL staining, activation of ERKs, and elevated spinal inflammation. Supplementation with vitamin E, another inhibitor of ferroptosis, delayed the onset of paralysis and death induced by Gpx4 ablation. Also, lipid peroxidation and mitochondrial dysfunction appeared to be involved in ferroptosis of motor neurons induced by Gpx4 ablation. Taken together, the dramatic motor neuron degeneration and paralysis induced by Gpx4 ablation suggest that ferroptosis inhibition by GPX4 is essential for motor neuron health and survival in vivo. PMID:26400084

  10. Redesign of cytochrome c peroxidase into a manganese peroxidase: role of tryptophans in peroxidase activity.

    PubMed

    Gengenbach, A; Syn, S; Wang, X; Lu, Y

    1999-08-31

    Trp191Phe and Trp51Phe mutations have been introduced into an engineered cytochrome c peroxidase (CcP) containing a Mn(II)-binding site reported previously (MnCcP; see Yeung, B. K.-S., et al. (1997) Chem. Biol. 5, 215-221). The goal of the present study is to elucidate the role of tryptophans in peroxidase activity since CcP contains both Trp51 and Trp191 while manganese peroxidase (MnP) contains phenylalanine residues at the corresponding positions. The presence of Trp191 in CcP allows formation of a unique high-valent intermediate containing a ferryl oxo and tryptophan radical called compound I'. The absence of a tryptophan residue at this position in MnP is the main reason for the formation of an intermediate called compound I which contains a ferryl oxo and porphyrin pi-cation radical. In this study, we showed that introduction of the Trp191Phe mutation to MnCcP did not improve MnP activity (specific activity: MnCcP, 0.750 micromol min-1 mg-1; MnCcP(W191F), 0.560 micromol min-1 mg-1. k(cat)/K(m): MnCcP, 0.0517 s-1 mM-1; MnCcP(W191F), 0.0568 s-1 mM-1) despite the fact that introduction of the same mutation to WTCcP caused the formation of a transient compound I (decay rate, 60 s-1). However, introducing both the Trp191Phe and Trp51Phe mutations not only resulted in a longer lived compound I in WTCcP (decay rate, 18 s-1), but also significantly improved MnP activity in MnCcP (MnCcP(W51F, W191F): specific activity, 8.0 micromol min-1 mg-1; k(cat)/K(m), 0. 599 s-1 mM-1). The increase in activity can be attributed to the Trp51Phe mutation since MnCcP(W51F) showed significantly increased MnP activity relative to MnCcP (specific activity, 3.2 micromol min-1 mg-1; k(cat)/K(m), 0.325 s-1 mM-1). As with MnP, the activity of MnCcP(W51F, W191F) was found to increase with decreasing pH. Our results demonstrate that, while the Trp191Phe and Trp51Phe mutations both play important roles in stabilizing compound I, only the Trp51Phe mutation contributes significantly to

  11. Tranilast alleviates endothelial dysfunctions and insulin resistance via preserving glutathione peroxidase 1 in rats fed a high-fat emulsion.

    PubMed

    Yang, Xuan; Feng, Lei; Li, Changjiang; Li, Yu

    2014-01-01

    We investigated the effects of treatment with tranilast on vascular and metabolic dysfunction induced by a high-fat emulsion intragastric administration. Wistar rats were randomized to receive water or high-fat emulsion with or without tranilast treatment (400 mg/kg per day) for 4 weeks. Insulin sensitivity was determined with a hyperinsulinemic-euglycemic clamp experiment and short insulin tolerance test. Vascular reactivity was evaluated using aortic rings in organ chambers. Glutathione peroxidase 1 (GPX1) expressions, eNOS phosphorylation and activity, MCP-1, H2O2 formation, and NO production were determined in vascular or soleus tissues. Tranilast treatment was found to prevent alterations in vascular reactivity and insulin sensitivity and to prevent increases in plasma glucose and insulin noted in the high-fat emulsion-treated rats. These were associated with increased antioxidant enzyme GPX1 expression, eNOS phosphorylation and activity, and NO production, but reductions in H2O2 accumulation. Moreover, tranilast preserved GPX1 expression in palmitic acid (PA)-treated endothelial cells with a consequent decreased ROS formation and increased eNOS phosphorylation and NO production. Therefore, oxidative stress induced by a relatively short-term high-fat diet could cause the early development of vascular and metabolic abnormalities in rats, and tranilast has a beneficial effect in vascular dysfunctions and insulin resistance via preserving GPX1 and alleviating oxidative stress. PMID:24389817

  12. Glutathione peroxidase 3 localizes to the epithelial lining fluid and the extracellular matrix in interstitial lung disease

    PubMed Central

    Schamberger, Andrea C.; Schiller, Herbert B.; Fernandez, Isis E.; Sterclova, Martina; Heinzelmann, Katharina; Hennen, Elisabeth; Hatz, Rudolf; Behr, Jürgen; Vašáková, Martina; Mann, Matthias; Eickelberg, Oliver; Staab-Weijnitz, Claudia A.

    2016-01-01

    Aberrant antioxidant activity and excessive deposition of extracellular matrix (ECM) are hallmarks of interstitial lung diseases (ILD). It is known that oxidative stress alters the ECM, but extracellular antioxidant defence mechanisms in ILD are incompletely understood. Here, we extracted abundance and detergent solubility of extracellular antioxidant enzymes from a proteomic dataset of bleomycin-induced lung fibrosis in mice and assessed regulation and distribution of glutathione peroxidase 3 (GPX3) in murine and human lung fibrosis. Superoxide dismutase 3 (Sod3), Gpx3, and Gpx activity were increased in mouse BALF during bleomycin-induced lung fibrosis. In lung tissue homogenates, Gpx3, but not Sod3, was upregulated and detergent solubility profiling indicated that Gpx3 associated with ECM proteins. Immunofluorescence analysis showed that Gpx3 was expressed by bronchial epithelial cells and interstitial fibroblasts and localized to the basement membrane and interstitial ECM in lung tissue. As to human ILD samples, BALF of some patients contained high levels of GPX3, and GPX3 was upregulated in lung homogenates from IPF patients. GPX3 expression in primary human bronchial epithelial cells and lung fibroblasts was downregulated by TNF-α, but more variably regulated by TGF-β1 and menadione. In conclusion, the antioxidant enzyme GPX3 localizes to lung ECM and is variably upregulated in ILD. PMID:27435875

  13. Cytochrome bd Displays Significant Quinol Peroxidase Activity

    PubMed Central

    Al-Attar, Sinan; Yu, Yuanjie; Pinkse, Martijn; Hoeser, Jo; Friedrich, Thorsten; Bald, Dirk; de Vries, Simon

    2016-01-01

    Cytochrome bd is a prokaryotic terminal oxidase that catalyses the electrogenic reduction of oxygen to water using ubiquinol as electron donor. Cytochrome bd is a tri-haem integral membrane enzyme carrying a low-spin haem b558, and two high-spin haems: b595 and d. Here we show that besides its oxidase activity, cytochrome bd from Escherichia coli is a genuine quinol peroxidase (QPO) that reduces hydrogen peroxide to water. The highly active and pure enzyme preparation used in this study did not display the catalase activity recently reported for E. coli cytochrome bd. To our knowledge, cytochrome bd is the first membrane-bound quinol peroxidase detected in E. coli. The observation that cytochrome bd is a quinol peroxidase, can provide a biochemical basis for its role in detoxification of hydrogen peroxide and may explain the frequent findings reported in the literature that indicate increased sensitivity to hydrogen peroxide and decreased virulence in mutants that lack the enzyme. PMID:27279363

  14. Cloning and functional analysis of glutathione peroxidase gene in red swamp crayfish Procambarus clarkii.

    PubMed

    Xia, Xiao-Fei; Zheng, Jin-Jing; Shao, Guang-Ming; Wang, Jia-Lin; Liu, Xu-Sheng; Wang, Yu-Feng

    2013-06-01

    Glutathione peroxidases (GPxs) are key enzymes in the antioxidant defense systems of living organisms, including crustaceans. The red swamp crayfish Procambarus clarkii is the most commonly farmed freshwater crayfish in Chinese inland nowadays due to its commercial value. However, high stocking density has resulted in adverse effects in growth performance and health. To investigate the function of GPxs in immune defense of the crayfish, we cloned and characterized a full length GPx (PcGPx) from P. clarkii by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The 931 bp PcGPx cDNA contains a 38 bp 5'-untranslated region (UTR), a 519 bp coding sequence (CDS) and a 375 bp 3'-UTR with a selenocysteine insertion sequence (SECIS). The PcGPx was predicted to encode 172 amino acids, and its putative molecular mass was 20.9 kDa with a pI of 4.37. A selenocysteine (Sec) encoded by the unusual stop codon, TGA, was in the protein coding region. Phylogenetic analysis showed that PcGPx clustered with the GPxs from the penaeid shrimp Metapenaeus ensis and Caenorhabditis elegans, sharing much higher similarity with vertebrate GPx1 and GPx2 than with GPx3 and GPx5. Quantitative RT-PCR revealed that PcGPx was extremely highly expressed in ovary and early embryos. In addition, the levels of PcGPx mRNA and reactive oxygen species (ROS) significantly increased after challenge with gram-negative Vibrio harveyi, gram-positive Staphyloccocus aureus or white spot syndrome virus (WSSV). These results suggest that PcGPx may play important roles not only in immune defense, but also in oogenesis in the crayfish.

  15. Comparison of molecular properties of rat plasma and erythrocyte selenium-dependent glutathione peroxidase.

    PubMed

    Stýblo, M

    1992-07-01

    The molecular structure of plasma and erythrocyte selenium-dependent glutathione peroxidase (GSH-Px) was studied in rats drinking water containing [75Se]selenious acid, 1.3 mg Se/L. Substantial differences were found using three-step fractionation, including gel filtration of crude plasma and erythrocyte lysate, gel filtration of 75Se-GSH-Px treated by mercaptoethanol, and SDS-electrophoresis. Native plasma 75Se-GSH-Px, which exhibited a molecular weight (M(r)) of approx. 700,000, could be destroyed by mercaptoethanol action, resulting in disintegration of enzyme into several different 75Se-protein fragments and release of part of low-mol-wt 75Se. Native erythrocyte 75Se-GSH-Px M(r) value was found to be 113,000; two 75Se-protein fragments arose after mercaptoethanol treatment without 75Se release from the enzyme. The 75Se-subunits of 22,500 and 21,900 were isolated from plasma and erythrocyte 75Se-GSH-Px, respectively. Another minor 75Se-GSH-Px was identified in erythrocyte lysate (M(r) 214,000, subunit 22,100), which was considered to be a dimer of the above-mentioned erythrocyte enzyme. It can be assumed, based on these data, that native plasma GSH-Px, in contrast to erythrocyte enzyme, represents a high-molecular wt complex composed of several tetramers linked with S-S bonds. A certain part of selenium present in this complex is probably not selenocysteine and may be released with the mercaptoethanol treatment.

  16. Deletion of Glutathione Peroxidase-2 Inhibits Azoxymethane-Induced Colon Cancer Development

    PubMed Central

    Müller, Mike F.; Florian, Simone; Pommer, Stefanie; Osterhoff, Martin; Esworthy, R. Steven; Chu, Fong-Fong; Brigelius-Flohé, Regina; Kipp, Anna P.

    2013-01-01

    The selenoprotein glutathione peroxidase-2 (GPx2) appears to have a dual role in carcinogenesis. While it protected mice from colon cancer in a model of inflammation-triggered carcinogenesis (azoxymethane and dextran sodium sulfate treatment), it promoted growth of xenografted tumor cells. Therefore, we analyzed the effect of GPx2 in a mouse model mimicking sporadic colorectal cancer (azoxymethane-treatment only). GPx2-knockout (KO) and wild-type (WT) mice were adjusted to an either marginally deficient (−Se), adequate (+Se), or supranutritional (++Se) selenium status and were treated six times with azoxymethane (AOM) to induce tumor development. In the −Se and ++Se groups, the number of tumors was significantly lower in GPx2-KO than in respective WT mice. On the +Se diet, the number of dysplastic crypts was reduced in GPx2-KO mice. This may be explained by more basal and AOM-induced apoptotic cell death in GPx2-KO mice that eliminates damaged or pre-malignant epithelial cells. In WT dysplastic crypts GPx2 was up-regulated in comparison to normal crypts which might be an attempt to suppress apoptosis. In contrast, in the +Se groups tumor numbers were similar in both genotypes but tumor size was larger in GPx2-KO mice. The latter was associated with an inflammatory and tumor-promoting environment as obvious from infiltrated inflammatory cells in the intestinal mucosa of GPx2-KO mice even without any treatment and characterized as low-grade inflammation. In WT mice the number of tumors tended to be lowest in +Se compared to −Se and ++Se feeding indicating that selenium might delay tumorigenesis only in the adequate status. In conclusion, the role of GPx2 and presumably also of selenium depends on the cancer stage and obviously on the involvement of inflammation. PMID:23977205

  17. High Glutathione and Glutathione Peroxidase-2 Levels Mediate Cell-Type-Specific DNA Damage Protection in Human Induced Pluripotent Stem Cells

    PubMed Central

    Dannenmann, Benjamin; Lehle, Simon; Hildebrand, Dominic G.; Kübler, Ayline; Grondona, Paula; Schmid, Vera; Holzer, Katharina; Fröschl, Mirjam; Essmann, Frank; Rothfuss, Oliver; Schulze-Osthoff, Klaus

    2015-01-01

    Summary Pluripotent stem cells must strictly maintain genomic integrity to prevent transmission of mutations. In human induced pluripotent stem cells (iPSCs), we found that genome surveillance is achieved via two ways, namely, a hypersensitivity to apoptosis and a very low accumulation of DNA lesions. The low apoptosis threshold was mediated by constitutive p53 expression and a marked upregulation of proapoptotic p53 target genes of the BCL-2 family, ensuring the efficient iPSC removal upon genotoxic insults. Intriguingly, despite the elevated apoptosis sensitivity, both mitochondrial and nuclear DNA lesions induced by genotoxins were less frequent in iPSCs compared to fibroblasts. Gene profiling identified that mRNA expression of several antioxidant proteins was considerably upregulated in iPSCs. Knockdown of glutathione peroxidase-2 and depletion of glutathione impaired protection against DNA lesions. Thus, iPSCs ensure genomic integrity through enhanced apoptosis induction and increased antioxidant defense, contributing to protection against DNA damage. PMID:25937369

  18. Protection from inactivation of the adenine nucleotide translocator during hypoglycaemia-induced apoptosis by mitochondrial phospholipid hydroperoxide glutathione peroxidase.

    PubMed Central

    Imai, Hirotaka; Koumura, Tomoko; Nakajima, Ryo; Nomura, Kazuhiro; Nakagawa, Yasuhito

    2003-01-01

    We demonstrated that mitochondrial phospholipid hydroperoxide glutathione peroxidase (PHGPx) first suppressed the dissociation of cytochrome c (cyt c) from cardiolipin (CL) in mitochondrial inner membranes and then apoptosis caused by the hypoglycaemia by the prevention of peroxidation of CL [Nomura, Imai, Koumura, Arai and Nakagawa (1999) J. Biol. Chem. 274, 29294-29302; Nomura, Imai, Koumura, Kobayashi and Nakagawa (2000) Biochem. J. 351, 183-193]. The present study shows the involvement of peroxidation of CL in the inactivation of adenine nucleotide translocator (ANT) and the opening of permeability transition pores by using the system of ANT-reconstituted liposome and isolated mitochondria. ANT activity appeared in dioleoyl phosphatidylcholine proteoliposome containing 10% (mol/mol) CL or phosphatidylglycerol (PG), but not other classes of phospholipids. ANT activity was competitively inhibited by the addition of cardiolipin hydroperoxide (CLOOH) in reconstituted liposomes containing CL. However, phosphatidylcholine hydroperoxide failed to inactivate the activity of ANT. The activity of ANT in reconstituted liposomes, including CLOOH, recovered when CLOOH in reconstituted liposome was reduced to hydroxycardiolipin by incubation with PHGPx. The activity of ANT was determined in rat basophil leukaemia RBL2H3 cells after their exposure to 2-deoxyglucose. ANT activity decreased to 50% of the control level by 4 h in response to apoptosis. In parallel, cyt c and apoptosis-inducing factor (AIF) were released from mitochondria. Suppression of the accumulation of CLOOH by overexpression of PHGPx in mitochondria effectively prevented the inactivation of ANT, the opening of permeability transition pores and the release of cyt c and AIF from mitochondria in hypoglycaemia-induced apoptotic cells. These findings suggest that mitochondrial PHGPx might be involved in the modulation of the activity of ANT and the opening of pores for the release of cyt c via the modulation of

  19. Changes in cerebrospinal fluid levels of malondialdehyde and glutathione reductase activity in multiple sclerosis.

    PubMed

    Calabrese, V; Raffaele, R; Cosentino, E; Rizza, V

    1994-01-01

    The chemical composition of human cerebrospinal fluid (CSF) is considered to reflect brain metabolism. In this study we measured malondialdehyde (MDA) levels and the activity of enzymes involved in antioxidative processes, glutathione reductase and glutathione peroxidase, in human cerebrospinal fluid of multiple-sclerosis (MS) patients and normal healthy volunteers. Our results indicated that the cerebrospinal fluid in MS showed significantly higher endogenous levels of MDA than the control, as well as a much greater resistance to in-vitro stimulation test. In addition, we found the activity of GSH reductase significantly increased, about twice the control values, whereas the activity of glutathione peroxidase was markedly decreased as compared to control values. Our findings suggest that in MS the activity of antioxidant enzymes is modified, and indicates the conceivable possibility of a pathogenic role of oxidative stress in the determinism of the disease. PMID:7607784

  20. Unbalanced activation of glutathione metabolic pathways suggests potential involvement in plant defense against the gall midge Mayetiola destructor in wheat.

    PubMed

    Liu, Xuming; Zhang, Shize; Whitworth, R Jeff; Stuart, Jeffrey J; Chen, Ming-Shun

    2015-01-01

    Glutathione, γ-glutamylcysteinylglycine, exists abundantly in nearly all organisms. Glutathione participates in various physiological processes involved in redox reactions by serving as an electron donor/acceptor. We found that the abundance of total glutathione increased up to 60% in resistant wheat plants within 72 hours following attack by the gall midge Mayetiola destructor, the Hessian fly. The increase in total glutathione abundance, however, is coupled with an unbalanced activation of glutathione metabolic pathways. The activity and transcript abundance of glutathione peroxidases, which convert reduced glutathione (GSH) to oxidized glutathione (GSSG), increased in infested resistant plants. However, the enzymatic activity and transcript abundance of glutathione reductases, which convert GSSG back to GSH, did not change. This unbalanced regulation of the glutathione oxidation/reduction cycle indicates the existence of an alternative pathway to regenerate GSH from GSSG to maintain a stable GSSG/GSH ratio. Our data suggest the possibility that GSSG is transported from cytosol to apoplast to serve as an oxidant for class III peroxidases to generate reactive oxygen species for plant defense against Hessian fly larvae. Our results provide a foundation for elucidating the molecular processes involved in glutathione-mediated plant resistance to Hessian fly and potentially other pests as well. PMID:25627558

  1. Distribution of superoxide dismutase 1 and glutathione peroxidase 1 in the cyclic canine endometrium.

    PubMed

    Santos, Celso; Pires, Maria Dos Anjos; Santos, Dario; Payan-Carreira, Rita

    2016-08-01

    Superoxide dismutase (SOD) and glutathione peroxidase (GPx) are two important antioxidant enzymes involved in tissue homeostasis by protecting cells and tissues from an accumulation of reactive oxygen species. Information concerning antioxidant enzymes in the canine uterus is almost inexistent. This work intends to establish the pattern of distribution of SOD1 and GPx1 immunoreaction in canine endometrium throughout the estrous cycle, using 46 endometrium samples of healthy dogs representing different cycle stages (anestrus-10, proestrus-10, estrus-10, early diestrus-7, and diestrus-9). SOD1 distribution in canine endometrium showed cyclic variations (P ≤ 0.001), with higher immunoscores in the progesterone-associated stages. Changing immunoreaction also concerned the different epithelial structures considered (surface epithelium, superficial glandular epithelium, and deep glandular epithelium) (P ≤ 0.001), but it was always higher than in the stroma (P ≤ 0.001). Deep glandular epithelial cells usually showed higher scores of immunoreaction compared with the other epithelial cells. Interestingly, in epithelial cells, distinct subcellular patterns for SOD1 were seen: the nuclear labeling was observed in estrus and early diestrus (P ≤ 0.001), whereas an apical reinforcement was observed in estrus (P = 0.011) in the glandular epithelia but not in the surface epithelia. In general, GPx1 distribution in canine endometrium remained relatively unchanged throughout the estrous cycle (P = 0.169) despite the slight decrease observed from proestrus to early diestrus. The highest scores were found in anestrus and diestrus (P < 0.05), varying with of the structure considered. An apical reinforcement pattern was also found for this molecule, which peaked in proestrus and estrus (P < 0.005). In summary, the present study showed that SOD1 and GPx1 are consistently distributed in the canine endometrium. The cyclic changes registered for both molecules

  2. Blood haematology, serum thyroid hormones and glutathione peroxidase status in kacang goats fed inorganic iodine and selenium supplemented diets.

    PubMed

    Aghwan, Z A; Sazili, A Q; Alimon, A R; Goh, Y M; Hilmi, M

    2013-11-01

    The effects of dietary supplementation of selenium (Se), iodine (I), and a combination of both on the blood haematology, serum free thyroxine (FT4) and free triiodothyronine (FT3) hormones and glutathione peroxidase enzyme (GSH-Px) activity were examined on twenty four (7 to 8 months old, 22±1.17 kg live weight) Kacang crossbred male goats. Animals were randomly assigned to four dietary treatments (6 animals in each group). Throughout 100 d of feeding trial, the animals of control group (CON) received a basal diet, while the other three groups were offered basal diet supplemented with 0.6 mg/kg diet DM Se (SS), or 0.6 mg/kg diet DM I (PI), or a combination of both Se and I, each at 0.6 mg/kg diet DM (SSPI). The haematological attributes which are haemoglobin (Hb), red blood cell (RBC), packed cell volume (PCV), mean cell volume (MCV), white blood cells (WBC), band neutrophils (B Neut), segmented neutrophils (S Neut), lymphocytes (Lymph), monocytes (Mono), eosinophils (Eosin) and basophils (Baso) were similar among the four treatment groups, while serum levels of Se and I increased significantly (p<0.05) in the supplemented groups. The combined dietary supplementation of Se and I (SSPI) significantly increased serum FT3 in the supplemented animals. Serum GSH-Px activity increased significantly in the animals of SS and SSPI groups. It is concluded that the dietary supplementation of inorganic Se and I at a level of 0.6 mg/kg DM increased serum Se and I concentration, FT3 hormone and GSH-Px activity of Kacang crossbred male goats. PMID:25049744

  3. A selenium-deficient Caco-2 cell model for assessing differential incorporation of chemical or food selenium into glutathione peroxidase.

    PubMed

    Zeng, Huawei; Botnen, James H; Johnson, Luann K

    2008-01-01

    Assessing the ability of a selenium (Se) sample to induce cellular glutathione peroxidase (GPx) activity in Se-deficient animals is the most commonly used method to determine Se bioavailability. Our goal is to establish a Se-deficient cell culture model with differential incorporation of Se chemical forms into GPx, which may complement the in vivo studies. In the present study, we developed a Se-deficient Caco-2 cell model with a serum gradual reduction method. It is well recognized that selenomethionine (SeMet) is the major nutritional source of Se; therefore, SeMet, selenite, or methylselenocysteine (SeMSC) was added to cell culture media with different concentrations and treatment time points. We found that selenite and SeMSC induced GPx more rapidly than SeMet. However, SeMet was better retained as it is incorporated into proteins in place of methionine; compared with 8-, 24-, or 48-h treatment, 72-h Se treatment was a more sensitive time point to measure the potential of GPx induction in all tested concentrations. Based on induction of GPx activity, the cellular bioavailability of Se from an extract of selenobroccoli after a simulated gastrointestinal digestion was comparable with that of SeMSC and SeMet. These in vitro data are, for the first time, consistent with previous published data regarding selenite and SeMet bioavailability in animal models and Se chemical speciation studies with broccoli. Thus, Se-deficient Caco-2 cell model with differential incorporation of chemical or food forms of Se into GPx provides a new tool to study the cellular mechanisms of Se bioavailability.

  4. Identification and Comparative Analysis of H2O2-Scavenging Enzymes (Ascorbate Peroxidase and Glutathione Peroxidase) in Selected Plants Employing Bioinformatics Approaches.

    PubMed

    Ozyigit, Ibrahim I; Filiz, Ertugrul; Vatansever, Recep; Kurtoglu, Kuaybe Y; Koc, Ibrahim; Öztürk, Münir X; Anjum, Naser A

    2016-01-01

    Among major reactive oxygen species (ROS), hydrogen peroxide (H2O2) exhibits dual roles in plant metabolism. Low levels of H2O2 modulate many biological/physiological processes in plants; whereas, its high level can cause damage to cell structures, having severe consequences. Thus, steady-state level of cellular H2O2 must be tightly regulated. Glutathione peroxidases (GPX) and ascorbate peroxidase (APX) are two major ROS-scavenging enzymes which catalyze the reduction of H2O2 in order to prevent potential H2O2-derived cellular damage. Employing bioinformatics approaches, this study presents a comparative evaluation of both GPX and APX in 18 different plant species, and provides valuable insights into the nature and complex regulation of these enzymes. Herein, (a) potential GPX and APX genes/proteins from 18 different plant species were identified, (b) their exon/intron organization were analyzed, (c) detailed information about their physicochemical properties were provided, (d) conserved motif signatures of GPX and APX were identified, (e) their phylogenetic trees and 3D models were constructed, (f) protein-protein interaction networks were generated, and finally (g) GPX and APX gene expression profiles were analyzed. Study outcomes enlightened GPX and APX as major H2O2-scavenging enzymes at their structural and functional levels, which could be used in future studies in the current direction. PMID:27047498

  5. Identification and Comparative Analysis of H2O2-Scavenging Enzymes (Ascorbate Peroxidase and Glutathione Peroxidase) in Selected Plants Employing Bioinformatics Approaches

    PubMed Central

    Ozyigit, Ibrahim I.; Filiz, Ertugrul; Vatansever, Recep; Kurtoglu, Kuaybe Y.; Koc, Ibrahim; Öztürk, Münir X.; Anjum, Naser A.

    2016-01-01

    Among major reactive oxygen species (ROS), hydrogen peroxide (H2O2) exhibits dual roles in plant metabolism. Low levels of H2O2 modulate many biological/physiological processes in plants; whereas, its high level can cause damage to cell structures, having severe consequences. Thus, steady-state level of cellular H2O2 must be tightly regulated. Glutathione peroxidases (GPX) and ascorbate peroxidase (APX) are two major ROS-scavenging enzymes which catalyze the reduction of H2O2 in order to prevent potential H2O2-derived cellular damage. Employing bioinformatics approaches, this study presents a comparative evaluation of both GPX and APX in 18 different plant species, and provides valuable insights into the nature and complex regulation of these enzymes. Herein, (a) potential GPX and APX genes/proteins from 18 different plant species were identified, (b) their exon/intron organization were analyzed, (c) detailed information about their physicochemical properties were provided, (d) conserved motif signatures of GPX and APX were identified, (e) their phylogenetic trees and 3D models were constructed, (f) protein-protein interaction networks were generated, and finally (g) GPX and APX gene expression profiles were analyzed. Study outcomes enlightened GPX and APX as major H2O2-scavenging enzymes at their structural and functional levels, which could be used in future studies in the current direction. PMID:27047498

  6. Blood selenium and glutathione peroxidase levels and dietary selenium of free-living and institutionalized elderly subjects.

    PubMed

    Lane, H W; Warren, D C; Taylor, B J; Stool, E

    1983-05-01

    The purpose of this study was to evaluate the selenium status of healthy free-living and institutionalized elderly people. For the 36 free-living elderly dietary selenium intake averaged 94 +/- 44 micrograms Se/day and a positive correlation coefficient was found between dietary selenium and dietary calories (r = 0.46; P less than 0.05), dietary protein (r = 0.60; P less than 0.01), and dietary fat (r = 0.43; P less than 0.05). Diet histories from the institutionalized subjects revealed a strong correlation coefficient between selenium and carbohydrate (r = 0.51; P less than 0.005) and selenium and calories (r = 0.44; P less than 0.05). Mean erythrocyte and plasma selenium levels for the free-living subjects were 0.20 +/- 0.06 micrograms/ml and 0.10 +/- 0.03 micrograms/ml, respectively, while mean erythrocyte glutathione peroxidase (GSH-Px) activity was 27.5 +/- 5.0 units/g protein. For the free-living subjects positive correlation was found between dietary selenium and erythrocyte selenium levels (r = 0.38; P less than 0.05) but no correlation existed between dietary selenium and plasma selenium (r = 0.13; P greater than 0.05) and RBC GSH-Px (r = -0.15; P greater than 0.05). The dietary selenium levels and blood selenium and GSH-Px levels were above the levels found in populations proposed to be at risk for selenium deficiency. Thus, these elderly appear to have adequate selenium status.

  7. Effect of tocotrienol on the activities of cytosolic glutathione-dependent enzymes in rats treated with 2-acetylaminofluorene.

    PubMed

    Shamaan, N A; Wan Ngah, W Z; Ibrahim, R; Jarien, Z; Top, A G; Abdul Kadir, K

    1993-04-01

    The effect of tocotrienol on the activities of glutathione S-transferases (GSTs), glutathione reductase (GR) and glutathione peroxidase (GPx) in rats given 2-acetylaminofluorene (AAF) was investigated over a 20 week period. Liver and kidney GST and liver GR activities were significantly increased after AAF administration. Kidney GPx activities were significantly affected; activity assayed with cumene hydroperoxide (cu-OOH) was increased but activity assayed with H2O2 was reduced. Supplementation of the diet with tocotrienol in the AAF-treated rats reduced the increase in enzyme activities. Tocotrienol on its own had no effect on the enzyme activities.

  8. IgG abzymes with peroxidase and oxidoreductase activities from the sera of healthy humans.

    PubMed

    Tolmacheva, Anna S; Blinova, Elena A; Ermakov, Evgeny A; Buneva, Valentina N; Vasilenko, Nataliya L; Nevinsky, Georgy A

    2015-09-01

    We present the evidence showing that small fractions of electrophoretically homogeneous immunoglobulin G (IgGs) from the sera of healthy humans and their Fab and F(ab)2 fragments oxidize 3,3'-diaminobenzidine through a peroxidase activity in the presence of H2 O2 and through an oxidoreductase activity in the absence of H2 O2 . During purification on protein G-Sepharose and gel filtration, the polyclonal IgGs partially lose the Me(2+) ions. After extensive dialysis of purified Abs against agents chelating metal ions, the relative peroxidase activity decreased dependently of IgG analyzed from 100 to ~10-85%, while oxidoreductase activity from 100 to 14-83%. Addition of external metal ions to dialyzed and non-dialyzed IgGs leads to a significant increase in their activity. Chromatography of the IgGs on Chelex non-charged with Cu(2+) ions results in the adsorption of a small IgG fraction bound with metal ions (~5%), while Chelex charged with Cu(2+) ions bind additionally ~38% of the total IgGs. Separation of Abs on both sorbents results in IgG separation to many different subfractions demonstrating various affinities to the chelating resin and different levels of the specific oxidoreductase and peroxidase activities. In the presence of external Cu(2+) ions, the specific peroxidase activity of several IgG subfractions achieves 20-27 % as compared with horseradish peroxidase (HRP, taken for 100%). The oxidoreductase activity of these fractions is ~4-6-fold higher than that for HRP. Antioxidant enzymes such as superoxide dismutases, catalases, and glutathione peroxidases are known to represent critical defence mechanisms for preventing oxidative modifications of DNA, proteins, and lipids. Peroxidase and oxidoreductase activities of human IgGs could also play an important role in the protection of organisms from oxidative stress and toxic compounds.

  9. ATP-enhanced peroxidase-like activity of gold nanoparticles.

    PubMed

    Shah, Juhi; Purohit, Rahul; Singh, Ragini; Karakoti, Ajay Singh; Singh, Sanjay

    2015-10-15

    Gold nanoparticles (AuNPs) are known to possess intrinsic biological peroxidase-like activity that has applications in development of numerous biosensors. The reactivity of the Au atoms at the surface of AuNPs is critical to the performance of such biosensors, yet little is known about the effect of biomolecules and ions on the peroxidase-like activity. In this work, the effect of ATP and other biologically relevant molecules and ions over peroxidase-like activity of AuNPs are described. Contrary to the expectation that nanoparticles exposed to biomolecules may lose the catalytic property, ATP and ADP addition enhanced the peroxidase-like activity of AuNPs. The catalytic activity was unaltered by the addition of free phosphate, sulphate and carbonate anions however, addition of ascorbic acid to the reaction mixture diminished the intrinsic peroxidase-like activity of AuNPs, even in the presence of ATP and ADP. In contrast to AuNPs, ATP did not synergize and improve the peroxidase activity of the natural peroxidase enzyme, horseradish peroxidase.

  10. Blood glutathione peroxidase-1 mRNA levels can be used as molecular biomarkers to determine dietary selenium requirements in rats.

    PubMed

    Sunde, Roger A; Thompson, Kevin M; Evenson, Jacqueline K; Thompson, Britta M

    2009-11-01

    Transcript (mRNA) levels are increasingly being used in medicine as molecular biomarkers for disease and disease risk, including use of whole blood as a target tissue for analysis. Development of blood molecular biomarkers for nutritional status, too, has potential application that parallels opportunities in medicine, including providing solid data for individualized nutrition. We previously reported that blood glutathione peroxidase-1 (Gpx1) mRNA was expressed at levels comparable to major tissues in rats and humans. To determine the efficacy of using blood Gpx1 mRNA to assess selenium (Se) status and requirements, we fed graded levels of Se (0-0.3 microg Se/g as selenite) to weanling male rats. Se status was determined by liver Se concentration and selenoenzyme activity, and selenoprotein mRNA abundance in liver and blood was determined by ribonuclease protection analysis. Liver Se and plasma glutathione peroxidase-3 and liver Gpx1 activities indicated that minimal Se requirements were at 0.08 microg Se/g diet. When total RNA was isolated from whole blood, Gpx1 mRNA in Se-deficient rats decreased to 10% of levels in Se-adequate (0.2 microg Se/g diet) rats. With Se supplementation, blood Gpx1 mRNA levels increased sigmoidally to a plateau with a minimum Se requirement of 0.08 microg Se/g diet, whereas glutathione peroxidase-4 mRNA levels were unaffected. Similarly, Gpx1 mRNA in RNA isolated from fractionated red blood cells decreased in Se-deficient rats to 23% of Se-adequate levels, with a minimum Se requirement of 0.09 microg Se/g diet. Additional studies showed that the preponderance of whole blood Gpx1 mRNA arises from erythroid cells, most likely reticulocytes and young erythrocytes. In summary, whole blood selenoprotein mRNA levels can be used as molecular biomarkers for assessing Se requirements, illustrating that whole blood has potential as a target tissue in development of molecular biomarkers for use in nutrition as well as in medicine.

  11. Blood glutathione peroxidase-1 mRNA levels can be used as molecular biomarkers to determine dietary selenium requirements in rats.

    PubMed

    Sunde, Roger A; Thompson, Kevin M; Evenson, Jacqueline K; Thompson, Britta M

    2009-11-01

    Transcript (mRNA) levels are increasingly being used in medicine as molecular biomarkers for disease and disease risk, including use of whole blood as a target tissue for analysis. Development of blood molecular biomarkers for nutritional status, too, has potential application that parallels opportunities in medicine, including providing solid data for individualized nutrition. We previously reported that blood glutathione peroxidase-1 (Gpx1) mRNA was expressed at levels comparable to major tissues in rats and humans. To determine the efficacy of using blood Gpx1 mRNA to assess selenium (Se) status and requirements, we fed graded levels of Se (0-0.3 microg Se/g as selenite) to weanling male rats. Se status was determined by liver Se concentration and selenoenzyme activity, and selenoprotein mRNA abundance in liver and blood was determined by ribonuclease protection analysis. Liver Se and plasma glutathione peroxidase-3 and liver Gpx1 activities indicated that minimal Se requirements were at 0.08 microg Se/g diet. When total RNA was isolated from whole blood, Gpx1 mRNA in Se-deficient rats decreased to 10% of levels in Se-adequate (0.2 microg Se/g diet) rats. With Se supplementation, blood Gpx1 mRNA levels increased sigmoidally to a plateau with a minimum Se requirement of 0.08 microg Se/g diet, whereas glutathione peroxidase-4 mRNA levels were unaffected. Similarly, Gpx1 mRNA in RNA isolated from fractionated red blood cells decreased in Se-deficient rats to 23% of Se-adequate levels, with a minimum Se requirement of 0.09 microg Se/g diet. Additional studies showed that the preponderance of whole blood Gpx1 mRNA arises from erythroid cells, most likely reticulocytes and young erythrocytes. In summary, whole blood selenoprotein mRNA levels can be used as molecular biomarkers for assessing Se requirements, illustrating that whole blood has potential as a target tissue in development of molecular biomarkers for use in nutrition as well as in medicine. PMID:19855070

  12. Genetic evidence for an androgen-regulated epididymal secretory glutathione peroxidase whose transcript does not contain a selenocysteine codon.

    PubMed Central

    Perry, A C; Jones, R; Niang, L S; Jackson, R M; Hall, L

    1992-01-01

    Epididymal glutathione peroxidase (GPX) has been suggested as a major factor in combating loss of fertility of spermatozoa due to lipid peroxidation. We report here the isolation and sequence of putative GPX cDNAs from rat (Rattus rattus) and cynomolgus-monkey (Macaca fascicularis) epididymis, which exhibit marked sequence identity with known GPXs. In both species the cDNAs encode predicted preproteins containing 221 amino acid residues. Unlike other characterized GPX sequences, epididymal GPX mRNA does not contain a selenocysteine codon (UGA). However, sequence comparison and molecular-modelling studies suggest a high degree of structural conservation between epididymal and other GPXs. Transcripts corresponding to epididymal GPX are not detected in a variety of other tissues (liver, spleen, kidney and testis) and appear to be androgen-regulated in the epididymis. Images Fig. 1. Fig. 2. PMID:1386734

  13. Transcriptional regulation of selenium-dependent glutathione peroxidase from Venerupis philippinarum in response to pathogen and contaminants challenge.

    PubMed

    Zhang, Linbao; Liu, Xiaoli; Chen, Leilei; You, Liping; Pei, Dong; Cong, Ming; Zhao, Jianmin; Li, Chenghua; Liu, Dongyan; Yu, Junbao; Wu, Huifeng

    2011-12-01

    Glutathione peroxidases (GPx) are key enzymes in the antioxidant systems of living organisms by catalyzing the reduction of peroxides to non-reactive products. In the present study, the full-length cDNA encoding a selenium-dependent GPx was identified from Venerupis philippinarum (designated as VpSe-GPx), and the spatial and temporal expression patterns post-Vibrio anguillarum, heavy metals and benzo[a]pyrene (B[a]P) challenge were also investigated. VpSe-GPx possessed all the conserved features critical for the fundamental structure and function of glutathione peroxidase. The VpSe-GPx mRNA was found to be most abundantly expressed in hepatopancreas. Vibrio challenge could significantly up-regulate the mRNA expression of VpSe-GPx, and the highest expression level was detected at 24 h post-infection with 6.5-fold increase compared with that in the control group. For heavy metals exposure, the expression of VpSe-GPx was significantly induced by 20, 40 μg L(-1) Cd and 10, 20 μg L(-1) Cu but depressed by 10 μg L(-1) Cd and 40 μg L(-1) Cu. With regards to B[a]P exposure, the expression of VpSe-GPx mRNA was significantly induced at 48 and 96 h post challenge. All these results suggested that VpSe-GPx was potentially involved in mediating the immune response and antioxidant defense in V. Philippinarum.

  14. The role of zinc, copper, plasma glutathione peroxidase enzyme, and vitamins in the development of allergic diseases in early childhood: The Polish mother and child cohort study.

    PubMed

    Stelmach, Iwona; Grzelewski, Tomasz; Bobrowska-Korzeniowska, Monika; Kopka, Monika; Majak, Paweł; Jerzynska, Joanna; Stelmach, Wlodzimierz; Polańska, Kinga; Sobala, Wojciech; Gromadzińska, Jolanta; Wąsowicz, Wojciech; Hanke, Wojciech

    2014-01-01

    It has been hypothesized that the increase in allergic disorders may, in part, be a consequence of changing diet. The primary aim of this study was to assess the associations between occurrence of atopic dermatitis; food allergy; the incidence of wheeze inhaled glucocorticosteroid use in children during the 1st year of life; and cord blood concentrations of copper, zinc, vitamins (A and E), and glutathione peroxidase activity. We evaluated 240 1-year-old children from the Polish Mother and Child Cohort Study. Women were interviewed during pregnancy to collect demographic and socioeconomic data and medical and reproductive history. Exposure to tobacco constituents was assessed based on questionnaire data. At delivery, umbilical cord blood plasma was sampled. One year after the birth, the child's exposure and health status were examined. In the analyses a multivariable model was used. Higher zinc and copper concentrations in cord blood were associated with increased likelihood of wheezing in 1-year-old children. This effect was seen only among children exposed to tobacco smoke at home. We also showed significantly lower activity of glutathione peroxidase enzyme 3 in umbilical cord blood plasma of children with atopic dermatitis during the 1st year of life. There were no significant associations between vitamin A and E concentrations in plasma and children's health. We showed imbalance in the antioxidant defense system in cord blood, which may lead to development of atopic dermatitis or wheezing in infancy. The association between maternal nutrient status during pregnancy and child's health is complex and interacts with other environmental factors such as tobacco exposure. This study was a part of the clinical trial NCT01861548 registered at ClinicalTrials.gov. PMID:24801465

  15. Molecular characterization of two glutathione peroxidase genes of Panax ginseng and their expression analysis against environmental stresses.

    PubMed

    Kim, Yu-Jin; Jang, Moon-Gi; Noh, Hae-Yong; Lee, Hye-Jin; Sukweenadhi, Johan; Kim, Jong-Hak; Kim, Se-Yeong; Kwon, Woo-Saeng; Yang, Deok-Chun

    2014-02-01

    Glutathione peroxidases (GPXs) are a group of enzymes that protect cells against oxidative damage generated by reactive oxygen species (ROS). GPX catalyzes the reduction of hydrogen peroxide (H2O2) or organic hydroperoxides to water or alcohols by reduced glutathione. The presence of GPXs in plants has been reported by several groups, but the roles of individual members of this family in a single plant species have not been studied. Two GPX cDNAs were isolated and characterized from the embryogenic callus of Panax ginseng. The two cDNAs had an open reading frame (ORF) of 723 and 681bp with a deduced amino acid sequence of 240 and 226 residues, respectively. The calculated molecular mass of the matured proteins are approximately 26.4kDa or 25.7kDa with a predicated isoelectric point of 9.16 or 6.11, respectively. The two PgGPXs were elevated strongly by salt stress and chilling stress in a ginseng seedling. In addition, the two PgGPXs showed different responses against biotic stress. The positive responses of PgGPX to the environmental stimuli suggested that ginseng GPX may help to protect against environmental stresses.

  16. An amphiphilic selenide catalyst behaves like a hybrid mimic of protein disulfide isomerase and glutathione peroxidase 7.

    PubMed

    Arai, Kenta; Moriai, Kenji; Ogawa, Akinobu; Iwaoka, Michio

    2014-12-01

    Protein disulfide isomerase (PDI) and glutathione peroxidase 7 (GPx7) cooperatively promote the oxidative folding of disulfide (SS)-containing proteins in endoplasmic reticulum by recognizing the nascent proteins to convert them into the native folds by means of SS formation and SS isomerization and by catalyzing reoxidation of reduced PDI with H2O2, respectively. In this study, new amphiphilic selenides with a long-chain alkyl group were designed as hybrid mimics of PDI and GPx7 and were applied to the refolding of reduced hen egg-white lysozyme (HEL-R). Competitive SS formation at pH 4 using HEL-R and glutathione (GSH) in the presence of the selenide catalyst and H2O2 showed that the amphiphilic selenides can preferentially catalyze SS formation of HEL-R, probably on account of hydrophobic interactions between the protein and the catalyst. In contrast, simple water-soluble selenides did not exhibit such behavior. In addition, when the pH of the solution was adjusted to 8.5 after the SS formation, surviving GSH promoted the SS isomerization of misfolded HEL to recover the native SS linkages. Thus, the amphiphilic selenides designed here could mimic the function of the PDI-GPx7 system. The combination of a water-soluble selenide and a long-chain alkyl group would be a useful motif in designing medicines for both protein misfolding diseases and antioxidant therapy.

  17. Effects of polymorphisms in vitamin E-, vitamin C-, and glutathione peroxidase-related genes on serum biomarkers and associations with glaucoma

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To study the association of selected polymorphism in genes related to vitamin E, vitamin C, and glutathione peroxidase with these biomarkers and primary open-angle glaucoma (POAG) risk. A case-control study matched for age, sex, and bodyweight was undertaken. Two hundred fifty POAG cases and 250 con...

  18. Is Peroxiredoxin II's peroxidase activity strongly inhibited in human erythrocytes?

    PubMed

    Benfeitas, Rui; Selvaggio, Gianluca; Antunes, Fernando; Coelho, Pedro; Salvador, Armindo

    2014-10-01

    H2O2 elimination in human erythrocytes is mainly carried out by catalase (Cat), glutathione peroxidase (GPx1) and the more recently discovered peroxiredoxin 2 (Prx2). However, the contribution of Prx2 to H2O2 consumption is still unclear. Prx2's high reactivity with H2O2 (kPrx2=10×10(7) M(-1)s(-1), kCat =7×10(7) M(-1)s(-1), kGPx1 =4×10(7) M(-1)s(-1)) and high abundance ([Prx2]= 570µM, [Cat]= 32µM, [GPx1]= 1µM) suggest that under low H2O2 supply rates it should consume >99% of the H2O2. However, extensive evidence indicates that in intact erythrocytes Prx2 contributes no more than Cat to H2O2 consumption. In order for this to be attained, Prx2's effective rate constant with H2O2would have to be just ~10(5) M(-1)s(-1), much lower than that determined in multiple experiments with the purified proteins. Nevertheless, nearly all Prx2 is oxidized within 1min of exposing erythrocytes to a H2O2 bolus, which is inconsistent with an irreversible inhibition. A mathematical model of the H2O2 metabolism in human erythrocytes [Benfeitas et al. (2014) Free Radic. Biol. Med.] where Prx2 either has a low kPrx2 or is subject to a strong (>99%) but readily reversible inhibition achieves quantitative agreement with detailed experimental observations of the responses of the redox status of Prx2 in human erythrocytes and suggests functional advantages of this design (see companion abstract). By contrast, a variant where Prx2 is fully active with kPrx2=10(8) M(-1)s(-1) shows important qualitative discrepancies. Altogether, these results suggest that Prx2's peroxidase activity is strongly inhibited in human erythrocytes. We acknowledge fellowship SFRH/BD/51199/2010, grants PEst-C/SAU/LA0001/2013-2014, PEst-OE/QUI/UI0612/2013, PEst-OE/QUI/UI0313/2014, and FCOMP-01-0124-FEDER-020978 (PTDC/QUI-BIQ/119657/2010) co-financed by FEDER through the COMPETE program and by FCT.

  19. Mouse Splenic Peroxidase and Its Role in Bactericidal Activity 1

    PubMed Central

    Strauss, R. R.; Paul, B. B.; Jacobs, A. A.; Sbarra, A. J.

    1972-01-01

    Spleen cell suspensions from AKR and CD-1 mice contain peroxidase activity as determined by guaiacol oxidation. This activity is found predominately in the 20,000 × g pellet fraction of spleen cell homogenates. In the presence of H2O2 and chloride ion at acidic pH, splenic peroxidase mediates the oxidation of d- or l-alanine to CO2, NH3, and acetaldehyde. The same reaction mixture without added amino acid can kill both gram-positive and gram-negative bacteria. The conditions for both reactions are similar. Both have an absolute requirement for H2O2 and chloride ion, neither is active at neutral or alkaline pH, and both are inhibited by the sulfonic amino acid taurine. In these aspects, splenic peroxidase is qualitatively similar in its activity to myeloperoxidase (MPO) from polymorphonuclear leukocytes. It is quantitatively different from MPO in that the latter is more potent on a per guaiacol unit basis with respect to both amino acid oxidation and bactericidal activity. Still another quantitative difference is that splenic peroxidase requires 0.1 m NaCl for activity, whereas MPO functions with as little as 0.005 m NaCl. Splenic peroxidase and MPO both appear to differ qualitatively from horseradish peroxidase in that the latter enzyme does not mediate amino acid oxidation. PMID:4632463

  20. Reaction kinetics and targeting to cellular glutathione S-transferase of the glutathione peroxidase mimetic PhSeZnCl and its D,L-polylactide microparticle formulation.

    PubMed

    Bartolini, D; Piroddi, M; Tidei, C; Giovagnoli, S; Pietrella, D; Manevich, Y; Tew, K D; Giustarini, D; Rossi, R; Townsend, D M; Santi, C; Galli, F

    2015-01-01

    Catalytic properties and cellular effects of the glutathione peroxidase (GPx)-mimetic compound PhSeZnCl or its d,l-lactide polymer microencapsulation form (M-PhSeZnCl) were investigated and compared with the prototypical Se-organic compounds ebselen and diselenide (PhSe)2. PhSeZnCl was confirmed to catalyze the ping-pong reaction of GPx with higher Vmax than ebselen and (PhSe)2, but the catalytic efficiency calculated for the cosubstrates glutathione (GSH) and H2O2, and particularly the high reactivity against thiols (lowest KM for GSH in the series of test molecules), suggested poor biological applicability of PhSeZnCl as a GPx mimetic. Cytotoxicity of PhSeZnCl was demonstrated in various cancer cell lines via increased reactive oxygen species (ROS) generation, depletion of intracellular thiols, and induction of apoptosis. Experiments carried out in GSH S-transferase P (GSTP)-overexpressing K562 human erythroleukemia cells and in GSTP1-1-knockout murine embryonic fibroblasts (MEFs) demonstrated that this cytosolic enzyme represents a preferential target of the redox disturbances produced by this Se-compound with a key role in controlling H2O2 generation and the perturbation of stress/survival kinase signaling. Microencapsulation was adopted as a strategy to control the thiol reactivity and oxidative stress effects of PhSeZnCl, then assessing applications alternative to anticancer. The uptake of this "depowered" GPx-mimetic formulation, which occurred through an endocytosis-like mechanism, resulted in a marked reduction of cytotoxicity. In MCF-7 cells transfected with different allelic variants of GSTP, M-PhSeZnCl lowered the burst of cellular ROS induced by the exposure to extracellular H2O2, and the extent of this effect changed between the GSTP variants. Microencapsulation is a straightforward strategy to mitigate the toxicity of thiol-reactive Se-organic drugs that enhanced the antioxidant and cellular protective effects of PhSeZnCl. A mechanistic linkage of

  1. A global transcriptomic view of the multifaceted role of glutathione peroxidase-1 in cerebral ischemic-reperfusion injury.

    PubMed

    Chen, Minghui Jessica; Wong, Connie H Y; Peng, Zhao Feng; Manikandan, Jayapal; Melendez, Alirio J; Tan, Theresa M; Crack, Peter J; Cheung, Nam Sang

    2011-03-15

    Transient cerebral ischemia often results in secondary ischemic/reperfusion injury, the pathogenesis of which remains unclear. This study provides a comprehensive, temporal description of the molecular events contributing to neuronal injury after transient cerebral ischemia. Intraluminal middle cerebral artery occlusion (MCAO) was performed to induce a 2-h ischemia with reperfusion. Microarray analysis was then performed on the infarct cortex of wild-type (WT) and glutathione peroxidase-1 (a major antioxidant enzyme) knockout (Gpx1(-/-)) mice at 8 and 24h postreperfusion to identify differential gene expression profile patterns and potential alternative injury cascades in the absence of Gpx1, a crucial antioxidant enzyme, in cerebral ischemia. Genes with at least ±1.5-fold change in expression at either time point were considered significant. Global transcriptomic analyses demonstrated that 70% of the WT-MCAO profile overlapped with that of Gpx1(-/-)-MCAO, and 28% vice versa. Critical analysis of the 1034 gene probes specific to the Gpx1(-/-)-MCAO profile revealed regulation of additional novel pathways, including the p53-mediated proapoptotic pathway and Fas ligand (CD95/Apo1)-mediated pathways; downplay of the Nrf2 antioxidative cascade; and ubiquitin-proteasome system dysfunction. Therefore, this comparative study forms the foundation for the establishment of screening platforms for target definition in acute cerebral ischemia intervention.

  2. High-resolution imaging of selenium in kidneys: a localized selenium pool associated with glutathione peroxidase 3

    SciTech Connect

    Malinouski, M.; Kehr, S.; Finney, L.; Vogt, S.; Carlson, B.A.; Seravalli, J.; Jin, R.; Handy, D.E.; Park, T.J.; Loscalzo, J.; Hatfield, D.L.; Gladyshev, V.N.

    2012-04-17

    Recent advances in quantitative methods and sensitive imaging techniques of trace elements provide opportunities to uncover and explain their biological roles. In particular, the distribution of selenium in tissues and cells under both physiological and pathological conditions remains unknown. In this work, we applied high-resolution synchrotron X-ray fluorescence microscopy (XFM) to map selenium distribution in mouse liver and kidney. Liver showed a uniform selenium distribution that was dependent on selenocysteine tRNA{sup [Ser]Sec} and dietary selenium. In contrast, kidney selenium had both uniformly distributed and highly localized components, the latter visualized as thin circular structures surrounding proximal tubules. Other parts of the kidney, such as glomeruli and distal tubules, only manifested the uniformly distributed selenium pattern that co-localized with sulfur. We found that proximal tubule selenium localized to the basement membrane. It was preserved in Selenoprotein P knockout mice, but was completely eliminated in glutathione peroxidase 3 (GPx3) knockout mice, indicating that this selenium represented GPx3. We further imaged kidneys of another model organism, the naked mole rat, which showed a diminished uniformly distributed selenium pool, but preserved the circular proximal tubule signal. We applied XFM to image selenium in mammalian tissues and identified a highly localized pool of this trace element at the basement membrane of kidneys that was associated with GPx3. XFM allowed us to define and explain the tissue topography of selenium in mammalian kidneys at submicron resolution.

  3. Effect of subcutaneous selenium injection and supplementary selenium source on blood selenium and glutathione peroxidase in feedlot heifers

    PubMed Central

    Chorfi, Younes; Girard, Vincent; Fournier, Alain; Couture, Yvon

    2011-01-01

    This study measured the effect on glutathione peroxidase (GSH-Px) and selenium (Se) in whole blood and plasma associated with subcutaneous Se injections in beef heifers fed organic or inorganic Se. Heifers (n = 120) were randomly divided into 2 groups, 1 of which received subcutaneous Se injections. Both groups were given the same total mixed ration with 3 mg of organic or inorganic Se daily. Until week 2, heifers that had received Se injections showed higher concentrations of plasma Se and GSH-Px and whole blood Se (P < 0.001) than those having had no injections. Concentrations of plasma Se and GSH-Px were higher in the group receiving organic Se than the group receiving inorganic Se. Whole blood GSH-Px concentrations increased significantly (P < 0.001) throughout a 12-week period but were not affected by Se source. Combination of Se injections and supplementation could help maintain normal Se and GSH-Px blood status in beef heifers during the first few weeks in the feedlot. PMID:22467963

  4. Increases of Catalase and Glutathione Peroxidase Expressions by Lacosamide Pretreatment Contributes to Neuroprotection Against Experimentally Induced Transient Cerebral Ischemia.

    PubMed

    Choi, Hyun Young; Park, Joon Ha; Chen, Bai Hui; Shin, Bich Na; Lee, Yun Lyul; Kim, In Hye; Cho, Jeong-Hwi; Lee, Tae-Kyeong; Lee, Jae-Chul; Won, Moo-Ho; Ahn, Ji Hyeon; Tae, Hyun-Jin; Yan, Bing Chun; Hwang, In Koo; Cho, Jun Hwi; Kim, Young-Myeong; Kim, Sung Koo

    2016-09-01

    Lacosamide is a new antiepileptic drug which is widely used to treat partial-onset seizures. In this study, we examined the neuroprotective effect of lacosamide against transient ischemic damage and expressions of antioxidant enzymes such as Zn-superoxide dismutase (SOD1), Mn-superoxide dismutase (SOD2), catalase (CAT) and glutathione peroxidase (GPX) in the hippocampal cornu ammonis 1 (CA1) region following 5 min of transient global cerebral ischemia in gerbils. We found that pre-treatment with 25 mg/kg lacosamide protected CA1 pyramidal neurons from transient global cerebral ischemic insult using hematoxylin-eosin staining and neuronal nuclear antigen immunohistochemistry. Transient ischemia dramatically changed expressions of SOD1, SOD2 and GPX, not CAT, in the CA1 pyramidal neurons. Lacosamide pre-treatment increased expressions of CAT and GPX, not SOD1 and 2, in the CA1 pyramidal neurons compared with controls, and their expressions induced by lacosamide pre-treatment were maintained after transient cerebral ischemia. In brief, pre-treatment with lacosamide protected hippocampal CA1 pyramidal neurons from ischemic damage induced by transient global cerebral ischemia, and the lacosamide-mediated neuroprotection may be closely related to increases of CAT and GPX expressions by lacosamide pre-treatment. PMID:27209305

  5. The importance of Arabidopsis glutathione peroxidase 8 for protecting Arabidopsis plant and E. coli cells against oxidative stress

    PubMed Central

    Gaber, Ahmed

    2014-01-01

    Glutathione peroxidases (GPXs) are major family of the reactive oxygen species (ROS) scavenging enzymes. Recently, database analysis of the Arabidopsis genome revealed a new open-reading frame, thus increasing the total number of AtGPX gene family to eight (AtGPX1–8). The effect of plant hormones like; i. e. salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), indoleacetic acid (IAA), and mannitol on the expression of the genes confirm that the AtGPX genes family is regulated by multiple signaling pathways. The survival rate of AtGPX8 knockout plants (KO8) was significantly decreased under heat stress compared with the wild type. Moreover, the content of malondialdehyde (MDA) and protein oxidation was significantly increased in the KO8 plant cells under heat stress. Results indicating that the deficiency of AtGPX8 accelerates the progression of oxidative stress in KO8 plants. On the other hand, the overexpression of AtGPX8 in E. coli cells enhance the growth of the recombinant enzyme on media supplemented with 0.2 mM cumene hydroperoxide, 0.3 mM H2O2 or 600 mM NaCl. PMID:24217216

  6. Association Between Plasma Selenium and Glutathione Peroxidase Levels And Severity of Diabetic Nephropathy in Patients With Type Two Diabetes Mellitus

    PubMed Central

    Sedighi, Omid; Makhlough, Atieh; Shokrzadeh, Mohammad; Hoorshad, Shiva

    2014-01-01

    Background: Oxidative stress is thought to be involved in the pathogenesis of diabetic nephropathy. Selenium (Se), and antioxidant enzymes such as glutathione peroxidase (GPx) play an important protective role in diabetes complications. Objectives: This study aimed to evaluate the association between plasma Se and GPx levels with severity of diabetic nephropathy. Patients and Methods: In a case-control study, we measured plasma Se and GPx concentrations in patients with type two diabetes without microalbuminuria (group 1), with microalbuminuria (group 2), with macroalbuminuria (group 3), and healthy control subjects (group 4). We also assessed plasma glucose, urea, creatinine, and glycated hemoglobin levels in all study patients. Results: Plasma Se and GPx concentrations were significantly lower in diabetic patients with macroalbuminuria than other study groups (P < 0.001). Albuminuria (Alb/Cr in random urine sample) had a negative correlation with plasma Se (r = -0.40, P = 0.01), and GPx (r = -0.23, P = 0.03) concentrations. Conclusions: Plasma Se and GPx levels were lower in type two diabetic patients with macroalbuminuria and related to the stage of diabetic nephropathy. PMID:25695036

  7. Cantaloupe melon peroxidase: characterization and effects of additives on activity.

    PubMed

    Lamikanra, O; Watson, M A

    2000-06-01

    Peroxidase in cantaloupe melon (Cucumis melo L. var. reticulatus Naud.), a fruit commonly fresh cut processed, was characterized to determine reaction pathway, optimal conditions for activity and effect of some additives on enzymatic action. Mn2+, CaCl2, NaNO2 and kinetin had partial inhibitory effects on enzyme activity. Activity was effectively inhibited by compounds capable of chelating peroxidase heme iron such as diethyldithiocarbamate and tiron, but unaffected by EDTA. Free radical scavenger, superoxide dismutase, also had no effect on reaction velocity. Enzymatic action was consistent with that of ascorbate peroxidase based on the relatively higher affinity for ascorbate over guaiacol. Optimum activity temperature was 50-55 degrees C. The enzyme was stable at temperatures below 40 degrees C and at 50 degrees C for up to 10 min. Over 90% of total activity was lost at 80 degrees C within 5 min. Broad pH optima, 5.5-7.5 at 50 degrees C and 6-7 at 30 degrees C, were obtained. Peroxidase activity in cantaloupe was higher than those in strawberry (Fragaria ananassa Duch.) and lettuce (Lactuca sativa L.), suggesting a relatively high oxidative stress in fresh cut cantaloupe. The potential use of ascorbate as an additive in fresh cut cantaloupe melon was demonstrated by its ability to preserve color in minimally processed fruits for 25 days at 4 degrees C, possibly as a result of an enhanced antioxidative action of the ascorbate-peroxidase complex and trace metal ion cofactors.

  8. Peroxidase activation of cytoglobin by anionic phospholipids: Mechanisms and consequences.

    PubMed

    Tejero, Jesús; Kapralov, Alexandr A; Baumgartner, Matthew P; Sparacino-Watkins, Courtney E; Anthonymutu, Tamil S; Vlasova, Irina I; Camacho, Carlos J; Gladwin, Mark T; Bayir, Hülya; Kagan, Valerian E

    2016-05-01

    Cytoglobin (Cygb) is a hexa-coordinated hemoprotein with yet to be defined physiological functions. The iron coordination and spin state of the Cygb heme group are sensitive to oxidation of two cysteine residues (Cys38/Cys83) and/or the binding of free fatty acids. However, the roles of redox vs lipid regulators of Cygb's structural rearrangements in the context of the protein peroxidase competence are not known. Searching for physiologically relevant lipid regulators of Cygb, here we report that anionic phospholipids, particularly phosphatidylinositolphosphates, affect structural organization of the protein and modulate its iron state and peroxidase activity both conjointly and/or independently of cysteine oxidation. Thus, different anionic lipids can operate in cysteine-dependent and cysteine-independent ways as inducers of the peroxidase activity. We establish that Cygb's peroxidase activity can be utilized for the catalysis of peroxidation of anionic phospholipids (including phosphatidylinositolphosphates) yielding mono-oxygenated molecular species. Combined with the computational simulations we propose a bipartite lipid binding model that rationalizes the modes of interactions with phospholipids, the effects on structural re-arrangements and the peroxidase activity of the hemoprotein.

  9. Preventive (myoglobin, transferrin) and scavenging (superoxide dismutase, glutathione peroxidase) anti-oxidative properties of raw liquid extract of Morinda lucida leaf in the traditional treatment of Plasmodium infection

    PubMed Central

    Olaniyan, Mathew Folaranmi; Babatunde, Elizabeth Moyinoluwa

    2016-01-01

    Background: Liquid extract of Morinda lucida leaf has been demonstrated to have antiplasmodial activities. Some phytochemicals act as preventive and or scavenging antioxidants. This study aimed to investigate the preventative and scavenging properties of the raw liquid extract of M. lucida leaf using plasma myoglobin, transferrin, superoxide dismutase (SOD), and glutathione (GSH) peroxidase. Materials and Methods: Forty-eight Plasmodium-infected patients aged 29-47 years that have not been treated with any antimalaria medication but have decided to be treated traditionally using M. lucida leaf extract were recruited from 15 traditional homes in ATISBO, Saki-East, and Saki-West local government areas of Oke-Ogun — the Northern part of Oyo State-Nigeria. Identification of Plasmodium in the blood of the test and normal control subjects were carried out by Giemsha thick film technique. Packed cell volume, total bile acids, blood glucose, blood pressure, plasma myoglobin, transferrin, SOD, and GSH peroxidase (GPx) were evaluated in the normal control subjects and in the Plasmodium-infected patients before and after the treatment with raw liquid extract of M. lucida leaf. Results: A significant (P < 0.05) biochemical alterations were observed in the plasma values of transferrin, SOD, and GPx in the Plasmodium-infected patients when compared with the normal control subjects and after treatment with the raw liquid extract of M. lucida leaf. Conclusion: Our study supports the possible preventative and scavenging antioxidative effect of the raw liquid extract of M. lucida leaf in the traditional treatment of Plasmodium infection. PMID:27003969

  10. Silencing of glutathione peroxidase 3 through DNA hypermethylation is associated with lymph node metastasis in gastric carcinomas.

    PubMed

    Peng, Dun-Fa; Hu, Tian-Ling; Schneider, Barbara G; Chen, Zheng; Xu, Ze-Kuan; El-Rifai, Wael

    2012-01-01

    Gastric cancer remains the second leading cause of cancer-related death in the world. H. pylori infection, a major risk factor for gastric cancer, generates high levels of reactive oxygen species (ROS). Glutathione peroxidase 3 (GPX3), a plasma GPX member and a major scavenger of ROS, catalyzes the reduction of hydrogen peroxide and lipid peroxides by reduced glutathione. To study the expression and gene regulation of GPX3, we examined GPX3 gene expression in 9 gastric cancer cell lines, 108 primary gastric cancer samples and 45 normal gastric mucosa adjacent to cancers using quantitative real-time RT-PCR. Downregulation or silencing of GPX3 was detected in 8 of 9 cancer cell lines, 83% (90/108) gastric cancers samples, as compared to non-tumor adjacent normal gastric samples (P<0.0001). Examination of GPX3 promoter demonstrated DNA hypermethylation (≥ 10% methylation level determined by Bisulfite Pyrosequencing) in 6 of 9 cancer cell lines and 60% of gastric cancer samples (P = 0.007). We also detected a significant loss of DNA copy number of GPX3 in gastric cancers (P<0.001). Treatment of SNU1 and MKN28 cells with 5-Aza-2' Deoxycytidine restored the GPX3 gene expression with a significant demethylation of GPX3 promoter. The downregulation of GPX3 expression and GPX3 promoter hypermethylation were significantly associated with gastric cancer lymph node metastasis (P = 0.018 and P = 0.029, respectively). We also observed downregulation, DNA copy number losses, and promoter hypermethylation of GPX3 in approximately one-third of tumor-adjacent normal gastric tissue samples, suggesting the presence of a field defect in areas near tumor samples. Reconstitution of GPX3 in AGS cells reduced the capacity of cell migration, as measured by scratch wound healing assay. Taken together, the dysfunction of GPX3 in gastric cancer is mediated by genetic and epigenetic alterations, suggesting impairment of mechanisms that regulate ROS and its possible involvement in gastric

  11. Modular evolution of glutathione peroxidase genes in association with different biochemical properties of their encoded proteins in invertebrate animals

    PubMed Central

    Bae, Young-An; Cai, Guo-Bin; Kim, Seon-Hee; Zo, Young-Gun; Kong, Yoon

    2009-01-01

    Background Phospholipid hydroperoxide glutathione peroxidases (PHGPx), the most abundant isoforms of GPx families, interfere directly with hydroperoxidation of lipids. Biochemical properties of these proteins vary along with their donor organisms, which has complicated the phylogenetic classification of diverse PHGPx-like proteins. Despite efforts for comprehensive analyses, the evolutionary aspects of GPx genes in invertebrates remain largely unknown. Results We isolated GPx homologs via in silico screening of genomic and/or expressed sequence tag databases of eukaryotic organisms including protostomian species. Genes showing strong similarity to the mammalian PHGPx genes were commonly found in all genomes examined. GPx3- and GPx7-like genes were additionally detected from nematodes and platyhelminths, respectively. The overall distribution of the PHGPx-like proteins with different biochemical properties was biased across taxa; selenium- and glutathione (GSH)-dependent proteins were exclusively detected in platyhelminth and deuterostomian species, whereas selenium-independent and thioredoxin (Trx)-dependent enzymes were isolated in the other taxa. In comparison of genomic organization, the GSH-dependent PHGPx genes showed a conserved architectural pattern, while their Trx-dependent counterparts displayed complex exon-intron structures. A codon for the resolving Cys engaged in reductant binding was found to be substituted in a series of genes. Selection pressure to maintain the selenocysteine codon in GSH-dependent genes also appeared to be relaxed during their evolution. With the dichotomized fashion in genomic organizations, a highly polytomic topology of their phylogenetic trees implied that the GPx genes have multiple evolutionary intermediate forms. Conclusion Comparative analysis of invertebrate GPx genes provides informative evidence to support the modular pathways of GPx evolution, which have been accompanied with sporadic expansion/deletion and exon

  12. Activities of gamma-glutamyl transpeptidase and erythrocyte glutathione dependent enzymes in nasopharyngeal carcinoma patients and normal controls.

    PubMed

    Ngah, W Z; Shamaan, N A; Said, M H; Azhar, M T

    1993-01-01

    Plasma gamma-glutamyltranspeptidase (gamma-GT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities were determined in normal and nasopharyngeal carcinoma (NPC) patients. No difference in enzyme activities was observed in the three major races of the Malaysian population, i.e. Malay, Chinese and Indian patients. However, plasma gamma-GT, erythrocyte glutathione S-transferase (GST) and GPx activities were significantly increased in all NPC patients, while GR activity remained unchanged. Patients with elevated plasma gamma-GT activities also had increased GST and GPx activities. Plasma gamma-GT and GPx activities were then found to be affected by treatment. Patients with plasma gamma-GT activity greater than 70 IU/l had very poor prognoses but patients with decreased gamma-GT activities were found to be in remission.

  13. Response of selenium-dependent glutathione peroxidase in the freshwater bivalve Anodonta woodiana exposed to 2,4-dichlorophenol,2,4,6-trichlorophenol and pentachlorophenol.

    PubMed

    Xia, Xichao; Hua, Chunxiu; Xue, Shipeng; Shi, Bingqin; Gui, Gaixia; Zhang, Dongxian; Wang, Xiying; Guo, Lianghong

    2016-08-01

    2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) pose a health risk to aquatic organism and humans, and are recognized as persistent priority pollutants. Selenium dependent glutathione peroxidase (Se-GPx) belongs to the family of selenoprotein, which acts mainly as an antioxidant role in the cellular defense system. In the current study, a Se-GPx full length cDNA was cloned from Anodonta woodiana and named as AwSeGPx. It had a characteristic codon at 165TGA167 that corresponds to selenocysteine(Sec) amino acid as U44. The full length cDNA consists of 870 bp, an open reading frame (ORF) of 585 bp encoded a polypeptide of 195 amino in which conserved domain (68LGFPCNQF75) and a glutathione peroxide-1 GPx active site (32GKVILVENVASLUGTT47) were observed. Additionally, the eukaryotic selenocysteine insertion sequence (SECIS) was conserved in the 3'UTR. The AwSeGPx amino acid sequence exhibited a high similarity with that of other Se-GPx. Real-time PCR analysis revealed that AwSeGPx mRNA had a widely distribution, but the highest level was observed in hepatopancreas. AwSeGPx mRNA expression was significantly up-regulated in hepatopancreas, gill and hemocytes after 2,4-DCP, 2,4,6-TCP and PCP exposure. Under similar environment, clams A. woodiana showed a more sensitive to PCP than that of 2,4-DCP and 2,4,6-TCP. These results indicate that AwSeGPx plays a protective role in eliminating oxidative stress derived from 2,4-DCP, 2,4,6-TCP and PCP treatment. PMID:27291351

  14. Effect of dietary fat on plasma glutathione peroxidase levels and intestinal absorption of /sup 75/Se-labeled sodium selenite in chicks

    SciTech Connect

    Mutanen, M.L.; Mykkaenen, H.M.

    1984-05-01

    The effect of dietary fat on the availability of selenium was investigated in chicks fed either 4 or 20% butter, olive oil, rape oil, corn oil or sunflower oil in the diet for 3 weeks after hatching. Plasma glutathione peroxidase (GSH-Px) activity was used as an indicator of the body selenium status. In addition, the intestinal absorption of sodium selenite (/sup 75/Se-labeled) was determined by using both the in vivo ligated loop procedure and oral administration of the isotope. The plasma GSH-Px levels increased with increasing proportion of the polyunsaturated fatty acids in the diet. Increasing the amount of fat from 4 to 20% significantly enhanced the GSH-Px activity in the groups receiving butter or olive oil, but had no effect in animals fed the unsaturated fats. The absorption of (/sup 75/Se)selenite from the ligated duodenal loops tended to be reduced in chicks fed corn oil or sunflower oil as compared to the animals receiving butter in their diet. On the other hand, the type of dietary fat did not appear to affect the absorption of the orally administered selenite. The present study demonstrates that the type of dietary fat can affect the plasma GSH-Px levels in chicks without altering the intestinal absorption of selenite. However, the results on the absorption of the intraduodenally injected sodium selenite suggest that dietary fat plays some role in the intestinal transport of selenium.

  15. [Blood deficiency values of polyunsaturated fatty acids of phospholipids, vitamin E and glutathione peroxidase as possible risk factors in the onset and development of acquired immunodeficiency syndrome].

    PubMed

    Passi, S; De Luca, C; Picardo, M; Morrone, A; Ippolito, F

    1990-04-01

    Plasma levels of vitamin E (vit E) and polyunsatured fatty acids of phospholipids (PUFA-PL) as well as erythrocyte glutathione peroxidase (GSH-Px) activity are significantly lower (p less than 0.001) in patients HIV sero-positive (AIDS and ARC cases) both affected and not affected with seborrheic dermatitis and in 32% of HIV sero-negative intravenous drug abusers (IVDA, A subgroup) than in controls. The deficiency of PUFA-PL (mainly C20:3 n-6, C20:4 n-6 and C22:6 n-3) which is associated with a significant increase (p less than 0.001) of saturated palmitic and stearic acids and monounsaturated oleic acid, cannot be correlated to an active lipoperoxidative process. In fact the levels of thiobarbituric acid-reactive materials (TBA-RM) are not increased in the plasma of HIV sero-positive patients and A subgroup of IVDA. It is likely that the reduction of PUFA-PL is due to an inhibition of hepatic microsomal desaturase enzymes (delta 6 desaturase, delta 5 desaturase, delta 4 desaturase) which are involved in both n-6 and n-3 pathways. Since IVDA represent, and not only in Italy, a major risk category for HIV infection, we suggest that reduced blood levels of vit E, GSH-Px and particularly PUFA-PL may be added to the list of risk factors favouring the onset and the development of AIDS.

  16. Glutathione peroxidase 1 expression, malondialdehyde levels and histological alterations in the liver of Acrossocheilus fasciatus exposed to cadmium chloride.

    PubMed

    Liu, Guo-Di; Sheng, Zhang; Wang, You-Fa; Han, Ying-Li; Zhou, Yang; Zhu, Jun-Quan

    2016-03-10

    Cadmium (Cd) is known as a widespread pollutant in aquatic environment. The accumulation of reactive oxygen species (ROS) is attributed to Cd exposure, which may affect the growth, development and physiological metabolism of aquatic organisms. In response to these unfavorable damages, antioxidant systems have been developed to protect against oxidative stress. In this study, we investigated the expression pattern of glutathione peroxidase 1 genes (GPx-1a and GPx-1b) in the liver of Acrossocheilus fasciatus after Cd administration. Total RNA extraction, reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) were performed in order to clone the A. fasciatus GPx-1a and GPx-1b full-length cDNA sequences and partial fragment of β-actin cDNA from the liver for the first time. Tissue-specific expression analysis proved that GPx-1 genes were widely expressed in the liver, kidney, gill, testis, muscle, spleen, heart and brain. The changes of GPx-1 mRNA and malondialdehyde (MDA) levels in the liver treated with Cd were measured. In addition, the acute toxic effects of Cd on the microstructure of the liver were studied using light microscopy. These results suggest that GPx-1, MDA and liver histology which represent molecular, biochemical and histological levels, can be used as potential biomarkers to monitor Cd pollution. The overall findings also highlight the potential use of those three bio-indicators combined together as a multi-level tool (molecular, biochemical and histological levels) when monitoring Cd contamination and other possible exogenetic pollutants in aquatic environment. PMID:26707212

  17. Dietary fish oil replacement with canola oil up-regulates glutathione peroxidase 1 gene expression in yellowtail kingfish (Seriola lalandi).

    PubMed

    Bowyer, Jenna N; Rout-Pitt, Nathan; Bain, Peter A; Stone, David A J; Schuller, Kathryn A

    2012-08-01

    The marine carnivore yellowtail kingfish (YTK, Seriola lalandi) was fed diets containing 5% residual fish oil (from the dietary fish meal) plus either 20% fish oil (FO), 20% canola oil (CO), 20% poultry oil (PO), 10% fish oil plus 10% canola oil (FO/CO) or 10% fish oil plus 10% poultry oil (FO/PO) and the effects on fish growth and hepatic expression of two glutathione peroxidase (GPx 1 and GPx 4) and two peroxiredoxin (Prx 1 and Prx 4) antioxidant genes were investigated. Partial (50%) replacement of the added dietary fish oil with poultry oil significantly improved fish growth whereas 100% replacement with canola oil significantly depressed fish growth. The fatty acid profiles of the fish fillets generally reflected those of the dietary oils except that there was apparent selective utilization of palmitic acid (16:0) and oleic acid (18:1n-9) and apparent selective retention of eicospentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). The Prx 1 and 4 genes were expressed at 10- and 100-fold the level of the GPx 4 and 1 genes, respectively, and at one-tenth the level of the highly expressed β-actin reference gene. Dietary fish oil replacement with canola oil significantly up-regulated GPx 1 gene expression and there was a non-significant tendency towards down-regulation of Prx 1 and Prx 4. The results are discussed in terms of the effects of fish oil replacement on the peroxidation index of the diets and the resulting effects on the target antioxidant enzymes. PMID:22521527

  18. Glutathione peroxidase 1 expression, malondialdehyde levels and histological alterations in the liver of Acrossocheilus fasciatus exposed to cadmium chloride.

    PubMed

    Liu, Guo-Di; Sheng, Zhang; Wang, You-Fa; Han, Ying-Li; Zhou, Yang; Zhu, Jun-Quan

    2016-03-10

    Cadmium (Cd) is known as a widespread pollutant in aquatic environment. The accumulation of reactive oxygen species (ROS) is attributed to Cd exposure, which may affect the growth, development and physiological metabolism of aquatic organisms. In response to these unfavorable damages, antioxidant systems have been developed to protect against oxidative stress. In this study, we investigated the expression pattern of glutathione peroxidase 1 genes (GPx-1a and GPx-1b) in the liver of Acrossocheilus fasciatus after Cd administration. Total RNA extraction, reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) were performed in order to clone the A. fasciatus GPx-1a and GPx-1b full-length cDNA sequences and partial fragment of β-actin cDNA from the liver for the first time. Tissue-specific expression analysis proved that GPx-1 genes were widely expressed in the liver, kidney, gill, testis, muscle, spleen, heart and brain. The changes of GPx-1 mRNA and malondialdehyde (MDA) levels in the liver treated with Cd were measured. In addition, the acute toxic effects of Cd on the microstructure of the liver were studied using light microscopy. These results suggest that GPx-1, MDA and liver histology which represent molecular, biochemical and histological levels, can be used as potential biomarkers to monitor Cd pollution. The overall findings also highlight the potential use of those three bio-indicators combined together as a multi-level tool (molecular, biochemical and histological levels) when monitoring Cd contamination and other possible exogenetic pollutants in aquatic environment.

  19. [GLUTATHIONE SYSTEM ACTIVITY IN RAT TISSUES UNDER PHENYLETHYL BIGUANIDE ACTION ON THE BACKGROUND OF EXPERIMENTAL BRAIN ISCHEMIA/REPERFUSION DEVELOPMENT].

    PubMed

    Safonova, O A; Popova, T N; Kryl'skii, D V

    2016-01-01

    It was studied the total antioxidant activity, content of primary lipid peroxidation (LPO) products and reduced glutathione, and the activity of glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, and NADP-isocitrate dehydrogenase in rat tissues under phenylethyl biguanide (phenfor- min) action on the background of experimental brain ischemia/reperfusion development. It is stablished the analyzed parameters, increasing under ischemia/reperfusion conditions in the brain and blood serum of animals, exhibit a decrease upon the introduction of this biguanide derivative. The obtained data can be explained by a decrease in degree of mobilization of the antioxidant system--in particular, of its glutathione chain--in the pathologic state. Hence, there is a need in NADPH supply for the system functioning compared with the pathology. Thus, phenylethyl biguanide demonstrates its antioxidant and protective properties under oxidative stress development that is accompanied by accumulation of the products of free radical oxidation of biomolecules during the ischemic brain injury. PMID:27159954

  20. Clinical significance and therapeutic value of glutathione peroxidase 3 (GPx3) in hepatocellular carcinoma

    PubMed Central

    Qi, Xiang; Ng, Kevin Tak Pan; Lian, Qi Zhou; Liu, Xiao Bing; Li, Chang Xian; Geng, Wei; Ling, Chang Chun; Ma, Yuen Yuen; Yeung, Wai Ho; Tu, Wen Wei; Fan, Sheung Tat; Lo, Chung Mau; Man, Kwan

    2014-01-01

    Aims: We aimed to investigate the clinical significance of GPx3 in hepatocellular carcinoma (HCC) and to characterize its tumor suppressive role. Methods: HCC patients (113) who underwent hepatectomy were recruited to examine the clinical relevance of GPx3. The tumor suppressive role of GPx3 was studied by administration of recombinant GPx3 (rGPx3) or over-expression of GPx3 in HCC cells in vitro and in vivo. The therapeutic value of GPx3 for HCC was further investigated using human induced pluripotent stem cell derived mesenchymal stem cells (hiPSC-MSCs) as its delivery vehicle. Results: Down-regulation of GPx3 significantly correlated with advanced tumor stage (P = 0.024), venous infiltration (P = 0.043) and poor overall survival (P = 0.007) after hepatectomy. Lower plasma GPx3 in HCC patients was significantly associated with larger tumor size (P = 0.011), more tumor nodules (P = 0.032) and higher recurrence (P = 0.016). Over-expression of GPx3 or administration of rGPx3 significantly inhibited proliferation and invasiveness of HCC cells in vitro and in vivo. Tumor suppressive activity of GPx3 was mediated through Erk-NFκB-SIP1 pathway. GPx3 could be delivered by hiPSC-MSCs into the tumor and exhibited tumor suppressive activity in vivo. Conclusions: GPx3 is a tumor suppressor gene in HCC and may possess prognostic and therapeutic value for HCC patients. PMID:25333265

  1. Glutathione peroxidase response in tissues of rats fed diets containing fish protein concentrate prepared from shark flesh of known mercury and selenium contents

    SciTech Connect

    Thrower, S.J.; Andrewartha, K.A.

    1981-01-01

    Studies have been reported using experimental animals and synthetic diets containing selenium and mercury compounds to demonstrate detoxification of mercury by selenium. The mechanism of detoxification remains obscure. Most experiments have involved the use of high levels of both elements and relied on the observation of gross symptoms. The measurement of enzyme systems may be useful in detecting effects of mercury at a lower, subclinical level and in elucidating the biochemistry of mercury/selenium interactions. The activity of the selenoenzyme glutathione peroxidase (GSH-Px) in rats is dependent on dietary selenium and attempts have been made to use this enzyme as an indicator of mercury/selenium interactions. The research described in this paper was designed to investigate the effect of mercury, in the form and amounts which occur naturally in seafood, on the availability of selenium at levels approximating the nutritional requirement. In anticipation of mercury lowering the GSH-Px response a range of selenium concentrations was used, from nutritional deficiency to three times the nutritional requirement.

  2. Knocking down the transcript of protein kinase C-lambda modulates hypothalamic glutathione peroxidase, melanocortin receptor and neuropeptide Y gene expression in amphetamine-treated rats.

    PubMed

    Hsieh, Yih-Shou; Yang, Shun-Fa; Chen, Pei-Ni; Chu, Shu-Chen; Chen, Chin-Hsiu; Kuo, Dong-Yih

    2011-07-01

    It has been reported that neuropeptide Y (NPY) contributes to the behavioral response of amphetamine (AMPH), a psychostimulant. The present study examined whether protein kinase C (PKC)-λ signaling was involved in this action. Moreover, possible roles of glutathione peroxidase (GP) and melanocortin receptor 4 (MC4R) were also examined. Rats were given AMPH daily for 4 days. Hypothalamic NPY, PKCλ, GP and MC4R were determined and compared. Pretreatment with α-methyl-para-tyrosine could block AMPH-induced anorexia, revealing that endogenous catecholamine was involved in regulating AMPH anorexia. PKCλ, GP and MC4R were increased with maximal response on Day 2 during AMPH treatment, which were concomitant with the decreases in NPY. cAMP response element binding protein (CREB) DNA binding activity was increased during AMPH treatment, revealing the involvement of CREB-dependent gene transcription. An interruption of cerebral PKCλ transcript could partly block AMPH-induced anorexia and partly reverse NPY, MC4R and GP mRNA levels to normal. These results suggest that PKCλ participates in regulating AMPH-induced anorexia via a modulation of hypothalamic NPY gene expression and that increases of GP and MC4R may contribute to this modulation. Our results provided molecular evidence for the regulation of AMPH-induced behavioral response.

  3. [Peroxidase activity of catalase modified by progesterone].

    PubMed

    Artemchik, V D; Matveentsev, V D; Metelitsa, D I

    1986-08-01

    Catalase conjugates with 3, 7, 9 and 42 progesterone molecules were obtained by the reaction between the enzyme and N-oxy-succinimide ether of 3-0-carboxymethyloxime of progesterone. The enzyme modified by 42 progesterone molecules is effective in o-dianisidine oxidation by hydrogen peroxide and has a kcat/KM value of 512 M-1 s-1. The catalase conjugates with 3, 7 and 9 progesterone molecules exhibit a high activity during o-dianisidine oxidation by cumene hydroperoxide. The activity of conjugates is higher than that of the native non-modified enzyme in the same reaction. The maximum effectiveness was observed for catalase modified by 7 progesterone molecules. This conjugate is characterized by kcat/KM of 99,000 M-1 s-1 at 30 degrees C. The effect of the degree of enzyme modification on the kinetic parameters of o-dianisidine oxidation by H2O2 and cumene hydroperoxide is discussed. PMID:3021241

  4. Glutathione-Mediated Regulation of ATP Sulfurylase Activity, SO42- Uptake, and Oxidative Stress Response in Intact Canola Roots.

    PubMed

    Lappartient, A. G.; Touraine, B.

    1997-05-01

    The dual role of glutathione as a transducer of S status (A.G. Lappartient and B. Touraine [1996] Plant Physiol 111: 147-157) and as an antioxidant was examined by comparing the effects of S deprivation, glutathione feeding, and H2O2 (oxidative stress) on SO42- uptake and ATP sulfurylase activity in roots of intact canola (Brassica napus L.). ATP sulfurylase activity increased and SO42- uptake rate severely decreased in roots exposed to 10 mM H2O2, whereas both increased in S-starved plants. In split-root experiments, an oxidative stress response was induced in roots remote from H2O2 exposure, as revealed by changes in the reduced glutathione (GSH) level and the GSH/oxidized glutathione (GSSG) ratio, but there was only a small decrease in SO42- uptake rate and no effect on ATP sulfurylase activity. Feeding plants with GSH increased GSH, but did not affect the GSH/GSSG ratio, and both ATP sulfurylase activity and SO42- uptake were inhibited. The responses of the H2O2-scavenging enzymes ascorbate peroxidase and glutathione reductase to S starvation, GSH treatment, and H2O2 treatment were not to glutathione-mediated S demand regulatory process. We conclude that the regulation of ATP sulfurylase activity and SO42- uptake by S demand is related to GSH rather than to the GSH/GSSG ratio, and is distinct from the oxidative stress response. PMID:12223697

  5. Superoxide dismutase 1 and glutathione peroxidase 1 are involved in the protective effect of sulodexide on vascular endothelial cells exposed to oxygen-glucose deprivation.

    PubMed

    Gabryel, Bożena; Jarząbek, Karolina; Machnik, Grzegorz; Adamczyk, Jakub; Belowski, Dariusz; Obuchowicz, Ewa; Urbanek, Tomasz

    2016-01-01

    Sulodexide (SDX) is widely used in the treatment of both arterial and venous thrombotic disorders. In addition to its recognized antithrombotic action, SDX has endothelial protective potential, which is independent of the coagulation/fibrinolysis system. However, the detailed molecular mechanisms of the endothelioprotective action of the drug are still unresolved. The aim of the present study was to determine whether treatment with SDX at concentrations of 0.125-0.5 lipase releasing unit (LRU)/ml have on the expression and activity of antioxidant enzymes in ischemic endothelial cells and how these effects might be related to the antiapoptotic properties of SDX. In the present study, human umbilical vein endothelial cells (HUVECs) were subjected to ischemia-simulating conditions (combined oxygen and glucose deprivation, OGD) for 6h to determine the protective effects of SDX. SDX (0.25 and 0.5LRU/ml) in OGD significantly increased the cell viability and prevented mitochondrial depolarization in the HUVECs. Moreover, SDX protected the HUVECs against OGD-induced apoptosis. At concentrations of 0.25 and 0.5LRU/ml, the drug increased both superoxide dismutase 1 (SOD1) and glutathione peroxidase 1 (GPx1) mRNA/protein expression together with a significant attenuation of oxidative stress in ischemic HUVECs. Our findings also demonstrate that an increase in both SOD and GPx activity is involved in the protective effect of SDX on ischemic endothelial cells. Altogether, these results suggest that SDX has a positive effect on ischemia-induced endothelial damage because of its antioxidant and antiapoptotic properties.

  6. Superoxide dismutase 1 and glutathione peroxidase 1 are involved in the protective effect of sulodexide on vascular endothelial cells exposed to oxygen-glucose deprivation.

    PubMed

    Gabryel, Bożena; Jarząbek, Karolina; Machnik, Grzegorz; Adamczyk, Jakub; Belowski, Dariusz; Obuchowicz, Ewa; Urbanek, Tomasz

    2016-01-01

    Sulodexide (SDX) is widely used in the treatment of both arterial and venous thrombotic disorders. In addition to its recognized antithrombotic action, SDX has endothelial protective potential, which is independent of the coagulation/fibrinolysis system. However, the detailed molecular mechanisms of the endothelioprotective action of the drug are still unresolved. The aim of the present study was to determine whether treatment with SDX at concentrations of 0.125-0.5 lipase releasing unit (LRU)/ml have on the expression and activity of antioxidant enzymes in ischemic endothelial cells and how these effects might be related to the antiapoptotic properties of SDX. In the present study, human umbilical vein endothelial cells (HUVECs) were subjected to ischemia-simulating conditions (combined oxygen and glucose deprivation, OGD) for 6h to determine the protective effects of SDX. SDX (0.25 and 0.5LRU/ml) in OGD significantly increased the cell viability and prevented mitochondrial depolarization in the HUVECs. Moreover, SDX protected the HUVECs against OGD-induced apoptosis. At concentrations of 0.25 and 0.5LRU/ml, the drug increased both superoxide dismutase 1 (SOD1) and glutathione peroxidase 1 (GPx1) mRNA/protein expression together with a significant attenuation of oxidative stress in ischemic HUVECs. Our findings also demonstrate that an increase in both SOD and GPx activity is involved in the protective effect of SDX on ischemic endothelial cells. Altogether, these results suggest that SDX has a positive effect on ischemia-induced endothelial damage because of its antioxidant and antiapoptotic properties. PMID:26477504

  7. Cloning and expression of a single-chain catalytic antibody that acts as a glutathione peroxidase mimic with high catalytic efficiency.

    PubMed Central

    Ren, X; Gao, S; You, D; Huang, H; Liu, Z; Mu, Y; Liu, J; Zhang, Y; Yan, G; Luo, G; Yang, T; Shen, J

    2001-01-01

    Glutathione peroxidase (GPX) has a powerful role in scavenging reactive oxygen species. In previous papers we have developed a new strategy for generating abzymes: the monoclonal antibody with a substrate-binding site is first prepared, then a catalytic group is incorporated into the monoclonal antibody's binding site by using chemical mutation [Luo, Zhu, Ding, Gao, Sun, Liu, Yang and Shen (1994) Biochem. Biophys. Res. Commun. 198, 1240-1247; Ding, Liu, Zhu, Luo, Zhao and Ni (1998) Biochem. J. 332, 251-255]. Since then we have established a series of catalytic antibodies capable of catalysing the decomposition of hydroperoxides by GSH. The monoclonal antibody 2F3 was raised against GSH-S-2,4-dinitrophenyl t-butyl ester and exhibited high catalytic efficiency, exceeding that of rabbit liver GPX, after chemical mutation. To produce pharmaceutical proteins and to study the reason why it exhibits high catalytic efficiency, we sequenced, cloned and expressed the variable regions of 2F3 antibody as a single-chain Fv fragment (2F3-scFv) in different bacterial strains. The amounts of 2F3-scFv proteins expressed from JM109 (DE3), BL21 (DE3), and BL21 (coden plus) were 5-10%, 15-20% and 25-30% of total bacterial proteins respectively. The 2F3-scFv was expressed as inclusion bodies, purified in the presence of 8 M urea by Co(2+)-immobilized metal-affinity chromatography (IMAC) and renatured to the active form in vitro by gel filtration. The binding constants of the active 2F3-scFv for GSH and GSSG were 2.46 x 10(5) M(-1) and 1.03 x 10(5) M(-1) respectively, which were less by one order of magnitude than that of the intact 2F3 antibody. The active 2F3-scFv was converted into selenium-containing 2F3-scFv (Se-2F3-scFv) by chemical modification of the reactive serine; the GPX activity of the Se-2F3-scFv was 3394 units/micromol, which approaches the activity of rabbit liver GPX. PMID:11583583

  8. Colorimetric Glucose Assay Based on Magnetic Particles Having Pseudo-peroxidase Activity and Immobilized Glucose Oxidase.

    PubMed

    Martinkova, Pavla; Opatrilova, Radka; Kruzliak, Peter; Styriak, Igor; Pohanka, Miroslav

    2016-05-01

    Magnetic particles (MPs) are currently used as a suitable alternative for peroxidase in the construction of novel biosensors, analytic and diagnostic methods. Their better chemical and thermal stabilities predestine them as appropriate pseudo-enzymatic catalysts. In this point of view, our research was focused on preparation of simply and fast method for immobilization of glucose oxidase onto surface of MPs with peroxidase-like activity. Spectrophotometric method (wavelength 450 nm) optimized for glucose determination using modified MPs has been successfully developed. Concentration curve for optimization of method was assayed, and Michaelis-Menten constant (K m) calculated, maximum reaction rate (V max), limit of detection, and correlation coefficient were determined to be 0.13 mmol/l (2.34 mg/dl), 1.79 pkat, 3.74 µmol/l (0.067 mg/dl), and 0.996, respectively. Interferences of other sugars such as sucrose, sorbitol, deoxyribose, maltose, and fructose were determined as well as effect of substances presenting in plasma (ascorbic acid, reduced glutathione, trolox, and urea). Results in comparison with positive and negative controls showed no interferences of the other sugars and no influence of plasma substances to measuring of glucose. The constructed method showed corresponding results with linear dependence and a correlation coefficient of 0.997. Possibility of repeated use of modified MPs was successfully proved. PMID:27041274

  9. Specificity of an HPETE peroxidase from rat PMN

    SciTech Connect

    Skoog, M.T.; Nichols, J.S.; Harrison, B.L.; Wiseman, J.S.

    1988-09-01

    The 15,000xg supernatant of sonicated rat PMN contains 5-lipoxygenase that converts arachidonic acid to 5-hydroperoxyeicosatetraenoic acid (5-HPETE) and leukotriene A4 and an HPETE peroxidase that catalyzes reduction of the 5-HPETE. The specificity of this HPETE peroxidase for peroxides, reducing agents, and inhibitors has been characterized to distinguish this enzyme from other peroxidase activities. In addition to 5-HPETE, the HPETE peroxidase will catalyze reduction of 15-hydroperoxyeicosatetraenoic acid, 13-hydroperoxyoctadecadienoic acid, and 15-hydroperoxy-8,11,13-eicosatrienoic acid, but not cumene or t-butylhydroperoxides. The HPETE peroxidase accepted 5 of 11 thiols tested as reducing agents. However, glutathione is greater than 15 times more effective than any other thiol tested. Other reducing agents, ascorbate, NADH, NADPH, phenol, p-cresol, and homovanillic acid, were not accepted by HPETE peroxidase. This enzyme is not inhibited by 10 mM KCN, 2 mM aspirin, 2 mM salicylic acid, or 0.5 mM indomethacin. When 5-(14C)HPETE is generated from (14C)arachidonic acid in the presence of unlabeled 5-HPETE and the HPETE peroxidase, the 5-(14C)HETE produced is of much lower specific activity than the (14C)arachidonic acid. This indicates that the 5-(14C)HPETE leaves the active site of 5-lipoxygenase and mixes with the unlabeled 5-HPETE in solution prior to reduction and is a kinetic demonstration that 5-lipoxygenase has no peroxidase activity. Specificity for peroxides, reducing agents, and inhibitors differentiates HPETE peroxidase from glutathione peroxidase, phospholipid-hydroperoxide glutathione peroxidase, a 12-HPETE peroxidase, and heme peroxidases. The HPETE peroxidase could be a glutathione S-transferase selective for fatty acid hydroperoxides.

  10. In vitro release of arachidonic acid metabolites, glutathione peroxidase, and oxygen-free radicals from platelets of asthmatic patients with and without aspirin intolerance.

    PubMed Central

    Plaza, V.; Prat, J.; Rosellò, J.; Ballester, E.; Ramis, I.; Mullol, J.; Gelpí, E.; Vives-Corrons, J. L.; Picado, C.

    1995-01-01

    BACKGROUND--An abnormal platelet release of oxygen-free radicals has been described in acetylsalicylic acid (aspirin)-induced asthma, a finding which might suggest the existence of an intrinsic, specific platelet abnormality of arachidonic acid metabolism in these patients. The objective of this study was to evaluate platelet arachidonic acid metabolism in asthmatic patients with or without intolerance to aspirin. METHODS--Thirty subjects distributed into three groups were studied: group 1, 10 healthy subjects; group 2, 10 asthmatic patients with aspirin tolerance; and group 3, 10 aspirin-intolerant asthmatics. Platelets were isolated from blood, preincubated with 3H-arachidonic acid for 30 minutes and then incubated for 10 minutes with platelet activating factor (PAF) and aspirin. Cyclo-oxygenase (thromboxane, PGE2, PGF2 alpha, and HHT) and lipoxygenase (12-HETE) arachidonic acid metabolites were measured by high pressure liquid chromatography. Release of oxygen free radicals after incubation with PAF and aspirin was measured by chemiluminescence. Platelet levels of glutathione peroxidase (GSH-Px) were also measured using spectrophotometry. RESULTS--Platelets from aspirin-intolerant asthmatic patients produced higher quantities of arachidonic acid metabolites than the control group at baseline conditions. This increase was significant only for lipoxygenase products. No differences were found amongst the three groups in the response of arachidonic acid metabolism to PAF and aspirin. Incubation with aspirin but not with PAF caused an increase in oxygen-free radical production in aspirin-intolerant patients whereas in aspirin-tolerant patients PAF, rather than aspirin, was the more potent stimulus for oxygen-free radical production. No differences in GSH-Px levels were found amongst the three groups. CONCLUSIONS--These results suggest that the platelet lipoxygenase pathway is activated in aspirin-intolerant patients and that the production of oxygen-free radicals may

  11. Thioltransferase activity of bovine lens glutathione S-transferase.

    PubMed Central

    Dal Monte, M; Cecconi, I; Buono, F; Vilardo, P G; Del Corso, A; Mura, U

    1998-01-01

    A Mu-class glutathione S-transferase purified to electrophoretic homogeneity from bovine lens displayed thioltransferase activity, catalysing the transthiolation reaction between GSH and hydroxyethyldisulphide. The thiol-transfer reaction is composed of two steps, the formation of GSSG occurring through the generation of an intermediate mixed disulphide between GSH and the target disulphide. Unlike glutaredoxin, which is only able to catalyse the second step of the transthiolation process, glutathioneS-transferase catalyses both steps of the reaction. Data are presented showing that bovine lens glutathione S-transferase and rat liver glutaredoxin, which was used as a thioltransferase enzyme model, can operate in synergy to catalyse the GSH-dependent reduction of hydroxyethyldisulphide. PMID:9693102

  12. Peroxidase activity and superficial scald development in apple fruit.

    PubMed

    Fernández-Trujillo, J Pablo; Nock, Jacqueline F; Kupferman, Eugene M; Brown, Susan K; Watkins, Christopher B

    2003-11-19

    The relationship between soluble peroxidase (EC 1.11.1.7; POX) activity and the development of a chilling-related disorder, superficial scald, was studied in three apple fruit (Malus x domestica Borkh.) systems: a White Angel x Rome Beauty population with progeny with different scald susceptibilities; Delicious from three harvests with progressively declining scald susceptibility; and the scald-resistant Idared and the scald-susceptible Law Rome. Differences in incidence and severity of scald in progeny from White Angel x Rome Beauty progeny tended to show relationships with POX activity at harvest, but, overall, associations were not consistent. However, greater scald incidence and lower POX activity were found in less mature Delicious fruit than in later harvested fruit. Also, the scald-resistant Iotadared had a much higher POX activity compared with the scald-susceptible Law Rome. A general hypothesis that POX activity is related to scald susceptibility was generally supported, but exceptions were observed.

  13. Toll-Like Receptor 4 Reduces Oxidative Injury via Glutathione Activity in Sheep

    PubMed Central

    Deng, Shoulong; Yu, Kun; Wu, Qian; Li, Yan; Zhang, Xiaosheng; Zhang, Baolu; Liu, Guoshi; Liu, Yixun; Lian, Zhengxing

    2016-01-01

    Toll-like receptor 4 (TLR4) is an important sensor of Gram-negative bacteria and can trigger activation of the innate immune system. Increased activation of TLR4 can lead to the induction of oxidative stress. Herein, the pathway whereby TLR4 affects antioxidant activity was studied. In TLR4-overexpressing sheep, TLR4 expression was found to be related to the integration copy number when monocytes were challenged with lipopolysaccharide (LPS). Consequently, production of malondialdehyde (MDA) was increased, which could increase the activation of prooxidative stress enzymes. Meanwhile, activation of an antioxidative enzyme, glutathione peroxidase (GSH-Px), was increased. Real-time PCR showed that expression of activating protein-1 (AP-1) and the antioxidative-related genes was increased. By contrast, the expression levels of superoxide dismutase 1 (SOD1) and catalase (CAT) were reduced. In transgenic sheep, glutathione (GSH) levels were dramatically reduced. Furthermore, transgenic sheep were intradermally injected with LPS in each ear. The amounts of inflammatory infiltrates were correlated with the number of TLR4 copies that were integrated in the genome. Additionally, the translation of γ-glutamylcysteine synthetase (γ-GCS) was increased. Our findings indicated that overexpression of TLR4 in sheep could ameliorate oxidative injury through GSH secretion that was induced by LPS stimulation. Furthermore, TLR4 promoted γ-GCS translation through the AP-1 pathway, which was essential for GSH synthesis. PMID:26640618

  14. Toll-Like Receptor 4 Reduces Oxidative Injury via Glutathione Activity in Sheep.

    PubMed

    Deng, Shoulong; Yu, Kun; Wu, Qian; Li, Yan; Zhang, Xiaosheng; Zhang, Baolu; Liu, Guoshi; Liu, Yixun; Lian, Zhengxing

    2016-01-01

    Toll-like receptor 4 (TLR4) is an important sensor of Gram-negative bacteria and can trigger activation of the innate immune system. Increased activation of TLR4 can lead to the induction of oxidative stress. Herein, the pathway whereby TLR4 affects antioxidant activity was studied. In TLR4-overexpressing sheep, TLR4 expression was found to be related to the integration copy number when monocytes were challenged with lipopolysaccharide (LPS). Consequently, production of malondialdehyde (MDA) was increased, which could increase the activation of prooxidative stress enzymes. Meanwhile, activation of an antioxidative enzyme, glutathione peroxidase (GSH-Px), was increased. Real-time PCR showed that expression of activating protein-1 (AP-1) and the antioxidative-related genes was increased. By contrast, the expression levels of superoxide dismutase 1 (SOD1) and catalase (CAT) were reduced. In transgenic sheep, glutathione (GSH) levels were dramatically reduced. Furthermore, transgenic sheep were intradermally injected with LPS in each ear. The amounts of inflammatory infiltrates were correlated with the number of TLR4 copies that were integrated in the genome. Additionally, the translation of γ-glutamylcysteine synthetase (γ-GCS) was increased. Our findings indicated that overexpression of TLR4 in sheep could ameliorate oxidative injury through GSH secretion that was induced by LPS stimulation. Furthermore, TLR4 promoted γ-GCS translation through the AP-1 pathway, which was essential for GSH synthesis. PMID:26640618

  15. Two variants of selenium-dependent glutathione peroxidase from the disk abalone Haliotis discus discus: Molecular characterization and immune responses to bacterial and viral stresses.

    PubMed

    Bathige, S D N K; Umasuthan, Navaneethaiyer; Godahewa, G I; Thulasitha, William Shanthakumar; Whang, Ilson; Won, Seung Hwan; Kim, Chul; Lee, Jehee

    2015-08-01

    Glutathione peroxidase (GPx) is an essential member of the antioxidant systems of living organisms and may be involved in immune defense against pathogenic invasion. In the current study, two selenium-dependent glutathione peroxidases (AbSeGPxs) that shared 54.3% identity were identified from the disk abalone Haliotis discus discus. The open reading frames (ORFs) of AbSeGPx-a and AbSeGPx-b coded for 222 and 220 amino acids, respectively, with a characteristic selenocysteine residue encoded by an opal stop codon (TGA). The conserved selenocysteine insertion sequence (SECIS) element was predicted in the 3' untranslated region (UTR) of both isoforms, and they were found to form two stem-loop structures. Amino acid comparison and phylogenetic studies revealed that the AbSeGPxs were closely related to those in other mollusk species and were evolutionarily distinct from those of other taxonomic groups. The SYBR Green qPCR was employed in investigating the transcripts of AbSeGPxs. The expression of AbSeGPxs mRNA was examined in different embryonic developmental stages and differential expression patterns for AbSeGPx-a and AbSeGPx-b were noted. Meanwhile, the highest expression of AbSeGPxs was detected in the hepatopancreas of healthy adult animals. Next, transcriptional levels were profiled in hemocytes of adults to determine the immune responses of AbSeGPxs to microbial infections. The results revealed the significant up-regulation of AbSeGPx-a in a time-dependent manner after bacterial (Listeria monocytogenes and Vibrio parahaemolyticus) and viral (viral hemorrhagic septicemia virus) infections. Consequently, these findings indicate that AbSeGPx-a and AbSeGPx-b might be involved in the embryonic development of disk abalone and the regulation of immune defense system of adult animals. PMID:26025184

  16. Two variants of selenium-dependent glutathione peroxidase from the disk abalone Haliotis discus discus: Molecular characterization and immune responses to bacterial and viral stresses.

    PubMed

    Bathige, S D N K; Umasuthan, Navaneethaiyer; Godahewa, G I; Thulasitha, William Shanthakumar; Whang, Ilson; Won, Seung Hwan; Kim, Chul; Lee, Jehee

    2015-08-01

    Glutathione peroxidase (GPx) is an essential member of the antioxidant systems of living organisms and may be involved in immune defense against pathogenic invasion. In the current study, two selenium-dependent glutathione peroxidases (AbSeGPxs) that shared 54.3% identity were identified from the disk abalone Haliotis discus discus. The open reading frames (ORFs) of AbSeGPx-a and AbSeGPx-b coded for 222 and 220 amino acids, respectively, with a characteristic selenocysteine residue encoded by an opal stop codon (TGA). The conserved selenocysteine insertion sequence (SECIS) element was predicted in the 3' untranslated region (UTR) of both isoforms, and they were found to form two stem-loop structures. Amino acid comparison and phylogenetic studies revealed that the AbSeGPxs were closely related to those in other mollusk species and were evolutionarily distinct from those of other taxonomic groups. The SYBR Green qPCR was employed in investigating the transcripts of AbSeGPxs. The expression of AbSeGPxs mRNA was examined in different embryonic developmental stages and differential expression patterns for AbSeGPx-a and AbSeGPx-b were noted. Meanwhile, the highest expression of AbSeGPxs was detected in the hepatopancreas of healthy adult animals. Next, transcriptional levels were profiled in hemocytes of adults to determine the immune responses of AbSeGPxs to microbial infections. The results revealed the significant up-regulation of AbSeGPx-a in a time-dependent manner after bacterial (Listeria monocytogenes and Vibrio parahaemolyticus) and viral (viral hemorrhagic septicemia virus) infections. Consequently, these findings indicate that AbSeGPx-a and AbSeGPx-b might be involved in the embryonic development of disk abalone and the regulation of immune defense system of adult animals.

  17. [Thiol peroxidase activities in rat blood plasma determined with hydrogen peroxide and 5,5`-dithio-bis(2-nitrobenzoic acid)].

    PubMed

    Razygraev, A V; Taborskaya, K I; Petrosyan, M A; Tumasova, Zh N

    2016-05-01

    Earlier it has been shown that extracellular glutathione peroxidase (GPx3) from human plasma is able to use cysteine (Cys-SH) instead of glutathione (GSH) as a thiol substrate. In the present study, the ability of rat plasma to utilize not only GSH, but also Cys-SH and homocysteine (Hcy-SH), in the thiol peroxidase reaction has been confirmed. The molar ratio between thiol and H2O2 in the catalyzed reaction was 2:1. The specific activity increased with fractionation of proteins. At a fixed thiol concentration of 0.23 mM, the saturation by H2O2 with vmax app of 100, 128, and 132 nmol H2O2 / s per 1 ml of plasma was found for DL-Cys-SH, L-GSH, and DL-Hcy-SH, respectively. Rank distributions of activities towards all three thiol substrates within plasma protein fractions are fully identical (the probability of random full coincidence was less than 0.01). The statistical analysis confirms that Cys-SH peroxidase, Hcy-SH peroxidase, and GSH peroxidase activities are closely associated with each other. The most probable outcome of this result is the ability of rat GPx3 to utilize all three thiols as substrates for oxidation. Probably, thiol peroxidase is a participant of formation of plasma cystine (Cys-SS-Cys) from Cys-SH in plasma. If the forms of Hcy exhibit different toxic effects, it can be suggested that thiol peroxidase regulates Hcy toxicity in hyperhomocysteinemia through Hcy-SH oxidation to homocystine (Hcy-SS-Hcy). PMID:27562997

  18. Melatonin and nitric oxide modulate glutathione content and glutathione reductase activity in sunflower seedling cotyledons accompanying salt stress.

    PubMed

    Kaur, Harmeet; Bhatla, Satish C

    2016-09-30

    The present findings demonstrate significant modulation of total glutathione content, reduced glutathione (GSH) content, oxidized glutathione (GSSG) content, GSH/GSSG ratio and glutathione reductase (GR; EC 1.6.4.2) activity in dark-grown seedling cotyledons in response to salt-stress (120 mM NaCl) in sunflower (Helianthus annuus L.) seedlings. A differential spatial distribution of GR activity (monitored by confocal laser scanning microscopic (CLSM) imaging) is also evident. Melatonin and nitric oxide (NO) differentially ameliorate salt stress effect by modulating GR activity and GSH content in seedling cotyledons. Total glutathione content (GSH + GSSG) exhibit a seedling age-dependent increase in the cotyledons, more so in salt-stressed conditions and when subjected to melatonin treatment. Seedlings raised in presence of 15 μM of melatonin exhibit significant increase in GR activity in cotyledon homogenates (10,000 g supernatant) coinciding with significant increase in GSH content. GSSG content and GSH/GSSG ratio also increased due to melatonin treatment. A correlation is thus evident in NaCl-sensitized modulation of GSH content and GR activity by melatonin. GSH content is down regulated by NO provided as 250 μM of sodium nitroprusside (SNP) although total glutathione content remained in similar range. A reversal of response (enhanced total glutathione accumulation) by NO scavenger (cPTIO) highlights the critical role of NO in modulating glutathione homeostasis. SNP lowers the activity of hydroxyindole-O-methyltransferase (HIOMT) - a regulatory enzyme in melatonin biosynthesis in control seedlings whereas its activity is upregulated in salt-stressed seedling cotyledons. Melatonin content of seedling cotyledons is also modulated by NO. NO and melatonin thus seem to modulate GR activity and GSH content during seedling growth under salt stress. PMID:27432590

  19. Zonal Changes in Ascorbate and Hydrogen Peroxide Contents, Peroxidase, and Ascorbate-Related Enzyme Activities in Onion Roots1

    PubMed Central

    del Carmen Córdoba-Pedregosa, María; Córdoba, Francisco; Villalba, José Manuel; González-Reyes, José Antonio

    2003-01-01

    Onion (Allium cepa) roots growing hydroponically show differential zonal values for intra- (symplastic) and extra- (apoplastic) cellular ascorbate (ASC) and dehydroascorbate (DHA) contents and for related enzyme activities. In whole roots, ASC and DHA concentrations were higher in root apex and meristem and gradually decreased toward the root base. Guaiacol peroxidase, ASC peroxidase, monodehydroascorbate oxidoreductase, DHA reductase, catalase, and glutathione reductase activities showed differential activity patterns depending on the zone of the root and their apoplastic or symplastic origin. An in vivo staining of peroxidase activity also revealed a specific distribution pattern along the root axis. Using electron microscopy, hydrogen peroxide was found at different locations depending on the root zone but was mainly located in cell walls from epidermal and meristematic cells and in cells undergoing lignification. A balanced control of all of these molecules seems to exist along the root axis and may be directly related to the mechanisms in which the ASC system is involved, as cell division and elongation. The role of ASC on growth and development in relation to its presence at the different zones of the root is discussed. PMID:12586893

  20. Zonal changes in ascorbate and hydrogen peroxide contents, peroxidase, and ascorbate-related enzyme activities in onion roots.

    PubMed

    Del Carmen Córdoba-Pedregosa, María; Córdoba, Francisco; Villalba, José Manuel; González-Reyes, José Antonio

    2003-02-01

    Onion (Allium cepa) roots growing hydroponically show differential zonal values for intra- (symplastic) and extra- (apoplastic) cellular ascorbate (ASC) and dehydroascorbate (DHA) contents and for related enzyme activities. In whole roots, ASC and DHA concentrations were higher in root apex and meristem and gradually decreased toward the root base. Guaiacol peroxidase, ASC peroxidase, monodehydroascorbate oxidoreductase, DHA reductase, catalase, and glutathione reductase activities showed differential activity patterns depending on the zone of the root and their apoplastic or symplastic origin. An in vivo staining of peroxidase activity also revealed a specific distribution pattern along the root axis. Using electron microscopy, hydrogen peroxide was found at different locations depending on the root zone but was mainly located in cell walls from epidermal and meristematic cells and in cells undergoing lignification. A balanced control of all of these molecules seems to exist along the root axis and may be directly related to the mechanisms in which the ASC system is involved, as cell division and elongation. The role of ASC on growth and development in relation to its presence at the different zones of the root is discussed. PMID:12586893

  1. Intrinsic peroxidase-like activity of ferromagnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Gao, Lizeng; Zhuang, Jie; Nie, Leng; Zhang, Jinbin; Zhang, Yu; Gu, Ning; Wang, Taihong; Feng, Jing; Yang, Dongling; Perrett, Sarah; Yan, Xiyun

    2007-09-01

    Nanoparticles containing magnetic materials, such as magnetite (Fe3O4), are particularly useful for imaging and separation techniques. As these nanoparticles are generally considered to be biologically and chemically inert, they are typically coated with metal catalysts, antibodies or enzymes to increase their functionality as separation agents. Here, we report that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools. Based on this finding, we have developed a novel immunoassay in which antibody-modified magnetite nanoparticles provide three functions: capture, separation and detection. The stability, ease of production and versatility of these nanoparticles makes them a powerful tool for a wide range of potential applications in medicine, biotechnology and environmental chemistry.

  2. Dietary habits and selenium, glutathione peroxidase and total antioxidant status in the serum of patients with relapsing-remitting multiple sclerosis

    PubMed Central

    2014-01-01

    Background Dietary habits and adequate dietary intake of antioxidants in the diet may be one of the most important environmental factors for the prevention of Multiple Sclerosis (MS). Objectives The aim of this study was to estimate selenium (Se) concentration, glutathione peroxidase (GSH-Px) activity and total antioxidant status (TAS) in the serum of patients with MS and the influence of dietary habits on the status. Methods 101 patients with relapsing-remitting MS (aged 18-58 years), as well as control group of 63 healthy people (aged 19-65 years) were studied. Food-frequency questionnaires were implemented to collect the dietary data. Se concentration in the serum samples was determined by atomic absorption spectrometry. GSH-Px activity and TAS in examined serum was measured using the ready-made sets of tests by Randox Laboratories Ltd., UK. Results Serum Se concentration and GSH-Px activity in the serum of patients with MS (55.2±16.2 μg/L, 6676.1±2386.4 U/L; respectively) were significantly decreased (p<0.01, p<0.05; respectively) compared with control group (79.2±20.6 μg/L, 8029.9±2650.1 U/L; respectively). A significant correlation (r=0.39, p<0.01) was observed between Se concentration and GSH-Px activity in the serum of examined patients. TAS value in the serum of patients with MS (1.03±0.37 mmol/L) was also significantly lower (p<0.01) than in healthy volunteers (1.48±0.41 mmol/L). Frequent consumption of poultry, bakery products, pulses and fish seemed to increase serum Se concentration in the group of patients; whereas frequent consumption of butter, wholegrain bread, sweet beverages and sugar was found to accompany with lower values of Se in the serum. We have observed significant decrease TAS (p<0.05, p<0.01; respectively) in the serum of smokers and those patients who received immunomodulatory drugs (0.95±0.39 mmol/L, 0.92±0.34 mmol/L; respectively) compared with no-smoking patients and not taking immunomodulators (1.14±0.33 mmol/L, 1.31±0

  3. Calcium promotes activity and confers heat stability on plant peroxidases

    PubMed Central

    Plieth, Christoph; Vollbehr, Sonja

    2012-01-01

    In this paper we demonstrate how peroxidase (PO) activities and their heat stability correlate with the availability of free Ca2+ ions. Calcium ions work as a molecular switch for PO activity and exert a protective function, rendering POs heat stable. The concentration ranges of these two activities differ markedly. POs are activated by µM Ca2+ concentration ranges, whereas heat stabilization is observed in the nM range. This suggests the existence of different Ca2+ binding sites. The heat stability of POs depends on the source plant species. Terrestrial plants have POs that exhibit higher temperature stability than those POs from limnic and marine plants. Different POs from a single species can differ in terms of heat stability. The abundance of different POs within a plant is dependent on age and developmental stage. The heat stability of a PO does not necessarily correlate with the maximum temperature the source species is usually exposed to in its natural habitat. This raises questions on the role of POs in the heat tolerance of plants. Consequently, detailed investigations are needed to identify and characterize individual POs, with regard to their genetic origin, subcellular expression, tissue abundance, developmental emergence and their functions in innate and acquired heat tolerance. PMID:22580695

  4. Ascorbate Peroxidase and Catalase Activities and Their Genetic Regulation in Plants Subjected to Drought and Salinity Stresses.

    PubMed

    Sofo, Adriano; Scopa, Antonio; Nuzzaci, Maria; Vitti, Antonella

    2015-06-12

    Hydrogen peroxide (H2O2), an important relatively stable non-radical reactive oxygen species (ROS) is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses). Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT), ascorbate peroxidases (APX), some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in drought- and salt-stressed plants.

  5. Ascorbate Peroxidase and Catalase Activities and Their Genetic Regulation in Plants Subjected to Drought and Salinity Stresses

    PubMed Central

    Sofo, Adriano; Scopa, Antonio; Nuzzaci, Maria; Vitti, Antonella

    2015-01-01

    Hydrogen peroxide (H2O2), an important relatively stable non-radical reactive oxygen species (ROS) is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses). Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT), ascorbate peroxidases (APX), some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in drought- and salt-stressed plants. PMID:26075872

  6. Peroxidase synthesis and activity in the interaction of soybean with Phytophthora megasperma f. sp. glycinea (Pmg)

    SciTech Connect

    Chibbar, R.N.; Esnault, R.; Lee, D.; van Huystee, R.B.; Ward, E.W.B.

    1986-04-01

    Changes, in peroxidase (EC1.11.1.7) have been reported following infection. However, determinations of biosynthesis of quantities of the peroxidase protein molecule have not been madeexclamation In this study hypocotyl of soybean seedlings (Glycine max; cv Harosoy, susceptible; cv Harosoy 63, resistant) were inoculated with zoospores of Pmg. Incorporation of /sup 35/S-methionine (supplied with inoculum) in TCA precipitates was measured. Peroxidase synthesis was measured by immuno precipitation using antibodies against a cationic and an anionic peroxidase derived from peanut cells. Specific peroxidase activity increased rapidly from 5 to 9 h following infection in the resistant reaction but not in the susceptible reaction or the water controls. There was increased synthesis of the anionic peroxidase but not of the cationic peroxidase in the resistant reaction. The anionic peroxidase did not increase in the susceptible until 15 h. The ratio of peroxidase synthesis to total protein synthesis decreased in inoculated tissues compared to control. Peroxidase synthesis is, therefore, a relative minor host response to infection.

  7. Regulative roles of glutathione reductase and four glutaredoxins in glutathione redox, antioxidant activity, and iron homeostasis of Beauveria bassiana.

    PubMed

    Zhang, Long-Bin; Tang, Li; Ying, Sheng-Hua; Feng, Ming-Guang

    2016-07-01

    Multiple glutaredoxins (Grx) and glutathione reductase (Glr) are vital for the thiol-disulfide redox system in budding yeast but generally unexplored in filamentous fungi. Here we characterized the Beauveria bassiana redox system comprising dithiol Grx1, monothiol Grx2-4, Grx-like Grx5, and Glr orthologue. Each grx or glr deletion was compensated by increased transcripts of some other grx genes in normal cultures. Particularly, grx3 compensated the absence of grx1, grx2, grx5, or glr under oxidative stress while its absence was compensated only by undeletable grx4 under normal conditions but by most of other undeleted grx and glr genes in response to menadione. Consequently, the redox state was disturbed in Δglr more than in Δgrx3 but not in Δgrx1/2/5. Superoxide dismutases were more active in normal Δgrx1-3 cultures but less in Δgrx5 or Δglr response to menadione. Total catalase activity increased differentially in all the mutant cultures stressed with or without H2O2 while total peroxidase activity decreased more in the normal or H2O2-stressed culture of Δglr than of Δgrx3. Among the mutants, Δgrx3 showed slightly increased sensitivity to menadione or H2O2; Δglr exhibited greater sensitivity to thiol-oxidizing diamide than thiol-reducing 1-chloro-2,4-dinitrobenzene as well as increased sensitivity to the two oxidants. Intriguingly, all the mutants grew slower in a Fe(3+)-inclusive medium perhaps due to elevated transcripts of two Fe(3+) transporter genes. More or fewer phenotypes linked with biocontrol potential were altered in four deletion mutants excluding Δgrx5. All the changes were restored by targeted gene complementation. Overall, Grx3 played more critical role than other Grx homologues in the Glr-dependent redox system of the fungal entomopathogen. PMID:26969041

  8. Oxidation of pharmaceutically active compounds by a ligninolytic fungal peroxidase.

    PubMed

    Eibes, Gemma; Debernardi, Gianfranco; Feijoo, Gumersindo; Moreira, M Teresa; Lema, Juan M

    2011-06-01

    Pharmaceuticals are an important group of emerging pollutants with increasing interest due to their rising consumption and the evidence for ecotoxicological effects associated to trace amounts in aquatic environments. In this paper, we assessed the potential degradation of a series of pharmaceuticals: antibiotics (sulfamethoxazole), antidepressives (citalopram hydrobromide and fluoxetine hydrochloride), antiepileptics (carbamazepine), anti-inflammatory drugs (diclofenac and naproxen) and estrogen hormones (estrone, 17β-estradiol, 17α-ethinylestradiol) by means of a versatile peroxidase (VP) from the ligninolytic fungus Bjerkandera adusta. The effects of the reaction conditions: VP activity, organic acid concentration and H(2)O(2) addition rate, on the kinetics of the VP based oxidation system were evaluated. Diclofenac and estrogens were completely degraded after only 5-25 min even with a very low VP activity (10 U l(-1)). High degradation percentages (80%) were achieved for sulfamethoxazole and naproxen. Low or undetectable removal yields were observed for citalopram (up to 18%), fluoxetine (lower than 10%) and carbamazepine (not degraded). PMID:20972884

  9. The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase.

    PubMed

    Harrison-Findik, Duygu Dee; Lu, Sizhao

    2015-05-06

    This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1(-/-) mice. Alcohol increased H2O2 production in catalase(-/-) and wild-type, but not gpx-1(-/-), mice. Hepcidin expression was inhibited in alcohol-fed catalase(-/-) and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1(-/-) mice. Gpx-1(-/-) mice also displayed higher level of basal liver CHOP protein expression than catalase(-/-) mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1(-/-) mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1(-/-) mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

  10. Selenium content of wheat for bread making in Scotland and the relationship between glutathione peroxidase (EC 1.11.1.9) levels in whole blood and bread consumption.

    PubMed

    Barclay, M N; MacPherson, A

    1992-07-01

    The selenium content of the 1989 harvest of wheat used for bread making in Scotland ranged from 0.028 microgram/g dry weight for home-grown wheat to 0.518 microgram/g for Canadian wheat. The tonnage values indicate that 13.8% of the wheat used in bread making came from Canada. This reflects in a calculated dietary intake of 31 micrograms/d which is well below the recommended levels of 70 and 55 micrograms for adult males and females respectively (National Research Council, 1989). The average glutathione peroxidase (EC 1.11.1.9) level in 478 samples of human whole blood was 6.08 (SE 0.065) units/ml. This increased to 6.65 (SE 0.321) in sixty-two subjects consuming brown or wholemeal bread but was unaffected by oily fish consumption. Analysis of a small number of samples of whole milk, eggs and meat indicated slightly higher concentrations than previously published values but this trend was insufficient to compensate for the lower cereal provision of Se.

  11. Polymorphisms of glutathione peroxidase 1 (GPX1 Pro198Leu) and catalase (CAT C-262T) in women with spontaneous abortion.

    PubMed

    Sabet, Eliza Eskafi; Salehi, Zivar; Khodayari, Siamak; Zarafshan, Samin Sabouhi; Zahiri, Ziba

    2014-10-01

    About 10%-15% of conceptions are lost spontaneously prior to 20 weeks. Apart from the clinical problems, genetic variations have also been proposed as a susceptibility factor to miscarriage. Glutathione peroxidase 1 (GPX1) and catalase (CAT) encode two antioxidant enzymes that detoxify H2O2 and protect the cells from oxidative damage. A functional polymorphism at codon 198 of the GPX1 gene causes a C/T substitution in exon 2, which encodes for either proline or leucine (Pro198Leu). The CAT gene has a polymorphic site in the promoter region at position -262 (C-262T) which alters the expression and enzyme blood levels, leading to some pathological clinical conditions. In this study, we evaluated the association of these two polymorphisms with the risk of spontaneous abortion. Genomic DNA from 105 cases with spontaneous abortion and 90 healthy women were genotyped using allele-specific PCR (AS-PCR) and polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP). The genetic distributions for GPX1 did not differ significantly between cases and controls (p = 0.680). However, C-262T polymorphism was significantly associated with the risk of the disease (OR, 5.50; 95% CI, 1.43-21.09; p = 0.012). In conclusion, this study indicates that CAT -262T/T genotype confers less susceptibility to spontaneous abortion, while GPX1 Pro198Leu polymorphism may not be correlated with the disease.

  12. Selective oxidation of enzyme extracts for improved quantification of peroxidase activity.

    PubMed

    Jiang, Shu; Penner, Michael H

    2015-05-01

    Natural components endogenous to plant material extracts often interfere with traditional peroxidase assays by reducing the oxidized product generated as a result of the peroxidase-catalyzed reaction. This leads to an underestimation of peroxidase activity when the oxidized product provides the signal for enzyme activity quantification. This article describes a relatively simple way to alleviate complications arising due to the presence of such confounding compounds. The method is based on using 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as the reducing substrate. The oxidized product of the reaction is ABTS(+), the accumulation of which can be followed spectrophotometrically. It is shown here that one can selectively inactivate the endogenous compounds that confound the peroxidase assay by treating the enzyme preparation with the oxidized product itself, ABTS(+), prior to initiating the quantification assay. This approach is selective for those compounds likely to interfere with peroxidase quantification. The presented method is shown to alleviate the complications associated with lag phases typical of plant extract peroxidase assays and, thus, to more accurately reflect total peroxidase activity. The presented assay is expected to be applicable to the wide range of biological systems for which the determination of peroxidase activity is desired. PMID:25640588

  13. Prostaglandin endoperoxide H synthases: peroxidase hydroperoxide specificity and cyclooxygenase activation.

    PubMed

    Liu, Jiayan; Seibold, Steve A; Rieke, Caroline J; Song, Inseok; Cukier, Robert I; Smith, William L

    2007-06-22

    The cyclooxygenase (COX) activity of prostaglandin endoperoxide H synthases (PGHSs) converts arachidonic acid and O2 to prostaglandin G2 (PGG2). PGHS peroxidase (POX) activity reduces PGG2 to PGH2. The first step in POX catalysis is formation of an oxyferryl heme radical cation (Compound I), which undergoes intramolecular electron transfer forming Intermediate II having an oxyferryl heme and a Tyr-385 radical required for COX catalysis. PGHS POX catalyzes heterolytic cleavage of primary and secondary hydroperoxides much more readily than H2O2, but the basis for this specificity has been unresolved. Several large amino acids form a hydrophobic "dome" over part of the heme, but when these residues were mutated to alanines there was little effect on Compound I formation from H2O2 or 15-hydroperoxyeicosatetraenoic acid, a surrogate substrate for PGG2. Ab initio calculations of heterolytic bond dissociation energies of the peroxyl groups of small peroxides indicated that they are almost the same. Molecular Dynamics simulations suggest that PGG2 binds the POX site through a peroxyl-iron bond, a hydrogen bond with His-207 and van der Waals interactions involving methylene groups adjoining the carbon bearing the peroxyl group and the protoporphyrin IX. We speculate that these latter interactions, which are not possible with H2O2, are major contributors to PGHS POX specificity. The distal Gln-203 four residues removed from His-207 have been thought to be essential for Compound I formation. However, Q203V PGHS-1 and PGHS-2 mutants catalyzed heterolytic cleavage of peroxides and exhibited native COX activity. PGHSs are homodimers with each monomer having a POX site and COX site. Cross-talk occurs between the COX sites of adjoining monomers. However, no cross-talk between the POX and COX sites of monomers was detected in a PGHS-2 heterodimer comprised of a Q203R monomer having an inactive POX site and a G533A monomer with an inactive COX site.

  14. A Stable Bacterial Peroxidase with Novel Halogenating Activity and an Autocatalytically Linked Heme Prosthetic Group*

    PubMed Central

    Auer, Markus; Gruber, Clemens; Bellei, Marzia; Pirker, Katharina F.; Zamocky, Marcel; Kroiss, Daniela; Teufer, Stefan A.; Hofbauer, Stefan; Soudi, Monika; Battistuzzi, Gianantonio; Furtmüller, Paul G.; Obinger, Christian

    2013-01-01

    Reconstructing the phylogenetic relationships of the main evolutionary lines of the mammalian peroxidases lactoperoxidase and myeloperoxidase revealed the presence of novel bacterial heme peroxidase subfamilies. Here, for the first time, an ancestral bacterial heme peroxidase is shown to possess a very high bromide oxidation activity (besides conventional peroxidase activity). The recombinant protein allowed monitoring of the autocatalytic peroxide-driven formation of covalent heme to protein bonds. Thereby, the high spin ferric rhombic heme spectrum became similar to lactoperoxidase, the standard reduction potential of the Fe(III)/Fe(II) couple shifted to more positive values (−145 ± 10 mV at pH 7), and the conformational and thermal stability of the protein increased significantly. We discuss structure-function relationships of this new peroxidase in relation to its mammalian counterparts and ask for its putative physiological role. PMID:23918925

  15. The poplar Phi class glutathione transferase: expression, activity and structure of GSTF1

    PubMed Central

    Pégeot, Henri; Koh, Cha San; Petre, Benjamin; Mathiot, Sandrine; Duplessis, Sébastien; Hecker, Arnaud; Didierjean, Claude; Rouhier, Nicolas

    2014-01-01

    Glutathione transferases (GSTs) constitute a superfamily of enzymes with essential roles in cellular detoxification and secondary metabolism in plants as in other organisms. Several plant GSTs, including those of the Phi class (GSTFs), require a conserved catalytic serine residue to perform glutathione (GSH)-conjugation reactions. Genomic analyses revealed that terrestrial plants have around ten GSTFs, eight in the Populus trichocarpa genome, but their physiological functions and substrates are mostly unknown. Transcript expression analyses showed a predominant expression of all genes both in reproductive (female flowers, fruits, floral buds) and vegetative organs (leaves, petioles). Here, we show that the recombinant poplar GSTF1 (PttGSTF1) possesses peroxidase activity toward cumene hydroperoxide and GSH-conjugation activity toward model substrates such as 2,4-dinitrochlorobenzene, benzyl and phenetyl isothiocyanate, 4-nitrophenyl butyrate and 4-hydroxy-2-nonenal but interestingly not on previously identified GSTF-class substrates. In accordance with analytical gel filtration data, crystal structure of PttGSTF1 showed a canonical dimeric organization with bound GSH or 2-(N-morpholino)ethanesulfonic acid molecules. The structure of these protein-substrate complexes allowed delineating the residues contributing to both the G and H sites that form the active site cavity. In sum, the presence of GSTF1 transcripts and proteins in most poplar organs especially those rich in secondary metabolites such as flowers and fruits, together with its GSH-conjugation activity and its documented stress-responsive expression suggest that its function is associated with the catalytic transformation of metabolites and/or peroxide removal rather than with ligandin properties as previously reported for other GSTFs. PMID:25566286

  16. A thiol peroxidase is an H2O2 receptor and redox-transducer in gene activation.

    PubMed

    Delaunay, Agnès; Pflieger, Delphine; Barrault, Marie Bénédicte; Vinh, Joelle; Toledano, Michel B

    2002-11-15

    The Yap1 transcription factor regulates hydroperoxide homeostasis in S. cerevisiae. Yap1 is activated by oxidation when hydroperoxide levels increase. We show that Yap1 is not directly oxidized by hydroperoxide. We identified the glutathione peroxidase (GPx)-like enzyme Gpx3 as a second component of the pathway, serving the role of sensor and transducer of the hydroperoxide signal to Yap1. When oxidized by H2O2, Gpx3 Cys36 bridges Yap1 Cys598 by a disulfide bond. This intermolecular disulfide bond is then resolved into a Yap1 intramolecular disulfide bond, the activated form of the regulator. Thioredoxin turns off the pathway by reducing both sensor and regulator. These data reveal a redox-signaling function for a GPx-like enzyme and elucidate a eukaryotic hydroperoxide-sensing mechanism. Gpx3 is thus a hydroperoxide receptor and redox-transducer. PMID:12437921

  17. Selection for low or high primary dormancy in Lolium rigidum Gaud seeds results in constitutive differences in stress protein expression and peroxidase activity

    PubMed Central

    Goggin, Danica E.; Powles, Stephen B.; Steadman, Kathryn J.

    2011-01-01

    Seed dormancy in wild Lolium rigidum Gaud (annual ryegrass) populations is highly variable and not well characterized at the biochemical level. To identify some of the determinants of dormancy level in these seeds, the proteomes of subpopulations selected for low and high levels of primary dormancy were compared by two-dimensional polyacrylamide gel electrophoresis of extracts from mature, dry seeds. High-dormancy seeds showed higher expression of small heat shock proteins, enolase, and glyoxalase I than the low-dormancy seeds. The functional relevance of these differences in protein expression was confirmed by the fact that high-dormancy seeds were more tolerant to high temperatures imposed at imbibition and had consistently higher glyoxalase I activity over 0–42 d dark stratification. Higher expression of a putative glutathione peroxidase in low-dormancy seeds was not accompanied by higher activity, but these seeds had a slightly more oxidized glutathione pool and higher total peroxidase activity. Overall, these biochemical and physiological differences suggest that L. rigidum seeds selected for low dormancy are more prepared for rapid germination via peroxidase-mediated cell wall weakening, whilst seeds selected for high dormancy are constitutively prepared to survive environmental stresses, even in the absence of stress during seed development. PMID:20974739

  18. Age-Related Changes in Antioxidant and Glutathione S-Transferase Enzyme Activities in the Asian Clam.

    PubMed

    Vranković, J

    2016-03-01

    Aging is accompanied by increased production of free oxygen radicals and impairment of normal cellular functions. The aim of this work was to provide preliminary data on age-related differences in the activities of antioxidant enzymes and phase II biotransformation enzyme glutathione S-transferase (GST) in a wild population of the Asian clam Corbicula fluminea. The antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and GST were assessed in visceral mass of four age classes (0+-, 1+-, 2+-, and 3+-year-old) of C. fluminea clams. Age-related changes were seen in antioxidant enzyme status: levels of total SOD (totSOD) (P < 0.05), MnSOD, and CuZnSOD (P < 0.05) activities increased progressively during aging from younger to older clams. Changes in CAT and GR activities with advancing age were found, the levels being the highest in age class II, then being lower in age classes III and IV (P < 0.05). Activities of GPX and GST were lower in the senescent individuals (2+- and 3+-year-old clams) compared with young individuals (0+- and 1+-year-old clams). Overall, the decline of glutathione-dependent enzyme activities, coupled with higher and lower activities of totSOD and CAT, respectively, as the individual grows older, may render the older animals more susceptible to oxidative stress. Data reported here are not intended to be exhaustive since they concern only age/size structure of the population at one locality, so more detailed studies on both the developmental stages and levels of antioxidant enzymes of this new alien species in Serbian rivers are required. PMID:27262191

  19. Glutathione Peroxidase 5 Is Expressed by the Entire Pig Male Genital Tract and Once in the Seminal Plasma Contributes to Sperm Survival and In Vivo Fertility.

    PubMed

    Barranco, Isabel; Tvarijonaviciute, Asta; Perez-Patiño, Cristina; Vicente-Carrillo, Alejandro; Parrilla, Inmaculada; Ceron, Jose J; Martinez, Emilio A; Rodriguez-Martinez, Heriberto; Roca, Jordi

    2016-01-01

    Glutathione peroxidase-5 (GPX5) is an H2O2-scavenging enzyme identified in boar seminal plasma (SP). This study attempted to clarify its origin and role on sperm survival and fertility after artificial insemination (AI). GPX5 was expressed (Western blot and immunocytochemistry using a rabbit primary polyclonal antibody) in testes, epididymis and accessory sex glands (6 boars). SP-GPX5 concentration differed among boars (11 boars, P < 0.001), among ejaculates within boar (44 ejaculates, P < 0.001) and among portions within ejaculate (15 ejaculates). The first 10 mL of the sperm rich fraction (SRF, sperm-peak portion) had a significantly lower concentration (8.87 ± 0.78 ng/mL) than the rest of the SRF and the post-SRF (11.66 ± 0.79 and 12.37 ± 0.79 ng/mL, respectively, P < 0.005). Sperm motility of liquid-stored semen AI-doses (n = 44, at 15-17°C during 72h) declined faster in AI-doses with low concentrations of SP-GPX5 compared to those with high-levels. Boars (n = 11) with high SP-GPX5 showed higher farrowing rates and litter sizes than those with low SP-GPX5 (a total of 5,275 inseminated sows). In sum, GPX5 is widely expressed in the boar genital tract and its variable presence in SP shows a positive relationship with sperm quality and fertility outcomes of liquid-stored semen AI-doses. PMID:27627110

  20. Superoxide dismutase, catalase, glutathione peroxidase and gluthatione S-transferases M1 and T1 gene polymorphisms in three Brazilian population groups.

    PubMed

    de Oliveira Hiragi, Cássia; Miranda-Vilela, Ana Luisa; Rocha, Dulce Maria Sucena; de Oliveira, Silviene Fabiana; Hatagima, Ana; de Nazaré Klautau-Guimarães, Maria

    2011-01-01

    Antioxidants such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX1) reduce the oxidation rates in the organism. Gluthatione S-transferases (GSTs) play a vital role in phase 2 of biotransformation of many substances. Variation in the expression of these enzymes suggests individual differences for the degree of antioxidant protection and geographical differences in the distribution of these variants. We described the distribution frequency of CAT (21A/T), SOD2 (Ala9Val), GPX1 (Pro198Leu), GSTM1 and GSTT1 polymorphisms in three Brazilian population groups: Kayabi Amerindians (n = 60), Kalunga Afro-descendants (n = 72), and an urban mixed population from Federal District (n = 162). Frequencies of the variants observed in Kalunga (18% to 58%) and Federal District (33% to 63%) were similar to those observed in Euro and Afro-descendants, while in Kayabi (3% to 68%), depending on the marker, frequencies were similar to the ones found in different ethnic groups. Except for SOD2 in all population groups studied here, and for GPX1 in Kalunga, the genotypic distributions were in accordance with Hardy-Weinberg Equilibrium. These data can clarify the contribution of different ethnicities in the formation of mixed populations, such as that of Brazil. Moreover, outcomes will be valuable resources for future functional studies and for genetic studies in specific populations. If these studies are designed to comprehensively explore the role of these genetic polymorphisms in the etiology of human diseases they may help to prevent inconsistent genotype-phenotype associations in pharmacogenetic studies.

  1. The Effect of Alcohol and Hydrogen Peroxide on Liver Hepcidin Gene Expression in Mice Lacking Antioxidant Enzymes, Glutathione Peroxidase-1 or Catalase

    PubMed Central

    Harrison-Findik, Duygu Dee; Lu, Sizhao

    2015-01-01

    This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1−/−) and catalase (catalase−/−) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1−/− displayed significantly higher hepatic H2O2 levels than catalase−/− compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1−/− mice. Alcohol increased H2O2 production in catalase−/− and wild-type, but not gpx-1−/−, mice. Hepcidin expression was inhibited in alcohol-fed catalase−/− and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1−/− mice. Gpx-1−/− mice also displayed higher level of basal liver CHOP protein expression than catalase−/− mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1−/− mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1−/− mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH. PMID:25955433

  2. Sex-specific associations of variants in regulatory regions of NADPH oxidase-2 (CYBB) and glutathione peroxidase 4 (GPX4) genes with kidney disease in type 1 diabetes.

    PubMed

    Monteiro, M B; Patente, T A; Mohammedi, K; Queiroz, M S; Azevedo, M J; Canani, L H; Parisi, M C; Marre, M; Velho, G; Corrêa-Giannella, M L

    2013-10-01

    Oxidative stress is involved in the pathophysiology of diabetic nephropathy. The superoxide-generating nicotinamide adenine dinucleotide phosphate-oxidase 2 (NOX2, encoded by the CYBB gene) and the antioxidant enzyme glutathione peroxidase 4 (GPX4) play opposing roles in the balance of cellular redox status. In the present study, we investigated associations of single nucleotide polymorphisms (SNPs) in the regulatory regions of CYBB and GPX4 with kidney disease in patients with type 1 diabetes. Two functional SNPs, rs6610650 (CYBB promoter region, chromosome X) and rs713041 (GPX4 3'untranslated region, chromosome 19), were genotyped in 451 patients with type 1 diabetes from a Brazilian cohort (diabetic nephropathy: 44.6%) and in 945 French/Belgian patients with type 1 diabetes from Genesis and GENEDIAB cohorts (diabetic nephropathy: 62.3%). The minor A-allele of CYBB rs6610650 was associated with lower estimated glomerular filtration rate (eGFR) in Brazilian women, and with the prevalence of established/advanced nephropathy in French/Belgian women (odds ratio 1.75, 95% CI 1.11-2.78, p = 0.016). The minor T-allele of GPX4 rs713041 was inversely associated with the prevalence of established/advanced nephropathy in Brazilian men (odds ratio 0.30, 95% CI 0.13-0.68, p = 0.004), and associated with higher eGFR in French/Belgian men. In conclusion, these heterogeneous results suggest that neither CYBB nor GPX4 are major genetic determinants of diabetic nephropathy, but nevertheless, they could modulate in a gender-specific manner the risk for renal disease in patients with type 1 diabetes. PMID:23919599

  3. Selenium Alleviates Aflatoxin B₁-Induced Immune Toxicity through Improving Glutathione Peroxidase 1 and Selenoprotein S Expression in Primary Porcine Splenocytes.

    PubMed

    Hao, Shu; Hu, Junfa; Song, Suquan; Huang, Da; Xu, Haibing; Qian, Gang; Gan, Fang; Huang, Kehe

    2016-02-17

    Selenium (Se) is generally known as an essential micronutrient and antioxidant for humans and animals. Aflatoxin B1 (AFB1) is a frequent contaminant of food and feed, causing immune toxicity and hepatotoxicity. Little has been done about the mechanisms of how Se protects against AFB1-induced immune toxicity. The aim of this present study is to investigate the protective effects of Se against AFB1 and the underlying mechanisms. The primary splenocytes isolated from healthy pigs were stimulated by anti-pig-CD3 monoclonal antibodies and treated by various concentrations of different Se forms and AFB1. The results showed that Se supplementation alleviated the immune toxicity of AFB1 in a dose-dependent manner, as demonstrated by increasing T-cell proliferation and interleukin-2 production. Addition of buthionine sulfoximine abrogated the protective effects of SeMet against AFB1. SeMet enhanced mRNA and protein expression of glutathione peroxidase 1 (GPx1), selenoprotein S (SelS), and thioredoxin reductase 1 without and with AFB1 treatments. Furthermore, knockdown of GPx1 and SelS by GPx1-specific siRNA and SelS-specific siRNA diminished the protective effects of SeMet against AFB1-induced immune toxicity. It is concluded that SeMet diminishes AFB1-induced immune toxicity through increasing antioxidant ability and improving GPx1 and SelS expression in splenocytes. This study suggests that organic selenium may become a promising supplementation to protect humans and animals against the decline in immunity caused by AFB1.

  4. Glutathione Peroxidase 5 Is Expressed by the Entire Pig Male Genital Tract and Once in the Seminal Plasma Contributes to Sperm Survival and In Vivo Fertility

    PubMed Central

    Barranco, Isabel; Tvarijonaviciute, Asta; Perez-Patiño, Cristina; Vicente-Carrillo, Alejandro; Parrilla, Inmaculada; Ceron, Jose J.; Martinez, Emilio A.; Rodriguez-Martinez, Heriberto; Roca, Jordi

    2016-01-01

    Glutathione peroxidase-5 (GPX5) is an H2O2-scavenging enzyme identified in boar seminal plasma (SP). This study attempted to clarify its origin and role on sperm survival and fertility after artificial insemination (AI). GPX5 was expressed (Western blot and immunocytochemistry using a rabbit primary polyclonal antibody) in testes, epididymis and accessory sex glands (6 boars). SP-GPX5 concentration differed among boars (11 boars, P < 0.001), among ejaculates within boar (44 ejaculates, P < 0.001) and among portions within ejaculate (15 ejaculates). The first 10 mL of the sperm rich fraction (SRF, sperm-peak portion) had a significantly lower concentration (8.87 ± 0.78 ng/mL) than the rest of the SRF and the post-SRF (11.66 ± 0.79 and 12.37 ± 0.79 ng/mL, respectively, P < 0.005). Sperm motility of liquid-stored semen AI-doses (n = 44, at 15–17°C during 72h) declined faster in AI-doses with low concentrations of SP-GPX5 compared to those with high-levels. Boars (n = 11) with high SP-GPX5 showed higher farrowing rates and litter sizes than those with low SP-GPX5 (a total of 5,275 inseminated sows). In sum, GPX5 is widely expressed in the boar genital tract and its variable presence in SP shows a positive relationship with sperm quality and fertility outcomes of liquid-stored semen AI-doses. PMID:27627110

  5. Genetic association of glutathione peroxidase-1 with coronary artery calcification in type 2 diabetes: a case control study with multi-slice computed tomography

    PubMed Central

    Nemoto, Masami; Nishimura, Rimei; Sasaki, Takashi; Hiki, Yoshito; Miyashita, Yumi; Nishioka, Makiko; Fujimoto, Kei; Sakuma, Toru; Ohashi, Toya; Fukuda, Kunihiko; Eto, Yoshikatsu; Tajima, Naoko

    2007-01-01

    Background Although oxidative stress by accumulation of reactive oxygen species (ROS) in diabetes has become evident, it remains unclear what genes, involved in redox balance, would determine susceptibility for development of atherosclerosis in diabetes. This study evaluated the effect of genetic polymorphism of enzymes producing or responsible for reducing ROS on coronary artery calcification in type 2 diabetes (T2D). Methods An index for coronary-arteriosclerosis, coronary artery calcium score (CACS) was evaluated in 91 T2D patients using a multi-slice computed tomography. Patients were genotyped for ROS-scavenging enzymes, Glutathione peroxidase-1 (GPx-1), Catalase, Mn-SOD, Cu/Zn-SOD, as well as SNPs of NADPH oxidase as ROS-promoting elements, genes related to onset of T2D (CAPN10, ADRB3, PPAR gamma, FATP4). Age, blood pressure, BMI, HbA1c, lipid and duration of diabetes were evaluated for a multivariate regression analysis. Results CACS with Pro/Leu genotype of the GPx-1 gene was significantly higher than in those with Pro/Pro (744 ± 1,291 vs. 245 ± 399, respectively, p = 0.006). In addition, genotype frequency of Pro/Leu in those with CACS ≥ 1000 was significantly higher than in those with CACS < 1000 (45.5% vs. 18.8%; OR = 3.61, CI = 0.97–13.42; p = 0.045) when tested for deviation from Hardy-Weinberg's equilibrium. Multivariate regression analyses revealed that CACS significantly correlated with GPx-1 genotypes and age. Conclusion The presence of Pro197Leu substitution of the GPx-1 gene may play a crucial role in determining genetic susceptibility to coronary-arteriosclerosis in T2D. The mechanism may be associated with a decreased ability to scavenge ROS with the variant GPx-1. PMID:17825092

  6. Sex-specific associations of variants in regulatory regions of NADPH oxidase-2 (CYBB) and glutathione peroxidase 4 (GPX4) genes with kidney disease in type 1 diabetes.

    PubMed

    Monteiro, M B; Patente, T A; Mohammedi, K; Queiroz, M S; Azevedo, M J; Canani, L H; Parisi, M C; Marre, M; Velho, G; Corrêa-Giannella, M L

    2013-10-01

    Oxidative stress is involved in the pathophysiology of diabetic nephropathy. The superoxide-generating nicotinamide adenine dinucleotide phosphate-oxidase 2 (NOX2, encoded by the CYBB gene) and the antioxidant enzyme glutathione peroxidase 4 (GPX4) play opposing roles in the balance of cellular redox status. In the present study, we investigated associations of single nucleotide polymorphisms (SNPs) in the regulatory regions of CYBB and GPX4 with kidney disease in patients with type 1 diabetes. Two functional SNPs, rs6610650 (CYBB promoter region, chromosome X) and rs713041 (GPX4 3'untranslated region, chromosome 19), were genotyped in 451 patients with type 1 diabetes from a Brazilian cohort (diabetic nephropathy: 44.6%) and in 945 French/Belgian patients with type 1 diabetes from Genesis and GENEDIAB cohorts (diabetic nephropathy: 62.3%). The minor A-allele of CYBB rs6610650 was associated with lower estimated glomerular filtration rate (eGFR) in Brazilian women, and with the prevalence of established/advanced nephropathy in French/Belgian women (odds ratio 1.75, 95% CI 1.11-2.78, p = 0.016). The minor T-allele of GPX4 rs713041 was inversely associated with the prevalence of established/advanced nephropathy in Brazilian men (odds ratio 0.30, 95% CI 0.13-0.68, p = 0.004), and associated with higher eGFR in French/Belgian men. In conclusion, these heterogeneous results suggest that neither CYBB nor GPX4 are major genetic determinants of diabetic nephropathy, but nevertheless, they could modulate in a gender-specific manner the risk for renal disease in patients with type 1 diabetes.

  7. Inhibition of Peroxidase Activity of Cytochrome c: De Novo Compound Discovery and Validation

    PubMed Central

    Bakan, Ahmet; Kapralov, Alexandr A.; Bayir, Hulya; Hu, Feizhou; Kagan, Valerian E.

    2015-01-01

    Cytochrome c (cyt c) release from mitochondria is accepted to be the point of no return for eliciting a cascade of interactions that lead to apoptosis. A strategy for containing sustained apoptosis is to reduce the mitochondrial permeability pore opening. Pore opening is enhanced by peroxidase activity of cyt c gained upon its complexation with cardiolipin in the presence of reactive oxygen species. Blocking access to the heme group has been proposed as an effective intervention method for reducing, if not eliminating, the peroxidase activity of cyt c. In the present study, using a combination of druggability simulations, pharmacophore modeling, virtual screening, and in vitro fluorescence measurements to probe peroxidase activity, we identified three repurposable drugs and seven compounds that are validated to effectively inhibit the peroxidase activity of cyt c. PMID:26078313

  8. Glutathione transferase classes alpha, pi, and mu: GSH activation mechanism.

    PubMed

    Dourado, Daniel F A R; Fernandes, Pedro Alexandrino; Ramos, Maria João

    2010-10-14

    Since the early 1960s, glutathione transferases (GSTs) have been described as detoxification enzymes. In fact, GSTs are the most important enzymes involved in the metabolism of electrophilic xenobiotic/endobiotic compounds. These enzymes are able to catalyze the nucleophilic addition of glutathione (GSH) sulfur thiolate to a wide range of electrophilic substrates, building up a less toxic and more soluble compound. Cytosolic classes alpha, pi, and mu are the most extensively studied GSTs. However, many of the catalytic events are still poorly understood. In the present work, we have resorted to density functional theory (DFT) and to potential of mean force (PMF) calculations to determine the GSH activation mechanism of GSTP1-1 and GSTM1-1 isoenzymes. For the GSTP1-1 enzyme, we have demonstrated that a water molecule, after an initial conformational rearrangement of GSH, can assist a proton transfer between the GSH cysteine thiol (GSH-SH) and the GSH glutamate alpha carboxylate (GSH-COO(-)) groups. The energy barrier associated with the proton transfer is 11.36 kcal·mol(-1). The GSTM1-1 enzyme shows a completely different behavior from the previous isoenzyme. In this case, two water molecules, positioned between the GSH-SH and the ξ N atom of His107, working like a bridge, are able to promote the proton transfer between these two active groups with an energy barrier of 7.98 kcal·mol(-1). All our results are consistent with all the enzymes kinetics and mutagenesis experimental studies.

  9. The Mn-superoxide dismutase single nucleotide polymorphism rs4880 and the glutathione peroxidase 1 single nucleotide polymorphism rs1050450 are associated with aging and longevity in the oldest old

    PubMed Central

    Soerensen, Mette; Christensen, Kaare; Stevnsner, Tinna; Christiansen, Lene

    2009-01-01

    The free radical theory of aging states that reactive oxygen species (ROS) play a key role in age-related accumulation of cellular damage, and consequently influence aging and longevity. Therefore, variation in genes encoding proteins protecting against ROS could be expected to influence variation in aging and life span. The rs4880 and rs1050450 SNPs in the manganese superoxide dismutase (MnSOD) and glutathione peroxidase 1 (GPX1) genes, respectively, are associated with age-related diseases and appear to affect the activities of the encoded variant proteins. In this study we genotyped these SNPs in 1650 individuals from the Danish 1905 cohort (follow-up time: 1998–2008, age at intake: 92–93 years, number of deaths: 1589 (96.3%)) and investigated the association with aging and longevity. We found decreased mortality of individuals holding either the MnSOD rs4880 C or the GPX1 rs1050450 T alleles (HR (MnSOD(CC/CT)) = 0.91, p = 0.002), HR (GPX1(TT/TC)) = 0.93, p = 0.008)). Furthermore, a synergetic effect of the alleles was observed (HR = 0.76, p = 0.001). Finally, moderate positive associations with good self rated health, decreased disability and increased cognitive capacity were observed. Our results thus indicate that genetic variation in MnSOD and GPX1 may be associated with aging and longevity. PMID:19428448

  10. Cardiolipin activates cytochrome c peroxidase activity since it facilitates H(2)O(2) access to heme.

    PubMed

    Vladimirov, Yu A; Proskurnina, E V; Izmailov, D Yu; Novikov, A A; Brusnichkin, A V; Osipov, A N; Kagan, V E

    2006-09-01

    In this work, the effect of liposomes consisting of tetraoleyl cardiolipin and dioleyl phosphatidylcholine (1 : 1, mol/mol) on the rate of three more reactions of Cyt c heme with H2O2 was studied: (i) Cyt c (Fe2+) oxidation to Cyt c (Fe3+), (ii) Fe...S(Met80) bond breaking, and (iii) heme porphyrin ring decomposition. It was revealed that the rates of all those reactions increased greatly in the presence of liposomes containing cardiolipin and not of those consisting of only phosphatidylcholine, and approximately to the same extent as peroxidase activity. These data suggest that cardiolipin activates specifically Cyt c peroxidase activity not only because it promotes Fe...S(Met80) bond breaking but also facilitates H2O2 penetration to the reaction center. PMID:17009954

  11. Rapid and reliable determination of the halogenating peroxidase activity in blood samples.

    PubMed

    Flemmig, Jörg; Schwarz, Pauline; Bäcker, Ingo; Leichsenring, Anna; Lange, Franziska; Arnhold, Jürgen

    2014-12-15

    By combining easy and fast leukocyte enrichment with aminophenyl-fluorescein (APF) staining we developed a method to quickly and specifically address the halogenating activity of the immunological relevant blood heme peroxidases myeloperoxidase and eosinophil peroxidase, respectively. For leukocyte enrichment a two-fold hypotonic lysis procedure of the blood with Millipore water was chosen which represents a cheap, fast and reliable method to diminish the amount of erythrocytes in the samples. This procedure is shown to be suitable both to human and murine blood micro-samples, making it also applicable to small animal experiments with recurring blood sampling. As all types of leukocytes are kept in the sample during the preparation, they can be analysed separately after discrimination during the flow cytometry analysis. This also holds for all heme peroxidase-containing cells, namely neutrophils, eosinophils and monocytes. Moreover additional parameters (e.g. antibody staining) can be combined with the heme peroxidase activity determination to gain additional information about the different immune cell types. Based on previous results we applied APF for specifically addressing the halogenating activity of leukocyte peroxidases in blood samples. This dye is selectively oxidized by the MPO and EPO halogenation products hypochlorous and hypobromous acid. This approach may provide a suitable tool to gain more insights into the immune-physiological role of the halogenating activity of heme peroxidases.

  12. Bifunctionalized mesoporous silica-supported gold nanoparticles: intrinsic oxidase and peroxidase catalytic activities for antibacterial applications.

    PubMed

    Tao, Yu; Ju, Enguo; Ren, Jinsong; Qu, Xiaogang

    2015-02-11

    Bifunctionalized mesoporous silica-supported gold nanoparticles as oxidase and peroxidase mimics for antibacterial applications are demonstrated. For the first time, these mesoporous silica-supported gold nanoparticles are applied as oxidase and peroxidase mimics. Taking advantage of their prominent enzyme activities, the MSN-AuNPs show excellent antibacterial properties against both Gram-negative and Gram-positive bacteria. Furthermore, MSN-AuNPs also exhibit outstanding performance in biofilm elimination . PMID:25655182

  13. Proton NMR investigation of the heme active site structure of an engineered cytochrome c peroxidase that mimics manganese peroxidase.

    PubMed

    Wang, X; Lu, Y

    1999-07-13

    The heme active site structure of an engineered cytochrome c peroxidase [MnCcP; see Yeung, B. K., et al. (1997) Chem. Biol. 4, 215-221] that closely mimics manganese peroxidase (MnP) has been characterized by both one- and two-dimensional NMR spectroscopy. All hyperfine-shifted resonances from the heme pocket as well as resonances from catalytically relevant amino acid residues in the congested diamagnetic envelope have been assigned. From the NMR spectral assignment and the line broadening pattern of specific protons in NOESY spectra of MnCcP, the location of the engineered Mn(II) center is firmly identified. Furthermore, we found that the creation of the Mn(II)-binding site in CcP resulted in no detectable structural changes on the distal heme pocket of the protein. However, notable structural changes are observed at the proximal side of the heme cavity. Both CepsilonH shift of the proximal histidine and (15)N shift of the bound C(15)N(-) suggest a weaker heme Fe(III)-N(His) bond in MnCcP compared to WtCcP. Our results indicate that the engineered Mn(II)-binding site in CcP resulted in not only a similar Mn(II)-binding affinity and improved MnP activity, but also weakened the Fe(III)-N(His) bond strength of the template protein CcP so that its bond strength is similar to that of the target protein MnP. The results presented here help elucidate the impact of designing a metal-binding site on both the local and global structure of the enzyme, and provide a structural basis for engineering the next generation of MnCcP that mimics MnP more closely. PMID:10413489

  14. Involvement of peroxidase activity in developing somatic embryos of Medicago arborea L. Identification of an isozyme peroxidase as biochemical marker of somatic embryogenesis.

    PubMed

    Gallego, Piedad; Martin, Luisa; Blazquez, Antonio; Guerra, Hilario; Villalobos, Nieves

    2014-01-15

    The legume Medicago arborea L. is very interesting as regards the regeneration of marginal arid soils. The problem is that it does not have a good germinative yield. It was therefore decided to regenerate via somatic embryogenesis and find a marker of embryogenic potential. In this study, peroxidase activity was evaluated in non-embryogenic and embryogenic calli from M. arborea L. A decrease in soluble peroxidase activity is observed in its embryonic calli at the time at which the somatic embryos begin to appear. This activity is always lower in embryonic calli than in non-embryonic ones (unlike what happens in the case of wall-bound peroxidases). These results suggest that peroxidases can be considered to be enzymes involved in somatic embryogenesis in M. arborea. In addition, isozyme analyses were carried out on protein extracts using polyacrylamide gel electrophoresis. The band called P5 was detected only in embryogenic cultures at very early stages of development. This band was digested with trypsin and analyzed using linear ion trap (LTQ) mass spectrometer. In P5 isoform a peroxidase-L-ascorbate peroxidase was identified. It can be used as a marker that allows the identification of embryological potential.

  15. Manganese peroxidase gene transcription in Phanerochaete chrysosporium: Activation by manganese

    SciTech Connect

    Brown, J.A.; Alic, M. Gold, M.H. )

    1991-07-01

    The expression of manganese peroxidase in nitrogen-limited cultures of Phanerochaete chrysosporium is dependent on Mn, and initial work suggested that Mn regulates transcription of the mnp gene. In this study, using Northern (RNA) blot analysis of kinetic, dose-response, and inhibitor experiments, the authors demonstrate unequivocally that Mn regulates mnp gene transcription. The amount of mnp mRNA in cells of 4-day-old nitrogen-limited cultures is a direct function of the concentration of Mn in the culture medium up to a maximum of 180 {mu}M. Addition of Mn to nitrogen-limited Mn-deficient secondary metabolic (4-, 5-, and 6-day-old) cultures results in the appearance of mnp mRNA within 40 min. The appearance of this message is completely inhibited by the RNA synthesis inhibitor dactinomycin but not by the protein synthesis inhibitor cycloheximide. Furthermore, the amount of mnp mRNA produced is a direct function of the concentration of added Mn. In contrast, addition of Mn to low-nitrogen Mn-deficient 2- or 3-day-old cultures does not result in the appearance of mnp mRNA. Manganese peroxidase protein is detected by specific immunoprecipitation of the in vitro translation products of poly(A) RNA isolated from Mn-supplemented (but nor from Mn-deficient) cells. All of these results demonstrate that Mn, the substrate for the enzyme, regulates mnp gene transcription via a growth-stage-specific and concentration-dependent mechanism.

  16. Activity and Isoenzyme Profile of Peroxidase as Affected by Microgravity Stress

    NASA Astrophysics Data System (ADS)

    Sarnatska, V. V.; Gladun, H. O.; Padalko, S. F.

    2008-06-01

    To investigate microgravity (clinorotation) effect on activity and isoenzyme pattern of peroxidase the culture of primary explants of potato tubers with normal activation of proliferation in vitro, explants inoculated with Agrobacterium tumefaciens(A.t.), where crown-gall tumors were formed and dormant potato tubers were used. Substantial decrease of total peroxidase activity after one day-clinorotation of potato explants, normal and inoculated with A.t., was revealed. Seven day- clinorotation resulted in the decreased peroxidase activity in normal clinorotated explants, while peroxidase activity in clinorotated explants, inoculated with A.t., returned to the level of its stationary control. When peroxidase of potato explants was analyzed by PAGE, the result obtained show the decrease in activity of one electrophoretic fractions with low migrating mobility and two fractions with moderate mobility in clinorotated explants, normal and with crown gall, as compared with the ones in stationary conditions. The decrease in activity of these fractions under microgravity was less pronounced in explants with crown-galls.

  17. 2,4,6-Trichlorophenol mediated increases in extracellular peroxidase activity in three species of Lemnaceae.

    PubMed

    Biswas, Dilip K; Scannell, Gillian; Akhmetov, Nurlan; Fitzpatrick, Dara; Jansen, Marcel A K

    2010-11-01

    Chlorinated phenols, or chlorophenols, are persistent priority pollutants that are widespread in the environment. Class III peroxidases are well-characterised plant enzymes that can catalyse the oxidative dechlorination of chlorophenols. Expression of these enzymes by plants is commonly associated with plant stress, therefore limiting scope for phytoremediation. In this study, we have quantitatively compared peroxidase activity and phytotoxicity as a function of 2,4,6-trichlorophenol (TCP) concentration in three species of Lemnaceae; Lemna minor, Lemna gibba and Landoltia punctata. Effects of TCP on the growth rates of the three species differed considerably with L. punctata being the most tolerant species. TCP also affected photosynthetic parameters, causing a decrease in open photosystem II reaction centres (qP) and, in L. punctata only, a decrease in non-photochemical quenching (qN). In parallel, TCP exposure resulted in increased peroxidase activity in all three species. Peroxidase activity in L. minor and L. gibba displayed an inverse relationship with biomass accumulation, i.e. the more growth reduction the more peroxidase activity. In contrast, induction of peroxidase activity in L. punctata was bi-phasic, with a TCP-induced activity peak at concentrations that had no major effect on growth, and further induction under phytotoxic concentrations. The mechanism by which L. punctata recognises and responds to low concentrations of an anthropogenic compound, in the absence of wide-ranging stress, remains enigmatic. However, we conclude that this "window" of peroxidase production in the absence of major growth inhibition offers potential for the development of sustainable, peroxidise-mediated phytoremediation systems. PMID:20810175

  18. Characterization of a human blood monocyte subset with low peroxidase activity.

    PubMed Central

    Akiyama, Y; Miller, P J; Thurman, G B; Neubauer, R H; Oliver, C; Favilla, T; Beman, J A; Oldham, R K; Stevenson, H C

    1983-01-01

    Two human monocyte subsets from the peripheral blood of healthy donors have been isolated in greater than 90% purity by countercurrent centrifugal elutration and human serum albumin gradients and their functional capabilities have been assessed. We have demonstrated that one subset ("regular" monocytes, RM) showed intense cytoplasmic peroxidase staining and contained substantial peroxidase activity. In contrast, another subset ("intermediate" monocytes, IM) stained poorly for peroxidase and had low peroxidase activity. By electron microscopic analysis combined with peroxidase localization, it was found that IM had fewer peroxidase-positive granules per cell than did RM. IM coelutriated with some lymphocytes and by cell sizing analysis were shown to be slightly smaller than RM. Functional and cytochemical analysis of these subsets indicated that IM had less activity than RM in assays such as accessory cell function for mitogen-induced T lymphocyte proliferation and antibody-dependent cellular cytotoxicity, and that fewer IM expressed OKM1 antigen and pokeweed mitogen (PWM) receptors on their membranes than did RM. The subset of IM not bearing either the PWM receptor or the OKM1 antigen had very low peroxidase activity. IM also were found to have a greater sensitivity to polyriboinosinic and polyribocytidilic acid (100 micrograms/ml)-induced secretion of interferon. There was no significant difference in the phagocytic capability, the percentage of Fc receptor-positive cells, 5'-nucleotidase activity, DR antigen expression, or the responsiveness to migration inhibitory factor of IM as compared with RM. Furthermore, it was found that the ratio of IM to RM increased after prolonged cytapheresis, which suggests that IM are more mobilizable than RM from the extravascular reservoirs of human monocytes. Images FIGURE 5 PMID:6193141

  19. Phenylbutazone Oxidation via Cu,Zn-SOD Peroxidase Activity: An EPR Study.

    PubMed

    Aljuhani, Naif; Whittal, Randy M; Khan, Saifur R; Siraki, Arno G

    2015-07-20

    We investigated the effect of Cu,Zn-superoxide dismutase (Cu,Zn-SOD)-peroxidase activity on the oxidation of the nonsteroidal anti-inflammatory drug phenylbutazone (PBZ). We utilized electron paramagnetic resonance (EPR) spectroscopy to detect free radical intermediates of PBZ, UV-vis spectrophotometry to monitor PBZ oxidation, oxygen analysis to determine the involvement of C-centered radicals, and LC/MS to determine the resulting metabolites. Using EPR spectroscopy and spin-trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), we found that the spin adduct of CO3(•-) (DMPO/(•)OH) was attenuated with increasing PBZ concentrations. The resulting PBZ radical, which was assigned as a carbon-centered radical based on computer simulation of hyperfine splitting constants, was trapped by both DMPO and MNP spin traps. Similar to Cu,Zn-SOD-peroxidase activity, an identical PBZ carbon-centered radical was also detected with the presence of both myeloperoxidase (MPO/H2O2) and horseradish peroxidase (HRP/H2O2). Oxygen analysis revealed depletion in oxygen levels when PBZ was oxidized by SOD peroxidase-activity, further supporting carbon radical formation. In addition, UV-vis spectra showed that the λmax for PBZ (λ = 260 nm) declined in intensity and shifted to a new peak that was similar to the spectrum for 4-hydroxy-PBZ when oxidized by Cu,Zn-SOD-peroxidase activity. LC/MS evidence supported the formation of 4-hydroxy-PBZ when compared to that of a standard, and 4-hydroperoxy-PBZ was also detected in significant yield. These findings together indicate that the carbonate radical, a product of SOD peroxidase activity, appears to play a role in PBZ metabolism. Interestingly, these results are similar to findings from heme peroxidase enzymes, and the context of this metabolic pathway is discussed in terms of a mechanism for PBZ-induced toxicity. PMID:26090772

  20. Effect of Low and Very Low Doses of Simple Phenolics on Plant Peroxidase Activity

    PubMed Central

    Malarczyk, Elżbieta; Kochmańska-Rdest, Janina; Paździoch-Czochra, Marzanna

    2004-01-01

    Changes in the activity of horseradish peroxidase resulting from an addition of ethanol water dilutions of 19 phenolic compounds were observed. For each compound, the enzyme activity was plotted against the degree of dilution expressed as n = –log100 (mol/L) in the range 0 ≤ n ≥ 20. All the curves showed sinusoidal activity, more or less regular, with two to four peaks on average. Each analyzed compound had a characteristic sinusoidal shape, which was constant for samples of peroxidase from various commercial firms. This was clearly visible after function fitting to experimental results based on the Marquadt–Levenberg algorithm using the least-squares method. Among the 19 phenolics, the highest amplitudes were observed for phenol and iso- and vanillate acids and aldehydes. The specific character of each of the analyzed curves offers a possibility of choosing proper dilutions of phenolic compound for activating or inhibiting of peroxidase activity. PMID:19330128

  1. Cytochrome c peroxidase activity of heme bound amyloid β peptides.

    PubMed

    Seal, Manas; Ghosh, Chandradeep; Basu, Olivia; Dey, Somdatta Ghosh

    2016-09-01

    Heme bound amyloid β (Aβ) peptides, which have been associated with Alzheimer's disease (AD), can catalytically oxidize ferrocytochrome c (Cyt c(II)) in the presence of hydrogen peroxide (H2O2). The rate of catalytic oxidation of Cyt(II) c has been found to be dependent on several factors, such as concentration of heme(III)-Aβ, Cyt(II) c, H2O2, pH, ionic strength of the solution, and peptide chain length of Aβ. The above features resemble the naturally occurring enzyme cytochrome c peroxidase (CCP) which is known to catalytically oxidize Cyt(II) c in the presence of H2O2. In the absence of heme(III)-Aβ, the oxidation of Cyt(II) c is not catalytic. Thus, heme-Aβ complex behaves as CCP.

  2. Cytochrome c peroxidase activity of heme bound amyloid β peptides.

    PubMed

    Seal, Manas; Ghosh, Chandradeep; Basu, Olivia; Dey, Somdatta Ghosh

    2016-09-01

    Heme bound amyloid β (Aβ) peptides, which have been associated with Alzheimer's disease (AD), can catalytically oxidize ferrocytochrome c (Cyt c(II)) in the presence of hydrogen peroxide (H2O2). The rate of catalytic oxidation of Cyt(II) c has been found to be dependent on several factors, such as concentration of heme(III)-Aβ, Cyt(II) c, H2O2, pH, ionic strength of the solution, and peptide chain length of Aβ. The above features resemble the naturally occurring enzyme cytochrome c peroxidase (CCP) which is known to catalytically oxidize Cyt(II) c in the presence of H2O2. In the absence of heme(III)-Aβ, the oxidation of Cyt(II) c is not catalytic. Thus, heme-Aβ complex behaves as CCP. PMID:27270708

  3. In vitro glutathione peroxidase mimicry of ebselen is linked to its oxidation of critical thiols on key cerebral suphydryl proteins - A novel component of its GPx-mimic antioxidant mechanism emerging from its thiol-modulated toxicology and pharmacology.

    PubMed

    Kade, I J; Balogun, B D; Rocha, J B T

    2013-10-25

    The antioxidant mechanism of ebselen in rats brain is largely linked with its glutathione peroxidase (GPx) rather than its peroxiredoxin mimicry ability. However, the precise molecular dynamics between the GPx-mimicry of ebselen and thiol utilization is yet to be fully clarified and thus still open. Herein, we investigated the influence of dithiothreitol (DTT) on the antioxidant action of ebselen against oxidant-induced cerebral lipid peroxidation and deoxyribose degradation. Furthermore, the critical inhibitory concentrations of ebselen on the activities of sulphydryl enzymes such as cerebral sodium pump, δ-aminolevulinic acid dehydratase (δ-ALAD) and lactate dehydrogenase (LDH) were also investigated. We observe that ebselen (at ≥42 μM) markedly inhibited lipid peroxidation in the presence and absence of DTT, whereas it inhibited deoxyribose degradation only in the presence of DTT. Furthermore, under in vitro conditions, ebselen inhibited the thiol containing enzymes; cerebral sodium pump (at ≥40 μM), δ-ALAD (≥10 μM) and LDH (≥1 μM) which were either prevented or reversed by DTT. However, the inhibition of the activities of these sulphydryl proteins in diabetic animals was prevented by ebselen. Summarily, it is apparent that the effective in vitro inhibitory doses of ebselen on the activity of the sulphydryl proteins are far less than its antioxidant doses. In addition, the presence of DTT is evidently a critical requirement for ebselen to effect its antioxidant action against deoxyribose degeradation and not lipid peroxidation. Consequently, we conclude that ebselen possibly utilizes available thiols on sulphydryl proteins to effect its GPx mimicry antioxidant action against lipid peroxidation in rat brain homogenate.

  4. Thiol-Based Peroxidases and Ascorbate Peroxidases: Why Plants Rely on Multiple Peroxidase Systems in the Photosynthesizing Chloroplast?

    PubMed

    Dietz, Karl-Josef

    2016-01-01

    Photosynthesis is a highly robust process allowing for rapid adjustment to changing environmental conditions. The efficient acclimation depends on balanced redox metabolism and control of reactive oxygen species release which triggers signaling cascades and potentially detrimental oxidation reactions. Thiol peroxidases of the peroxiredoxin and glutathione peroxidase type, and ascorbate peroxidases are the main peroxide detoxifying enzymes of the chloroplast. They use different electron donors and are linked to distinct redox networks. In addition, the peroxiredoxins serve functions in redox regulation and retrograde signaling. The complexity of plastid peroxidases is discussed in context of suborganellar localization, substrate preference, metabolic coupling, protein abundance, activity regulation, interactions, signaling functions, and the conditional requirement for high antioxidant capacity. Thus the review provides an opinion on the advantage of linking detoxification of peroxides to different enzymatic systems and implementing mechanisms for their inactivation to enforce signal propagation within and from the chloroplast.

  5. The Ustilago maydis effector Pep1 suppresses plant immunity by inhibition of host peroxidase activity.

    PubMed

    Hemetsberger, Christoph; Herrberger, Christian; Zechmann, Bernd; Hillmer, Morten; Doehlemann, Gunther

    2012-01-01

    The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1) as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H₂O₂ strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction.

  6. Ca2+ activation of wheat peroxidase: a possible physiological mechanism of control.

    PubMed

    Converso, D A; Fernández, M E

    1996-09-01

    Peroxidation of substrates such as ascorbic acid, pyrogallol, or ferulic acid, as well as indole acetic acid oxidation catalyzed by wheat germ peroxidase (WGP)2 C2, were found to be activated by Ca2+. This activation is independent of the stabilizing effect of structural Ca2+ reported for peroxidases. Steady state kinetics of ferulic acid oxidation catalyzed by WGP C2 showed an increase in the rate of compound I formation and of compound II decomposition in the presence of the ion, evidenced as an increase in rate constants k1, from 8.9 x 10(5) to 4.5 x 10(5) M-1 cm-1, and k3, from 4.4 x 10(5) to 1.1 x 10(6) M-1 cm-1. The dissociation constant Kd, for the cyanide derivative of the enzyme showed a marked decrease from 220 to 34 microM in the presence of Ca2+, thus implying an effect of the ion in the H2O2 binding step. In the presence of Ca2+, a conformational change in the protein was revealed by tryptophan fluorescence, providing a basis for the activation mechanism. Other peroxidases such as horseradish peroxidase and WGP C3 were not activated by Ca2+. The results suggest the existence of a physiological mechanism of control of peroxidase isozymes activity mediated by Ca2+.

  7. Atypical thioredoxins in poplar: the glutathione-dependent thioredoxin-like 2.1 supports the activity of target enzymes possessing a single redox active cysteine.

    PubMed

    Chibani, Kamel; Tarrago, Lionel; Gualberto, José Manuel; Wingsle, Gunnar; Rey, Pascal; Jacquot, Jean-Pierre; Rouhier, Nicolas

    2012-06-01

    Plant thioredoxins (Trxs) constitute a complex family of thiol oxidoreductases generally sharing a WCGPC active site sequence. Some recently identified plant Trxs (Clot, Trx-like1 and -2, Trx-lilium1, -2, and -3) display atypical active site sequences with altered residues between the two conserved cysteines. The transcript expression patterns, subcellular localizations, and biochemical properties of some representative poplar (Populus spp.) isoforms were investigated. Measurements of transcript levels for the 10 members in poplar organs indicate that most genes are constitutively expressed. Using transient expression of green fluorescent protein fusions, Clot and Trx-like1 were found to be mainly cytosolic, whereas Trx-like2.1 was located in plastids. All soluble recombinant proteins, except Clot, exhibited insulin reductase activity, although with variable efficiencies. Whereas Trx-like2.1 and Trx-lilium2.2 were efficiently regenerated both by NADPH-Trx reductase and glutathione, none of the proteins were reduced by the ferredoxin-Trx reductase. Only Trx-like2.1 supports the activity of plastidial thiol peroxidases and methionine sulfoxide reductases employing a single cysteine residue for catalysis and using a glutathione recycling system. The second active site cysteine of Trx-like2.1 is dispensable for this reaction, indicating that the protein possesses a glutaredoxin-like activity. Interestingly, the Trx-like2.1 active site replacement, from WCRKC to WCGPC, suppresses its capacity to use glutathione as a reductant but is sufficient to allow the regeneration of target proteins employing two cysteines for catalysis, indicating that the nature of the residues composing the active site sequence is crucial for substrate selectivity/recognition. This study provides another example of the cross talk existing between the glutathione/glutaredoxin and Trx-dependent pathways.

  8. Coal Depolymerising Activity and Haloperoxidase Activity of Mn Peroxidase from Fomes durissimus MTCC-1173

    PubMed Central

    Singh, Sunil Kumar; Yadav, Meera; Yadava, Sudha; Yadav, Kapil Deo Singh

    2011-01-01

    Mn peroxidase has been purified to homogeneity from the culture filtrate of a new fungal strain Fomes durissimus MTCC-1173 using concentration by ultrafiltration and anion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The molecular mass of the purified enzyme has been found to be 42.0 kDa using SDS-PAGE analysis. The Km values using MnSO4 and H2O2 as the variable substrates in 50 mM lactic acid-sodium lactate buffer pH 4.5 at 30°C were 59 μM and 32 μM, respectively. The catalytic rate constants using MnSO4 and H2O2 were 22.4 s−1 and 14.0 s−1, respectively, giving the values of kcat/Km 0.38 μM−1s−1 and 0.44 μM−1s−1, respectively. The pH and temperature optima of the Mn peroxidase were 4 and 26°C, respectively. The purified MnP depolymerises humic acid in presence of H2O2. The purified Mn peroxidase exhibits haloperoxidase activity at low pH. PMID:22162670

  9. Michaelis-Menten Kinetics and the Activation Energy Relate Soil Peroxidase Kinetics to the Lignin Chemistry

    NASA Astrophysics Data System (ADS)

    Triebwasser-Freese, D.; Tharayil, N.; Preston, C. M.; Gerard, P.

    2013-12-01

    Recently, it has been suggested that lignin exhibit a turnover rate of less than 6 years, suggesting that the enzymatic mechanisms mediating the decay of lignin are less understood. One factor that could be affecting the mean residence time of lignin in the soil is the catalytic efficiency of soil oxidoreductase enzymes. We characterized the spatial and seasonal transitions in the Michaelis-Menten kinetics and activation energy of the soil oxidoreductase enzyme, peroxidase, across three ecosystems of differing litter chemistries- pine, deciduous forest, and a cultivated field- and associate it to the soil lignin chemistries. To interpret the combined effect of Vmax and Km, the two parameters were integrated into one term which we defined as the catalytic efficiency. Generally, the peroxidases in pine soils exhibited the highest Vmax and Km, resulting in the lowest catalytic efficiency, followed by that in the deciduous soils. Meanwhile, the agricultural soils which exhibited the lowest Vmax and Km contained the highest catalytic efficiency of peroxidase. Through linear regression analysis of the kinetic parameters to the soil lignin chemistry, we discerned that the catalytic efficiency term best associated to the lignin monomer ratios (C/V, P/V, and SCV/V). The Activation Energy of peroxidase varied by depth, and seasons across the ecosystems. However, the Activation Energy of peroxidase did not relate to the lignin chemistry or quantity. Collectively, our results show that although the peroxidase Vmax and Km in the phenolic-poor soils are low, the degradation efficiency of peroxidases in this soils can be equivalent or exceed that of phenolic-rich soils. This study, through the characterization of Michaelis-Menten kinetics, provides a new insight into the mechanisms that could moderate the decomposition of lignin in soils.

  10. Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples.

    PubMed

    Flemmig, Jörg; Schwarz, Pauline; Bäcker, Ingo; Leichsenring, Anna; Lange, Franziska; Arnhold, Jürgen

    2016-01-01

    In this paper a protocol for the quick and standardized enrichment of leukocytes from small whole blood samples is described. This procedure is based on the hypotonic lysis of erythrocytes and can be applied to human samples as well as to blood of non-human origin. The small initial sample volume of about 50 to 100 µl makes this method applicable to recurrent blood sampling from small laboratory animals. Moreover, leukocyte enrichment is achieved within minutes and with low material efforts regarding chemicals and instrumentation, making this method applicable in multiple laboratory environments. Standardized purification of leukocytes is combined with a highly selective staining method to evaluate halogenating peroxidase activity of the heme peroxidases, myeloperoxidase (MPO) and eosinophil peroxidase (EPO), i.e., the formation of hypochlorous and hypobromous acid (HOCl and HOBr). While MPO is strongly expressed in neutrophils, the most abundant immune cell type in human blood as well as in monocytes, the related enzyme EPO is exclusively expressed in eosinophils. The halogenating activity of these enzymes is addressed by using the almost HOCl- and HOBr-specific dye aminophenyl fluorescein (APF) and the primary peroxidase substrate hydrogen peroxide. Upon subsequent flow cytometry analysis all peroxidase-positive cells (neutrophils, monocytes, eosinophils) are distinguishable and their halogenating peroxidase activity can be quantified. Since APF staining may be combined with the application of cell surface markers, this protocol can be extended to specifically address leukocyte sub-fractions. The method is applicable to detect HOCl and HOBr production both in human and in rodent leukocytes. Given the widely and diversely discussed immunological role of these enzymatic products in chronic inflammatory diseases, this protocol may contribute to a better understanding of the immunological relevance of leukocyte-derived heme peroxidases. PMID:27501318

  11. Cloning, heterologous expression and properties of a recombinant active turnip peroxidase.

    PubMed

    Rodriguez-Cabrera, Norma A; Regalado, C; Garcia-Almendarez, Blanca E

    2011-07-13

    Turnip (Brassica napus) roots peroxidase isoforms have been used in diagnostic kits and can also efficiently polymerize phenolic compounds from wastewaters. Heterologous expression of a turnip acidic peroxidase (BnPA) was investigated to increase availability of this widely used enzyme. The mature BnPA was ligated into the pET28a(+) vector and used to transform Escherichia coli Rosetta 2. Recombinant BnPA peroxidase was overexpressed and accumulated in inclusion bodies from which it was purified to homogeneity by immobilized metal affinity chromatography under denaturing conditions. Peroxidase activity was observed after a refolding process under oxidative conditions. The yield of pure recombinant BnPA was 29 mg L(-1) of culture with a specific activity of 981 ± 20 ABTS units mg(-1) at optimal conditions (pH 6, 45 °C). Recombinant BnPA showed similar kinetic properties compared to native turnip peroxidase, and its secondary structure evaluated by circular dichroism comprised 20% α-helix, 32% β-sheet and 48% random structure. Recombinant BnPA showed high yield and good kinetic properties which are key steps for future structure-function studies and biotechnological applications. PMID:21591783

  12. Interaction between vitamin B6 and source of selenium on the response of the selenium-dependent glutathione peroxidase system to oxidative stress induced by oestrus in pubertal pig.

    PubMed

    Dalto, Danyel Bueno; Roy, Mélanie; Audet, Isabelle; Palin, Marie-France; Guay, Frédéric; Lapointe, Jérôme; Matte, J Jacques

    2015-10-01

    This study aimed to assess the interaction between vitamin B6 and selenium (Se) for the flow of Se towards the Se-dependent glutathione peroxidase (GPX) system in response to oxidative stress naturally induced by oestrus in a pubertal pig model. At first oestrus, forty-five gilts were randomly assigned to the experimental diets (n=9/group): basal diet (CONT); CONT+0.3mg/kg of Na-selenite (MSeB60); MSeB60+10mg/kg of HCl-B6 (MSeB610); CONT+0.3mg/kg of Se-enriched yeast (OSeB60); and OSeB60+10mg/kg of HCl-B6 (OSeB610). Blood samples were collected at each oestrus (long-term profiles), and daily from day -4 to +3 (slaughter) of the fourth oestrus (peri-oestrus profiles) after which liver, kidneys, and ovaries were collected. For long-term profiles, CONT had lower blood Se than Se-supplemented gilts (p<0.01) and OSe was higher than MSe (p<0.01). Lower erythrocyte pyridoxal-5-phosphate was found in B60 than B610 (p<0.01). No treatment effect was observed on GPX activity. For peri-oestrus profiles, treatment effects were similar to long-term profiles. Treatment effects on liver Se were similar to those for long-term blood Se profiles and OSe had higher renal Se concentrations than MSe gilts (p<0.01). Gene expressions of GPX1, GPX3, GPX4, and selenocysteine lyase in liver and kidney were greatest in OSeB610 gilts (p<0.05). These results suggest that dietary B6 modulate the metabolic pathway of OSe towards the GPX system during the peri-oestrus period in pubertal pigs. PMID:26302908

  13. Interaction between vitamin B6 and source of selenium on the response of the selenium-dependent glutathione peroxidase system to oxidative stress induced by oestrus in pubertal pig.

    PubMed

    Dalto, Danyel Bueno; Roy, Mélanie; Audet, Isabelle; Palin, Marie-France; Guay, Frédéric; Lapointe, Jérôme; Matte, J Jacques

    2015-10-01

    This study aimed to assess the interaction between vitamin B6 and selenium (Se) for the flow of Se towards the Se-dependent glutathione peroxidase (GPX) system in response to oxidative stress naturally induced by oestrus in a pubertal pig model. At first oestrus, forty-five gilts were randomly assigned to the experimental diets (n=9/group): basal diet (CONT); CONT+0.3mg/kg of Na-selenite (MSeB60); MSeB60+10mg/kg of HCl-B6 (MSeB610); CONT+0.3mg/kg of Se-enriched yeast (OSeB60); and OSeB60+10mg/kg of HCl-B6 (OSeB610). Blood samples were collected at each oestrus (long-term profiles), and daily from day -4 to +3 (slaughter) of the fourth oestrus (peri-oestrus profiles) after which liver, kidneys, and ovaries were collected. For long-term profiles, CONT had lower blood Se than Se-supplemented gilts (p<0.01) and OSe was higher than MSe (p<0.01). Lower erythrocyte pyridoxal-5-phosphate was found in B60 than B610 (p<0.01). No treatment effect was observed on GPX activity. For peri-oestrus profiles, treatment effects were similar to long-term profiles. Treatment effects on liver Se were similar to those for long-term blood Se profiles and OSe had higher renal Se concentrations than MSe gilts (p<0.01). Gene expressions of GPX1, GPX3, GPX4, and selenocysteine lyase in liver and kidney were greatest in OSeB610 gilts (p<0.05). These results suggest that dietary B6 modulate the metabolic pathway of OSe towards the GPX system during the peri-oestrus period in pubertal pigs.

  14. An ionizable active-site tryptophan imparts catalase activity to a peroxidase core.

    PubMed

    Loewen, Peter C; Carpena, Xavi; Vidossich, Pietro; Fita, Ignacio; Rovira, Carme

    2014-05-21

    Catalase peroxidases (KatG's) are bifunctional heme proteins that can disproportionate hydrogen peroxide (catalatic reaction) despite their structural dissimilarity with monofunctional catalases. Using X-ray crystallography and QM/MM calculations, we demonstrate that the catalatic reaction of KatG's involves deprotonation of the active-site Trp, which plays a role similar to that of the distal His in monofunctional catalases. The interaction of a nearby mobile arginine with the distal Met-Tyr-Trp essential adduct (in/out) acts as an electronic switch, triggering deprotonation of the adduct Trp.

  15. Proton nuclear Overhauser effect study of the heme active site structure of Coprinus macrorhizus peroxidase.

    PubMed

    Dugad, L B; Goff, H M

    1992-07-13

    Proton nuclear Overhauser effect and paramagnetic relaxation measurements have been used to define more extensively the heme active site structure of Coprinus macrorhizus peroxidase, CMP (previously known as Coprinus cinereus peroxidase), as the ferric low-spin cyanide ligated complex. The results are compared with other well-characterized peroxidase enzymes. The NMR spectrum of CMPCN shows changes in the paramagnetically shifted resonances as a function of time, suggesting a significant heme disorder for CMP. The presence of proximal and distal histidine amino acid residues are common to the heme environments of both CMPCN and HRPCN. However, the upfield distal arginine signals of HRPCN are not evident in the 1H-NMR spectra of CMPCN.

  16. Structure of a mitochondrial cytochrome c conformer competent for peroxidase activity

    PubMed Central

    McClelland, Levi J.; Mou, Tung-Chung; Jeakins-Cooley, Margaret E.; Sprang, Stephen R.; Bowler, Bruce E.

    2014-01-01

    At the onset of apoptosis, the peroxidation of cardiolipin at the inner mitochondrial membrane by cytochrome c requires an open coordination site on the heme. We report a 1.45-Å resolution structure of yeast iso-1-cytochrome c with the Met80 heme ligand swung out of the heme crevice and replaced by a water molecule. This conformational change requires modest adjustments to the main chain of the heme crevice loop and is facilitated by a trimethyllysine 72-to-alanine mutation. This mutation also enhances the peroxidase activity of iso-1-cytochrome c. The structure shows a buried water channel capable of facilitating peroxide access to the active site and of moving protons produced during peroxidase activity to the protein surface. Alternate positions of the side chain of Arg38 appear to mediate opening and closing of the buried water channel. In addition, two buried water molecules can adopt alternate positions that change the network of hydrogen bonds in the buried water channel. Taken together, these observations suggest that low and high proton conductivity states may mediate peroxidase function. Comparison of yeast and mammalian cytochrome c sequences, in the context of the steric factors that permit opening of the heme crevice, suggests that higher organisms have evolved to inhibit peroxidase activity, providing a more stringent barrier to the onset of apoptosis. PMID:24760830

  17. [Participation of the active oxygen forms in the induction of ascorbate peroxidase and guaiacol peroxidase under heat hardening of wheat seedlings].

    PubMed

    Kolupaev, Iu E; Oboznyĭ, A I

    2012-01-01

    The influence of one-minute hardening heating at 42 degrees C on the dynamics of hydrogen peroxide generation and activity of antioxidant enzymes in roots of winter wheat seedlings has been investigated. It was shown that the content of hydrogen peroxide increased within the first 30 minutes after heat influence, whereupon it approached the level of control variant. The activity of superoxide dismutase (SOD) increased significantly within 10 min after heating and was maintained at a high level during 24 hours of observation. The activity of ascorbate peroxidase and guaiacol peroxidase increased after 3-6 hours after the hardening and reached its maximum after 24 hours, when there was the most significant increase in heat resistance of seedlings. The short-term increase in hydrogen peroxide content caused by hardening heating was suppressed by treatment of seedlings with H2O2 scavenger dimethylthiourea, inhibitors of NADPH-oxidase (imidazole) and SOD (sodium diethyldithiocarbamate). All these effectors levelled the increase of activity of ascorbate peroxidase and guaiacol peroxidase and significantly inhibited the development of heat resistance of seedlings. The conclusion was made about the role of hydrogen peroxide produced with the participation of NADPH-oxidase and SOD in the induction of antioxidant system by heat hardening of wheat seedlings.

  18. [Participation of the active oxygen forms in the induction of ascorbate peroxidase and guaiacol peroxidase under heat hardening of wheat seedlings].

    PubMed

    Kolupaev, Iu E; Oboznyĭ, A I

    2012-01-01

    The influence of one-minute hardening heating at 42 degrees C on the dynamics of hydrogen peroxide generation and activity of antioxidant enzymes in roots of winter wheat seedlings has been investigated. It was shown that the content of hydrogen peroxide increased within the first 30 minutes after heat influence, whereupon it approached the level of control variant. The activity of superoxide dismutase (SOD) increased significantly within 10 min after heating and was maintained at a high level during 24 hours of observation. The activity of ascorbate peroxidase and guaiacol peroxidase increased after 3-6 hours after the hardening and reached its maximum after 24 hours, when there was the most significant increase in heat resistance of seedlings. The short-term increase in hydrogen peroxide content caused by hardening heating was suppressed by treatment of seedlings with H2O2 scavenger dimethylthiourea, inhibitors of NADPH-oxidase (imidazole) and SOD (sodium diethyldithiocarbamate). All these effectors levelled the increase of activity of ascorbate peroxidase and guaiacol peroxidase and significantly inhibited the development of heat resistance of seedlings. The conclusion was made about the role of hydrogen peroxide produced with the participation of NADPH-oxidase and SOD in the induction of antioxidant system by heat hardening of wheat seedlings. PMID:23387278

  19. Assessment of Antioxidant Enzyme Activity and Mineral Nutrients in Response to NaCl Stress and its Amelioration Through Glutathione in Chickpea.

    PubMed

    Shankar, Vinay; Kumar, Dinesh; Agrawal, Veena

    2016-01-01

    Salinity stress has been reckoned as one of the major threat towards crop productivity as it causes significant decline in the yield. The impact of NaCl stress (0, 1, 10, 50, 100 and 200 mg L(-1)) as well as glutathione (10 mg L(-1)) either alone or in combination has been evaluated on the induction of multiple shoots, antioxidant enzymes' activity, lipid peroxidation, relative permeability, concentration of nutrients, photosynthetic pigments, protein and proline content of nodal segments of chickpea after 14 days of culture. The antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and glutathione reductase (GR) were found to be increased under salt stress as well as glutathione-supplemented medium. A significant decrease in the concentrations of chlorophylls a, b, total chlorophyll and carotenoid was observed under salt stress. Concentrations of nitrogen, phosphorus, potassium, calcium, carbon, magnesium and sulphur showed an initial increase up to 10 mg L(-1) NaCl, but a decline was seen at higher NaCl levels. Proline content and malondialdehyde concentration were found to be increased under salt stress. Three isoforms of SOD, one of CAT and four of GPX were expressed during native polyacrylamide gel electrophoresis (PAGE) analysis. However, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the stressed nodal explants revealed the over-expression of several polypeptide bands related to NaCl stress. These findings for the first time suggest that glutathione (GSH) helps in ameliorating NaCl stress in nodal explants of chickpea by manipulating various biochemical and physiological responses of plants. PMID:26440314

  20. Understanding the formation of CuS concave superstructures with peroxidase-like activity

    NASA Astrophysics Data System (ADS)

    He, Weiwei; Jia, Huimin; Li, Xiaoxiao; Lei, Yan; Li, Jing; Zhao, Hongxiao; Mi, Liwei; Zhang, Lizhi; Zheng, Zhi

    2012-05-01

    Copper sulfide (CuS) concave polyhedral superstructures (CPSs) have been successfully prepared in an ethanolic solution by a simple solvothermal reaction without the use of surfactants or templates. Two typical well defined, high symmetry CuS concave polyhedrons, forming a concave truncated cuboctahedron and icosahedron were prepared. The effect of the reaction time, temperature and different Cu ion and sulfur sources on the formation of CuS CPSs were investigated and a possible formation mechanism was proposed and discussed based on gas chromatography-mass spectrometry. More importantly, we found, for the first time, that the CuS CPSs exhibit intrinsic peroxidase-like activity, as they can quickly catalyze the oxidation of typical horseradish peroxidase (HRP) substrates, 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD), in the presence of hydrogen peroxide. In addition to the recent discoveries regarding peroxidase mimetics on Fe3O4 NPs and carbon nanostructures, our findings suggest a new kind of candidate for peroxidase mimics. This may open up a new application field of CuS micro-nano structures in biodetection, biocatalysis and environmental monitoring.Copper sulfide (CuS) concave polyhedral superstructures (CPSs) have been successfully prepared in an ethanolic solution by a simple solvothermal reaction without the use of surfactants or templates. Two typical well defined, high symmetry CuS concave polyhedrons, forming a concave truncated cuboctahedron and icosahedron were prepared. The effect of the reaction time, temperature and different Cu ion and sulfur sources on the formation of CuS CPSs were investigated and a possible formation mechanism was proposed and discussed based on gas chromatography-mass spectrometry. More importantly, we found, for the first time, that the CuS CPSs exhibit intrinsic peroxidase-like activity, as they can quickly catalyze the oxidation of typical horseradish peroxidase (HRP) substrates, 3

  1. Changes in biosynthesis and metabolism of glutathione upon ochratoxin A stress in Arabidopsis thaliana.

    PubMed

    Wang, Yan; Zhao, Weiwei; Hao, Junran; Xu, Wentao; Luo, Yunbo; Wu, Weihong; Yang, Zhuojun; Liang, Zhihong; Huang, Kunlun

    2014-06-01

    Ochratoxin A (OTA) is one of the most toxic mycotoxins, which is toxic to plants and simulates oxidative stress. Glutathione is an important antioxidant in plants and is closely associated with detoxification in cells. We have previously shown that OTA exposure induces obvious expression differences in genes associated with glutathione metabolism. To characterize glutathione metabolism and understand its role in OTA phytotoxicity, we observed the accumulation of GSH in the detached leaves of Arabidopsis thaliana under OTA treatment. OTA stimulated a defense response through enhancing glutathione-S-transferase, glutathione peroxidase, glutathione reductase activities, and the transcript levels of these enzymes were increased to maintain the total glutathione content. Moreover, the level of oxidized glutathione (GSSG) was increased and the ascorbate-glutathione cycle fluctuated in response to OTA. The depletion of glutathione using buthionine sulfoximine (BSO, inhibitor of glutamate-cysteine ligase) had no profound effect on OTA toxicity, as glutathione was regenerated through the ascorbate-glutathione cycle to maintain the total glutathione content. The ROS, MDA and GSH accumulation was significantly affected in the mutant gsh1, gr1 and gpx2 after treatment with OTA, which indicated that glutathione metabolism is directly involved in the oxidative stress response of Arabidopsis thaliana subjected to OTA. In conclusion, date demonstrate that glutathione-associated metabolism is closely related with OTA stress and glutathione play a role in resistance of Arabidopsis subjected to OTA.

  2. Activity and isoforms of peroxidases, lignin and anatomy, during adventitious rooting in cuttings of Ebenus cretica L.

    PubMed

    Syros, Thomas; Yupsanis, Traianos; Zafiriadis, Helias; Economou, Athanasios

    2004-01-01

    Adventitious rooting of Ebenus cretica cuttings was studied in order to examine a) the rooting ability of different genotypes in relation to electrophoretic patterns of peroxidases. b) the activity and electrophoretic patterns of soluble and wall ionically bound peroxidases, the lignin content and anatomical changes in the control and IBA treated cuttings of and genotypes in the course of adventitious root formation. In addition, a fraction of soluble cationic peroxidases was separated by gel filtration chromatography from the total soluble peroxidases of a genotype. No rooting occurred in cuttings without IBA-treatment. In both genotypes, electrophoretic patterns of soluble anionic peroxidases revealed two common peroxidase isoforms, while a fast-migrating anionic peroxidase isoform (A3) appeared only in genotypes. Both genotypes showed similar patterns of soluble, as well as wall ionically bound cationic peroxidase isoforms. The number of isoforms was unchanged during the rooting process (induction, initiation and expression phase) but an increase in peroxidase activity (initiation phase) followed by decrease has been found in IBA-treated cuttings. During initiation phase the lignin content was almost similar to that on day 0 in genotype while it was reduced at by about 50% in genotype at the respective time. Microscopic observations revealed anatomical differences between genotypes. According to this study, the and genotypes display differences in anatomy, lignin content, activity of soluble peroxidases and the electrophoretic patterns of soluble anionic peroxidase isoforms. The A3-anionic peroxidase isoform could be used as biochemical marker to distinguish and genotypes of E. cretica and seems to be correlated to lignin synthesis in rooting process. PMID:15002666

  3. Changes in thyroid peroxidase activity in response to various chemicals.

    PubMed

    Song, Mee; Kim, Youn-Jung; Park, Yong-Keun; Ryu, Jae-Chun

    2012-08-01

    Thyroperoxidase (TPO) is a large heme-containing glycoprotein that catalyzes the transfer of iodine to thyroglobulin during thyroid hormone (TH) synthesis. Previously, we established an in vitro assay for TPO activity based on human recombinant TPO (hrTPO) stably transfected into human follicular thyroid carcinoma (FTC-238) cells. It is important to determine whether environmental chemicals can disrupt TPO activity because it is an important factor in the TH axis. In this study, we used our assay to examine the changes in TPO activity in response to various chemicals, including benzophenones (BPs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs). Overall, BPs, PAHs, and POPs slightly altered TPO activity at low doses, as compared with the positive controls methimazole (MMI), genistein, and 2,2',4,4'-tetrahydroxy BP. Benzophenone, benzhydrol, 3-methylchloranthracene, pyrene, benzo(k)fluoranthene, benzo(e)pyrene, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and heptachlor decreased TPO activity, while 2,4-dihydroxy BP, 2,2'-dihydroxy-4-methoxy BP, and dibenzo(a,h)anthracene increased TPO activity. From these data, we can predict the disruption of TPO activity by various chemicals as a sensitive TH end point. TPO activity should be considered when enacting measures to regulate environmental exposure to thyroid-disrupting chemicals. PMID:22699773

  4. Intrinsic electrophilicity of the 4-methylsulfonyl-2-pyridone scaffold in glucokinase activators: role of glutathione-S-transferases and in vivo quantitation of a glutathione conjugate in rats.

    PubMed

    Litchfield, John; Sharma, Raman; Atkinson, Karen; Filipski, Kevin J; Wright, Stephen W; Pfefferkorn, Jeffrey A; Tan, Beijing; Kosa, Rachel E; Stevens, Benjamin; Tu, Meihua; Kalgutkar, Amit S

    2010-11-01

    Previous studies on the in vitro metabolism of 4-alkylsulfonyl-2-pyridone-based glucokinase activators revealed a facile, non-enzymatic displacement of the 4-alkylsulfonyl group by glutathione. In the present studies, a role for glutathione-S-transferases (GST) as catalysts in the desulfonylation reaction was demonstrated using a combination of human liver microsomes, human liver cytosol and human GSTs. The identification of a glutathione conjugate in circulation following intravenous administration of a candidate 4-methylsulfonyl-2-pyridone to rats confirmed the relevance of the in vitro findings.

  5. Epsilon glutathione transferases possess a unique class-conserved subunit interface motif that directly interacts with glutathione in the active site.

    PubMed

    Wongsantichon, Jantana; Robinson, Robert C; Ketterman, Albert J

    2015-10-20

    Epsilon class glutathione transferases (GSTs) have been shown to contribute significantly to insecticide resistance. We report a new Epsilon class protein crystal structure from Drosophila melanogaster for the glutathione transferase DmGSTE6. The structure reveals a novel Epsilon clasp motif that is conserved across hundreds of millions of years of evolution of the insect Diptera order. This histidine-serine motif lies in the subunit interface and appears to contribute to quaternary stability as well as directly connecting the two glutathiones in the active sites of this dimeric enzyme.

  6. Epsilon glutathione transferases possess a unique class-conserved subunit interface motif that directly interacts with glutathione in the active site

    PubMed Central

    Wongsantichon, Jantana; Robinson, Robert C.; Ketterman, Albert J.

    2015-01-01

    Epsilon class glutathione transferases (GSTs) have been shown to contribute significantly to insecticide resistance. We report a new Epsilon class protein crystal structure from Drosophila melanogaster for the glutathione transferase DmGSTE6. The structure reveals a novel Epsilon clasp motif that is conserved across hundreds of millions of years of evolution of the insect Diptera order. This histidine-serine motif lies in the subunit interface and appears to contribute to quaternary stability as well as directly connecting the two glutathiones in the active sites of this dimeric enzyme. PMID:26487708

  7. Structural insight into the active site of a Bombyx mori unclassified glutathione transferase.

    PubMed

    Hossain, Md Tofazzal; Yamamoto, Kohji

    2015-01-01

    Glutathione transferases (GSTs) are major detoxification enzymes that play central roles in the defense against various environmental toxicants as well as oxidative stress. Here, we identify amino acid residues of an unclassified GST from Bombyx mori, bmGSTu-interacting glutathione (GSH). Site-directed mutagenesis of bmGSTu mutants indicated that amino acid residues Asp103, Ser162, and Ser166 contribute to catalytic activity.

  8. Comparative analysis of lignin peroxidase and manganese peroxidase activity on coniferous and deciduous wood using ToF-SIMS.

    PubMed

    MacDonald, Jacqueline; Goacher, Robyn E; Abou-Zaid, Mamdouh; Master, Emma R

    2016-09-01

    White-rot fungi are distinguished by their ability to efficiently degrade lignin via lignin-modifying type II peroxidases, including manganese peroxidase (MnP) and lignin peroxidase (LiP). In the present study, time-of flight secondary ion mass spectrometry (ToF-SIMS) was used to evaluate lignin modification in three coniferous and three deciduous wood preparations following treatment with commercial preparations of LiP and MnP from two different white-rot fungi. Percent modification of lignin was calculated as a loss of intact methoxylated lignin over nonfunctionalized aromatic rings, which is consistent with oxidative cleavage of methoxy moieties within the lignin structure. Exposure to MnP resulted in greater modification of lignin in coniferous compared to deciduous wood (28 vs. 18 % modification of lignin); and greater modification of G-lignin compared to S-lignin within the deciduous wood samples (21 vs. 12 %). In contrast, exposure to LiP resulted in similar percent modification of lignin in all wood samples (21 vs 22 %), and of G- and S-lignin within the deciduous wood (22 vs. 23 %). These findings suggest that the selected MnP and LiP may particularly benefit delignification of coniferous and deciduous wood, respectively. Moreover, the current analysis further demonstrates the utility of ToF-SIMS for characterizing enzymatic modification of lignin in wood fibre along with potential advantages over UV and HPCL-MS detection of solubilized delignification products.

  9. Peroxidase activity as an indicator of exposure of wetland seedlings to metals

    SciTech Connect

    Sutton, H.D.; Klaine, S.J.

    1995-12-31

    The enzyme peroxidase has been found to increase quantitatively in several aquatic plant species in response to increasing exposure to various contaminants. In this study, a number of wetland species are tested for their usefulness as bioindicators of metal exposure using the peroxidase assay. Woody species tested include Liquidambar styraciflua (sweetgum), Fraxinus pennsylvanica (green ash), and Cephalanthus occidentalis (buttonbush), while herbaceous species include Saururus cernuus (lizard`s tail) and Sparganium americanum (bur-reed). The assay has been optimized for all of these species. In all cases the pH optimum has been found to be either 5.5 or 6.0 and the substrate optimum is 2.8 or 1.4mM hydrogen peroxide. There is considerable variation in baseline peroxidase activity among the species when tested under their optimal assay conditions. These species are being dosed with copper, nickel, and cadmium in order to determine whether a response elicited. Seedlings will be dosed using both petri dish culture conditions and test tubes filled with vermiculite and sand combinations. The peroxidase response will be compared to germination and root elongation endpoints. Lettuce (Lactuca saliva) and radish (Raphanus sativus) are being tested alongside the wetland species as reference organisms for which background data is available. The wetland species tested in the present study have rarely if ever been used in toxicological studies.

  10. Effects of ageing on peroxidase activity and localization in radish (Raphanus sativus L.) seeds.

    PubMed

    Scialabba, A; Bellani, L M; Dell'Aquila, A

    2002-01-01

    Peroxidase activity was assayed in crude extracts of integument, cotyledons and embryo axis of radish seeds, deteriorated under accelerated ageing conditions. Over five days of ageing, in which germination decreased from 100 to 52%, the enzyme activity in integument was higher than that in other seed parts, increasing in the first days of ageing and then decreasing sharply in extremely aged seeds. Polyacrylamide gel electrophoresis analysis showed four peroxidase isoenzymes with MM of 98, 52.5, 32.8 and 29.5 kDa in the embryo axis of unaged seeds, and only the 32.8 and 29.5 kDa MM isoforms in the integument and cotyledons. In these parts of the seed, only the 29.5 kDa MM isoenzyme increased in activity in early days of ageing and decreased there-after. In the embryo axis, the 29.5 kDa MM isoenzyme activity increased slowly in the first day of ageing, while the 98 and 52.5 kDa MM isoenzyme activities disappeared. A cytochemical localization of peroxidase activity in the various tissues showed that main differences between unaged and extremely aged seeds occurred in the embryo axis.

  11. Screening of laccase, manganese peroxidase, and versatile peroxidase activities of the genus Pleurotus in media with some raw plant materials as carbon sources.

    PubMed

    Stajic, Mirjana; Persky, Limor; Cohen, Emanuel; Hadar, Yitzhak; Brceski, Ilija; Wasser, Solomon P; Nevo, Eviatar

    2004-06-01

    Species of the genus Pleurotus are among the most efficient natural species in lignin degradation belonging to the subclass of ligninolytic organisms that produce laccase (Lac), Mn-dependent peroxidase (MnP), versatile peroxidase (VP), and the H2O2-generating enzyme aryl-alcohol oxidase, but not lignin peroxidases. Production of Lac and oxidation of 2,6-dimethoxyphenol (DMP) in the presence and absence of Mn2+ were detected both in submerged fermentation (SF) of dry ground mandarine peels and in solid-state fermentation (SSF) of grapevine sawdust in all investigated Pleurotus species and strains. Evidence of cultivation methods having a distinct influence on the level of enzyme activities has been demonstrated. Most of the species and strains had higher Lac activity under SSF conditions than under SF conditions. DMP oxidation in the presence and absence of Mn2+ was detected in all investigated species and strains, but was lower under SF conditions than under SSF conditions for most of them. However, relative activities of DMP oxidation in the absence of Mn2+, as percentages of activity against DMP in the presence of Mn2+, were higher under conditions of SF than in SSF cultures in most of the investigated species and strains. The obtained results showed that strains of different origins have different efficiently ligninolytic systems and that conditions of SSF are more favorable for ligninolytic activity than those in SF owing to their similarity to natural conditions on wood substrates. PMID:15304767

  12. Not so monofunctional--a case of thermostable Thermobifida fusca catalase with peroxidase activity.

    PubMed

    Lončar, Nikola; Fraaije, Marco W

    2015-03-01

    Thermobifida fusca is a mesothermophilic organism known for its ability to degrade plant biomass and other organics, and it was demonstrated that it represents a rich resource of genes encoding for potent enzymes for biocatalysis. The thermostable catalase from T. fusca has been cloned and overexpressed in Escherichia coli with a yield of 400 mg/L. Heat treatment of disrupted cells at 60 °C for 1 h resulted in enzyme preparation of high purity; hence, no chromatography steps are needed for large-scale production. Except for catalyzing the dismutation of hydrogen peroxide, TfuCat was also found to catalyze oxidations of phenolic compounds. The catalase activity was comparable to other described catalases while peroxidase activity was quite remarkable with a k obs of nearly 1000 s(-1) for catechol. Site directed mutagenesis was used to alter the ratio of peroxidase/catalase activity. Resistance to inhibition by classic catalase inhibitors and an apparent melting temperature of 74 °C classifies this enzyme as a robust biocatalyst. As such, it could compete with other commercially available catalases while the relatively high peroxidase activity also offers new biocatalytic possibilities.

  13. Immobilization of peroxidase enzyme onto the porous silicon structure for enhancing its activity and stability

    NASA Astrophysics Data System (ADS)

    Sahare, Padmavati; Ayala, Marcela; Vazquez-Duhalt, Rafael; Agrawal, Vivechana

    2014-08-01

    In this work, a commercial peroxidase was immobilized onto porous silicon (PS) support functionalized with 3-aminopropyldiethoxysilane (APDES) and the performance of the obtained catalytic microreactor was studied. The immobilization steps were monitored and the activity of the immobilized enzyme in the PS pores was spectrophotometrically determined. The enzyme immobilization in porous silicon has demonstrated its potential as highly efficient enzymatic reactor. The effect of a polar organic solvent (acetonitrile) and the temperature (up to 50°C) on the activity and stability of the biocatalytic microreactor were studied. After 2-h incubation in organic solvent, the microreactor retained 80% of its initial activity in contrast to the system with free soluble peroxidase that lost 95% of its activity in the same period of time. Peroxidase immobilized into the spaces of the porous silicon support would be perspective for applications in treatments for environmental security such as removal of leached dye in textile industry or in treatment of different industrial effluents. The system can be also applied in the field of biomedicine.

  14. Immobilization of peroxidase enzyme onto the porous silicon structure for enhancing its activity and stability

    PubMed Central

    2014-01-01

    In this work, a commercial peroxidase was immobilized onto porous silicon (PS) support functionalized with 3-aminopropyldiethoxysilane (APDES) and the performance of the obtained catalytic microreactor was studied. The immobilization steps were monitored and the activity of the immobilized enzyme in the PS pores was spectrophotometrically determined. The enzyme immobilization in porous silicon has demonstrated its potential as highly efficient enzymatic reactor. The effect of a polar organic solvent (acetonitrile) and the temperature (up to 50°C) on the activity and stability of the biocatalytic microreactor were studied. After 2-h incubation in organic solvent, the microreactor retained 80% of its initial activity in contrast to the system with free soluble peroxidase that lost 95% of its activity in the same period of time. Peroxidase immobilized into the spaces of the porous silicon support would be perspective for applications in treatments for environmental security such as removal of leached dye in textile industry or in treatment of different industrial effluents. The system can be also applied in the field of biomedicine. PMID:25221454

  15. Detection of the halogenating activity of heme peroxidases in leukocytes by aminophenyl fluorescein.

    PubMed

    Flemmig, J; Remmler, J; Zschaler, J; Arnhold, J

    2015-06-01

    The formation of hypochlorous and hypobromous acids by heme peroxidases is a key property of certain immune cells. These products are not only involved in defense against pathogenic microorganisms and in regulation of inflammatory processes, but contribute also to tissue damage in certain pathologies. After a short introduction about experimental approaches for the assessment of the halogenating activity in vitro and in cell suspensions, we are focusing on novel applications of fluorescent dye systems to detect the formation of hypochlorous acid (HOCl) in leukocytes. Special attention is directed to properties and applications of the non-fluorescent dye aminophenyl fluorescein that is converted by HOCl, HOBr, and other strong oxidants to fluorescein. This dye allows the detection of the halogenating activity in samples containing free myeloperoxidase and eosinophil peroxidase as well as in intact granulocytes using fluorescence spectroscopy and flow cytometry, respectively.

  16. The Molecular Mechanism of the Catalase-like Activity in Horseradish Peroxidase.

    PubMed

    Campomanes, Pablo; Rothlisberger, Ursula; Alfonso-Prieto, Mercedes; Rovira, Carme

    2015-09-01

    Horseradish peroxidase (HRP) is one of the most relevant peroxidase enzymes, used extensively in immunochemistry and biocatalysis applications. Unlike the closely related catalase enzymes, it exhibits a low activity to disproportionate hydrogen peroxide (H2O2). The origin of this disparity remains unknown due to the lack of atomistic information on the catalase-like reaction in HRP. Using QM(DFT)/MM metadynamics simulations, we uncover the mechanism for reduction of the HRP Compound I intermediate by H2O2 at atomic detail. The reaction begins with a hydrogen atom transfer, forming a peroxyl radical and a Compound II-like species. Reorientation of the peroxyl radical in the active site, concomitant with the transfer of the second hydrogen atom, is the rate-limiting step, with a computed free energy barrier (18.7 kcal/mol, ∼ 6 kcal/mol higher than the one obtained for catalase) in good agreement with experiments. Our simulations reveal the crucial role played by the distal pocket residues in accommodating H2O2, enabling formation of a Compound II-like intermediate, similar to catalases. However, out of the two pathways for Compound II reduction found in catalases, only one is operative in HRP. Moreover, the hydrogen bond network in the distal side of HRP compensates less efficiently than in catalases for the energetic cost required to reorient the peroxyl radical at the rate-determining step. The distal Arg and a water molecule in the "wet" active site of HRP have a substantial impact on the reaction barrier, compared to the "dry" active site in catalase. Therefore, the lower catalase-like efficiency of heme peroxidases compared to catalases can be directly attributed to the different distal pocket architecture, providing hints to engineer peroxidases with a higher rate of H2O2 disproportionation.

  17. Direct electrochemical detection of kanamycin based on peroxidase-like activity of gold nanoparticles.

    PubMed

    Wang, Chunshuai; Liu, Chang; Luo, Jibao; Tian, Yaping; Zhou, Nandi

    2016-09-14

    An enzyme-free, ultrasensitive electrochemical detection of kanamycin residue was achieved based on mimetic peroxidase activity of gold nanoparticles (AuNPs) and target-induced replacement of the aptamer. AuNPs which were synthesized using tyrosine as a reducing and capping agent, exhibited mimetic peroxidase activity. In the presence of kanamycin-specific aptamer, however, the single-stranded DNA (ssDNA) adsorbed on the surface of AuNPs via the interaction between the bases of ssDNA and AuNPs, and therefore blocked the catalytic site of AuNPs, and inhibited their peroxidase activity. While in the presence of target kanamycin, it bound with the adsorbed aptamer on AuNPs with high affinity, exposed the surface of AuNPs and recovered the peroxidase activity. Then AuNPs catalyzed the reaction between H2O2 and reduced thionine to produce oxidized thionine. The latter exhibited a distinct reduction peak on gold electrode in differential pulse voltammetry (DPV), and could be utilized to quantify the concentration of kanamycin. Under the optimized conditions, the proposed electrochemical assay showed an extremely high sensitivity towards kanamycin, with a linear relationship between the peak current and the concentration of kanamycin in the range of 0.1-60 nM, and a detection limit of 0.06 nM. Moreover, the established approach was successfully applied in the detection of kanamycin in honey samples. Therefore, the proposed electrochemical assay has great potential in the fields of food quality control and environmental monitoring. PMID:27566341

  18. Visual detection of melamine based on the peroxidase-like activity enhancement of bare gold nanoparticles.

    PubMed

    Ni, Pengjuan; Dai, Haichao; Wang, Yilin; Sun, Yujing; Shi, Yan; Hu, Jingting; Li, Zhuang

    2014-10-15

    In this study, a facile method to sensitively detect melamine and highly improve the peroxidase-like activity of bare gold nanoparticles (Au NPs) at the same time is proposed for the first time. It is interesting to find that the addition of melamine could improve the peroxidase-like activity of Au NPs. By coupling with 3,3',5,5'-tetramethlybenzidine (TMB)-H2O2 chormogenic reaction, a novel method for colorimetic detection of melamine is developed. The detection limit of this method is as low as 0.2 nM with the help of UV-vis spectroscopy and 0.5 µM by naked-eye observation, both which are far below the US food and Drug Administration estimated melamine safety limit of 20 µM. In addition, the present method is successfully applied for the detection of melamine in raw milk and milk powder. More importantly, the proposed method could also improve the peroxidase-like activity of Au NPs, which may not only provide a new approach to develop effective nanomaterials-based mimetic enzyme, but also irradiative to develop new applications for Au NPs in varieties of cost-effective and simple sensors in medicine, biotechnology and environmental chemistry.

  19. Influence of 400, 900, and 1900 MHz electromagnetic fields on Lemna minor growth and peroxidase activity.

    PubMed

    Tkalec, Mirta; Malarić, Kresimir; Pevalek-Kozlina, Branka

    2005-04-01

    Increased use of radio and microwave frequencies requires investigations of their effects on living organisms. Duckweed (Lemna minor L.) has been commonly used as a model plant for environmental monitoring. In the present study, duckweed growth and peroxidase activity was evaluated after exposure in a Gigahertz Transversal Electromagnetic (GTEM) cell to electric fields of frequencies 400, 900, and 1900 MHz. The growth of plants exposed for 2 h to the 23 V/m electric field of 900 MHz significantly decreased in comparison with the control, while an electric field of the same strength but at 400 MHz did not have such effect. A modulated field at 900 MHz strongly inhibited the growth, while at 400 MHz modulation did not influence the growth significantly. At both frequencies a longer exposure mostly decreased the growth and the highest electric field (390 V/m) strongly inhibited the growth. Exposure of plants to lower field strength (10 V/m) for 14 h caused significant decrease at 400 and 1900 MHz while 900 MHz did not influence the growth. Peroxidase activity in exposed plants varied, depending on the exposure characteristics. Observed changes were mostly small, except in plants exposed for 2 h to 41 V/m at 900 MHz where a significant increase (41%) was found. Our results suggest that investigated electromagnetic fields (EMFs) might influence plant growth and, to some extent, peroxidase activity. However, the effects of EMFs strongly depended on the characteristics of the field exposure. PMID:15768427

  20. Active Site Structure and Peroxidase Activity of Oxidatively Modified Cytochrome c Species in Complexes with Cardiolipin.

    PubMed

    Capdevila, Daiana A; Oviedo Rouco, Santiago; Tomasina, Florencia; Tortora, Verónica; Demicheli, Verónica; Radi, Rafael; Murgida, Daniel H

    2015-12-29

    We report a resonance Raman and UV-vis characterization of the active site structure of oxidatively modified forms of cytochrome c (Cyt-c) free in solution and in complexes with cardiolipin (CL). The studied post-translational modifications of Cyt-c include methionine sulfoxidation and tyrosine nitration, which lead to altered heme axial ligation and increased peroxidase activity with respect to those of the wild-type protein. In spite of the structural and activity differences between the protein variants free in solution, binding to CL liposomes induces in all cases the formation of a spectroscopically identical bis-His axial coordination conformer that more efficiently promotes lipid peroxidation. The spectroscopic results indicate that the bis-His form is in equilibrium with small amounts of high-spin species, thus suggesting a labile distal His ligand as the basis for the CL-induced increase in enzymatic activity observed for all protein variants. For Cyt-c nitrated at Tyr74 and sulfoxidized at Met80, the measured apparent binding affinities for CL are ∼4 times larger than for wild-type Cyt-c. On the basis of these results, we propose that these post-translational modifications may amplify the pro-apoptotic signal of Cyt-c under oxidative stress conditions at CL concentrations lower than for the unmodified protein.

  1. Construction of a Fusion Enzyme Exhibiting Superoxide Dismutase and Peroxidase Activity.

    PubMed

    Sharapov, M G; Novoselov, V I; Ravin, V K

    2016-04-01

    A chimeric gene construct encoding human peroxiredoxin 6 and Mn-superoxide dismutase from Escherichia coli was developed. Conditions for expression of the fusion protein in E. coli cell were optimized. Fusing of the enzymes into a single polypeptide chain with peroxiredoxin 6 at the N-terminus (PSH) did not affect their activities. On the contrary, the chimeric protein with reverse order of enzymes (SPH) was not obtained in a water-soluble active form. The active chimeric protein (PSH) exhibiting both peroxidase and superoxide dismutase activities was prepared and its physicochemical properties were characterized. PMID:27293100

  2. Characterisation of Fasciola hepatica cytochrome c peroxidase as an enzyme with potential antioxidant activity in vitro.

    PubMed

    Campos, E G; Hermes-Lima, M; Smith, J M; Prichard, R K

    1999-05-01

    Cytochrome c peroxidase oxidises hydrogen peroxide using cytochrome c as the electron donor. This enzyme is found in yeast and bacteria and has been also described in the trematodes Fasciola hepatica and Schistosoma mansoni. Using partially purified cytochrome c peroxidase samples from Fasciola hepatica we evaluated its role as an antioxidant enzyme via the investigation of its ability to protect against oxidative damage to deoxyribose in vitro. A system containing FeIII-EDTA plus ascorbate was used to generate reactive oxygen species superoxide radical, H2O2 as well as the hydroxyl radical. Fasciola hepatica cytochrome c peroxidase effectively protected deoxyribose against oxidative damage in the presence of its substrate cytochrome c. This protection was proportional to the amount of enzyme added and occurred only in the presence of cytochrome c. Due to the low specific activity of the final partially purified sample the effects of ascorbate and calcium chloride on cytochrome c peroxidase were investigated. The activity of the partially purified enzyme was found to increase between 10 and 37% upon reduction with ascorbate. However, incubation of the partially purified enzyme with 1 mM calcium chloride did not have any effect on enzyme activity. Our results showed that Fasciola hepatica CcP can protect deoxyribose from oxidative damage in vitro by blocking the formation of the highly toxic hydroxyl radical (.OH). We suggest that the capacity of CcP to inhibit .OH-formation, by efficiently removing H2O2 from the in vitro oxidative system, may extend the biological role of CcP in response to oxidative stress in Fasciola hepatica. PMID:10404259

  3. Emerging pollutants and plants--Metabolic activation of diclofenac by peroxidases.

    PubMed

    Huber, Christian; Preis, Martina; Harvey, Patricia J; Grosse, Sylvia; Letzel, Thomas; Schröder, Peter

    2016-03-01

    Human pharmaceuticals and their residues are constantly detected in our waterbodies, due to poor elimination rates, even in the most advanced waste water treatment plants. Their impact on the environment and human health still remains unclear. When phytoremediation is applied to aid water treatment, plants may transform and degrade xenobiotic contaminants through phase I and phase II metabolism to more water soluble and less toxic intermediates. In this context, peroxidases play a major role in activating compounds during phase I via oxidation. In the present work, the ability of a plant peroxidase to oxidize the human painkiller diclofenac was confirmed using stopped flow spectroscopy in combination with LC-MS analysis. Analysis of an orange colored product revealed the structure of the highly reactive Diclofenac-2,5-Iminoquinone, which may be the precursor of several biological conjugates and breakdown products in planta.

  4. Emerging pollutants and plants--Metabolic activation of diclofenac by peroxidases.

    PubMed

    Huber, Christian; Preis, Martina; Harvey, Patricia J; Grosse, Sylvia; Letzel, Thomas; Schröder, Peter

    2016-03-01

    Human pharmaceuticals and their residues are constantly detected in our waterbodies, due to poor elimination rates, even in the most advanced waste water treatment plants. Their impact on the environment and human health still remains unclear. When phytoremediation is applied to aid water treatment, plants may transform and degrade xenobiotic contaminants through phase I and phase II metabolism to more water soluble and less toxic intermediates. In this context, peroxidases play a major role in activating compounds during phase I via oxidation. In the present work, the ability of a plant peroxidase to oxidize the human painkiller diclofenac was confirmed using stopped flow spectroscopy in combination with LC-MS analysis. Analysis of an orange colored product revealed the structure of the highly reactive Diclofenac-2,5-Iminoquinone, which may be the precursor of several biological conjugates and breakdown products in planta. PMID:26741549

  5. Colorimetric detection of Shewanella oneidensis based on immunomagnetic capture and bacterial intrinsic peroxidase activity

    NASA Astrophysics Data System (ADS)

    Wen, Junlin; Zhou, Shungui; Chen, Junhua

    2014-06-01

    Rapid detection and enumeration of target microorganisms is considered as a powerful tool for monitoring bioremediation process that typically involves cleaning up polluted environments with functional microbes. A novel colorimetric assay is presented based on immunomagnetic capture and bacterial intrinsic peroxidase activity for rapidly detecting Shewanella oneidensis, an important model organism for environmental bioremediation because of its remarkably diverse respiratory abilities. Analyte bacteria captured on the immunomagnetic beads provided a bacterial out-membrane peroxidase-amplified colorimetric readout of the immunorecognition event by oxidizing 3, 3', 5, 5'-tetramethylbenzidine (TMB) in the present of hydrogen peroxide. The high-efficiency of immunomagnetic capture and signal amplification of peroxidase activity offers an excellent detection performance with a wide dynamic range between 5.0 × 103 and 5.0 × 106 CFU/mL toward target cells. Furthermore, this method was demonstrated to be feasible in detecting S. oneidensis cells spiked in environmental samples. The proposed colorimetric assay shows promising environmental applications for rapid detection of target microorganisms.

  6. Glutathione-dependent peroxidative metabolism in the alveolar macrophage

    PubMed Central

    Vogt, Molly T.; Thomas, Catherine; Vassallo, Charles L.; Basford, R. E.; Gee, J. Bernard L.

    1971-01-01

    Phagocytosis by rabbit alveolar macrophages (AM) is accompanied by increases in O2 consumption, glucose oxidation, and H2O2 formation. Two aspects of the interrelations between these metabolic features of phagocytosis have been studied. First, the following evidence indicates that glutathione, glutathione reductase, and peroxidase serve as a cytoplasmic shuttle between H2O2 and NADPH-dependent glucose oxidation: (a) AM contain 5.9 mμmoles of reduced glutathione per 106 cells and exhibit glutathione peroxidase and NADPH-specific glutathione reductase activity; (b) oxidized glutathione potentiates NADP stimulation of glucose oxidation; (c) an artificial H2O2-generating system stimulates glucose oxidation; (d) the cell penetrating thiol inhibitor, N-ethylmaleimide diminishes glucose oxidation. This effect largely depends on inhibition of the glutathione system rather than on inhibition of either H2O2 formation or enzymes directly subserving glucose oxidation. Second, three potential H2O2-generating oxidases have been sought. No cyanide-insensitive NADH or NADPH oxidase activity could be detected. D-amino acid oxidase activity was 0.48 ±0.07 U/106 cells with D-alanine as substrate. PMID:4395562

  7. Effect of architecture on the activity of glucose oxidase/horseradish peroxidase/carbon nanoparticle conjugates.

    PubMed

    Ciaurriz, Paula; Bravo, Ernesto; Hamad-Schifferli, Kimberly

    2014-01-15

    We investigate the activity of glucose oxidase (GOx) together with horseradish peroxidase (HRP) on carbon nanoparticles (CNPs). Because GOx activity relies on HRP, we probe how the arrangement of the enzymes on the CNPs affects enzymatic behavior. Colorimetric assays to probe activity found that the coupling strategy affects activity of the bienzyme-nanoparticle complex. GOx is more prone than HRP to denaturation on the CNP surface, where its activity is compromised, while HRP activity is enhanced when interfaced to the CNP. Thus, arrangements where HRP is directly on the surface of the CNP and GOx is not are more favorable for overall activity. Coverage also influenced activity of the bienzyme complex, but performing the conjugation in the presence of glucose did not improve GOx activity. These results show that the architecture of the assembly is an important factor in optimization of nanoparticle-protein interfaces. PMID:24231087

  8. Magnetosomes extracted from Magnetospirillum magneticum strain AMB-1 showed enhanced peroxidase-like activity under visible-light irradiation.

    PubMed

    Li, Kefeng; Chen, Chuanfang; Chen, Changyou; Wang, Yuzhan; Wei, Zhao; Pan, Weidong; Song, Tao

    2015-05-01

    Magnetosomes are intracellular structures produced by magnetotactic bacteria and are magnetic nanoparticles surrounded by a lipid bilayer membrane. Magnetosomes reportedly possess intrinsic enzyme mimetic activity similar to that found in horseradish peroxidase (HRP) and can scavenge reactive oxygen species depending on peroxidase activity. Our previous study has demonstrated the phototaxis characteristics of Magnetospirillum magneticum strain AMB-1 cells, but the mechanism is not well understood. Therefore, we studied the relationship between visible-light irradiation and peroxidase-like activity of magnetosomes extracted from M. magneticum strain AMB-1. We then compared this characteristic with that of HRP, iron ions, and naked magnetosomes using 3,3',5,5'-tetramethylbenzidine as a peroxidase substrate in the presence of H2O2. Results showed that HRP and iron ions had different activities from those of magnetosomes and naked magnetosomes when exposed to visible-light irradiation. Magnetosomes and naked magnetosomes had enhanced peroxidase-like activities under visible-light irradiation, but magnetosomes showed less affinity toward substrates than naked magnetosomes under visible-light irradiation. These results suggested that the peroxidase-like activity of magnetosomes may follow an ordered ternary mechanism rather than a ping-pong mechanism. This finding may provide new insight into the function of magnetosomes in the phototaxis in magnetotactic bacteria.

  9. Effect of copper and manganese ions on activities of laccase and peroxidases in three Pleurotus species grown on agricultural wastes.

    PubMed

    Stajic, Mirjana; Persky, Limor; Hadar, Yitzhak; Friesem, Dana; Duletic-Lausevic, Sonja; Wasser, Solomon P; Nevo, Eviatar

    2006-01-01

    Copper (Cu2+) and manganese (Mn2+) ions influenced laccase (Lac) and peroxidase production in Pleurotus eryngii, Pleurotus ostreatus, and Pleurotus pulmonarius. In P. eryngii, the optimum Cu2+ concentration for Lac production was 1 mM and for peroxidases 10 mM, and Mn2+ concentration of 5 mM led to peaks of Lac and peroxidase activity. In P. ostreatus HAI 493, the highest level of Lac activity was at Cu2+ concentrations of 1 and 10 mM and Mn2+ concentration of 1 mM, respectively. The absence of Cu2+ and Mn2+ caused the highest levels of peroxidase production. In P. ostreatus HAI 494, the highest level of Lac activity was at a Cu2+ concentration of 5 mM and at Mn2+ concentration of 1 mM, respectively. High levels of peroxidase activity were found in the medium without and with 1 mM Cu2+, and at 1 and 5 mM Mn2+, respectively. In P. pulmonarius, the highest Lac activity was found in the presence of 5 mM Cu2+ and 5 mM Mn2+, respectively. The absence of Cu2+ and Mn2+ as well as their presence at a concentration of 1 mM led to the peaks of peroxidase activities. PMID:16415481

  10. Generation of reactive species and fate of thiols during peroxidase-catalyzed metabolic activation of aromatic amines and phenols

    SciTech Connect

    Ross, D.; Moldeus, P.

    1985-12-01

    The horseradish peroxidase (HRP)-catalyzed oxidation of p-phenetidine and acetaminophen was investigated. Studies using the spin probe 2-ethyl-1-hydroxy-2,5,5-trimethyl-3-oxazolidine (OXANOH) suggested these oxidations involve the generation of substrate-derived free radicals. This was confirmed by using glutathione (GSH) in these incubations in the presence of the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), DMPO-glutathionyl radical adducts were observed using EPR spectroscopy during HRP-catalyzed oxidation of both p-phenetidine and acetaminophen. Investigations of oxygen uptake and oxidized glutathione (GSSG) formation during HRP-catalyzed oxidations of p-phenetidine and acetaminophen suggested that further reactions of the glutathionyl radical involve glutathione peroxysulfenyl radical and glutathione sulfenyl hydroperoxide production. Quinonoid products of the peroxidatic oxidations of p-phenetidine and acetaminophen, and their interaction with GSH via both conjugation and redox mechanisms are described. The relevance of these reactions of GSH with reactive species as detoxification mechanisms is discussed. 29 references.

  11. Changes in the activity of ascorbate peroxidase under anaerobiosis in cocoyam (Colocasia esculenta).

    PubMed

    Chibueze, Nwose

    2014-01-01

    This study was conducted to determine the activity of ascorbate peroxidase in the cormels of cocoyam (Colocasia esculenta var. antiquorum) immediately after harvest and in storage under anaerobiosis for one and three weeks, respectively. During stress condition in plants, hydrogen peroxide is released and mechanisms to detoxify it must be maintained. The cocoyam tubers that were neither damaged nor affected by disease were harvested from a local farm in Ugbogui, Ovia North Local Government Area in Edo State, Nigeria. The selected cocoyam tubers were peeled manually, washed with ice cold water and cut into pieces. The root tissues (50 g) were homogenised with 100 mL of ice cold 0.05 M phosphate buffer. The extract obtained was clarified by centrifugation for 15 min at 8000 g at 4 degrees C. Ascorbate-peroxidising activity was assayed using the initial rate of decrease in ascorbate concentration as measured by its absorbance at 290 nm using Milton Roy Spectron 21D. Results showed the weight of the cormels decreased all through during storage. Immediately after harvest the activity of ascorbate peroxidase was 15.49 unit mL(-1) with a significant increase (p < 0.05) after one week to 73.05 U mL(-1). Thereafter there was a significant decrease in activity of the enzyme after three weeks of storage to 33.33 U mL(-1). This increase in activity of ascorbate peroxidase after three weeks of storage may be related to increase in response to various biotic stresses. Therefore, manipulation of the capacity of cocoyam to tolerate anaerobiosis is a function of its ability to modulate the antioxidant enzymes' armory in case of need.

  12. Changes in the activity of ascorbate peroxidase under anaerobiosis in cocoyam (Colocasia esculenta).

    PubMed

    Chibueze, Nwose

    2014-01-01

    This study was conducted to determine the activity of ascorbate peroxidase in the cormels of cocoyam (Colocasia esculenta var. antiquorum) immediately after harvest and in storage under anaerobiosis for one and three weeks, respectively. During stress condition in plants, hydrogen peroxide is released and mechanisms to detoxify it must be maintained. The cocoyam tubers that were neither damaged nor affected by disease were harvested from a local farm in Ugbogui, Ovia North Local Government Area in Edo State, Nigeria. The selected cocoyam tubers were peeled manually, washed with ice cold water and cut into pieces. The root tissues (50 g) were homogenised with 100 mL of ice cold 0.05 M phosphate buffer. The extract obtained was clarified by centrifugation for 15 min at 8000 g at 4 degrees C. Ascorbate-peroxidising activity was assayed using the initial rate of decrease in ascorbate concentration as measured by its absorbance at 290 nm using Milton Roy Spectron 21D. Results showed the weight of the cormels decreased all through during storage. Immediately after harvest the activity of ascorbate peroxidase was 15.49 unit mL(-1) with a significant increase (p < 0.05) after one week to 73.05 U mL(-1). Thereafter there was a significant decrease in activity of the enzyme after three weeks of storage to 33.33 U mL(-1). This increase in activity of ascorbate peroxidase after three weeks of storage may be related to increase in response to various biotic stresses. Therefore, manipulation of the capacity of cocoyam to tolerate anaerobiosis is a function of its ability to modulate the antioxidant enzymes' armory in case of need. PMID:24783794

  13. Localized Changes in Peroxidase Activity Accompany Hydrogen Peroxide Generation during the Development of a Nonhost Hypersensitive Reaction in Lettuce1

    PubMed Central

    Bestwick, Charles S.; Brown, Ian R.; Mansfield, John W.

    1998-01-01

    Peroxidase activity was characterized in lettuce (Lactuca sativa L.) leaf tissue. Changes in the activity and distribution of the enzyme were examined during the development of a nonhost hypersensitive reaction (HR) induced by Pseudomonas syringae (P. s.) pv phaseolicola and in response to an hrp mutant of the bacterium. Assays of activity in tissue extracts revealed pH optima of 4.5, 6.0, 5.5 to 6.0, and 6.0 to 6.5 for the substrates tetramethylbenzidine, guaiacol, caffeic acid, and chlorogenic acid, respectively. Inoculation with water or with wild-type or hrp mutant strains of P. s. pv phaseolicola caused an initial decline in total peroxidase activity; subsequent increases depended on the hydrogen donor used in the assay. Guaiacol peroxidase recovered more rapidly in tissues undergoing the HR, whereas changes in tetramethylbenzidine peroxidase were generally similar in the two interactions. In contrast, increases in chlorogenic acid peroxidase were significantly higher in tissues inoculated with the hrp mutant. During the HR, increased levels of Mn2+/2,4-dichlorophenol-stimulated NADH and NADPH oxidase activities, characteristic of certain peroxidases, were found in intercellular fluids and closely matched the accumulation of H2O2 in the apoplast. Histochemical analysis of peroxidase distribution by electron microscopy revealed a striking, highly localized increase in activity within the endomembrane system and cell wall at the sites of bacterial attachment. However, no clear differences in peroxidase location were observed in tissue challenged by the wild-type strain or the hrp mutant. Our results highlight the significance of the subcellular control of oxidative reactions leading to the generation of reactive oxygen species, cell wall alterations, and the HR. PMID:9808752

  14. Glutathione redox system, GSH-Px activity and lipid peroxidation (LPO) levels in tadpoles of R.r.ridibunda and B.viridis.

    PubMed

    Cavas, Levent; Tarhan, Leman

    2003-03-01

    Total glutathione (t-GSH), reduced glutathione (GSH), glutathione disulphide (GSSG) levels, t-GSH/GSSG ratio, glutathione peroxidase (GSH-Px) activity and lipid peroxidation (LPO) levels were investigated during the development period of a predominantly aquatic amphibian R.r.ridibunda and a predominantly terrestrial amphibian B. viridis. While t-GSH and GSH showed a similar trend, GSSG concentration increased significantly (p<0.05) during the larval stages in R.r.ridibunda larvae. In contrast to R.r.ridibunda larvae, there was no significant (p>0.05) change between 1 and 5 weeks in the t-GSH and GSH concentrations of B. viridis. t-GSH and GSH concentrations of B. viridis larvae became sharply elevated after the fifth week, GSSG levels increased 3.25-fold during the metamorphosis. The t-GSH/GSSG ratio fluctuated and the lowest t-GSH/GSSG ratios were observed at the third week for both species. GSH-Px activities for both species increased significantly (p<0.05) during the growing period. The highest GSH-Px activities in R.r.ridibunda and B.viridis were observed at the eighth week and they were 3.45 +/- 0.17 and 4.1 +/- 0.21 IU mg(-1), respectively. The membrane LPO levels in the R.r.ridibunda and B. viridis tadpoles significantly (p<0.001) decreased from 206 +/- 10.3 to 146 +/- 7.3 and from 198 +/- 9.9 to 23 +/- 1.15 nmol MDA g(-1) w.w., respectively.

  15. Novel tungsten carbide nanorods: an intrinsic peroxidase mimetic with high activity and stability in aqueous and organic solvents.

    PubMed

    Li, Nan; Yan, Ya; Xia, Bao-Yu; Wang, Jing-Yuan; Wang, Xin

    2014-04-15

    Tungsten carbide nanorods (WC NRs) are demonstrated for the first time to possess intrinsic peroxidase-like activity towards typical peroxidase substrates, such as 3, 3', 5, 5'-tetramethylbenzidine (TMB) and ο-phenylenediamine (OPD) in the presence of hydrogen peroxide (H2O2). The reactions catalyzed by these nanorods follow the Michaelis-Menten kinetics. The excellent catalytic performance of WC NRs could be attributed to their intrinsic catalytic activity to efficiently accelerate the electron-transfer process and facilitate the decomposition of H2O2 to generate more numbers of reactive oxygen species (ROS). Based upon the strong peroxidase-like activity of these WC NRs, a colorimetric sensor for H2O2 is designed, which provides good response towards H2O2 concentration over a range of 2×10(-7)-8×10(-5) M with a detection limit of 60 nM. Moreover, the peroxidase-like activities of WC NRs with TMB as the substrate are investigated in both protic and aprotic organic media, showing different colorimetric reactions from that performed in aqueous solutions. In comparison with the natural horse radish peroxidase, WC NR exhibits excellent robustness of catalytic activity and considerable reusability, thus making it a promising mimic of peroxidase catalysts. PMID:24325981

  16. Stress protein synthesis and peroxidase activity in a submersed aquatic macrophyte exposed to cadmium

    SciTech Connect

    Siesko, M.M.; Grossfeld, R.M.; Fleming, W.J.

    1997-08-01

    Sago pondweed (Potamogeton pectinatus L.) was exposed to CdCl{sub 2} to evaluate peroxidase (POD) activity and stress protein (SP) synthesis as potential biomarkers of contaminant stress in an aquatic plant. Peroxidase activity did not increase in sago pondweed incubated for 24 h in a liquid culture medium containing 0.5, 0.75, or 1 mM CdCl{sub 2}. By contrast, at each of these CdCl{sub 2} concentrations, SPs of 162, 142, 1122, 82, and 61 kDa were preferentially synthesized, and synthesis of a 66-kDa protein was reduced relative to controls. Peroxidase activity also did not change in sago pondweed rooted for 21 d in agar containing 1 mM CdCl{sub 2}, despite the lower growth rate, lower protein content, and brown discoloration of the plants. Only when the plants were grown 7 or 21 d on agar containing 10 mM CdCl{sub 2} were the growth retardation and phenotypic deterioration accompanied by significantly increased POD activity. In contrast, plants rooted for 7 d in agar containing 1 mM CdCl{sub 2} were not significantly discolored or retarded in growth, yet they preferentially synthesized SPs of 122, 82, and 50 kDa and synthesized proteins of 59 and 52 kDa at reduced rates relative to controls. Similar changes in protein synthesis were accompanied by signs of depressed growth after 21 d of incubation with 1 mM CdCl{sub 2} and with 7 or 21 d of exposure to 10 mM CdCl{sub 2}. These data indicate that changes in SP synthesis may precede detectable alterations in growth of aquatic plants and, therefore, may be a potentially useful early biomarker of contaminant stress. However, further studies will be required to determine whether the SP response is measurable during exposure to environmentally relevant contaminant levels.

  17. Peroxidase-like oxidative activity of a manganese-coordinated histidyl bolaamphiphile self-assembly

    NASA Astrophysics Data System (ADS)

    Kim, Min-Chul; Lee, Sang-Yup

    2015-10-01

    A peroxidase-like catalyst was constructed through the self-assembly of histidyl bolaamphiphiles coordinated to Mn2+ ions. The prepared catalyst exhibited oxidation activity for the organic substrate o-phenylenediamine (OPD) in the presence of hydrogen peroxide (H2O2). The histidyl bolaamphiphiles of bis(N-alpha-amido-histidine)-1,7-heptane dicarboxylates self-assembled to make spherical structures in an aqueous solution. Subsequent association of Mn2+ ions with the histidyl imidazoles in the self-assembly produced catalytic active sites. The optimal Mn2+ ion concentration was determined and coordination of the Mn2+ ion with multiple histidine imidazoles was investigated using spectroscopy analysis. The activation energy of the produced catalysts was 55.0 kJ mol-1, which was comparable to other peroxidase-mimetic catalysts. A detailed kinetics study revealed that the prepared catalyst followed a ping-pong mechanism and that the turnover reaction was promoted by increasing the substrate concentration. Finally, application of the prepared catalyst for glucose detection was demonstrated through cascade enzyme catalysis. This study demonstrated a facile way to prepare an enzyme-mimetic catalyst through the self-assembly of an amphiphilic molecule containing amino acid segments.A peroxidase-like catalyst was constructed through the self-assembly of histidyl bolaamphiphiles coordinated to Mn2+ ions. The prepared catalyst exhibited oxidation activity for the organic substrate o-phenylenediamine (OPD) in the presence of hydrogen peroxide (H2O2). The histidyl bolaamphiphiles of bis(N-alpha-amido-histidine)-1,7-heptane dicarboxylates self-assembled to make spherical structures in an aqueous solution. Subsequent association of Mn2+ ions with the histidyl imidazoles in the self-assembly produced catalytic active sites. The optimal Mn2+ ion concentration was determined and coordination of the Mn2+ ion with multiple histidine imidazoles was investigated using spectroscopy

  18. ENHANCING FUNGICIDAL ACTIVITY OF FLUDIOXONIL BY DISRUPTING CELLULAR GLUTATHIONE HOMEOSTASIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungicidal activity of fludioxonil, a phenylpyrrole fungicide, is elevated by co-application with the aspirin/salicylic acid metabolite, 2,5-dihydroxybenzoic acid (2,5-DHBA). Fludioxonil fungicidal activity is potentiated through the mitogen-activated protein kinase (MAPK) pathway regulating osmotic...

  19. The involvement of polyphenols and peroxidase activities in heavy-metal accumulation by epidermal glands of the waterlily (Nymphaeaceae).

    PubMed

    Lavid, N; Schwartz, A; Yarden, O; Tel-Or, E

    2001-02-01

    Co-localization of polyphenols and peroxidase activity was demonstrated in epidermal glands of the waterlily (Nymphaea) by histochemistry. Total phenols, tannins and peroxidase activity were determined quantitatively in plant extracts. Polyphenols were partially identified and were found to consist mainly of hydrolyzable tannins, gallic and tannic acid derivatives. Nymphaea polyphenols were shown to chelate Cr, Hg, and Pb in vitro, and Cd-binding by polymerized polyphenols was demonstrated in leaves exposed to Cd in vivo. Both polyphenols and peroxidases were found at very high constitutive levels, which were not induced or altered by external conditions, such as light and heavy-metal stress. It is suggested that the polymerization of polyphenols by peroxidases, enhanced after heavy-metal uptake and detoxification, is responsible for the binding of heavy metals in Nymphaea epidermal glands.

  20. Nanostructures for peroxidases

    PubMed Central

    Carmona-Ribeiro, Ana M.; Prieto, Tatiana; Nantes, Iseli L.

    2015-01-01

    Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese, and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design, and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting, and reusability. PMID:26389124

  1. S-Nitrosylation Positively Regulates Ascorbate Peroxidase Activity during Plant Stress Responses1

    PubMed Central

    Yang, Huanjie; Mu, Jinye; Chen, Lichao; Feng, Jian; Hu, Jiliang; Li, Lei; Zhou, Jian-Min; Zuo, Jianru

    2015-01-01

    Nitric oxide (NO) and reactive oxygen species (ROS) are two classes of key signaling molecules involved in various developmental processes and stress responses in plants. The burst of NO and ROS triggered by various stimuli activates downstream signaling pathways to cope with abiotic and biotic stresses. Emerging evidence suggests that the interplay of NO and ROS plays a critical role in regulating stress responses. However, the underpinning molecular mechanism remains poorly understood. Here, we show that NO positively regulates the activity of the Arabidopsis (Arabidopsis thaliana) cytosolic ascorbate peroxidase1 (APX1). We found that S-nitrosylation of APX1 at cysteine (Cys)-32 enhances its enzymatic activity of scavenging hydrogen peroxide, leading to the increased resistance to oxidative stress, whereas a substitution mutation at Cys-32 causes the reduction of ascorbate peroxidase activity and abolishes its responsiveness to the NO-enhanced enzymatic activity. Moreover, S-nitrosylation of APX1 at Cys-32 also plays an important role in regulating immune responses. These findings illustrate a unique mechanism by which NO regulates hydrogen peroxide homeostasis in plants, thereby establishing a molecular link between NO and ROS signaling pathways. PMID:25667317

  2. Highly sensitive and robust peroxidase-like activity of porous nanorods of ceria and their application for breast cancer detection.

    PubMed

    Tian, Zhimin; Li, Jing; Zhang, Zhiyun; Gao, Wei; Zhou, Xuemei; Qu, Yongquan

    2015-08-01

    Porous nanorods of ceria (PN-Ceria), a novel ceria nanostructure with a large surface area and a high surface Ce(3+) fraction, exhibited strong intrinsic peroxidase activity toward a classical peroxidase substrate in the presence of H2O2. Peroxidase-like activity of ceria originated from surface Ce(3+) species as the catalytic center, thereby explaining the high performance of PN-Ceria as an artificial enzyme mimicking peroxidase. Compared with the natural enzyme horseradish peroxidase (HRP), PN-Ceria showed several advantages such as low cost, easy storage, high sensitivity, and, prominently, chemical and catalytic stability under harsh conditions. Importantly, the enzymatic activity of PN-Ceria remained nearly constant and stable over a wide range of temperature and pH values, ensuring the accuracy and reliability of measurements of its peroxidase-like activity. A PN-Ceria based novel diagnostic system was developed for breast cancer detection with a higher sensitivity than the standard HRP detection system. Our work has laid a solid foundation for the development of PN-Ceria as a novel diagnostic tool for clinical use.

  3. Temperature dependence of oxygen evolution through catalase-like activity of horseradish peroxidase

    NASA Astrophysics Data System (ADS)

    Popović-Bijelić, A.; Bijelić, G.; Kolar-Anić, Lj.; Vukojević, V.

    2007-09-01

    By experimental investigations of the temperature dependence of catalase-like activity of horseradish peroxidase in the temperature range 278 328 K, different kinetic profiles for oxygen evolution were found below and above 298 K. Extension of the model is proposed to account for these observations. By numeric simulations of the reaction kinetics at different temperatures, it was found that enhanced evaporation of molecular oxygen from the reaction solution is the main root through which oxygen is lost at elevated temperatures in laboratory conditions.

  4. Characterizing endogenous and exogenous peroxidase activity for bleaching of fluid whey and retentate.

    PubMed

    Campbell, R E; Gerard, P D; Drake, M A

    2014-03-01

    The lactoperoxidase (LP) system may be used to achieve the desired bleaching of fluid whey with the addition of low concentrations (<50mg/kg) of hydrogen peroxide. The addition of an exogenous peroxidase (EP) to whey may also be used to aid in whey bleaching when the LP system is not fully active. The objectives of this study were to monitor LP activity in previously refrigerated or frozen milk, fluid whey, and whey retentate (10% solids) and to evaluate peroxidase activity in fluid whey and whey retentate (10% solids), with and without additional EP (2, 1, or 0.5 dairy bleaching units), over a range of pH (5.5-6.5) and temperatures (4-60°C). Subsequent experiments were conducted to determine the relationship between enzyme activity and bleaching efficacy. Raw and pasteurized milk, fat-separated pasteurized whey, and whey retentate (10% solids) were evaluated for LP activity following storage at 4 or -20°C, using an established colorimetric method. A response surface model was applied to evaluate both endogenous and EP activity at various temperatures and pH in freshly manufactured whey and retentate. Refrigerated or frozen storage at the parameters evaluated did not affect LP activity in milk, whey, or retentate. In fluid whey, with and without added EP, as pH decreased (to 5.5) and temperature increased (to 60°C), peroxidase activity increased. Retentate with EP exhibited behavior similar to that of fluid whey: as pH decreased and temperature increased, activity increased. However, in retentate without EP, as pH increased and temperature increased, activity increased. Enzyme activity was negatively correlated to bleaching time (time for >80% norbixin destruction) in fluid whey but a linear relationship was not evident in retentate. When fluid whey is bleached enzymatically, if pH is decreased and temperature is increased, the rate of reaction increases (e.g., bleaching occurs in less time). When bleaching in retentate, a higher pH (pH 6.5 vs. pH 5.5) is

  5. Docking and molecular dynamics studies at trypanothione reductase and glutathione reductase active sites.

    PubMed

    Iribarne, Federico; Paulino, Margot; Aguilera, Sara; Murphy, Miguel; Tapia, Orlando

    2002-05-01

    A theoretical docking study on the active sites of trypanothione reductase (TR) and glutathione reductase (GR) with the corresponding natural substrates, trypanothione disulfide (T[S]2) and glutathione disulfide (GSSG), is reported. Molecular dynamics simulations were carried out in order to check the robustness of the docking results. The energetic results are in agreement with previous experimental findings and show the crossed complexes have lower stabilization energies than the natural ones. To test DOCK3.5, four nitro furanic compounds, previously designed as potentially active anti-chagasic molecules, were docked at the GR and TR active sites with the DOCK3.5 procedure. A good correlation was found between differential inhibitory activity and relative interaction energy (affinity). The results provide a validation test for the use of DOCK3.5 in connection with the design of anti-chagasic drugs.

  6. Selenium Deficiency Reduces the Abundance of mRNA for Se-Dependent Glutathione Peroxidase 1 by a UGA-Dependent Mechanism Likely To Be Nonsense Codon-Mediated Decay of Cytoplasmic mRNA

    PubMed Central

    Moriarty, Patrick M.; Reddy, C. Channa; Maquat, Lynne E.

    1998-01-01

    The mammalian mRNA for selenium-dependent glutathione peroxidase 1 (Se-GPx1) contains a UGA codon that is recognized as a codon for the nonstandard amino acid selenocysteine (Sec). Inadequate concentrations of selenium (Se) result in a decrease in Se-GPx1 mRNA abundance by an uncharacterized mechanism that may be dependent on translation, independent of translation, or both. In this study, we have begun to elucidate this mechanism. We demonstrate using hepatocytes from rats fed either a Se-supplemented or Se-deficient diet for 9 to 13 weeks that Se deprivation results in an ∼50-fold reduction in Se-GPx1 activity and an ∼20-fold reduction in Se-GPx1 mRNA abundance. Reverse transcription-PCR analyses of nuclear and cytoplasmic fractions revealed that Se deprivation has no effect on the levels of either nuclear pre-mRNA or nuclear mRNA but reduces the level of cytoplasmic mRNA. The regulation of Se-GPx1 gene expression by Se was recapitulated in transient transfections of NIH 3T3 cells, and experiments were extended to examine the consequences of converting the Sec codon (TGA) to either a termination codon (TAA) or a cysteine codon (TGC). Regardless of the type of codon, an alteration in the Se concentration was of no consequence to the ratio of nuclear Se-GPx1 mRNA to nuclear Se-GPx1 pre-mRNA. The ratio of cytoplasmic Se-GPx1 mRNA to nuclear Se-GPx1 mRNA from the wild-type (TGA-containing) allele was reduced twofold when cells were deprived of Se for 48 h after transfection, which has been shown to be the extent of the reduction for the endogenous Se-GPx1 mRNA of cultured cells incubated as long as 20 days in Se-deficient medium. In contrast to the TGA allele, Se had no effect on expression of either the TAA allele or the TGC allele. Under Se-deficient conditions, the TAA and TGC alleles generated, respectively, 1.7-fold-less and 3-fold-more cytoplasmic Se-GPx1 mRNA relative to the amount of nuclear Se-GPx1 mRNA than the TGA allele. These results indicate that (i

  7. Antioxidant effect of Ebselen (PZ 51): peroxidase mimetic activity on phospholipid and cholesterol hydroperoxides vs free radical scavenger activity.

    PubMed

    Maiorino, M; Roveri, A; Ursini, F

    1992-06-01

    The selenocompound Ebselen (PZ 51) is a potent inhibitor of lipid peroxidation. This antioxidant effect has been previously attributed both to a peroxidase mimetic activity and to a free radical scavenging capability. In the present paper the latter is ruled out by competition kinetic analysis based on the inhibition of carotenoid bleaching by hydroperoxyl radicals. Furthermore, evidence is reported indicating that Ebselen exhibits a peroxidase activity extended to cholesterol and cholesterol ester hydroperoxides, besides phospholipid hydroperoxides. According to this, we propose that the unique mechanism of the antioxidant capacity of Ebselen is the reduction of lipid hydroperoxides present in liposomes or lipoproteins, eventually leading to the prevention of hydroperoxide-dependent peroxidation. PMID:1586168

  8. A comparison of erythrocyte glutathione S-transferase activity from human foetuses and adults.

    PubMed Central

    Strange, R C; Johnston, J D; Coghill, D R; Hume, R

    1980-01-01

    Glutathione S-transferase activity was measured in partially purified haemolysates of erythrocytes from human foetuses and adults. Enzyme activity was present in erythrocytes obtained between 12 and 40 weeks of gestation. The catalytic properties of the enzyme from foetal cells were similar to those of the enzyme from adult erythrocytes, indicating that probably only one form of the erythrocytes enzyme exists throughout foetal and adult life. PMID:7396875

  9. Nitration transforms a sensitive peroxiredoxin 2 into a more active and robust peroxidase.

    PubMed

    Randall, Lía M; Manta, Bruno; Hugo, Martín; Gil, Magdalena; Batthyàny, Carlos; Trujillo, Madia; Poole, Leslie B; Denicola, Ana

    2014-05-30

    Peroxiredoxins (Prx) are efficient thiol-dependent peroxidases and key players in the mechanism of H2O2-induced redox signaling. Any structural change that could affect their redox state, oligomeric structure, and/or interaction with other proteins could have a significant impact on the cascade of signaling events. Several post-translational modifications have been reported to modulate Prx activity. One of these, overoxidation of the peroxidatic cysteine to the sulfinic derivative, inactivates the enzyme and has been proposed as a mechanism of H2O2 accumulation in redox signaling (the floodgate hypothesis). Nitration of Prx has been reported in vitro as well as in vivo; in particular, nitrated Prx2 was identified in brains of Alzheimer disease patients. In this work we characterize Prx2 tyrosine nitration, a post-translational modification on a noncatalytic residue that increases its peroxidase activity and its resistance to overoxidation. Mass spectrometry analysis revealed that treatment of disulfide-oxidized Prx2 with excess peroxynitrite renders mainly mononitrated and dinitrated species. Tyrosine 193 of the YF motif at the C terminus, associated with the susceptibility toward overoxidation of eukaryotic Prx, was identified as nitrated and is most likely responsible for the protection of the peroxidatic cysteine against oxidative inactivation. Kinetic analyses suggest that tyrosine nitration facilitates the intermolecular disulfide formation, transforming a sensitive Prx into a robust one. Thus, tyrosine nitration appears as another mechanism to modulate these enzymes in the complex network of redox signaling.

  10. Peroxidase-like activity of apoferritin paired gold clusters for glucose detection.

    PubMed

    Jiang, Xin; Sun, Cuiji; Guo, Yi; Nie, Guangjun; Xu, Li

    2015-02-15

    The discovery and application of noble metal nanoclusters have received considerable attention. In this paper, we reported that apoferritin paired gold clusters (Au-Ft) could efficiently catalyze oxidation of 3.3',5.5'-tetramethylbenzidine (TMB) by H2O2 to produce a blue color reaction. Compared with natural enzyme, Au-Ft exhibited higher activity near acidic pH and could be used over a wide range of temperatures. Apoferritin nanocage enhanced the reaction activity of substrate TMB by H2O2. The reaction catalyzed by Au-Ft was found to follow a typical Michaelis-Menten kinetics. The kinetic parameters exhibited a lower K(m) value (0.097 mM) and a higher K(cat) value (5.8 × 10(4) s(-1)) for TMB than that of horse radish peroxidase (HRP). Base on these findings, Au-Ft, acting as a peroxidase mimetic, performed enzymatic spectrophotometric analysis of glucose. This system exhibited acceptable reproducibility and high selectivity in biosening, suggesting that it could have promising applications in the future. PMID:25218100

  11. Nitration Transforms a Sensitive Peroxiredoxin 2 into a More Active and Robust Peroxidase*

    PubMed Central

    Randall, Lía M.; Manta, Bruno; Hugo, Martín; Gil, Magdalena; Batthyàny, Carlos; Trujillo, Madia; Poole, Leslie B.; Denicola, Ana

    2014-01-01

    Peroxiredoxins (Prx) are efficient thiol-dependent peroxidases and key players in the mechanism of H2O2-induced redox signaling. Any structural change that could affect their redox state, oligomeric structure, and/or interaction with other proteins could have a significant impact on the cascade of signaling events. Several post-translational modifications have been reported to modulate Prx activity. One of these, overoxidation of the peroxidatic cysteine to the sulfinic derivative, inactivates the enzyme and has been proposed as a mechanism of H2O2 accumulation in redox signaling (the floodgate hypothesis). Nitration of Prx has been reported in vitro as well as in vivo; in particular, nitrated Prx2 was identified in brains of Alzheimer disease patients. In this work we characterize Prx2 tyrosine nitration, a post-translational modification on a noncatalytic residue that increases its peroxidase activity and its resistance to overoxidation. Mass spectrometry analysis revealed that treatment of disulfide-oxidized Prx2 with excess peroxynitrite renders mainly mononitrated and dinitrated species. Tyrosine 193 of the YF motif at the C terminus, associated with the susceptibility toward overoxidation of eukaryotic Prx, was identified as nitrated and is most likely responsible for the protection of the peroxidatic cysteine against oxidative inactivation. Kinetic analyses suggest that tyrosine nitration facilitates the intermolecular disulfide formation, transforming a sensitive Prx into a robust one. Thus, tyrosine nitration appears as another mechanism to modulate these enzymes in the complex network of redox signaling. PMID:24719319

  12. Fluorometric microplate assay to measure glutathione S-transferase activity in insects and mites using monochlorobimane.

    PubMed

    Nauen, Ralf; Stumpf, Natascha

    2002-04-15

    Elevated levels of glutathione S-transferases (GSTs) play a major role as a mechanism of resistance to insecticides and acaricides in resistant pest insects and mites, respectively. Such compounds are either detoxicated directly via phase I metabolism or detoxicated by phase II metabolism of metabolites as formed by microsomal monooxygenases. Here we used monochlorobimane (MCB) as an artificial substrate and glutathione to determine total GST activity in equivalents of single pest insects and spider mites in a sensitive 96-well plate-based assay system by measuring the enzymatic conversion of MCB to its fluorescent bimane-glutathione adduct. The differentiation by their GST activity between several strains of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), with different degrees of resistance to numerous acaricides was more sensitive with MCB compared to the commonly used substrate 1-chloro-2,4-dinitrobenzene (CDNB). Compared to an acaricide-susceptible reference strain, one field population of T. urticae showed a more than 10-fold higher GST activity measured with MCB, in contrast to a less than 2-fold higher activity when CDNB was used. Furthermore, we showed that GST activity can be sensitively assessed with MCB in homogenates of pest insects such as Heliothis virescens, Spodoptera frugiperda (Lepidoptera: Noctuidae), Plutella xylostella (Lepidoptera: Yponomeutidae), and Myzus persicae (Hemiptera: Aphididae). PMID:11950219

  13. Comparison of the peroxidase-like activity of unmodified, amino-modified, and citrate-capped gold nanoparticles.

    PubMed

    Wang, Sheng; Chen, Wei; Liu, Ai-Lin; Hong, Lei; Deng, Hao-Hua; Lin, Xin-Hua

    2012-04-10

    The origin of the peroxidase-like activity of gold nanoparticles and the impact of surface modification are studied. Furthermore, some influencing factors, such as fabrication process, redox property of the modifier, and charge property of the substrate, are investigated. Compared to amino-modified or citrate-capped gold nanoparticles, unmodified gold nanoparticles show significantly higher catalytic activity toward peroxidase substrates, that is, the superficial gold atoms are a contributing factor to the observed peroxidase-like activity. The different catalytic activities of amino-modified and citrate-capped gold nanoparticles toward 3,3',5,5'-tetramethylbenzidine (TMB) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) show that the charge characteristics of the nanoparticles and the substrate also play an important role in the catalytic reactions. PMID:22383315

  14. Staining electrophoretic gels for laccase and peroxidase activity using 1,8-diaminonaphthalene.

    PubMed

    Hoopes, J T; Dean, J F

    2001-06-01

    A new chromogenic substrate for laccases and peroxidases, 1,8-diaminonapthalene, was used to detect phenoloxidase activity in gels after SDS-PAGE. This substrate has several advantages over other widely used phenoloxidase stains in that it is inexpensive, and the oxidized product has both high molar absorptivity and very low solubility. Furthermore, neither the substrate nor the product is known to have toxicity problems of the type associated with many other phenoloxidase stains. The sensitivity of detection using 1,8-diaminonapthalene was comparable to that obtained using the most sensitive stains commonly used for phenoloxidases, e.g., 3,3-diaminobenzidine, and was close to that attainable for protein detection using silver staining. Zymograms developed with 1,8-diaminonapthalene can be used with video densitometry to monitor the specific enzymatic activity of phenoloxidases during enzyme purification. PMID:11373084

  15. [Effect of lectins from Azospirillum brasilense to peroxidase and oxalate oxidase activity regulation in wheat roots].

    PubMed

    Alen'kina, S A; Nikitina, V E

    2010-01-01

    Lectins were extracted from the surface of nitrogen-fixing soil bacteria Azospirillum brasilense Sp7 and from its mutant A. brasilense Sp7.2.3 defective in lectin activity. The ability oflectins to stimulate the rapid formation of hydrogen peroxide related to increase of oxalate oxidase and peroxidase activity in the roots of wheat seedlings has been demonstrated. The most rapid induced pathway of hydrogen peroxide formation in the roots of wheat seedlings was the oxalic acid oxidation by oxalate oxidase which is the effect oflectin in under 10 min in a concentration of 10 microg/ml. The obtained results show that lectins from Azospirillum are capable of inducing the adaptation processes in the roots of wheat seedlings.

  16. Liv.52 attenuate copper induced toxicity by inhibiting glutathione depletion and increased antioxidant enzyme activity in HepG2 cells.

    PubMed

    Vidyashankar, Satyakumar; Patki, Pralhad Sadashiv

    2010-07-01

    Altered copper metabolism plays a pivotal role in the onset of several hepatic disorders and glutathione (GSH) plays an important role in its homeostasis. Hepatic diseases are often implicated with decreased content of intracellular GSH. GSH depleted cells are prone to increased oxidative damage eventually leading to its death. Liv.52 is used to treat hepatic ailments since long time. Hence, in the present study the potential cytoprotective effect of Liv.52 against toxicity induced by copper (Cu2+) was evaluated in HepG2 cells. Cu2+ at 750 microM induced cytotoxicity to HepG2 cells as determined by MTT assay. The toxicity was brought about by increased lipid peroxidation, DNA fragmentation and decreased GSH content. But, upon treatment with Liv.52 cell death induced by Cu2+ was significantly abrogated by inhibition of lipid peroxidation by 58% and DNA fragmentation by 37%. Liv.52 increased the GSH content by 74%. Activities of the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase were increased by 46%, 22% and 81% respectively in Liv.52 treated cells. Thus, it is apparent from these results that Liv.52 abrogates Cu2+ induced cytotoxicity in HepG2 cells by inhibiting lipid peroxidation and increased GSH content and antioxidant enzyme activity.

  17. Glutathione transferase activity and expression patterns during grain filling in flag leaves of wheat genotypes differing in drought tolerance: Response to water deficit.

    PubMed

    Gallé, Agnes; Csiszár, Jolán; Secenji, Maria; Guóth, Adrienn; Cseuz, László; Tari, Irma; Györgyey, János; Erdei, László

    2009-11-15

    Total glutathione S-transferase (GST, EC 2.5.1.18) and glutathione peroxidase (GPOX) activity were measured spectrophotometrically in Triticum aestivum cv. MV Emese and cv. Plainsman (drought tolerant) and cv. GK Elet and Cappelle Desprez (drought-sensitive) flag leaves under control and drought stress conditions during the grain-filling period, in order to reveal possible roles of different GST classes in the senescence of flag leaves. Six wheat GSTs, members of 3 GST classes, were selected and their regulation by drought and senescence was investigated. High GPOX activity (EC 1.11.1.9) was observed in well-watered controls of the drought-tolerant Plainsman cultivar. At the same time, TaGSTU1B and TaGSTF6 sequences, investigated by real-time PCR, showed high-expression levels that increased with time, indicating that the gene products of these genes may play important roles in monocarpic senescence of wheat. Expression of these genes was also induced by drought stress in all of the four investigated cultivars, but extremely high transcript amounts were detected in cv. Plainsman. Our data indicate genotypic variations of wheat GSTs. Expression levels and early induction of two senescence-associated GSTs under drought during grain filling in flag leaves correlated with high yield stability.

  18. A sensitive fluorescent assay for thiamine based on metal-organic frameworks with intrinsic peroxidase-like activity.

    PubMed

    Tan, Hongliang; Li, Qian; Zhou, Zhengchen; Ma, Chanjiao; Song, Yonghai; Xu, Fugang; Wang, Li

    2015-01-26

    Metal-organic frameworks (MOFs) with tunable structures and properties have recently been emerged as very interesting functional materials. However, the catalytic properties of MOFs as enzymatic mimics remain to be further investigated. In this work, we for the first time demonstrated the peroxidase-like activity of copper-based MOFs (HKUST-1) by employing thiamine (TH) as a peroxidase substrate. In the presence of H2O2, HKUST-1 can catalyze efficiently the conversion of non-fluorescent TH to strong fluorescent thiochrome. The catalytic activity of HKUST-1 is highly dependent on the temperature, pH and H2O2 concentrations. As a peroxidase mimic, HKUST-1 not only has the features of low cost, high stability and easy preparation, but also follows Michaelis-Menten behaviors and shows stronger affinity to TH than horseradish peroxidase (HRP). Based on the peroxidase-like activity of HKUST-1, a simple and sensitive fluorescent method for TH detection has been developed. As low as 1 μM TH can be detected with a linear range from 4 to 700 μM. The detection limit for TH is about 50 fold lower than that of HRP-based fluorescent assay. The proposed method was successfully applied to detect TH in tablets and urine samples and showed a satisfactory result. We believed that the present work could improve the understanding of catalytic behaviors of MOFs as enzymatic mimics and find out a wider application in bioanalysis.

  19. Ferromagnetic nanoparticles with peroxidase-like activity enhance the cleavage of biological macromolecules for biofilm elimination

    NASA Astrophysics Data System (ADS)

    GaoCurrent Address: University Of Pennsylvania, School Of Dental Medicine, Philadelphia, Pa 19104, Usa. E.-Mail: Gaoliz@Dental. Upenn. Edu, Lizeng; Giglio, Krista M.; Nelson, Jacquelyn L.; Sondermann, Holger; Travis, Alexander J.

    2014-02-01

    Hydrogen peroxide (H2O2) is a ``green chemical'' that has various cleaning and disinfectant uses, including as an anti-bacterial agent for hygienic and medical treatments. However, its efficacy is limited against biofilm-producing bacteria, because of poor penetration into the protective, organic matrix. Here we show new applications for ferromagnetic nanoparticles (Fe3O4, MNPs) with peroxidase-like activity in potentiating the efficacy of H2O2 in biofilm degradation and prevention. Our data show that MNPs enhanced oxidative cleavage of biofilm components (model nucleic acids, proteins, and oligosaccharides) in the presence of H2O2. When challenged with live, biofilm-producing bacteria, the MNP-H2O2 system efficiently broke down the existing biofilm and prevented new biofilms from forming, killing both planktonic bacteria and those within the biofilm. By enhancing oxidative cleavage of various substrates, the MNP-H2O2 system provides a novel strategy for biofilm elimination, and other applications utilizing oxidative breakdown.Hydrogen peroxide (H2O2) is a ``green chemical'' that has various cleaning and disinfectant uses, including as an anti-bacterial agent for hygienic and medical treatments. However, its efficacy is limited against biofilm-producing bacteria, because of poor penetration into the protective, organic matrix. Here we show new applications for ferromagnetic nanoparticles (Fe3O4, MNPs) with peroxidase-like activity in potentiating the efficacy of H2O2 in biofilm degradation and prevention. Our data show that MNPs enhanced oxidative cleavage of biofilm components (model nucleic acids, proteins, and oligosaccharides) in the presence of H2O2. When challenged with live, biofilm-producing bacteria, the MNP-H2O2 system efficiently broke down the existing biofilm and prevented new biofilms from forming, killing both planktonic bacteria and those within the biofilm. By enhancing oxidative cleavage of various substrates, the MNP-H2O2 system provides a novel

  20. The Biochemical Adaptations of Spotted Wing Drosophila (Diptera: Drosophilidae) to Fresh Fruits Reduced Fructose Concentrations and Glutathione-S Transferase Activities.

    PubMed

    Nguyen, Phuong; Kim, A-Young; Jung, Jin Kyo; Donahue, Kelly M; Jung, Chuleui; Choi, Man-Yeon; Koh, Young Ho

    2016-04-01

    Spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive and economically damaging pest in Europe and North America. The females have a serrated ovipositor that enables them to infest almost all ripening small fruits. To understand the physiological and metabolic basis of spotted wing drosophila food preferences for healthy ripening fruits, we investigated the biological and biochemical characteristics of spotted wing drosophila and compared them with those of Drosophila melanogaster Meigen. We found that the susceptibility to oxidative stressors was significantly increased in spotted wing drosophila compared with those of D. melanogaster. In addition, we found that spotted wing drosophila had significantly reduced glutathione-S transferase (GST) activity and gene numbers. Furthermore, fructose concentrations found in spotted wing drosophila were significantly lower than those of D. melanogaster. Our data strongly suggest that the altered food preferences of spotted wing drosophila may stem from evolutionary adaptations to fresh foods accompanied by alterations in carbohydrate metabolism and GST activities.

  1. The Biochemical Adaptations of Spotted Wing Drosophila (Diptera: Drosophilidae) to Fresh Fruits Reduced Fructose Concentrations and Glutathione-S Transferase Activities.

    PubMed

    Nguyen, Phuong; Kim, A-Young; Jung, Jin Kyo; Donahue, Kelly M; Jung, Chuleui; Choi, Man-Yeon; Koh, Young Ho

    2016-04-01

    Spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive and economically damaging pest in Europe and North America. The females have a serrated ovipositor that enables them to infest almost all ripening small fruits. To understand the physiological and metabolic basis of spotted wing drosophila food preferences for healthy ripening fruits, we investigated the biological and biochemical characteristics of spotted wing drosophila and compared them with those of Drosophila melanogaster Meigen. We found that the susceptibility to oxidative stressors was significantly increased in spotted wing drosophila compared with those of D. melanogaster. In addition, we found that spotted wing drosophila had significantly reduced glutathione-S transferase (GST) activity and gene numbers. Furthermore, fructose concentrations found in spotted wing drosophila were significantly lower than those of D. melanogaster. Our data strongly suggest that the altered food preferences of spotted wing drosophila may stem from evolutionary adaptations to fresh foods accompanied by alterations in carbohydrate metabolism and GST activities. PMID:26921228

  2. Comparison of structure and activities of peroxidases from Coprinus cinereus, Coprinus macrorhizus and Arthromyces ramosus.

    PubMed

    Kjalke, M; Andersen, M B; Schneider, P; Christensen, B; Schülein, M; Welinder, K G

    1992-04-17

    Initial structural and kinetic data suggested that peroxidases from Coprinus cinereus, Coprinus macrorhizus and Arthromyces ramosus were similar. Therefore they were characterized more fully. The three peroxidases were purified to RZ 2.5 and showed immunochemical identity as well as an identical M(r) of 38,000, pI about 3.5 and similar amino acid compositions. The N-termini were blocked for amino acid sequencing. The peroxidases had similar retention volumes by anion-exchange and gel-filtration chromatography. All peroxidases showed multiple peaks by Concanavalin A-Sepharose chromatography. The Concanavalin A-Sepharose profiles were different and depended furthermore on a fermentation batch. Tryptic peptide maps were very similar except for one peptide. This peptide contained an N-linked glycan composed of varying ratios of glucosamine and mannose for the three peroxidases. Rate constants and their pH dependence were the same for the three peroxidases using guaiacol or iodide as reducing substrates. We conclude that peroxidases from Coprinus cinereus, Coprinus macrorhizus and Arthromyces ramosus are most likely identical in their amino acid sequences, but deviate in glycosylation which, apparently, has no influence on the reaction rates of the enzyme. We suggest, that the Coprinus fungi express one peroxidase only in contrast to the lignin-degrading white-rot Basidiomycetes, which produce multiple peroxidase isozymes.

  3. Peroxidase Activity and Involvement in the Oxidative Stress Response of Roseobacter denitrificans Truncated Hemoglobin

    PubMed Central

    Wang, Yaya; Barbeau, Xavier; Bilimoria, Astha; Lagüe, Patrick; Couture, Manon; Tang, Joseph Kuo-Hsiang

    2015-01-01

    Roseobacter denitrificans is a member of the widespread marine Roseobacter genus. We report the first characterization of a truncated hemoglobin from R. denitrificans (Rd. trHb) that was purified in the heme-bound form from heterologous expression of the protein in Escherichia coli. Rd. trHb exhibits predominantly alpha-helical secondary structure and absorbs light at 412, 538 and 572 nm. The phylogenetic classification suggests that Rd. trHb falls into group II trHbs, whereas sequence alignments indicate that it shares certain important heme pocket residues with group I trHbs in addition to those of group II trHbs. The resonance Raman spectra indicate that the isolated Rd. trHb contains a ferric heme that is mostly 6-coordinate low-spin and that the heme of the ferrous form displays a mixture of 5- and 6-coordinate states. Two Fe-His stretching modes were detected, notably one at 248 cm-1, which has been reported in peroxidases and some flavohemoglobins that contain an Fe-His-Asp (or Glu) catalytic triad, but was never reported before in a trHb. We show that Rd. trHb exhibits a significant peroxidase activity with a (kcat/Km) value three orders of magnitude higher than that of bovine Hb and only one order lower than that of horseradish peroxidase. This enzymatic activity is pH-dependent with a pKa value ~6.8. Homology modeling suggests that residues known to be important for interactions with heme-bound ligands in group II trHbs from Mycobacterium tuberculosis and Bacillus subtilis are pointing toward to heme in Rd. trHb. Genomic organization and gene expression profiles imply possible functions for detoxification of reactive oxygen and nitrogen species in vivo. Altogether, Rd. trHb exhibits some distinctive features and appears equipped to help the bacterium to cope with reactive oxygen/nitrogen species and/or to operate redox biochemistry. PMID:25658318

  4. Different peroxidase activities and expression of abiotic stress-related peroxidases in apical root segments of wheat genotypes with different drought stress tolerance under osmotic stress.

    PubMed

    Csiszár, Jolán; Gallé, Agnes; Horváth, Edit; Dancsó, Piroska; Gombos, Magdolna; Váry, Zsolt; Erdei, László; Györgyey, János; Tari, Irma

    2012-03-01

    One-week-old seedlings of Triticum aestivum L. cv. Plainsman V, a drought tolerant; and Cappelle Desprez, a drought sensitive wheat cultivar were subjected gradually to osmotic stress using polyethylene glycol (PEG 6000) reaching 400 mOsm on the 11th day. Compared to controls cv. Plainsman V maintained the root growth and relative water content of root tissues, while these parameters were decreased in the drought sensitive cv. Cappelle Desprez under PEG-mediated osmotic stress. Simultaneously, H(2)O(2) content in 1-cm-long apical segment of roots comprising the proliferation and elongation zone, showed a transient increase in cv. Plainsman V and a permanent raise in cv. Cappelle Desprez. Measurements of the transcript levels of selected class III peroxidase (TaPrx) coding sequences revealed significant differences between the two cultivars on the 9th day, two days after applying 100 mOsm PEG. The abundance of TaPrx04 transcript was enhanced transitionally in the root apex of cv. Plainsman V but decreased in cv. Cappelle Desprez under osmotic stress while the expression of TaPrx01, TaPrx03, TaPrx19, TaPrx68, TaPrx107 and TaPrx109-C decreased to different extents in both cultivars. After a transient decrease, activities of soluble peroxidase fractions of crude protein extracts rose in both cultivars on day 11, but the activities of cell wall-bound fractions increased only in cv. Cappelle Desprez under osmotic stress. Parallel with high H(2)O(2) content of the tissues, certain isoenzymes of covalently bound fraction in cv. Cappelle Desprez showed increased activity suggesting that they may limit the extension of root cell walls in this cultivar.

  5. A mitochondria-targeted antioxidant can inhibit peroxidase activity of cytochrome c by detachment of the protein from liposomes.

    PubMed

    Firsov, Alexander M; Kotova, Elena A; Orlov, Viktor N; Antonenko, Yuri N; Skulachev, Vladimir P

    2016-09-01

    Interaction of cytochrome c with cardiolipin converts this respiratory chain electron-transfer protein into a peroxidase, supposedly involved in mitochondria-mediated apoptosis initiation. Liposome membrane permeabilization provoked by peroxidase activity of the cytochrome c/cardiolipin complex has been previously shown to be suppressed by conventional antioxidants. Here, the mitochondria-targeted antioxidant SkQ1 (plastoquinonyl-decyl-triphenylphosphonium) was found to strongly inhibit both cytochrome c/cardiolipin peroxidase activity and the permeabilization of liposomes composed of phosphatidylcholine and cardiolipin. A number of binding assays revealed a significant inhibiting effect of SkQ1 on cytochrome c binding to liposomes, thus suggesting that SkQ1-mediated protection of liposomes from the cytochrome c/H2 O2 -induced permeabilization involved distortion of the cytochrome c-membrane binding. It is suggested that antioxidant and antiapoptotic effects of alkyltriphenylphosphonium cations can be related to the prevention of cytochrome c/cardiolipin interaction.

  6. Platelet-activating factor induces eosinophil peroxidase release from purified human eosinophils.

    PubMed Central

    Kroegel, C; Yukawa, T; Dent, G; Chanez, P; Chung, K F; Barnes, P J

    1988-01-01

    The degranulation response of purified human eosinophils to platelet-activating factor (PAF) has been studied. PAF induced release of eosinophil peroxidase (EPO) and beta-glucuronidase from highly purified human eosinophils with an EC50 of 0.9 nM. The order of release was comparable with that induced by phorbol myristate acetate (PMA). The new specific PAF antagonist 3-[4-(2-chlorophenyl)-9-methyl-H-thieno[3,2-f] [1,2,4]triazolo-[4,3a][1,4]-diazepin-2-yl](4-morpholinyl)- 1-propane-one (WEB 2086) inhibited the PAF-induced enzyme release by human eosinophils in a dose-dependent manner. The viability of eosinophils were unaffected both by PAF and WEB 2086. The results suggest that PAF may amplify allergic and inflammatory reactions by release of preformed proteins from eosinophil granules. PMID:3410498

  7. Glutathione concentration and gamma-glutamyltransferase activity in water buffalo colostrum.

    PubMed

    Pero, M E; Pelagalli, A; Lombardi, P; Avallone, L

    2010-10-01

    Evidence is presented that the buffalo mammary gland contains enzymes that catalyse the synthesis and utilization of glutathione. A significant, inverse correlation (r = 0.79) was detected between colostrum gamma-glutamyltransferase (GGT) and glutathione (GSH), suggesting that the enzyme uses GSH as a substrate for its activity. A similar trend was shown in mammary gland homogenates (r = 0.75). Our results show that GSH is secreted into buffalo colostrum and suggest that the enzyme GGT degrades it. To the authors' knowledge, this is the first demonstration of the involvement of GGT-mediated GSH metabolism in the synthesis of colostrums, which elucidates the role of the enzyme that has always been reported very high in colostrum.

  8. Analysis of the Peroxidase Activity of Rice (Oryza Sativa) Recombinant Hemoglobin 1: Implications for the In Vivo Function of Hexacoordinate Non-Symbiotic Hemoglobins in Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In plants, it has been proposed that hexacoordinate (class 1) non-symbiotic Hbs (nsHb-1) function in vivo as peroxidases. However, little is known about the peroxidase activity of nsHb-1. We evaluated the peroxidase activity of rice recombinant Hb1 (a nsHb-1) by using the guaiacol/H2O2 system at pH ...

  9. pH-induced quaternary assembly of Vitreoscilla hemoglobin: the monomer exhibits better peroxidase activity.

    PubMed

    Li, Wei; Zhang, Yubin; Xu, Haoran; Wu, Lei; Cao, Yufeng; Zhao, Haifeng; Li, Zhengqiang

    2013-10-01

    pH-dependent (pH6.0-8.0) quaternary structural changes of ferric Vitreoscilla hemoglobin (VHb) have been investigated using dynamic light scattering. The VHb exhibits a monomeric state under neutral conditions at pH7.0, while the protein forms distinct homodimeric species at pH6.0 and 8.0, respectively. The dissociation constant obtained using the Bio-Layer Interferometry technology indicates that, at pH7.0, the monomer-monomer dissociation of VHb is about 6-fold or 5-fold higher (KD=6.34μM) compared with that at slightly acidic pH (KD=1.05μM) or slightly alkaline pH (KD=1.22μM). The pH-dependent absorption spectra demonstrate that the heme microenvironment of VHb is sensitive to the changes of pH value. The maximum absorption band of heme group of VHb shifts from 402nm to 407nm when pH changes from 6.0 to 8.0. In addition, the fluorescence emission spectra of VHb, taken at excitation wavelength of 295nm, suggest that the single Trp122 fluorescence quantum yields in VHb are decreased due to the formation of the homodimeric species. However, the circular dichroism spectra data display that the secondary structures of VHb are little affected by pH transitions. The pH-dependent peroxidase activity of VHb was also investigated in this study. The optimum pH for VHb using 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) as substrate is 7.0, which implies that the monomer state of VHb would exhibit better peroxidase activity than the homodimeric species of VHb at pH6.0 and 8.0. PMID:23886679

  10. Glutathion S-transferase activity and DDT-susceptibility of Malaysian mosquitos.

    PubMed

    Lee, H L; Chong, W L

    1995-03-01

    Comparative DDT-susceptibility status and glutathion s-transferase (GST) activity of Malaysian Anopheles maculatus, Culex quinquefasciatus and Aedes aegypti was investigated to ascertain the role of this enzyme in DDT resistance. The standardised WHO dose-mortality bioassay tests were used to determine DDT susceptibility in these mosquitos, whilst GST microassay (Brogdon and Barber, 1990) was conducted to measure the activity of this enzyme in mosquito homogenate. It appeared that DDT susceptibility status of Malaysian mosquitos was not correlated with GST activity.

  11. Transcriptional activation of glutathione pathways and role of glucose homeostasis during copper imbalance.

    PubMed

    Quiroz, Natalia; Rivas, Nicole; del Pozo, Talía; Burkhead, Jason; Suazo, Miriam; González, Mauricio; Latorre, Mauricio

    2015-04-01

    Copper is an essential micronutrient for organism health. Dietary changes or pathologies linked to this metal induce changes in intracellular glutathione concentrations. Here, we studied the transcriptional activation of glutathione pathways in Jurkat cell lines, analyzing the effect of change in glucose homeostasis during a physiological and supra-physiological copper exposure. An immortalized line of human T lymphocyte cell line (Jurkat) was exposed to different copper and glucose conditions to mimic concentrations present in human blood. We applied treatments for 6 (acute) and 24 h (sustained) to 2 µM (physiological) or 20 µM (supra-physiological, Wilson disease scenario) of CuSO4 in combination with 25 mg/dL (hypoglycemia), 100 mg/dL (normal) and 200 mg/dL (hyperglycemia, diabetes scenario) of glucose. The results indicate that a physiological concentration of copper exposure does not induce transcriptional changes in the glutathione synthesis pathway after 6 or 24 h. The G6PDH gene (regeneration pathway), however, is induced during a supra-physiological copper condition. This data was correlated with the viability assays, where fluctuation in both glucose conditions (hypo and hyperglycemia scenario) affected Jurkat proliferation when 20 µM of CuSO4 was added to the culture media. Under a copper overload condition, the transcription of a component of glutathione regeneration pathway (G6PDH gene) is activated in cells chronically exposed to a hyperglycemia scenario, indicating that fluctuations in glucose concentration impact the resistance against the metal. Our findings illustrate the importance of glucose homeostasis during copper excess.

  12. Caribbean yellow band disease compromises the activity of catalase and glutathione S-transferase in the reef-building coral Orbicella faveolata exposed to anthracene.

    PubMed

    Montilla, Luis Miguel; Ramos, Ruth; García, Elia; Cróquer, Aldo

    2016-05-01

    Healthy and diseased corals are threatened by different anthropogenic sources, such as pollution, a problem expected to become more severe in the near future. Despite the fact that coastal pollution and coral diseases might represent a serious threat to coral reef health, there is a paucity of controlled experiments showing whether the response of diseased and healthy corals to xenobiotics differs. In this study, we exposed healthy and Caribbean yellow band disease (CYBD)-affected Orbicella faveolata colonies to 3 sublethal concentrations of anthracene to test if enzymatic responses to this hydrocarbon were compromised in CYBD-affected tissues. For this, a 2-factorial fully orthogonal design was used in a controlled laboratory bioassay, using tissue condition (2 levels: apparently healthy and diseased) and pollutant concentration (4 levels: experimental control, 10, 30 and 100 ppb concentration) as fixed factors. A permutation-based ANOVA (PERMANOVA) was used to test the effects of condition and concentration on the specific activity of 3 enzymatic biomarkers: catalase, glutathione S-transferase, and glutathione peroxidase. We found a significant interaction between the concentration of anthracene and the colony condition for catalase (Pseudo-F = 3.84, df = 3, p < 0.05) and glutathione S-transferase (Pseudo-F = 3.29, df = 3, p < 0.05). Moreover, our results indicated that the enzymatic response to anthracene in CYBD-affected tissues was compromised, as the activity of these enzymes decreased 3- to 4-fold compared to healthy tissues. These results suggest that under a potential scenario of increasing hydrocarbon coastal pollution, colonies of O. faveolata affected with CYBD might become more vulnerable to the deleterious effects of chemical pollution.

  13. Caribbean yellow band disease compromises the activity of catalase and glutathione S-transferase in the reef-building coral Orbicella faveolata exposed to anthracene.

    PubMed

    Montilla, Luis Miguel; Ramos, Ruth; García, Elia; Cróquer, Aldo

    2016-05-01

    Healthy and diseased corals are threatened by different anthropogenic sources, such as pollution, a problem expected to become more severe in the near future. Despite the fact that coastal pollution and coral diseases might represent a serious threat to coral reef health, there is a paucity of controlled experiments showing whether the response of diseased and healthy corals to xenobiotics differs. In this study, we exposed healthy and Caribbean yellow band disease (CYBD)-affected Orbicella faveolata colonies to 3 sublethal concentrations of anthracene to test if enzymatic responses to this hydrocarbon were compromised in CYBD-affected tissues. For this, a 2-factorial fully orthogonal design was used in a controlled laboratory bioassay, using tissue condition (2 levels: apparently healthy and diseased) and pollutant concentration (4 levels: experimental control, 10, 30 and 100 ppb concentration) as fixed factors. A permutation-based ANOVA (PERMANOVA) was used to test the effects of condition and concentration on the specific activity of 3 enzymatic biomarkers: catalase, glutathione S-transferase, and glutathione peroxidase. We found a significant interaction between the concentration of anthracene and the colony condition for catalase (Pseudo-F = 3.84, df = 3, p < 0.05) and glutathione S-transferase (Pseudo-F = 3.29, df = 3, p < 0.05). Moreover, our results indicated that the enzymatic response to anthracene in CYBD-affected tissues was compromised, as the activity of these enzymes decreased 3- to 4-fold compared to healthy tissues. These results suggest that under a potential scenario of increasing hydrocarbon coastal pollution, colonies of O. faveolata affected with CYBD might become more vulnerable to the deleterious effects of chemical pollution. PMID:27137073

  14. Magnetic resonance spectral characterization of the heme active site of Coprinus cinereus peroxidase

    SciTech Connect

    Lukat, G.S.; Rodgers, K.R.; Jabro, M.N.; Goff, H.M. )

    1989-04-18

    Examination of the peroxidase isolated from the inkcap Basidiomycete Coprinus cinereus shows that the 42,000-dalton enzyme contains a protoheme IX prosthetic group. Reactivity assays and the electronic absorption spectra of native Coprinus peroxidase and several of its ligand complexes indicate that this enzyme has characteristics similar to those reported for horseradish peroxidase. In this paper, the authors characterize the H{sub 2}O{sub 2}-oxidized forms of Coprinus peroxidase compounds I, II, and III by electronic absorption and magnetic resonance spectroscopies. Electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) studies of this Coprinus peroxidase indicate the presence of high-spin Fe(III) in the native protein and a number of differences between the heme site of Coprinus peroxidase and horseradish peroxidase. Carbon-13 (of the ferrous CO adduct) and nitrogen-15 (of the cyanide complex) NMR studies together with proton NMR studies of the native and cyanide-complexed Caprinus peroxidase are consistent with coordination of a proximal histidine ligand. The EPR spectrum of the ferrous NO complex is also reported. Protein reconstitution with deuterated hemin has facilitated the assignment of the heme methyl resonances in the proton NMR spectrum.

  15. Magnetic resonance spectral characterization of the heme active site of Coprinus cinereus peroxidase.

    PubMed

    Lukat, G S; Rodgers, K R; Jabro, M N; Goff, H M

    1989-04-18

    Examination of the peroxidase isolated from the inkcap Basidiomycete Coprinus cinereus shows that the 42,000-dalton enzyme contains a protoheme IX prosthetic group. Reactivity assays and the electronic absorption spectra of native Coprinus peroxidase and several of its ligand complexes indicate that this enzyme has characteristics similar to those reported for horseradish peroxidase. In this paper, we characterize the H2O2-oxidized forms of Coprinus peroxidase compounds I, II, and III by electronic absorption and magnetic resonance spectroscopies. Electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) studies of this Coprinus peroxidase indicate the presence of high-spin Fe(III) in the native protein and a number of differences between the heme site of Coprinus peroxidase and horseradish peroxidase. Carbon-13 (of the ferrous CO adduct) and nitrogen-15 (of the cyanide complex) NMR studies together with proton NMR studies of the native and cyanide-complexed Coprinus peroxidase are consistent with coordination of a proximal histidine ligand. The EPR spectrum of the ferrous NO complex is also reported. Protein reconstitution with deuterated hemin has facilitated the assignment of the heme methyl resonances in the proton NMR spectrum.

  16. Loss of hepatic monooxygenase activities, glutathione, and 'green pigment' formation after the administration of vinyl-cyclooctane to mice.

    PubMed

    Gervasi, P G; Citti, L; Fassina, G; Testai, E; Turchi, G

    1983-05-01

    Vinylcyclooctane, when administered to mice at 500 mg/kg, produced reduction of microsomal cytochrome P-450, heme, aminopyrine-N-demethylase and ethoxycoumarin-O-deethylase activities with respect to control values; furthermore the hepatic reduced glutathione level was depleted suggesting that glutathione is involved in the vinylcyclooctane metabolism. The reduction of cytochrome P-450 and monooxygenase activities was accompanied by the formation of abnormal 'green pigments'.

  17. Detoxification and antioxidant effects of garlic and curcumin in Oreochromis niloticus injected with aflatoxin B₁ with reference to gene expression of glutathione peroxidase (GPx) by RT-PCR.

    PubMed

    El-Barbary, Manal I

    2016-04-01

    The present study aims to investigate the effects of both garlic and curcumin through evaluating their therapeutic properties as antioxidants on liver and kidney functions, hepatic antioxidants and GPx gene expression against aflatoxicosis of O. niloticus. In total, 180 of tilapia were divided into ten groups; T1 represented the negative control fed on a basal diet, and T2 was injected with a single intraperitoneal (i.p.) dose of AFB1 (6 mg/kg b.w.). Fish in T3-T6 were fed on a basal diet supplemented with both garlic (T3 and T4) and curcumin (T5 and T6) at the two concentrations of 10 and 20 g/kg diet, respectively. Fish in T7-T10 groups were injected with AFB1 and fed on the garlic (T7 and T8) and curcumin (T9 and T10) dietaries. The results showed that AFB1 has significant potency for increasing the activity of plasma AST, ALT, creatinine and uric acid values, and hepatic MDA as well as for reducing the concentrations of plasma TP, AL, GL and hepatic activity of TAC, while AFB1 led to up-regulated GPx gene expression when compared to the control (T1). These harmful effects of AFB1 were alleviated due to the garlic and curcumin dietaries in some studied parameters. Garlic reflected the highest induction of gene expression (T7); however, curcumin showed significant down-regulated (T9). These results concluded that the effects of garlic were better than curcumin at the two concentrations and the low concentration of them is more beneficial than the high concentration when it used against AFB1 in O. niloticus.

  18. Corneal aldehyde dehydrogenase and glutathione S-transferase activity after excimer laser keratectomy in guinea pigs

    PubMed Central

    Bilgihan, K.; Bilgihan, A.; Turkozkan, N.

    1998-01-01

    BACKGROUND—The free radical balance of the eye may be changed by excimer laser keratectomy. Previous studies have demonstrated that excimer laser keratectomy increases the corneal temperature, decreases the superoxide dismutase activity of the aqueous, and induces lipid peroxidation in the superficial corneal stroma. Aldehyde dehydrogenase (ALDH) and glutathione S-transferase (GST) are known to play an important role in corneal metabolism, particularly in detoxification of aldehydes, which are generated from free radical reactions.
METHODS—In three groups of guinea pigs mechanical corneal de-epithelialisation was performed in group I, superficial corneal photoablation in group II, and deep corneal photoablation in group III, and the corneal ALDH and GST activities measured after 48 hours.
RESULTS—The mean ALDH and GST activities of group I and II showed no differences compared with the controls (p>0.05). The corneal ALDH activities were found to be significantly decreased (p<0.05) and GST activities increased (p<0.05) in group III.
CONCLUSION—These results suggest that excimer laser treatment of high myopia may change the ALDH and GST activities, metabolism, and free radical balance of the cornea.

 Keywords: excimer laser keratectomy; aldehyde dehydrogenase; glutathione S-transferase PMID:9602629

  19. Possible peroxidase active site environment in amyloidogenic proteins: Native monomer or misfolded-oligomer; which one is susceptible to the enzymatic activity, with contribution of heme?

    PubMed

    Khodarahmi, Reza; Ashrafi-Kooshk, Mohammad Reza; Khodarahmi, Sina; Ghadami, Seyyed Abolghasem; Mostafaie, Ali

    2015-09-01

    Amyloid states of many proteins complex with heme and exhibit significant non-specific peroxidase activity, compared to free heme. Neurotransmitter deficiency, generation of neurotoxins, altered activity/metabolism of key enzymes and cellular DNA damage are possible evidences highlighting the importance of the uncontrollable peroxidase activity in Alzheimer's disease (AD)-involved brain cells. Despite extensive experimental work was carried out on this field, discrepancy on chronological precedence of amyloid aggregation and oxidative reactions as well as the mechanism involved in the peroxidase-induced oxidative stress is still not completely understood. In this study, we highlight further that heme cofactor readily complexes with structural intermediates of amyloid aggregates of ovalbumin, lactoglobulin and crystallin and report the ability of "heme-amyloid aggregate/oligomer") to produce peroxidase-like active site. Histidine side chains are also proposed as both distal and proximal residues required for proper function of these peroxidase systems. Taking uncontrollable peroxidase activity of "Aβ-heme" complex into account, it appears that this process, as a new opened dimension in AD pathologic research, provides structural/mechanistic basis for more efficient therapeutic strategies against neurodegenerative diseases. PMID:26123814

  20. Enhancing Mn(II)-Binding and Manganese Peroxidase Activity in a Designed Cytochrome c Peroxidase through Fine-Tuning Secondary-Sphere Interactions.

    PubMed

    Hosseinzadeh, Parisa; Mirts, Evan N; Pfister, Thomas D; Gao, Yi-Gui; Mayne, Christopher; Robinson, Howard; Tajkhorshid, Emad; Lu, Yi

    2016-03-15

    Noncovalent second-shell interactions are important in controlling metal-binding affinity and activity in metalloenzymes, but fine-tuning these interactions in designed metalloenzymes has not been fully explored. As a result, most designed metalloenzymes have low metal-binding affinity and activity. Here we identified three mutations in the second coordination shell of an engineered Mn(II)-binding site in cytochrome c peroxidase (called MnCcP.1, containing Glu45, Glu37, and Glu181 ligands) that mimics the native manganese peroxidase (MnP), and explored their effects on both Mn(II)-binding affinity and MnP activity. First, removing a hydrogen bond to Glu45 through Tyr36Phe mutation enhanced Mn(II)-binding affinity, as evidenced by a 2.8-fold decrease in the KM of Mn(II) oxidation. Second, introducing a salt bridge through Lys179Arg mutation improved Glu35 and Glu181 coordination to Mn(II), decreasing KM 2.6-fold. Third, eliminating a steric clash that prevented Glu37 from orienting toward Mn(II) resulted in an 8.6-fold increase in kcat/KM, arising primarily from a 3.6-fold decrease in KM, with a KM value comparable to that of the native enzyme (0.28 mM vs 0.19 mM for Pleurotus eryngii MnP PS3). We further demonstrated that while the effects of Tyr36Phe and Lys179Arg mutations are additive, because involved in secondary-shell interactions to different ligands, other combinations of mutations were antagonistic because they act on different aspects of the Mn(II) coordination at the same residues. Finally, we showed that these MnCcP variants are functional models of MnP that mimic its activity in both Mn(II) oxidation and degradation of a phenolic lignin model compound and kraft lignin. In addition to achieving KM in a designed protein that is similar to the that of native enzyme, our results offer molecular insight into the role of noncovalent interactions around metal-binding sites for improving metal binding and overall activity; such insight can be applied to

  1. Expression of a Catalytically Inactive Mutant Form of Glutathione Peroxidase 4 (Gpx4) Confers a Dominant-negative Effect in Male Fertility*

    PubMed Central

    Ingold, Irina; Aichler, Michaela; Yefremova, Elena; Roveri, Antonella; Buday, Katalin; Doll, Sebastian; Tasdemir, Adrianne; Hoffard, Nils; Wurst, Wolfgang; Walch, Axel; Ursini, Fulvio; Friedmann Angeli, José Pedro; Conrad, Marcus

    2015-01-01

    The selenoenzyme Gpx4 is essential for early embryogenesis and cell viability for its unique function to prevent phospholipid oxidation. Recently, the cytosolic form of Gpx4 was identified as an upstream regulator of a novel form of non-apoptotic cell death, called ferroptosis, whereas the mitochondrial isoform of Gpx4 was previously shown to be crucial for male fertility. Here, we generated and analyzed mice with a targeted mutation of the active site selenocysteine of Gpx4 (Gpx4_U46S). Mice homozygous for Gpx4_U46S died at the same embryonic stage (E7.5) as Gpx4−/− embryos as expected. Surprisingly, male mice heterozygous for Gpx4_U46S presented subfertility. Subfertility was manifested in a reduced number of litters from heterozygous breeding and an impairment of spermatozoa to fertilize oocytes in vitro. Morphologically, sperm isolated from heterozygous Gpx4_U46S mice revealed many structural abnormalities particularly in the spermatozoa midpiece due to improper oxidation and polymerization of sperm capsular proteins and malformation of the mitochondrial capsule surrounding and stabilizing sperm mitochondria. These findings are reminiscent of sperm isolated from selenium-deprived rodents or from mice specifically lacking mitochondrial Gpx4. Due to a strongly facilitated incorporation of Ser in the polypeptide chain as compared with selenocysteine at the UGA codon, expression of the catalytically inactive Gpx4_U46S was found to be strongly increased. Because the stability of the mitochondrial capsule of mature spermatozoa depends on the moonlighting function of Gpx4 both as an enzyme oxidizing capsular protein thiols and as a structural protein, tightly controlled expression of functional Gpx4 emerges as a key for full male fertility. PMID:25922076

  2. Temperature dependence of the activity of polyphenol peroxidases and polyphenol oxidases in modern and buried soils

    NASA Astrophysics Data System (ADS)

    Yakushev, A. V.; Kuznetsova, I. N.; Blagodatskaya, E. V.; Blagodatsky, S. A.

    2014-05-01

    Under conditions of the global climate warming, the changes in the reserves of soil humus depend on the temperature sensitivities of polyphenol peroxidases (PPPOs) and polyphenol oxidases (PPOs). They play an important role in lignin decomposition, mineralization, and humus formation. The temperature dependence of the potential enzyme activity in modern and buried soils has been studied during incubation at 10 or 20°C. The experimental results indicate that it depends on the availability of the substrate and the presence of oxygen. The activity of PPOs during incubation in the absence of oxygen for two months decreases by 2-2.5 times, which is balanced by an increase in the activity of PPPOs by 2-3 times. The increase in the incubation temperature to 20°C and the addition of glucose accelerates this transition due to the more abrupt decrease in the activity of PPOs. The preincubation of the soil with glucose doubles the activity of PPPOs but has no significant effect on the activity of PPOs. The different effects of temperature on two groups of the studied oxidases and the possibility of substituting enzymes by those of another type under changing aeration conditions should be taken into consideration in predicting the effect of the climate warming on the mineralization of the soil organic matter. The absence of statistically significant differences in the enzymatic activity between the buried and modern soil horizons indicates the retention by the buried soil of some of its properties (soil memory) and the rapid restoration of high enzymatic activity during the preincubation.

  3. Structural insights into the dehydroascorbate reductase activity of human omega-class glutathione transferases.

    PubMed

    Zhou, Huina; Brock, Joseph; Liu, Dan; Board, Philip G; Oakley, Aaron J

    2012-07-13

    The reduction of dehydroascorbate (DHA) to ascorbic acid (AA) is a vital cellular function. The omega-class glutathione transferases (GSTs) catalyze several reductive reactions in cellular biochemistry, including DHA reduction. In humans, two isozymes (GSTO1-1 and GSTO2-2) with significant DHA reductase (DHAR) activity are found, sharing 64% sequence identity. While the activity of GSTO2-2 is higher, it is significantly more unstable in vitro. We report the first crystal structures of human GSTO2-2, stabilized through site-directed mutagenesis and determined at 1.9 Å resolution in the presence and absence of glutathione (GSH). The structure of a human GSTO1-1 has been determined at 1.7 Å resolution in complex with the reaction product AA, which unexpectedly binds in the G-site, where the glutamyl moiety of GSH binds. The structure suggests a similar mode of ascorbate binding in GSTO2-2. This is the first time that a non-GSH-based reaction product has been observed in the G-site of any GST. AA stacks against a conserved aromatic residue, F34 (equivalent to Y34 in GSTO2-2). Mutation of Y34 to alanine in GSTO2-2 eliminates DHAR activity. From these structures and other biochemical data, we propose a mechanism of substrate binding and catalysis of DHAR activity.

  4. Construction and Characterization of Vitreoscilla Hemoglobin (VHb) with Enhanced Peroxidase Activity for Efficient Degradation of Textile Dye.

    PubMed

    Zhang, Zidong; Li, Wei; Li, Haichao; Zhang, Jing; Zhang, Yuebin; Cao, Yufeng; Ma, Jianzhang; Li, Zhengqiang

    2015-09-01

    Pollution resulting from the discharge of textile dyes into water systems has become a major global concern. Because peroxidases are known for their ability to decolorize and detoxify textile dyes, the peroxidase activity of Vitreoscilla hemoglobin (VHb) has recently been studied. It is found that VHb and variants of this enzyme show great promise for enzymatic decolorization of dyes and may play a role in achieving their successful removal from industrial wastewater. The level of VHb peroxidase activity correlates with two amino acid residues present within the conserved distal pocket, at positions 53 and 54. In this work, sitedirected mutagenesis of these residues was performed and resulted in improved VHb peroxidase activity. The double mutant, Q53H/P54C, shows the highest dye decolorization and removal efficiency, with 70% removal efficiency within 5 min. UV spectral studies of Q53H/P54C reveals a more compact structure and an altered porphyrin environment (λSoret = 413 nm) relative to that of wild-type VHb (λSoret = 406), and differential scanning calorimetry data indicate that the VHb variant protein structure is more stable. In addition, circular dichroism spectroscopic studies indicate that this variant's increased protein structural stability is due to an increase in helical structure, as deduced from the melting temperature, which is higher than 90°C. Therefore, the VHb variant Q53H/P54C shows promise as an excellent peroxidase, with excellent dye decolorization activity and a more stable structure than wild-type VHb under high-temperature conditions.

  5. Oxidized glutathione mediates cation channel activation in calf vascular endothelial cells during oxidant stress.

    PubMed

    Koliwad, S K; Elliott, S J; Kunze, D L

    1996-08-15

    1. The oxidant, tert-butylhydroperoxide (tBuOOH) depolarizes calf pulmonary artery endothelial cells by activating a non-selective cation channel. To identify the molecular mediator of channel activation during oxidant stress, the patch-clamp technique was used to compare tBuOOH-induced changes in membrane potential and channel activity with those induced by oxidized glutathione (GSSG), a cytosolic product of oxidant metabolism. 2. When recording pipettes contained GSSG (2 mM), whole-cell zero-current potential measured immediately following pipette break-in was not different from control values (-57 mV). However, within 20 min of break-in, zero-current potential was depolarized to -7 mV. The time course of depolarization was dependent on the concentration of GSSG and was accelerated by inhibition of GSSG metabolism. 3. In excised membrane patches, channels were activated by internal GSSG, but not by internal tBuOOH, reduced glutathione (GSH), or external GSSG. Channels were equal in size (28 pS) and in ionic selectivity to those activated by incubation of intact cells with tBuOOH. As little as 20 microM GSSG was sufficient to maximally activate channels. However, the time course of channel activation was concentration dependent between 20 microM and 2 mM GSSG. 4. Channel activation by GSSG was reversed by GSH and by increasing the [GSH]:[GSSG] ratio. Likewise, channel activation by pre-incubation of intact cells with tBuOOH was reversed by GSH applied after patch excision. 5. These results strongly suggest that GSSG is an endogenous intracellular mediator of channel activation and depolarization during oxidant stress. PMID:8866350

  6. A preliminary study on the antibacterial mechanism of Tegillarca granosa hemoglobin by derived peptides and peroxidase activity.

    PubMed

    Bao, Yongbo; Wang, Juanjuan; Li, Chenghua; Li, Peifen; Wang, Sufang; Lin, Zhihua

    2016-04-01

    The blood clam, Tegillarca granosa, is one of the few bivalve molluscs containing hemoglobin (Hb). In the present study, we purified two types of T. granosa hemoglobin, Tg-HbI and Tg-HbII, using size exclusion chromatography and measured their antibacterial and peroxidase activities. We also tested antibacterial activities of peptides prepared by trypsin digestion of purified Tg-Hb and reversed-phase high-performance liquid chromatography purification. Purified Tg-HbI and Tg-HbII showed antibacterial activity against Escherichia coli, Pseudomonas putida, Bacillus subtilis, and Bacillus firmus, with differences in minimal inhibitory concentrations (MICs), but lacked antibacterial activity against Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi and Staphylococcus aureus. In contrast, 7 Tg-Hb derived peptides exhibited varying degrees of antibacterial activity against V. alginolyticus (MICs: 12-200 μg/ml), V. parahaemolyticus (11-100 μg/ml) and V. harveyi (1-200 μg/ml). The antibacterial activity of Hb derived peptides was confirmed by fluorescence microscopy. In addition, peroxidase activity was detected in Tg-HbI and Tg-HbII. The results indicated that in addition to functioning as a respiratory protein T. granosa hemoglobins likely play a role in host antibacterial defense probably via a peroxidase activity of native molecules and some internal peptides released from the proteins. PMID:26876330

  7. Poly(2-hydroxyethyl methacrylate) for enzyme immobilization: impact on activity and stability of horseradish peroxidase.

    PubMed

    Lane, Sarah M; Kuang, Zhifeng; Yom, Jeannie; Arifuzzaman, Shafi; Genzer, Jan; Farmer, Barry; Naik, Rajesh; Vaia, Richard A

    2011-05-01

    On the basis of their versatile structure and chemistry as well as tunable mechanical properties, polymer brushes are well-suited as supports for enzyme immobilization. However, a robust surface design is hindered by an inadequate understanding of the impact on activity from the coupling motif and enzyme distribution within the brush. Herein, horseradish peroxidase C (HRP C, 44 kDa), chosen as a model enzyme, was immobilized covalently through its lysine residues on a N-hydroxysuccinimidyl carbonate-activated poly(2-hydroxyethyl methacrylate) (PHEMA) brush grafted chemically onto a flat impenetrable surface. Up to a monolayer coverage of HRP C is achieved, where most of the HRP C resides at or near the brush-air interface. Molecular modeling shows that lysines 232 and 241 are the most probable binding sites, leading to an orientation of the immobilized HRP C that does not block the active pocket of the enzyme. Michaelis-Menten kinetics of the immobilized HRP C indicated little change in the K(m) (Michaelis constant) but a large decrease in the V(max) (maximum substrate conversion rate) and a correspondingly large decrease in the k(cat) (overall catalytic rate). This indicates a loss in the percentage of active enzymes. Given the relatively ideal geometry of the HRPC-PHEMA brush, the loss of activity is most likely due to structural changes in the enzyme arising from either secondary constraints imposed by the connectivity of the N-hydroxysuccinimidyl carbonate linking moiety or nonspecific interactions between HRP C and DSC-PHEMA. Therefore, a general enzyme-brush coupling motif must optimize reactive group density to balance binding with neutrality of surroundings. PMID:21438540

  8. Peroxidase(s) in Environment Protection

    PubMed Central

    Bansal, Neelam; Kanwar, Shamsher S.

    2013-01-01

    Industrial discharges of untreated effluents into water bodies and emissions into air have deteriorated the quality of water and air, respectively. The huge amount of pollutants derived from industrial activities represents a threat for the environment and ecologic equilibrium. Phenols and halogenated phenols, polycyclic aromatic hydrocarbons (PAH), endocrine disruptive chemicals (EDC), pesticides, dioxins, polychlorinated biphenyls (PCB), industrial dyes, and other xenobiotics are among the most important pollutants. Peroxidases are enzymes that are able to transform a variety of compounds following a free radical mechanism, thereby yielding oxidized or polymerized products. The peroxidase transformation of these pollutants is accompanied by a reduction in their toxicity, due to loss of biological activity, reduction in the bioavailability, or the removal from aqueous phase, especially when the pollutant is found in water. The review describes the sources of peroxidases, the reactions catalyzed by them, and their applications in the management of pollutants in the environment. PMID:24453894

  9. Glutathione system in young spontaneously hypertensive rats.

    PubMed

    Lee, S K; Arunkumar, Sundaram; Sirajudeen, K N S; Singh, H J

    2010-12-01

    Glutathione (GSH) forms a part of the antioxidant system that plays a vital role in preventing oxidative stress, and an imbalance in the oxidant/antioxidant system has been linked to the pathogenesis of hypertension. The aim of this study was to investigate the status of the GSH system in the kidney of spontaneously hypertensive rats (SHR). Components of the GSH system, including glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), and total GSH content, were measured in the kidneys of 4, 6, 8, 12, and 16 weeks old SHR and Wistar-Kyoto (WKY) rats. Systolic blood pressure of SHR was significantly higher from the age of 6 weeks onwards compared with age-matched WKY rats. GPx activity in the SHR was significantly lower from the age of 8 weeks onwards when compared to that in age-matched WKY rats. No significant differences were evident in the GPx-1 protein abundance, and its relative mRNA levels, GR, GST activity, and total GSH content between SHR and age-matched WKY rats. The lower GPx activity suggests of an impairment of the GSH system in the SHR, which might be due to an abnormality in its protein rather than non-availability of a cofactor. Its role in the development of hypertension in SHR however remains unclear.

  10. A V2O3-ordered mesoporous carbon composite with novel peroxidase-like activity towards the glucose colorimetric assay

    NASA Astrophysics Data System (ADS)

    Han, Lei; Zeng, Lingxing; Wei, Mingdeng; Li, Chang Ming; Liu, Aihua

    2015-07-01

    It is of great scientific and practical significance to explore inorganic mimetic enzymes to replace natural enzymes due to their instability and high cost. Herein we present an interesting discovery that a V2O3-ordered mesoporous carbon composite (V2O3-OMC) has a novel peroxidase-like activity towards fast redox reaction of typical peroxidase substrates H2O2 and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS). Due to the small size effect and large surface area of V2O3 nanoparticles supported by OMC, V2O3-OMC exhibited excellent catalytic performance with a kcat of 1.28 × 104 s-1, KM (ABTS) of 0.067 mM and KM (H2O2) of 0.16 mM, and a significantly higher catalytic efficiency (kcat/KM) towards the oxidation of ABTS in comparison with the natural peroxidases. Furthermore, the Ping-pong BiBi mechanism was proposed to explain the catalytic reaction by V2O3-OMC. Based on this highly active biomimetic peroxidase and the colorimetric detection of H2O2, a facile analytical method was developed to detect glucose by using V2O3-OMC and glucose oxidase, which had a wide linear range (0.01-4 mM glucose), good selectivity and reliability for successful detection of various real samples. Thus, the novel V2O3-OMC peroxidase mimetic holds great promise for broad potential applications.It is of great scientific and practical significance to explore inorganic mimetic enzymes to replace natural enzymes due to their instability and high cost. Herein we present an interesting discovery that a V2O3-ordered mesoporous carbon composite (V2O3-OMC) has a novel peroxidase-like activity towards fast redox reaction of typical peroxidase substrates H2O2 and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS). Due to the small size effect and large surface area of V2O3 nanoparticles supported by OMC, V2O3-OMC exhibited excellent catalytic performance with a kcat of 1.28 × 104 s-1, KM (ABTS) of 0.067 mM and KM (H2O2) of 0.16 mM, and a

  11. Amino acids-incorporated nanoflowers with an intrinsic peroxidase-like activity

    NASA Astrophysics Data System (ADS)

    Wu, Zhuo-Fu; Wang, Zhi; Zhang, Ye; Ma, Ya-Li; He, Cheng-Yan; Li, Heng; Chen, Lei; Huo, Qi-Sheng; Wang, Lei; Li, Zheng-Qiang

    2016-03-01

    Functional molecules synthesized by self-assembly between inorganic salts and amino acids have attracted much attention in recent years. A simple method is reported here for fabricating hybrid organic-inorganic nanoflowers using copper (II) ions as the inorganic component and natural amino acids as the organic component. The results indicate that the interactions between amino acid and copper ions cause the growth of the nanoflowers composed by C, N, Cu, P and O elements. The Cu ions and Cu(AA)n complexes containing Cu-O bond are present in the nanoflowers. The nanoflowers have flower-like porous structure dominated by the R groups of amino acids with high surface-to-volume ratios, which is beneficial for exerting its peroxidase-like activity depending on Fenton-like reaction mechanism with ABTS and Rhodamine B as the substrates. It is expected that the nanoflowers hold great promise as enzyme mimics for application in the field of biosensor, bioanalysis and biocatalysis.

  12. Colorimetric cholesterol sensor based on peroxidase like activity of zinc oxide nanoparticles incorporated carbon nanotubes.

    PubMed

    Hayat, Akhtar; Haider, Waqar; Raza, Yousuf; Marty, Jean Louis

    2015-10-01

    A sensitive and selective colorimetric method based on the incorporation of zinc oxide nanoparticles (ZnO NPs) on the surface of carbon nanotubes (CNTs) was shown to posses synergistic peroxidase like activity for the detection of cholesterol. The proposed nanocomposite catalyzed the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) in the presence of hydrogen peroxide (H2O2) to produce a green colored product which can be monitored at 405 nm. H2O2 is the oxidative product of cholesterol in the presence of cholesterol oxidase. Therefore, the oxidation of cholesterol can be quantitatively related to the colorimetric response by combining these two reactions. Under the optimal experimental conditions, the colorimetric response was proportional to the concentration of cholesterol in the range of 0.5-500 nmol/L, with a detection limit of 0.2 nmol/L. The applicability of the proposed assays was demonstrated for the determination of cholesterol in milk powder samples with good recovery results. PMID:26078143

  13. Amino acids-incorporated nanoflowers with an intrinsic peroxidase-like activity

    PubMed Central

    Wu, Zhuo-Fu; Wang, Zhi; Zhang, Ye; Ma, Ya-Li; He, Cheng-Yan; Li, Heng; Chen, Lei; Huo, Qi-Sheng; Wang, Lei; Li, Zheng-Qiang

    2016-01-01

    Functional molecules synthesized by self-assembly between inorganic salts and amino acids have attracted much attention in recent years. A simple method is reported here for fabricating hybrid organic–inorganic nanoflowers using copper (II) ions as the inorganic component and natural amino acids as the organic component. The results indicate that the interactions between amino acid and copper ions cause the growth of the nanoflowers composed by C, N, Cu, P and O elements. The Cu ions and Cu(AA)n complexes containing Cu-O bond are present in the nanoflowers. The nanoflowers have flower-like porous structure dominated by the R groups of amino acids with high surface-to-volume ratios, which is beneficial for exerting its peroxidase-like activity depending on Fenton-like reaction mechanism with ABTS and Rhodamine B as the substrates. It is expected that the nanoflowers hold great promise as enzyme mimics for application in the field of biosensor, bioanalysis and biocatalysis. PMID:26926099

  14. Colorimetric cholesterol sensor based on peroxidase like activity of zinc oxide nanoparticles incorporated carbon nanotubes.

    PubMed

    Hayat, Akhtar; Haider, Waqar; Raza, Yousuf; Marty, Jean Louis

    2015-10-01

    A sensitive and selective colorimetric method based on the incorporation of zinc oxide nanoparticles (ZnO NPs) on the surface of carbon nanotubes (CNTs) was shown to posses synergistic peroxidase like activity for the detection of cholesterol. The proposed nanocomposite catalyzed the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) in the presence of hydrogen peroxide (H2O2) to produce a green colored product which can be monitored at 405 nm. H2O2 is the oxidative product of cholesterol in the presence of cholesterol oxidase. Therefore, the oxidation of cholesterol can be quantitatively related to the colorimetric response by combining these two reactions. Under the optimal experimental conditions, the colorimetric response was proportional to the concentration of cholesterol in the range of 0.5-500 nmol/L, with a detection limit of 0.2 nmol/L. The applicability of the proposed assays was demonstrated for the determination of cholesterol in milk powder samples with good recovery results.

  15. Ferromagnetic nanoparticles with peroxidase-like activity enhance the cleavage of biological macromolecules for biofilm elimination

    PubMed Central

    Gao, Lizeng; Giglio, Krista M.; Nelson, Jacquelyn L.; Sondermann, Holger; Travis, Alexander J.

    2014-01-01

    Hydrogen peroxide (H2O2) is a “green chemical” that has various cleaning and disinfectant uses, including as an anti-bacterial agent for hygienic and medical treatments. However, its efficacy is limited against biofilm-producing bacteria, because of poor penetration of the protective, organic matrix. Here we show new applications for ferromagnetic nanoparticles (Fe3O4, MNP) with peroxidase-like activity in potentiating the efficacy of H2O2 in biofilm degradation and prevention. Our data show that MNP enhanced oxidative cleavage of biofilm components (model nucleic acids, proteins, and oligosaccharides) in the presence of H2O2. When challenged with live, biofilm-producing bacteria, the MNP-H2O2 system efficiently broke down existing biofilm and prevented new biofilm from forming, killing both planktonic bacteria and those within biofilm. By enhancing oxidative cleavage of various substrates, the MNP-H2O2 system provides a novel strategy for biofilm elimination, and other applications utilizing oxidative breakdown. PMID:24468900

  16. Active site structure in cytochrome c peroxidase and myoglobin mutants: effects of altered hydrogen bonding to the proximal histidine.

    PubMed

    Sinclair, R; Hallam, S; Chen, M; Chance, B; Powers, L

    1996-11-26

    The globins and peroxidases, while performing completely different chemistry, share features of the iron heme active site: a protoporphyrin IX prosthetic group is linked to the protein by the proximal histidine residue. X-ray absorption spectroscopy provides a method to determine the local structure of iron heme active sites in proteins. Our previous studies using X-ray absorption spectroscopy revealed a significant difference in the Fe-N epsilon bond length between the peroxidases and the globins [for a review, see Powers, L. (1994) Molecular Electronics and Molecular Electronic Devices, Vol. 3, p 211 CRC Press Inc., Boca Raton, FL]. Globins typically have an Fe-N epsilon distance close to 2.1 A while the Fe-N epsilon distance in the peroxidases is closer to 1.9 A. We have proposed [Sinclair, R., Powers, L., Bumpus, J., Albo, A., & Brock, B. (1992) Biochemistry 31, 4892] that strong hydrogen bonding to the proximal histidine is responsible for the shorter bond length in the peroxidases. Here we use site-specific mutagenesis to eliminate the strong proximal hydrogen bonding in cytochrome c peroxidase and to introduce strong proximal hydrogen bonding in myoglobin. Consistent with our hypothesis, elimination of the Asp235-His175 hydrogen bond in CcP results in elongation of Fe-N epsilon from approximately 1.9 to approximately 2.1 A. Conversely, introduction of a similar strong proximal hydrogen bond in myoglobin shortens Fe-N epsilon from approximately 2.1 to approximately 1.9 A. These results correlate well with other biochemical data.

  17. Biogenic magnetic nanoparticles from Burkholderia sp. YN01 exhibiting intrinsic peroxidase-like activity and their applications.

    PubMed

    Pan, Yu; Li, Na; Mu, Jianshuai; Zhou, Runhong; Xu, Yan; Cui, Daizong; Wang, Yan; Zhao, Min

    2015-01-01

    A novel bacterial strain containing biogenic magnetic nanoparticles (BMNPs) was isolated from the sediments of Songhua River in Harbin, China, and was identified as Burkholderia sp. YN01. Extracted BMNPs from YN01 were characterized as pure face-centered cubic Fe3O4 with an average size of 80 nm through transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The hysteresis parameters of the BMNP samples such as Bc and Bcr and ratios Mrs/Ms were deduced as 35.6 mT, 43.2 mT, and 0.47, respectively, indicating that the BMNPs exhibit a ferromagnetic behavior. This is the first report concerning on biogenic Fe3O4 NPs produced in Burkholderia genus. Significantly, the BMNPs were proved to possess intrinsic peroxidase-like activity that could catalyze the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. Kinetic analysis indicates that the catalytic behavior is in accord with typical Michaelis-Menten kinetics and follows ping-pong mechanism. The catalytic constants (K cat) were 6.5 × 10(4) s(-1) and 0.78 × 10(4) s(-1) with H2O2 and TMB as substrate, respectively, which was higher than that of horseradish peroxidase (HRP). Electron spin resonance (ESR) spectroscopy experiments showed that the BMNPs could catalyze H2O2 to produce hydroxyl radicals. The origin of peroxidase-like activity is also associated with their ability to transfer electron between electrode and H2O2 according to an electrochemical study. As a novel peroxidase mimetic, the BMNPs were employed to offer a simple, sensitive, and selective colorimetric method for H2O2 and glucose determination, and the BMNPs could efficiently catalyze the degradation of phenol and Congo red dye. PMID:25030455

  18. Glutathione-dependent extracellular ferric reductase activities in dimorphic zoopathogenic fungi

    PubMed Central

    Zarnowski, Robert; Woods, Jon P.

    2009-01-01

    In this study, extracellular glutathione-dependent ferric reductase (GSH-FeR) activities in different dimorphic zoopathogenic fungal species were characterized. Supernatants from Blastomyces dermatitidis, Histoplasma capsulatum, Paracoccidioides brasiliensis and Sporothrix schenckii strains grown in their yeast form were able to reduce iron enzymically with glutathione as a cofactor. Some variations in the level of reduction were noted amongst the strains. This activity was stable in acidic, neutral and slightly alkaline environments and was inhibited when trivalent aluminium and gallium ions were present. Using zymography, single bands of GSH-FeRs with apparent molecular masses varying from 430 to 460 kDa were identified in all strains. The same molecular mass range was determined by size exclusion chromatography. These data demonstrate that dimorphic zoopathogenic fungi produce and secrete a family of similar GSH-FeRs that may be involved in the acquisition and utilization of iron. Siderophore production by these and other fungi has sometimes been considered to provide a full explanation of iron acquisition in these organisms. Our work reveals an additional common mechanism that may be biologically and pathogenically important. Furthermore, while some characteristics of these enzymes such as extracellular location, cofactor utilization and large size are not individually unique, when considered together and shared across a range of fungi, they represent an important novel physiological feature. PMID:16000713

  19. The ligninolytic peroxidases in the genus Pleurotus: divergence in activities, expression, and potential applications.

    PubMed

    Knop, Doriv; Yarden, Oded; Hadar, Yitzhak

    2015-02-01

    Mushrooms of the genus Pleurotus are comprised of cultivated edible ligninolytic fungi with medicinal properties and a wide array of biotechnological and environmental applications. Like other white-rot fungi (WRF), they are able to grow on a variety of lignocellulosic biomass substrates and degrade both natural and anthropogenic aromatic compounds. This is due to the presence of the non-specific oxidative enzymatic systems, which are mainly consisted of lacasses, versatile peroxidases (VPs), and short manganese peroxidases (short-MnPs). Additional, less studied, peroxidase are dye-decolorizing peroxidases (DyPs) and heme-thiolate peroxidases (HTPs). During the past two decades, substantial information has accumulated concerning the biochemistry, structure and function of the Pleurotus ligninolytic peroxidases, which are considered to play a key role in many biodegradation processes. The production of these enzymes is dependent on growth media composition, pH, and temperature as well as the growth phase of the fungus. Mn(2+) concentration differentially affects the expression of the different genes. It also severs as a preferred substrate for these preoxidases. Recently, sequencing of the Pleurotus ostreatus genome was completed, and a comprehensive picture of the ligninolytic peroxidase gene family, consisting of three VPs and six short-MnPs, has been established. Similar enzymes were also discovered and studied in other Pleurotus species. In addition, progress has been made in the development of molecular tools for targeted gene replacement, RNAi-based gene silencing and overexpression of genes of interest. These advances increase the fundamental understanding of the ligninolytic system and provide the opportunity for harnessing the unique attributes of these WRF for applied purposes.

  20. Comparison of glutathione reductase activity and the intracellular glutathione reducing effects of 13 derivatives of 1'-acetoxychavicol acetate in Ehrlich ascites tumor cells.

    PubMed

    Xu, Shenghui; Kojima-Yuasa, Akiko; Azuma, Hideki; Kennedy, David Opare; Konishi, Yotaro; Matsui-Yuasa, Isao

    2010-05-14

    In a previous study, we showed that (1'S)-acetoxychavicol acetate ((S)-ACA) caused a rapid decrease in glutathione (GSH) levels less than 15 min after exposure. (S)-ACA-induced cell death was reversed by the addition of N-acetylcysteine. In the current study, we investigated the inhibitory activities of 13 derivatives of (S)-ACA on tumor cell viability, intracellular GSH level and GR activity. Correlations were found among a decrease in cell viability, intracellular GSH levels and the activity of GR in Ehrlich ascites tumor cells treated with the various ACA analogues. A test of the 13 derivatives revealed that the structural factors regulating activity were as follows: (1) the para or 1'-position of acetoxyl group (or other acyl group) was essential, (2) the presence of a C2'-C3' double or triple bond was essential, and (3) the S configuration of the 1'-acetoxyl group was preferable.

  1. Effect of innate glutathione levels on activity of redox-responsive gene delivery vectors

    PubMed Central

    Manickam, Devika S.; Li, Jing; Putt, David A.; Zhou, Qing-Hui; Wu, Chao; Lash, Lawrence H.; Oupický, David

    2009-01-01

    Redox-responsive polyplexes represent a promising class of non-viral gene delivery vectors. The reducible disulfide bonds in the polyplexes undergo intracellular reduction owing to the presence of high concentrations of reduced glutathione (GSH). Available evidence suggests improved transfection activity of redox-sensitive polyplexes upon artificial modulation of intracellular GSH. This study investigates the effect of innate differences in GSH concentration in a panel of human pancreatic cancer cell lines on activity of reducible polyplexes of the four major classes of nucleic acid therapeutics: plasmid DNA (pDNA), messenger RNA (mRNA), antisense oligodeoxynucleotides (AON) and siRNA. In general, reducible polyplexes of linear poly(amido amines) (PAA) show improved activity compared to non-reducible polyplexes of PAA. Results demonstrate that increased GSH levels are associated with improved transfection of mRNA polyplexes but no clear trend is observed for pDNA, AON and siRNA polyplexes. PMID:19720098

  2. The effects of an engineered cation site on the structure, activity, and EPR properties of cytochrome c peroxidase.

    PubMed

    Bonagura, C A; Sundaramoorthy, M; Bhaskar, B; Poulos, T L

    1999-04-27

    Earlier work [Bonagura et al. (1996) Biochemistry 35, 6107] showed that the K+ site found in the proximal pocket of ascorbate peroxidase (APX) could be engineered into cytochrome c peroxidase (CCP). Binding of K+ at the engineered site results in a loss in activity and destabilization of the CCP compound I Trp191 cationic radical owing to long-range electrostatic effects. The engineered CCP mutant crystal structure has been refined to 1.5 A using data obtained at cryogenic temperatures which provides a more detailed basis for comparison with the naturally occurring K+ site in APX. The characteristic EPR signal associated with the Trp191 radical becomes progressively weaker as K+ is added, which correlates well with the loss in enzyme activity as [K+] is increased. These results coupled with stopped-flow studies support our earlier conclusions that the loss in activity and EPR signal is due to destabilization of the Trp191 cationic radical. PMID:10220341

  3. Haem peroxidase activity in Daphnia magna: a biomarker for sub-lethal toxicity assessments of kerosene-contaminated groundwater.

    PubMed

    Connon, Richard; Dewhurst, Rachel E; Crane, Mark; Callaghan, Amanda

    2003-10-01

    A novel biomarker was developed in Daphnia magna to detect organic pollution in groundwater. The haem peroxidase assay, which is an indirect means of measuring oxidase activity, was particularly sensitive to kerosene contamination. Exposure to sub-lethal concentrations of kerosene-contaminated groundwater resulted in a haem peroxidase activity increase by dose with a two-fold activity peak at 25%. Reproduction in D. magna remained unimpaired when exposed to concentrations below 25% for 21 days, and a decline in fecundity was only observed at concentrations above the peak in enzyme activity. The measurement of haem peroxidase activity in D. magna detected sublethal effects of kerosene in just 24 h, whilst offering information on the health status of the organisms. The biomarker may be useful in determining concentrations above which detrimental effects would occur from long-term exposure for fuel hydrocarbons. Moreover, this novel assay detects exposure to chemicals in samples that would normally be classified as non-toxic by acute toxicity tests.

  4. Effects of heavy metals (Cd, Cu, Cr, Pb, Zn) on fish glutathione metabolism.

    PubMed

    Eroglu, A; Dogan, Z; Kanak, E G; Atli, G; Canli, M

    2015-03-01

    The glutathione metabolism contains crucial antioxidant molecules to defend the organisms against oxidants. Thus, the aim of this study was to investigate the response of the glutathione metabolism in the liver of freshwater fish Oreochromis niloticus exposed to metals (Cu, Cd, Cr, Pb, Zn) in different periods. Fish were exposed to metals (as 1 μg/mL) individually for 1, 7, and 14 days and subsequently antioxidant enzymes (glutathione peroxidase, GPX; glutathione reductase, GR and glutathione S-transferase, GST) and glutathione levels (total glutathione, tGSH; reduced glutathione, rGSH; oxidized glutathione, GSSG and GSH/GSSG ratios) in the liver were measured. There was no fish mortality during the experiments, except Cu exposure. The antioxidant enzymes responded differently to metal exposures depending on metal types and exposure durations. GPX activity increased only after Cd exposure, while GST activity increased following 7 days of all metal exposures. However, GR activity did not alter in most cases. Total GSH and GSH/GSSG levels generally decreased, especially after 7 days. Data showed that metal exposures significantly altered the response of antioxidant system parameters, particularly at day 7 and some recovery occurred after 14 days. This study suggests that the response of antioxidant system could help to predict metal toxicity in the aquatic environments and be useful as an "early warning tool" in natural monitoring studies.

  5. Chemical Engineering of Enzymes: Altered Catalytic Activity, Predictable Selectivity and Exceptional Stability of the Semisynthetic Peroxidase Seleno-Subtilisin

    NASA Astrophysics Data System (ADS)

    Häring, Dietmar; Schreier, Peter

    The increasing demand for enzymes as highly selective, mild, and environmentally benign catalysts is often limited by the lack of an enzyme with the desired catalytic activity or substrate selectivity and by their instability in biotechnological processes. The previous answers to these problems comprised genetically engineered enzymes and several classes of enzyme mimics. Here we describe the potential of chemical enzyme engineering: native enzymes can be modified by merely chemical means and basic equipment yielding so-called semisynthetic enzymes. Thus, the high substrate selectivity of the enzymatic peptide framework is combined with the catalytic versatility of a synthetic active site. We illustrate the potential of chemically engineered enzymes with the conception of the semisynthetic peroxidase seleno-subtilisin. First, the serine endoprotease subtilisin was crystallized and cross-linked with glutaraldehyde to give cross-linked enzyme crystals which were found to be insoluble in water or organic solvents and highly stable. Second, serine 221 in the active site (Enz-OH) was chemically converted into an oxidized derivative of selenocystein (Enz-SeO2H). As a consequence, the former proteolytic enzyme gained peroxidase activity and catalyzed the selective reduction of hydroperoxides. Due to the identical binding sites of the semisynthetic peroxidase and the protease, the substrate selectivity of seleno-subtilisin was predictable in view of the well-known selectivity of subtilisin.

  6. A novel application of pulsed electric field (PEF) processing for improving glutathione (GSH) antioxidant activity.

    PubMed

    Wang, Jia; Wang, Ke; Wang, Ying; Lin, Songyi; Zhao, Ping; Jones, Gregory

    2014-10-15

    Glutathione (GSH) was treated by pulsed electric field (PEF) processing to investigate its effect on antioxidant activity. The antioxidant activity of GSH was evaluated using 2,2-diphenyl-1-picrylhydrazy (DPPH) radical inhibition. A Box-Behnken design (BBD) with three independent variables, which were concentration, electric field intensity and pulse frequency was used to establish the regression equation of second-order response surface. Optimal conditions were as follows: GSH concentration 8.86mg/mL, electric field intensity 9.74kV/cm and pulse frequency 2549.08Hz. The DPPH radical inhibition increased from 81.83% to 97.40%. Near-infrared spectroscopy (NIR) and mid-infrared spectroscopy (MIR) were used to analyse the change of structure and functional groups of GSH.

  7. Detection of Hg2+ based on the selective inhibition of peroxidase mimetic activity of BSA-Au clusters.

    PubMed

    Zhu, Rui; Zhou, Yan; Wang, Xi-Liang; Liang, Li-Ping; Long, Yi-Juan; Wang, Qin-Long; Zhang, Hai-Jie; Huang, Xiao-Xiao; Zheng, Hu-Zhi

    2013-12-15

    It was found that Hg(2+) can inhibit the peroxidase mimetic activity of bovine serum albumin (BSA) protected Au clusters (BSA-Au) due to the specific interaction between Hg(2+) and Au(+) existed onto the surface of BSA-Au clusters. By coupling with 3, 3', 5, 5'-tetramethylbenzidine (TMB)-H2O2 chromogenic reaction, a novel method for Hg(2+) detection was developed based on the inhibiting effect of Hg(2+) on BSA-Au clusters peroxidase-like activity. This method exhibited high selectivity and sensitivity. As low as 3 nM (0.6 ppb, 3σ) Hg(2+) could be detected with a linear range from 10 nM (2 ppb) to 10 µM (2 ppm) and this method was successfully applied for the determination of total mercury content in skin lightening products.

  8. Design, synthesis, and evaluation of latent alkylating agents activated by glutathione S-transferase.

    PubMed

    Satyam, A; Hocker, M D; Kane-Maguire, K A; Morgan, A S; Villar, H O; Lyttle, M H

    1996-04-12

    In search of compounds with improved specificity for targeting the important cancer-associated P1-1 glutathione S-transferase (GST) isozyme, new analogs 4 and 5 of the previously reported glutathione S-transferase (GST)-activated latent alkylating agent gamma-glutamyl-alpha-amino-beta-[[[2-[[bis[bis(2-chloroethyl)amino]ph osp horyl]oxy]ethyl]sulfonyl]propionyl]-(R)-(-)-phenylglycine (3) have been designed, synthesized, and evaluated. One of the diastereomers of 4 exhibited good selectivity for GST P1-1. The tetrabromo analog 5 of the tetrachloro compound 3 maintained its specificity and was found to be more readily activated by GSTs than 3. The GST activation concept was further broadened through design, synthesis, and evaluation of a novel latent urethane mustard 8 and its diethyl ester 9. Interestingly, 8 showed very good specificity for P1-1 GST. Cell culture studies were carried out on 4, 5, 8, and 9 using cell lines engineered to have varying levels of GST P1-1 isozyme. New analogs 4 and 5 exhibited increased toxicity to cell lines with overexpressed GST P1-1 isozyme. The urethane mustard 8 and its diethyl ester 9 were found to be not as toxic. However, they too exhibited more toxicity to a cell line engineered to have elevated P1-1 levels, which was in agreement with the observed in vitro specificity of 8 for P1-1 GST isozyme. Mechanistic studies on alkaline as well as enzyme-catalyzed decomposition of latent mustard 3 provided experimental proof for the hypothesis that 3 breaks down into an active phosphoramidate mustard and a reactive vinyl sulfone. The alkylating nature of the decomposition products was further demonstrated by trapping those transient species as relatively stable diethyldithiocarbamic acid adducts. These results substantially extend previous efforts to develop drugs targeting GST and provide a paradigm for development of other latent drugs. PMID:8648613

  9. Association of mercury and selenium with altered glutathione metabolism and oxidative stress in diving ducks from the San Francisco Bay region, USA

    SciTech Connect

    Hoffman, D.J.; Pendleton, G.W.; Ohlendorf, H.M.; Marn, C.M.

    1998-02-01

    Adult male greater scaup (Aythya marila), surf scoters (Melanitta perspicillata), and ruddy ducks (Oxyura jamaicensis) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic Se concentrations were highest in greater scaup and surf scoters in Suisun Bay, whereas hepatic Hg was highest in greater scaup and surf scoters from Tomales Bay. Hepatic Se and Hg were lower in ruddy ducks and did not differ between locations. Hepatic supernatants were assayed for enzymes related to glutathione metabolism and antioxidant activity, including glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase (GSH peroxidase), glutathione reductase (GSSG reductase), and glutathione-S-transferase (GSH transferase). Glutathione peroxidase activity was higher in surf scoters and ruddy ducks, and G-6-PDH was higher in greater scaup and surf scoters from Suisun Bay than Tomales Bay. Glutathione reductase (GSSG) was higher in SS from Suisun Bay. The ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) was greater in all species from Tomales Bay. The following significant relationships were found in one or more species with increasing hepatic Hg concentration; lower body, liver, and heart weights; decreased hepatic GSH concentration and G-6-PDH and GSH peroxidase activities; increased ratio of GSSG to GSH; and increased GSSG reductase activity. With increasing hepatic Se concentration, GSH peroxidase increased, but GSH decreased. It is concluded that measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. Concentrations of Hg and Se and the above variables affected have been associated with adverse effects on reproduction and neurological function in experimental studies with mallards.

  10. Highly dispersed CeO₂ on TiO₂ nanotube: a synergistic nanocomposite with superior peroxidase-like activity.

    PubMed

    Zhao, Hui; Dong, Yuming; Jiang, Pingping; Wang, Guangli; Zhang, Jingjing

    2015-04-01

    In this report, a novel nanocomposite of highly dispersed CeO2 on a TiO2 nanotube was designed and proposed as a peroxidase-like mimic. The best peroxidase-like activity was obtained for the CeO2/nanotube-TiO2 when the molar ratio of Ce/Ti was 0.1, which was much higher than that for CeO2/nanowire-TiO2, CeO2/nanorod-TiO2, or CeO2/nanoparticle-TiO2 with a similar molar ratio of Ce/Ti. Moreover, in comparison with other nanomaterial based peroxidase mimics, CeO2/nanotube-TiO2 nanocomposites exhibited higher affinity to H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB). Kinetic analysis indicated that the catalytic behavior was in accordance with typical Michaelis-Menten kinetics. Ce(3+) sites were confirmed as the catalytic active sites for the catalytic reaction. The first interaction of surface CeO2 with H2O2 chemically changed the surface state of CeO2 by transforming Ce(3+) sites into surface peroxide species causing adsorbed TMB oxidation. Compared with CeO2/nanowire-TiO2, CeO2/nanorod-TiO2, and CeO2/nanoparticle-TiO2, the combination of TiO2 nanotube with CeO2 presented the highest concentration of Ce(3+) thus leading to the best peroxidase-like activity. On the basis of the high activity of CeO2/nanotube-TiO2, the reaction provides a simple method for colorimetric detection of H2O2 and glucose with the detection limits of 3.2 and 6.1 μM, respectively.

  11. Synthesis of a peroxidase activity by the cells of hairy cell leukemia: a study by ultrastructural cytochemistry.

    PubMed

    Reyes, F; Gourdin, M F; Farcet, J P; Dreyfus, B; Breton-Gorius, J

    1978-09-01

    The nature of cells present in the blood, marrow, and spleen of patients with hairy cell leukemia is largely debated. These cells have been tentatively categorized on the basis of either monocytic or lymphocytic markers, and the accumulating data points to the fact that they share some characteristics of both cell types. Although hairy cells are known to lack myeloperoxidase-positive granules, present in normal human monocytes, we investigated the possible presence of other peroxidase activities differing from the granule-bound myeloperoxidase. The study was carried out with several methods based on the incubation of fixed and unfixed cells in the presence of diaminobenzidine and hydrogen peroxide. A peroxidase activity was found in hairy cells, located always in the endoplasmic reticulum but not in the Golgi apparatus or in any granule. By its cytochemical characteristics it appears to be closely related to that of tissue macrophages, activated blood monocytes, and other nonlymphocytic hematopoietic cells. This peroxidase is not found in lymphocytes with B or T phenotypes. PMID:678670

  12. Peroxidase-like activity of the Co3O4 nanoparticles used for biodetection and evaluation of antioxidant behavior

    NASA Astrophysics Data System (ADS)

    Jia, Huimin; Yang, Dongfang; Han, Xiangna; Cai, Junhui; Liu, Haiying; He, Weiwei

    2016-03-01

    Nanostructured enzyme mimics are of great interest as promising alternatives to artificial enzymes for biomedical and catalytic applications. Studying the chemical interactions between antioxidants and nano-enzymes may result in a better understanding of the antioxidant capability of antioxidants and may help improve the function of artificial enzymes to better mimic natural enzymes. In this study, using Co3O4 nanoparticles (NPs) as peroxidase mimics to catalyze the oxidation of chromophoric substrates by H2O2, we developed a platform that acts as a biosensor for hydrogen peroxide and glucose and that can study the inhibitory effects of natural antioxidants on peroxidase mimics. This method can be applied specifically to glucose detection in real samples. Three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA), were compared for their antioxidant capabilities. We found that these three antioxidants efficiently inhibit peroxidase-like activity with concentration dependence. The antioxidants showed different efficiencies, in the following order: tannic acid > gallic acid > ascorbic acid. They also showed distinct modes of inhibition based on different interaction mechanisms. This study serves as a proof-of-concept that nano-enzyme mimics can be used to evaluate antioxidant capabilities and to screen enzyme inhibitors.Nanostructured enzyme mimics are of great interest as promising alternatives to artificial enzymes for biomedical and catalytic applications. Studying the chemical interactions between antioxidants and nano-enzymes may result in a better understanding of the antioxidant capability of antioxidants and may help improve the function of artificial enzymes to better mimic natural enzymes. In this study, using Co3O4 nanoparticles (NPs) as peroxidase mimics to catalyze the oxidation of chromophoric substrates by H2O2, we developed a platform that acts as a biosensor for hydrogen peroxide and glucose and that can study the

  13. Spectroscopic evidence for an engineered, catalytically active Trp radical that creates the unique reactivity of lignin peroxidase

    PubMed Central

    Smith, Andrew T.; Doyle, Wendy A.; Dorlet, Pierre; Ivancich, Anabella

    2009-01-01

    The surface oxidation site (Trp-171) in lignin peroxidase (LiP) required for the reaction with veratryl alcohol a high-redox-potential (1.4 V) substrate, was engineered into Coprinus cinereus peroxidase (CiP) by introducing a Trp residue into a heme peroxidase that has similar protein fold but lacks this activity. To create the catalytic activity toward veratryl alcohol in CiP, it was necessary to reproduce the Trp site and its negatively charged microenvironment by means of a triple mutation. The resulting D179W+R258E+R272D variant was characterized by multifrequency EPR spectroscopy. The spectra unequivocally showed that a new Trp radical [g values of gx = 2.0035(5), gy = 2.0027(5), and gz = 2.0022(1)] was formed after the [Fe(IV)=O Por•+] intermediate, as a result of intramolecular electron transfer between Trp-179 and the porphyrin. Also, the EPR characterization crucially showed that [Fe(IV)=O Trp-179•] was the reactive intermediate with veratryl alcohol. Accordingly, our work shows that it is necessary to take into account the physicochemical properties of the radical, fine-tuned by the microenvironment, as well as those of the preceding [Fe(IV)=O Por•+] intermediate to engineer a catalytically competent Trp site for a given substrate. Manipulation of the microenvironment of the Trp-171 site in LiP allowed the detection by EPR spectroscopy of the Trp-171•, for which direct evidence has been missing so far. Our work also highlights the role of Trp residues as tunable redox-active cofactors for enzyme catalysis in the context of peroxidases with a unique reactivity toward recalcitrant substrates that require oxidation potentials not realized at the heme site. PMID:19805263

  14. Spectroscopic evidence for an engineered, catalytically active Trp radical that creates the unique reactivity of lignin peroxidase.

    PubMed

    Smith, Andrew T; Doyle, Wendy A; Dorlet, Pierre; Ivancich, Anabella

    2009-09-22

    The surface oxidation site (Trp-171) in lignin peroxidase (LiP) required for the reaction with veratryl alcohol a high-redox-potential (1.4 V) substrate, was engineered into Coprinus cinereus peroxidase (CiP) by introducing a Trp residue into a heme peroxidase that has similar protein fold but lacks this activity. To create the catalytic activity toward veratryl alcohol in CiP, it was necessary to reproduce the Trp site and its negatively charged microenvironment by means of a triple mutation. The resulting D179W+R258E+R272D variant was characterized by multifrequency EPR spectroscopy. The spectra unequivocally showed that a new Trp radical [g values of g(x) = 2.0035(5), g(y) = 2.0027(5), and g(z) = 2.0022(1)] was formed after the [Fe(IV)=O Por(*+)] intermediate, as a result of intramolecular electron transfer between Trp-179 and the porphyrin. Also, the EPR characterization crucially showed that [Fe(IV)=O Trp-179(*)] was the reactive intermediate with veratryl alcohol. Accordingly, our work shows that it is necessary to take into account the physicochemical properties of the radical, fine-tuned by the microenvironment, as well as those of the preceding [Fe(IV)=O Por(*+)] intermediate to engineer a catalytically competent Trp site for a given substrate. Manipulation of the microenvironment of the Trp-171 site in LiP allowed the detection by EPR spectroscopy of the Trp-171(*), for which direct evidence has been missing so far. Our work also highlights the role of Trp residues as tunable redox-active cofactors for enzyme catalysis in the context of peroxidases with a unique reactivity toward recalcitrant substrates that require oxidation potentials not realized at the heme site.

  15. Abolishing activity against ascorbate in a cytosolic ascorbate peroxidase from switchgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.) is being developed as a bioenergy species. Recently an early version of its genome has been released permitting a route to the cloning and analysis of key proteins. Ascorbate peroxidases (APx) are an important part of the antioxidant defense system of plant cells a...

  16. Endogenous peroxidase activity in brush cell-like cells in the large intestine of the bullfrog tadpole, Rana catesbeiana.

    PubMed

    Sugimoto, K; Ichikawa, Y; Nakamura, I

    1983-01-01

    A special cell type was identified in the mucosal epithelium of the large intestine of the tadpole of the bullfrog, Rana catesbeiana. It is a slender, columnar cell, with a dark, basally situated nucleus. By electron microscopy the cell displays prominent bundles of filaments emerging from each microvillus and extending deep into the cytoplasm without ending in the terminal web. It has longer and more crowded microvilli than the absorptive cell. The specialized cell is also characterized by the presence of many apical vesicles and numerous subapical dense bodies. These cytological features suggest that it may be a brush cell (Rhodin and Dalhamn 1956). These cells displayed endogenous peroxidase activity in smooth and rough endoplasmic reticulum, in the well-developed Golgi apparatus and in apical vesicles. Furthermore, peroxidase reaction product was frequently observed on their luminal surface membrane. These findings suggest that the brush cell in the large intestine of the bullfrog tadpole may be a secretory cell.

  17. Endogenous peroxidase activity in brush cell-like cells in the large intestine of the bullfrog tadpole, Rana catesbeiana.

    PubMed

    Sugimoto, K; Ichikawa, Y; Nakamura, I

    1983-01-01

    A special cell type was identified in the mucosal epithelium of the large intestine of the tadpole of the bullfrog, Rana catesbeiana. It is a slender, columnar cell, with a dark, basally situated nucleus. By electron microscopy the cell displays prominent bundles of filaments emerging from each microvillus and extending deep into the cytoplasm without ending in the terminal web. It has longer and more crowded microvilli than the absorptive cell. The specialized cell is also characterized by the presence of many apical vesicles and numerous subapical dense bodies. These cytological features suggest that it may be a brush cell (Rhodin and Dalhamn 1956). These cells displayed endogenous peroxidase activity in smooth and rough endoplasmic reticulum, in the well-developed Golgi apparatus and in apical vesicles. Furthermore, peroxidase reaction product was frequently observed on their luminal surface membrane. These findings suggest that the brush cell in the large intestine of the bullfrog tadpole may be a secretory cell. PMID:6601990

  18. Changes in Dehydrodiferulic Acids and Peroxidase Activity against Ferulic Acid Associated with Cell Walls during Growth of Pinus pinaster Hypocotyl.

    PubMed Central

    Sanchez, M.; Pena, M. J.; Revilla, G.; Zarra, I.

    1996-01-01

    Hydroxycinnamic acids associated with hypocotyl cell walls of dark-grown seedlings of Pinus pinaster Aiton were extracted with 1 N NaOH and identified by gas chromatography-mass spectrometry. The main hydroxycinnamic acid found was ferulic acid. Diferulic acid dehydrodimers were also found, with the 8,8-coupled isomer (compound 11) being the dehydrodiferulate present in the highest amount. However, the 5,5-coupled isomer, commonly referred to referred to as diferulic acid, was not detected. Two truxillic acids, 4-4[prime]-dihydroxy-3-3[prime]-dimethoxy-[alpha]-truxillic acids I and II, were tentatively identified. The 8,8-coupled dehydrodiferulic acid (compound 11) was the phenolic acid that showed the most conspicuous changes with hypocotyl age as well as along the hypocotyl axis. Peroxidase activity against ferulic acid was found in the apoplastic fluid as well as being ionically and covalently bound to the cell walls. The peroxidase activity increased with hypocotyl age as well as from the subapical toward the basal region of the hypocotyls. A key role in the cell-wall stiffening of 8,8 but not 5,5 dimerization of ferulic acid catalyzed by cell-wall peroxidases is proposed. PMID:12226339

  19. Cancer cell detection and therapeutics using peroxidase-active nanohybrid of gold nanoparticle-loaded mesoporous silica-coated graphene.

    PubMed

    Maji, Swarup Kumar; Mandal, Amal Kumar; Nguyen, Kim Truc; Borah, Parijat; Zhao, Yanli

    2015-05-13

    Development of efficient artificial enzymes is an emerging field in nanobiotechnology, since these artificial enzymes could overcome serious disadvantages of natural enzymes. In this work, a new nanostructured hybrid was developed as a mimetic enzyme for in vitro detection and therapeutic treatment of cancer cells. The hybrid (GSF@AuNPs) was prepared by the immobilization of gold nanoparticles (AuNPs) on mesoporous silica-coated nanosized reduced graphene oxide conjugated with folic acid, a cancer cell-targeting ligand. The GSF@AuNPs hybrid showed unprecedented peroxidase-like activity, monitored by catalytic oxidation of a typical peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), in the presence of H2O2. On basis of this peroxidase activity, the hybrid was utilized as a selective, quantitative, and fast colorimetric detection probe for cancer cells. Finally, the hybrid as a mimetic enzyme was employed for H2O2- and ascorbic acid (AA)-mediated therapeutics of cancer cells. In vitro experiments using human cervical cancer cells (HeLa cells) exhibited the formation of reactive oxygen species (OH(•) radical) in the presence of peroxidase-mimic GSF@AuNPs with either exogenous H2O2 or endogenous H2O2 generated from AA, leading to an enhanced cytotoxicity to HeLa cells. In the case of normal cells (human embryonic kidney HEK 293 cells), the treatment with the hybrid and H2O2 or AA showed no obvious damage, proving selective killing effect of the hybrid to cancer cells.

  20. Significance of Polymorphisms and Expression of Enzyme-Encoding Genes Related to Glutathione in Hematopoietic Cancers and Solid Tumors

    PubMed Central

    Zmorzyński, Szymon; Świderska-Kołacz, Grażyna; Koczkodaj, Dorota; Filip, Agata Anna

    2015-01-01

    Antioxidant compounds such as glutathione and its enzymes have become the focus of attention of medical sciences. Glutathione, a specific tripeptide, is involved in many intercellular processes. The glutathione concentration is determined by the number of GAG repeats in gamma-glutamylcysteine synthetase. GAG polymorphisms are associated with an increased risk of schizophrenia, berylliosis, diabetes, lung cancer, and nasopharyngeal tumors. Cancer cells with high glutathione concentration are resistant to chemotherapy treatment. The oxidized form of glutathione is formed by glutathione peroxidases (GPXs). The changes in activity of GPX1, GPX2, and GPX3 isoforms may be associated with the development of cancers, for example, prostate cancer or even colon cancer. Detoxification of glutathione conjugates is possible due to activity of glutathione S-transferases (GSTs). Polymorphisms in GSTM1, GSTP1, and GSTO1 enzymes increase the risk of developing breast cancer and hepatocellular carcinoma. Gamma-glutamyl transpeptidases (GGTs) are responsible for glutathione degradation. Increased activity of GGT correlates with adverse prognosis in patients with breast cancer. Studies on genes encoding glutathione enzymes are continued in order to determine the correlation between DNA polymorphisms in cancer patients. PMID:26682223

  1. Structure-activity relationships for chemical and glutathione S-transferase-catalysed glutathione conjugation reactions of a series of 2-substituted 1-chloro-4-nitrobenzenes.

    PubMed Central

    Van der Aar, E M; Bouwman, T; Commandeur, J N; Vermeulen, N P

    1996-01-01

    Glutathione S-transferases (GSTs) constitute an important class of phase II (de)toxifying enzymes, catalysing the conjugation of glutathione (GSH) with electrophilic compounds. In the present study, Km, kcat and kcat/Km values for the rat GST 1-1-, 3-3-, 4-4- and 7-7-catalysed conjugation reactions between GSH and a series of 10 different 2-substituted 1-chloro-4-nitrobenzenes, and the second-order rate constants (ks) of the corresponding base-catalysed reactions, were correlated with nine classical physicochemical parameters (electronic, steric and lipophilic) of the substituents and with 16 computer-calculated molecular parameters of the substrates and of the corresponding Meisenheimer complexes with MeS- as a model nucleophile for GS- (charge distributions and several energy values), giving structure-activity relationships. On the basis of an identical dependence of the base-catalysed as well as the GST 1-1- and GST 7-7-catalysed reactions on electronic parameters (among others, Hammett substituent constant sigma p and charge on p-nitro substituents), and the finding that the corresponding reactions catalysed by GSTs 3-3 and 4-4 depend to a significantly lesser extent on these parameters, it was concluded that the Mu-class GST isoenzymes have a rate-determining transition state in the conjugation reaction between 2-substituted 1-chloro-4-nitrobenzenes and GSH which is different from that of the other two GSTs. Several alternative rate-limiting transition states for GST 3-3 and 4-4 are discussed. Furthermore, based on the obtained structure-activity relationships, it was possible to predict the kcat/Km values of the four GST isoenzymes and the ks of the base-catalysed GSH conjugation of 1-chloro-4-nitrobenzene. PMID:8973562

  2. The reactivity of selected acrylate esters toward glutathione and deoxyribonucleosides in vitro: structure-activity relationships.

    PubMed

    McCarthy, T J; Hayes, E P; Schwartz, C S; Witz, G

    1994-05-01

    Acrylate esters are alpha,beta-unsaturated esters used as plastic monomers whose toxicity may involve reaction with tissue nucleophiles via Michael addition. Structure-activity relationships for reactivity of selected esters with glutathione (GSH) and deoxyribonucleosides were investigated in the present studies. The esters investigated were methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, tetraethyleneglycol diacrylate, tetraethyleneglycol dimethacrylate, and ethyleneglycol dimethacrylate. To compare their reactivities toward GSH, esters were incubated for up to 1 hr at 37 degrees C and pH 7.4 with either GSH or red blood cells in phosphate-buffered saline followed by measurement of free thiol. In both systems acrylate electrophilic reactivity decreased with alpha-methyl substitution; however, the decrease in electrophilic reactivity was more evident in the cell-free system than in the red blood cell model. Increased alcohol chain length moderately affected the apparent second-order rate constant for the spontaneous reaction of acrylate esters with GSH, but did not affect potency relative to cellular GSH depletion. The apparent second-order rate constants of bifunctional esters are more than twice the rate constants of the much smaller monofunctional esters. Ethyl acrylate, a reactive acrylate ester based upon glutathione alkylation, has been designated a class 2B (suspect human) carcinogen by the International Agency for Research on Cancer. To detect possible DNA alkylation by acrylate esters in vitro, ethyl acrylate was incubated with deoxyribonucleosides for up to 24 hr at pH 6.7 or 7.4 and 37 degrees C or up to 8 hr and 50 degrees C. HPLC analysis revealed no detectable adduct formation.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Peroxidase-like activity of the Co3O4 nanoparticles used for biodetection and evaluation of antioxidant behavior.

    PubMed

    Jia, Huimin; Yang, Dongfang; Han, Xiangna; Cai, Junhui; Liu, Haiying; He, Weiwei

    2016-03-21

    Nanostructured enzyme mimics are of great interest as promising alternatives to artificial enzymes for biomedical and catalytic applications. Studying the chemical interactions between antioxidants and nano-enzymes may result in a better understanding of the antioxidant capability of antioxidants and may help improve the function of artificial enzymes to better mimic natural enzymes. In this study, using Co3O4 nanoparticles (NPs) as peroxidase mimics to catalyze the oxidation of chromophoric substrates by H2O2, we developed a platform that acts as a biosensor for hydrogen peroxide and glucose and that can study the inhibitory effects of natural antioxidants on peroxidase mimics. This method can be applied specifically to glucose detection in real samples. Three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA), were compared for their antioxidant capabilities. We found that these three antioxidants efficiently inhibit peroxidase-like activity with concentration dependence. The antioxidants showed different efficiencies, in the following order: tannic acid > gallic acid > ascorbic acid. They also showed distinct modes of inhibition based on different interaction mechanisms. This study serves as a proof-of-concept that nano-enzyme mimics can be used to evaluate antioxidant capabilities and to screen enzyme inhibitors. PMID:26911916

  4. Mechanism of pH-switchable peroxidase and catalase-like activities of gold, silver, platinum and palladium.

    PubMed

    Li, Junnan; Liu, Wenqi; Wu, Xiaochun; Gao, Xingfa

    2015-04-01

    Despite being increasingly used as artificial enzymes, little has been known for the origin of the pH-switchable peroxidase-like and catalase-like activities of metals. Using calculations and experiments, we report the mechanisms for both activities and their pH-switchability for metals Au, Ag, Pd and Pt. The calculations suggest that both activities are intrinsic properties of metals, regardless of the surfaces and intersections of facets exposed to environments. The pre-adsorbed OH groups on the surfaces, which are only favorably formed in basic conditions, trigger the switch between both activities and render the pH-switchability. The adsorption energies between H2O2 and metals can be used as convenient descriptors to predict the relative enzyme-like activities of the metals with similar surface morphologies. The results agree with the enzyme-mimic activities that have been experimentally reported for Au, Ag, Pt and predict that Pd should have the similar properties. The prediction, as well as the predicted activity order for the four metals, has been verified by the experimental tests. The results thus provide an in-depth insight into the peroxidase-like and catalase-like activities of the metals and will guide the de novo design, synthesis and application of artificial enzymes based on inorganic materials.

  5. Chcanges in Germinability and Activities of Polyphenol Oxidase and Peroxidase in Seeds of Pentaclethramacrophylla During Lowtemperature Treatment

    NASA Astrophysics Data System (ADS)

    Udosen, I. R.; Nkang, A. E.; Sam, S. M.

    2012-07-01

    Activities of peroxidase (POD) and polyphenol Oxidase (PPO) were investigated in seeds of Pentaclethramacrophylla during low temperature treatment. The seeds from the small-sized fruits (variety A) and those of the big-sized fruits (variety B) showed high germination, with maximum germination values ranging between 60 ñ 90%. Low temperature treatment did not significantly (P< 0.5) affect maximum germination values. Activities of POD and PPO increased initially (2-4 days) but declined with prolonged (6ñ8 days) low temperature treatment.

  6. Glutathione S-transferases interact with AMP-activated protein kinase: evidence for S-glutathionylation and activation in vitro.

    PubMed

    Klaus, Anna; Zorman, Sarah; Berthier, Alexandre; Polge, Cécile; Ramirez, Sacnicte; Michelland, Sylvie; Sève, Michel; Vertommen, Didier; Rider, Mark; Lentze, Nicolas; Auerbach, Daniel; Schlattner, Uwe

    2013-01-01

    AMP-activated protein kinase (AMPK) is a cellular and whole body energy sensor with manifold functions in regulating energy homeostasis, cell morphology and proliferation in health and disease. Here we apply multiple, complementary in vitro and in vivo interaction assays to identify several isoforms of glutathione S-transferase (GST) as direct AMPK binding partners: Pi-family member rat GSTP1 and Mu-family members rat GSTM1, as well as Schistosoma japonicum GST. GST/AMPK interaction is direct and involves the N-terminal domain of the AMPK β-subunit. Complex formation of the mammalian GSTP1 and -M1 with AMPK leads to their enzymatic activation and in turn facilitates glutathionylation and activation of AMPK in vitro. GST-facilitated S-glutathionylation of AMPK may be involved in rapid, full activation of the kinase under mildly oxidative physiological conditions.

  7. Insight into the mechanism revealing the peroxidase mimetic catalytic activity of quaternary CuZnFeS nanocrystals: colorimetric biosensing of hydrogen peroxide and glucose.

    PubMed

    Dalui, Amit; Pradhan, Bapi; Thupakula, Umamahesh; Khan, Ali Hossain; Kumar, Gundam Sandeep; Ghosh, Tanmay; Satpati, Biswarup; Acharya, Somobrata

    2015-05-21

    Artificial enzyme mimetics have attracted immense interest recently because natural enzymes undergo easy denaturation under environmental conditions restricting practical usefulness. We report for the first time chalcopyrite CuZnFeS (CZIS) alloyed nanocrystals (NCs) as novel biomimetic catalysts with efficient intrinsic peroxidase-like activity. Novel peroxidase activities of CZIS NCs have been evaluated by catalytic oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). CZIS NCs demonstrate the synergistic effect of elemental composition and photoactivity towards peroxidase-like activity. The quaternary CZIS NCs show enhanced intrinsic peroxidase-like activity compared to the binary NCs with the same constituent elements. Intrinsic peroxidase-like activity has been correlated with the energy band position of CZIS NCs extracted using scanning tunneling spectroscopy and ultraviolet photoelectron spectroscopy. Kinetic analyses indicate Michaelis-Menten enzyme kinetic model catalytic behavior describing the rate of the enzymatic reaction by correlating the reaction rate with substrate concentration. Typical color reactions arising from the catalytic oxidation of TMB over CZIS NCs with H2O2 have been utilized to establish a simple and sensitive colorimetric assay for detection of H2O2 and glucose. CZIS NCs are recyclable catalysts showing high efficiency in multiple uses. Our study may open up the possibility of designing new photoactive multi-component alloyed NCs as enzyme mimetics in biotechnology applications. PMID:25921601

  8. Peroxidase-like activity of gold nanoparticles stabilized by hyperbranched polyglycidol derivatives over a wide pH range.

    PubMed

    Drozd, Marcin; Pietrzak, Mariusz; Parzuchowski, Paweł; Mazurkiewicz-Pawlicka, Marta; Malinowska, Elżbieta

    2015-12-11

    The aim of this work was to carry out comparative studies on the peroxidase-like activity of gold nanoparticles (AuNPs) stabilized with low molecular weight hyperbranched polyglycidol (HBPG-OH) and its derivative modified with maleic acid residues (HBPG-COOH). The influence of the stabilizer to gold precursor ratio on the size and morphology of nanoparticles obtained was checked, and prepared nanoparticles were characterized by means of transmission electron microscopy and UV-Vis spectroscopy. The results indicated the divergent effect of increasing the concentration of stabilizers (HBPG-OH or HBPG-COOH) on the size of the nanostructures obtained. The gold nanoparticles obtained were characterized as having intrinsic peroxidase-like activity and the mechanism of catalysis in acidic and alkaline mediums was consistent with the standard Michaelis-Menten kinetics, revealing a strong affinity of AuNPs with 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 3, 3', 5, 5'-tetramethylbenzidine (TMB), and significantly lower affinity towards phenol. By comparing the kinetic parameters, a negligible effect of polymeric ligand charge on activity against various types of substrates (anionic or cationic) was indicated. The superiority of steric stabilization via the application of tested low-weight hyperbranched polymers over typical stabilizers in preventing salt-induced aggregation and maintaining high catalytic activity in time was proved. The applied hyperbranched stabilizers provide a good tool for manufacturing gold-based nanozymes, which are highly stable and active over a wide pH range.

  9. Peroxidase-like activity of gold nanoparticles stabilized by hyperbranched polyglycidol derivatives over a wide pH range.

    PubMed

    Drozd, Marcin; Pietrzak, Mariusz; Parzuchowski, Paweł; Mazurkiewicz-Pawlicka, Marta; Malinowska, Elżbieta

    2015-12-11

    The aim of this work was to carry out comparative studies on the peroxidase-like activity of gold nanoparticles (AuNPs) stabilized with low molecular weight hyperbranched polyglycidol (HBPG-OH) and its derivative modified with maleic acid residues (HBPG-COOH). The influence of the stabilizer to gold precursor ratio on the size and morphology of nanoparticles obtained was checked, and prepared nanoparticles were characterized by means of transmission electron microscopy and UV-Vis spectroscopy. The results indicated the divergent effect of increasing the concentration of stabilizers (HBPG-OH or HBPG-COOH) on the size of the nanostructures obtained. The gold nanoparticles obtained were characterized as having intrinsic peroxidase-like activity and the mechanism of catalysis in acidic and alkaline mediums was consistent with the standard Michaelis-Menten kinetics, revealing a strong affinity of AuNPs with 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 3, 3', 5, 5'-tetramethylbenzidine (TMB), and significantly lower affinity towards phenol. By comparing the kinetic parameters, a negligible effect of polymeric ligand charge on activity against various types of substrates (anionic or cationic) was indicated. The superiority of steric stabilization via the application of tested low-weight hyperbranched polymers over typical stabilizers in preventing salt-induced aggregation and maintaining high catalytic activity in time was proved. The applied hyperbranched stabilizers provide a good tool for manufacturing gold-based nanozymes, which are highly stable and active over a wide pH range. PMID:26567596

  10. Platinum nanocatalysts loaded on graphene oxide-dispersed carbon nanotubes with greatly enhanced peroxidase-like catalysis and electrocatalysis activities

    NASA Astrophysics Data System (ADS)

    Wang, Hua; Li, Shuai; Si, Yanmei; Zhang, Ning; Sun, Zongzhao; Wu, Hong; Lin, Yuehe

    2014-06-01

    A powerful enzymatic mimetic has been fabricated by employing graphene oxide (GO) nanocolloids to disperse conductive carbon supports of hydrophobic carbon nanotubes (CNTs) before and after the loading of Pt nanocatalysts. The resulting GOCNT-Pt nanocomposites could present improved aqueous dispersion stability and Pt spatial distribution. Unexpectedly, they could show greatly enhanced peroxidase-like catalysis and electrocatalysis activities in water, as evidenced in the colorimetric and electrochemical investigations in comparison to some inorganic nanocatalysts commonly used. Moreover, it is found that the new enzyme mimetics could exhibit peroxidase-like catalysis activity comparable to natural enzymes; yet, they might circumvent some of their inherent problems in terms of catalysis efficiency, electron transfer, environmental stability, and cost effectiveness. Also, sandwiched electrochemical immunoassays have been successfully conducted using GOCNT-Pt as enzymatic tags. Such a fabrication avenue of noble metal nanocatalysts loaded on well-dispersed conductive carbon supports should be tailored for the design of different enzyme mimics promising the extensive catalysis applications in environmental, medical, industrial, and particularly aqueous biosensing fields.A powerful enzymatic mimetic has been fabricated by employing graphene oxide (GO) nanocolloids to disperse conductive carbon supports of hydrophobic carbon nanotubes (CNTs) before and after the loading of Pt nanocatalysts. The resulting GOCNT-Pt nanocomposites could present improved aqueous dispersion stability and Pt spatial distribution. Unexpectedly, they could show greatly enhanced peroxidase-like catalysis and electrocatalysis activities in water, as evidenced in the colorimetric and electrochemical investigations in comparison to some inorganic nanocatalysts commonly used. Moreover, it is found that the new enzyme mimetics could exhibit peroxidase-like catalysis activity comparable to natural

  11. Resonance Raman study of the active site of Coprinus cinereus peroxidase.

    PubMed

    Smulevich, G; Feis, A; Focardi, C; Tams, J; Welinder, K G

    1994-12-27

    Resonance Raman (RR) spectra for the resting state ferric and the reduced ferrous forms of recombinant Coprinus cinereus peroxidase (CIP), obtained with different excitation wavelengths and in polarized light, are reported. The spectra are compared with those obtained previously for cytochrome c peroxidase expressed in Escherichia coli [(CCP(MI)] and horseradish peroxidase (HRP-C). Although the enzymic properties of CIP and HRP-C are similar, the RR data show that, in terms of the heme cavity structures, CIP and CCP(MI) are much more closely related to each other than to HRP-C. The ferric state of CIP at neutral pH is characteristic mainly of a five-coordinate high spin heme. However, the lower frequency of the v2 mode and a higher frequency of the v(C = C) vinyl stretching modes for CIP as compared to CCP, indicate a higher degree of vibrational coupling between the two modes in CIP. In addition, CIP is rather unstable under low laser power irradiation as an irreversible transition to a six-coordinate high spin heme followed by a second transition to a six-coordinate low spin heme is observed. This instability of CIP as compared to CCP(MI) is proposed to be a consequence of the presence of a distal Phe54 in CIP rather than the homologous Trp51 in CCP, as Trp51 is hydrogen-bonded to a distal water molecule located above the heme Fe thereby preventing its coordination in CCP. In CIP the FeII-His RR band has two components with frequencies at 230 and 211 cm-1.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Three-Dimensional Graphene Supported Bimetallic Nanocomposites with DNA Regulated-Flexibly Switchable Peroxidase-Like Activity.

    PubMed

    Yuan, Fang; Zhao, Huimin; Zang, Hongmei; Ye, Fei; Quan, Xie

    2016-04-20

    A synergistic bimetallic enzyme mimetic catalyst, three-dimensional (3D) graphene/Fe3O4-AuNPs, was successfully fabricated which exhibited flexibly switchable peroxidase-like activity. Compared to the traditional 2D graphene-based monometallic composite, the introduced 3D structure, which was induced by the addition of glutamic acid, and bimetallic anchoring approach dramatically improved the catalytic activity, as well as the catalysis velocity and its affinity for substrate. Herein, Fe3O4NPs acted as supporters for AuNPs, which contributed to enhance the efficiency of electron transfer. On the basis of the measurement of Mott-Schottky plots of graphene and metal anchored hybrids, the catalysis mechanism was elucidated by the decrease of Fermi level resulted from the chemical doping behavior. Notably, the catalytic activity was able to be regulated by the adsorption and desorption of single-stranded DNA molecules, which laid a basis for its utilization in the construction of single-stranded DNA-based colorimetric biosensors. This strategy not only simplified the operation process including labeling, modification, and imprinting, but also protected the intrinsic affinity between the target and biological probe. Accordingly, based on the peroxidase-like activity and its controllability, our prepared nanohybrids was successfully adopted in the visualized and label-free sensing detections of glucose, sequence-specific DNA, mismatched nucleotides, and oxytetracycline. PMID:27018504

  13. Laccase and manganese peroxidase activities of Phellinus robustus and Ganoderma adspersum grown on food industry wastes in submerged fermentation.

    PubMed

    Songulashvili, G; Elisashvili, V; Wasser, S; Nevo, E; Hadar, Y

    2006-09-01

    Phellinus robustus produced both laccase (700-4,000 U l(-1)) and manganese peroxidase (MnP) (1,000-11,300 U l(-1)) in fermentation of nine food wastes, whereas Ganoderma adspersum produced only laccase (600-34,000 U l(-1)). Glucose provided high laccase and MnP activity of P. robustus but repressed enzyme production by G. adspersum. Ammonium sulphate and ammonium tartrate increased the P. robustus laccase yield (3-fold), whereas the accumulation of MnP was not enhanced by additional nitrogen. PMID:16823599

  14. The circadian clock regulates rhythmic activation of the NRF2/glutathione-mediated antioxidant defense pathway to modulate pulmonary fibrosis

    PubMed Central

    Pekovic-Vaughan, Vanja; Gibbs, Julie; Yoshitane, Hikari; Yang, Nan; Pathiranage, Dharshika; Guo, Baoqiang; Sagami, Aya; Taguchi, Keiko; Bechtold, David; Loudon, Andrew; Yamamoto, Masayuki; Chan, Jefferson; van der Horst, Gijsbertus T.J.; Fukada, Yoshitaka; Meng, Qing-Jun

    2014-01-01

    The disruption of the NRF2 (nuclear factor erythroid-derived 2-like 2)/glutathione-mediated antioxidant defense pathway is a critical step in the pathogenesis of several chronic pulmonary diseases and cancer. While the mechanism of NRF2 activation upon oxidative stress has been widely investigated, little is known about the endogenous signals that regulate the NRF2 pathway in lung physiology and pathology. Here we show that an E-box-mediated circadian rhythm of NRF2 protein is essential in regulating the rhythmic expression of antioxidant genes involved in glutathione redox homeostasis in the mouse lung. Using an in vivo bleomycin-induced lung fibrosis model, we reveal a clock “gated” pulmonary response to oxidative injury, with a more severe fibrotic effect when bleomycin was applied at a circadian nadir in NRF2 levels. Timed administration of sulforaphane, an NRF2 activator, significantly blocked this phenotype. Moreover, in the lungs of the arrhythmic ClockΔ19 mice, the levels of NRF2 and the reduced glutathione are constitutively low, associated with increased protein oxidative damage and a spontaneous fibrotic-like pulmonary phenotype. Our findings reveal a pivotal role for the circadian control of the NRF2/glutathione pathway in combating oxidative/fibrotic lung damage, which might prompt new chronotherapeutic strategies for the treatment of human lung diseases, including idiopathic pulmonary fibrosis. PMID:24637114

  15. Oscillations in the peroxidase-oxidase reaction: a comparison of different peroxidases.

    PubMed

    Kummer, U; Valeur, K R; Baier, G; Wegmann, K; Olsen, L F

    1996-04-17

    The nonlinear behavior of the peroxidase-oxidase reaction was studied using structurally different peroxidases. For the first time sustained oscillations with peroxidases other than horseradish peroxidase in a single-enzyme system were observed. All peroxidases that showed significant oxidase activity were able to generate sustained oscillations. When adjusting the overall reaction rate, either of the two modifiers 2,4-dichlorophenol or Methylene blue could be omitted from the reaction. Due to the observation of different enzyme intermediates when using different peroxidases, we conclude that the mechanisms responsible for oscillatory kinetics may vary from one peroxidase to the other.

  16. Structural re-arrangement and peroxidase activation of cytochrome c by anionic analogues of vitamin E, tocopherol succinate and tocopherol phosphate.

    PubMed

    Yanamala, Naveena; Kapralov, Alexander A; Djukic, Mirjana; Peterson, Jim; Mao, Gaowei; Klein-Seetharaman, Judith; Stoyanovsky, Detcho A; Stursa, Jan; Neuzil, Jiri; Kagan, Valerian E

    2014-11-21

    Cytochrome c is a multifunctional hemoprotein in the mitochondrial intermembrane space whereby its participation in electron shuttling between respiratory complexes III and IV is alternative to its role in apoptosis as a peroxidase activated by interaction with cardiolipin (CL), and resulting in selective CL peroxidation. The switch from electron transfer to peroxidase function requires partial unfolding of the protein upon binding of CL, whose specific features combine negative charges of the two phosphate groups with four hydrophobic fatty acid residues. Assuming that other endogenous small molecule ligands with a hydrophobic chain and a negatively charged functionality may activate cytochrome c into a peroxidase, we investigated two hydrophobic anionic analogues of vitamin E, α-tocopherol succinate (α-TOS) and α-tocopherol phosphate (α-TOP), as potential inducers of peroxidase activity of cytochrome c. NMR studies and computational modeling indicate that they interact with cytochrome c at similar sites previously proposed for CL. Absorption spectroscopy showed that both analogues effectively disrupt the Fe-S(Met(80)) bond associated with unfolding of cytochrome c. We found that α-TOS and α-TOP stimulate peroxidase activity of cytochrome c. Enhanced peroxidase activity was also observed in isolated rat liver mitochondria incubated with α-TOS and tBOOH. A mitochondria-targeted derivative of TOS, triphenylphosphonium-TOS (mito-VES), was more efficient in inducing H2O2-dependent apoptosis in mouse embryonic cytochrome c(+/+) cells than in cytochrome c(-/-) cells. Essential for execution of the apoptotic program peroxidase activation of cytochrome c by α-TOS may contribute to its known anti-cancer pharmacological activity. PMID:25278024

  17. Structural Re-arrangement and Peroxidase Activation of Cytochrome c by Anionic Analogues of Vitamin E, Tocopherol Succinate and Tocopherol Phosphate*

    PubMed Central

    Yanamala, Naveena; Kapralov, Alexander A.; Djukic, Mirjana; Peterson, Jim; Mao, Gaowei; Klein-Seetharaman, Judith; Stoyanovsky, Detcho A.; Stursa, Jan; Neuzil, Jiri; Kagan, Valerian E.

    2014-01-01

    Cytochrome c is a multifunctional hemoprotein in the mitochondrial intermembrane space whereby its participation in electron shuttling between respiratory complexes III and IV is alternative to its role in apoptosis as a peroxidase activated by interaction with cardiolipin (CL), and resulting in selective CL peroxidation. The switch from electron transfer to peroxidase function requires partial unfolding of the protein upon binding of CL, whose specific features combine negative charges of the two phosphate groups with four hydrophobic fatty acid residues. Assuming that other endogenous small molecule ligands with a hydrophobic chain and a negatively charged functionality may activate cytochrome c into a peroxidase, we investigated two hydrophobic anionic analogues of vitamin E, α-tocopherol succinate (α-TOS) and α-tocopherol phosphate (α-TOP), as potential inducers of peroxidase activity of cytochrome c. NMR studies and computational modeling indicate that they interact with cytochrome c at similar sites previously proposed for CL. Absorption spectroscopy showed that both analogues effectively disrupt the Fe-S(Met80) bond associated with unfolding of cytochrome c. We found that α-TOS and α-TOP stimulate peroxidase activity of cytochrome c. Enhanced peroxidase activity was also observed in isolated rat liver mitochondria incubated with α-TOS and tBOOH. A mitochondria-targeted derivative of TOS, triphenylphosphonium-TOS (mito-VES), was more efficient in inducing H2O2-dependent apoptosis in mouse embryonic cytochrome c+/+ cells than in cytochrome c−/− cells. Essential for execution of the apoptotic program peroxidase activation of cytochrome c by α-TOS may contribute to its known anti-cancer pharmacological activity. PMID:25278024

  18. Activation of family C G-protein-coupled receptors by the tripeptide glutathione.

    PubMed

    Wang, Minghua; Yao, Yi; Kuang, Donghui; Hampson, David R

    2006-03-31

    The Family C G-protein-coupled receptors include the metabotropic glutamate receptors, the gamma-aminobutyric acid, type B (GABAB) receptor, the calcium-sensing receptor (CaSR), which participates in the regulation of calcium homeostasis in the body, and a diverse group of sensory receptors that encompass the amino acid-activated fish 5.24 chemosensory receptor, the mammalian T1R taste receptors, and the V2R pheromone receptors. A common feature of Family C receptors is the presence of an amino acid binding site. In this study, a preliminary in silico analysis of the size and shape of the amino acid binding pocket in selected Family C receptors suggested that some members of this family could accommodate larger ligands such as peptides. Subsequent screening and docking experiments identified GSH as a potential ligand or co-ligand at the fish 5.24 receptor and the rat CaSR. These in silico predictions were confirmed using an [3H]GSH radioligand binding assay and a fluorescence-based functional assay performed on wild-type and chimeric receptors. Glutathione was shown to act as an orthosteric agonist at the 5.24 receptor and as a potent enhancer of calcium-induced activation of the CaSR. Within the mammalian receptors, this effect was specific to the CaSR because GSH neither directly activated nor potentiated other Family C receptors including GPRC6A (the putative mammalian homolog of the fish 5.24 receptor), the metabotropic glutamate receptors, or the GABAB receptor. Our findings reveal a potential new role for GSH and suggest that this peptide may act as an endogenous modulator of the CaSR in the parathyroid gland where this receptor is known to control the release of parathyroid hormone, and in other tissues such as the brain and gastrointestinal tract where the role of the calcium receptor appears to subserve other, as yet unknown, physiological functions. PMID:16455645

  19. Elevated ROS-scavenging enzymes contribute to acclimation to UV-B exposure in transplastomic tobacco plants, reducing the role of plastid peroxidases.

    PubMed

    Czégény, Gyula; Le Martret, Bénédicte; Pávkovics, Dóra; Dix, Philip J; Hideg, Éva

    2016-08-20

    Leaf peroxidases play a key role in the successful acclimation of plants to low UV-B doses. The aim of the present study was to examine whether selective enhancement of alternative chloroplast antioxidant pathways achieved by chloroplast transformation affected the need for peroxidase defense. Transplastomic tobacco lines expressing glutathione reductase in combination with either dehydroascorbate reductase or glutathione-S-transferase in their plastids exhibited better tolerance to supplemental UV-B than wild type plants. After 10days UV treatment, both the maximum and effective quantum yields of PSII decreased in the wild type by 10% but were unaffected in either of the transformed lines. Activities of total peroxidase and ascorbate peroxidase, in addition to dehydroascorbate reductase and gluthatione-S-transferase, were increased by UV in all lines. Gluthatione reductase activity was unaffected by UV in the transplastomic line engineered to have a higher constitutive level of this enzyme, but increased in the two other genotypes. However, the observed more successful acclimation required less activation of peroxidases in the doubly transformed plants than in the wild type and less increase in non-enzymatic hydroxyl radical neutralization in the dehydroascorbate reductase plus glutathione reductase fortified plants than in either of the other lines. These results highlight the fundamental role of efficient glutathione, and especially ascorbate, recycling in the chloroplast in response to exposure of plants to UV-B. They also identify chloroplast localized peroxidases among the large variety of leaf peroxidases as essential elements of defense, supporting our earlier hypothesis on hydrogen peroxide UV-B photo-cleavage as the primary mechanism behind damage.

  20. Elevated ROS-scavenging enzymes contribute to acclimation to UV-B exposure in transplastomic tobacco plants, reducing the role of plastid peroxidases.

    PubMed

    Czégény, Gyula; Le Martret, Bénédicte; Pávkovics, Dóra; Dix, Philip J; Hideg, Éva

    2016-08-20

    Leaf peroxidases play a key role in the successful acclimation of plants to low UV-B doses. The aim of the present study was to examine whether selective enhancement of alternative chloroplast antioxidant pathways achieved by chloroplast transformation affected the need for peroxidase defense. Transplastomic tobacco lines expressing glutathione reductase in combination with either dehydroascorbate reductase or glutathione-S-transferase in their plastids exhibited better tolerance to supplemental UV-B than wild type plants. After 10days UV treatment, both the maximum and effective quantum yields of PSII decreased in the wild type by 10% but were unaffected in either of the transformed lines. Activities of total peroxidase and ascorbate peroxidase, in addition to dehydroascorbate reductase and gluthatione-S-transferase, were increased by UV in all lines. Gluthatione reductase activity was unaffected by UV in the transplastomic line engineered to have a higher constitutive level of this enzyme, but increased in the two other genotypes. However, the observed more successful acclimation required less activation of peroxidases in the doubly transformed plants than in the wild type and less increase in non-enzymatic hydroxyl radical neutralization in the dehydroascorbate reductase plus glutathione reductase fortified plants than in either of the other lines. These results highlight the fundamental role of efficient glutathione, and especially ascorbate, recycling in the chloroplast in response to exposure of plants to UV-B. They also identify chloroplast localized peroxidases among the large variety of leaf peroxidases as essential elements of defense, supporting our earlier hypothesis on hydrogen peroxide UV-B photo-cleavage as the primary mechanism behind damage. PMID:27448725

  1. TiO2@CeOx core-shell nanoparticles as artificial enzymes with peroxidase-like activity.

    PubMed

    Artiglia, Luca; Agnoli, Stefano; Paganini, Maria Cristina; Cattelan, Mattia; Granozzi, Gaetano

    2014-11-26

    The Ce4+↔Ce3+ redox switch is at the basis of an all-inorganic catalytic cycle that is capable of mimicking the activity of several natural redox enzymes. The efficiency of these artificial enzymes (nanozymes) strongly depends on the Ce4+/Ce3+ ratio. By capitalizing on the results obtained on oxide/oxide model systems, we implemented a simple and effective procedure to obtain conformal TiO2@CeOx core-shell nanoparticles whose thickness is controlled with single-layer precision. Since the Ce3+ species are stabilized only at the interface by the electronic hybridization with the TiO2 states, the modulation of the shell thickness offers a simple method to tailor the Ce4+/Ce3+ ratio and therefore the catalytic properties. The activity of these nanoparticles as artificial peroxidase-like enzymes was tested, showing exceptional performances, even better than natural horseradish peroxidase enzyme. The main advantage with respect to other oxide/oxide nanozymes is that our nanoparticles, having a tunable Ce4+/Ce3+ ratio, are efficient already at low H2O2 concentrations.

  2. Platinum nanocatalysts loaded on graphene oxide-dispersed carbon nanotubes with greatly enhanced peroxidase-like catalysis and electrocatalysis activities.

    PubMed

    Wang, Hua; Li, Shuai; Si, Yanmei; Zhang, Ning; Sun, Zongzhao; Wu, Hong; Lin, Yuehe

    2014-07-21

    A powerful enzymatic mimetic has been fabricated by employing graphene oxide (GO) nanocolloids to disperse conductive carbon supports of hydrophobic carbon nanotubes (CNTs) before and after the loading of Pt nanocatalysts. The resulting GOCNT-Pt nanocomposites could present improved aqueous dispersion stability and Pt spatial distribution. Unexpectedly, they could show greatly enhanced peroxidase-like catalysis and electrocatalysis activities in water, as evidenced in the colorimetric and electrochemical investigations in comparison to some inorganic nanocatalysts commonly used. Moreover, it is found that the new enzyme mimetics could exhibit peroxidase-like catalysis activity comparable to natural enzymes; yet, they might circumvent some of their inherent problems in terms of catalysis efficiency, electron transfer, environmental stability, and cost effectiveness. Also, sandwiched electrochemical immunoassays have been successfully conducted using GOCNT-Pt as enzymatic tags. Such a fabrication avenue of noble metal nanocatalysts loaded on well-dispersed conductive carbon supports should be tailored for the design of different enzyme mimics promising the extensive catalysis applications in environmental, medical, industrial, and particularly aqueous biosensing fields.

  3. Glutathione S-transferase activity in follicular fluid from women undergoing ovarian stimulation: role in maturation.

    PubMed

    Meijide, Susana; Hernández, M Luisa; Navarro, Rosaura; Larreategui, Zaloa; Ferrando, Marcos; Ruiz-Sanz, José Ignacio; Ruiz-Larrea, M Begoña

    2014-10-01

    Female infertility involves an emotional impact for the woman, often leading to a state of anxiety and low self-esteem. The assisted reproduction techniques (ART) are used to overcome the problem of infertility. In a first step of the in vitro fertilization therapy women are subjected to an ovarian stimulation protocol to obtain mature oocytes, which will result in competent oocytes necessary for fertilization to occur. Ovarian stimulation, however, subjects the women to a high physical and psychological stress, thus being essential to improve ART and to find biomarkers of dysfunction and fertility. GSH is an important antioxidant, and is also used in detoxification reactions, catalysed by glutathione S-transferases (GST). In the present work, we have investigated the involvement of GST in follicular maturation. Patients with fertility problems and oocyte donors were recruited for the study. From each woman follicles at two stages of maturation were extracted at the preovulatory stage. Follicular fluid was separated from the oocyte by centrifugation and used as the enzyme source. GST activity was determined based on its conjugation with 3,4-dichloronitrobenzene and the assay was adapted to a 96-well microplate reader. The absorbance was represented against the incubation time and the curves were adjusted to linearity (R(2)>0.990). Results showed that in both donors and patients GST activity was significantly lower in mature oocytes compared to small ones. These results suggest that GST may play a role in the follicle maturation by detoxifying xenobiotics, thus contributing to the normal development of the oocyte. Supported by FIS/FEDER (PI11/02559), Gobierno Vasco (Dep. Educación, Universiades e Investigación, IT687-13), and UPV/EHU (CLUMBER UFI11/20 and PES13/58). The work was approved by the Ethics Committee of the UPV/EHU (CEISH/96/2011/RUIZLARREA), and performed according to the UPV/EHU and IVI-Bilbao agreement (Ref. 2012/01).

  4. Isoniazid-resistance conferring mutations in Mycobacterium tuberculosis KatG: Catalase, peroxidase, and INH-NADH adduct formation activities

    PubMed Central

    Cade, Christine E; Dlouhy, Adrienne C; Medzihradszky, Katalin F; Salas-Castillo, Saida Patricia; Ghiladi, Reza A

    2010-01-01

    Mycobacterium tuberculosis catalase-peroxidase (KatG) is a bifunctional hemoprotein that has been shown to activate isoniazid (INH), a pro-drug that is integral to frontline antituberculosis treatments. The activated species, presumed to be an isonicotinoyl radical, couples to NAD+/NADH forming an isoniazid-NADH adduct that ultimately confers anti-tubercular activity. To better understand the mechanisms of isoniazid activation as well as the origins of KatG-derived INH-resistance, we have compared the catalytic properties (including the ability to form the INH-NADH adduct) of the wild-type enzyme to 23 KatG mutants which have been associated with isoniazid resistance in clinical M. tuberculosis isolates. Neither catalase nor peroxidase activities, the two inherent enzymatic functions of KatG, were found to correlate with isoniazid resistance. Furthermore, catalase function was lost in mutants which lacked the Met-Tyr-Trp crosslink, the biogenic cofactor in KatG which has been previously shown to be integral to this activity. The presence or absence of the crosslink itself, however, was also found to not correlate with INH resistance. The KatG resistance-conferring mutants were then assayed for their ability to generate the INH-NADH adduct in the presence of peroxide (t-BuOOH and H2O2), superoxide, and no exogenous oxidant (air-only background control). The results demonstrate that residue location plays a critical role in determining INH-resistance mechanisms associated with INH activation; however, different mutations at the same location can produce vastly different reactivities that are oxidant-specific. Furthermore, the data can be interpreted to suggest the presence of a second mechanism of INH-resistance that is not correlated with the formation of the INH-NADH adduct. PMID:20054829

  5. Glutathione S-transferase and gamma-glutamyl transpeptidase activities in cultured rat hepatocytes treated with tocotrienol and tocopherol.

    PubMed

    Ong, F B; Wan Ngah, W Z; Shamaan, N A; Md Top, A G; Marzuki, A; Khalid, A K

    1993-09-01

    1. The effect of tocotrienol and tocopherol on glutathione S-transferase (GST) and gamma-glutamyl transpeptidase (GGT) activities in cultured rat hepatocytes were investigated. 2. Tocotrienol and tocopherol significantly decreased GGT activities at 5 days in culture but tocotrienol also significantly decreased GGT activities at 1-2 days. 3. Tocotrienol and tocopherol treatment significantly decreased GST activities at 3 days compared to the control but tocotrienol also decreased GST activities at 1-3 days. 4. Tocotrienol showed a more pronounced effect at a dosage of greater than 50 microM tocotrienol at 1-3 days in culture compared to the control.

  6. Effect of treatment on erythrocyte phosphoribosyl pyrophosphate synthetase and glutathione reductase activity in patients with primary gout.

    PubMed Central

    Braven, J; Hardwell, T R; Hickling, P; Whittaker, M

    1986-01-01

    The activities of erythrocyte phosphoribosyl pyrophosphate (PRPP) synthetase and glutathione reductase (GTR) were studied in 26 patients with primary gout who were receiving no treatment or treatment with either allopurinol or azapropazone, and compared with the activity in a group of healthy controls. The activity of PRPP synthetase was significantly higher in the gout group and was not influenced by either drug. No significant difference in the activity of GTR was observed. The failure of either drug to suppress the increased activity of PRPP synthetase associated with gout is discussed. PMID:3024593

  7. Site-directed mutagenesis of tobacco anionic peroxidase: Effect of additional aromatic amino acids on stability and activity.

    PubMed

    Poloznikov, A A; Zakharova, G S; Chubar, T A; Hushpulian, D M; Tishkov, V I; Gazaryan, I G

    2015-08-01

    Tobacco anionic peroxidase (TOP) is known to effectively catalyze luminol oxidation without enhancers, in contrast to horseradish peroxidase (HRP). To pursue structure-activity relationship studies for TOP, two amino acids have been chosen for mutation, namely Thr151, close to the heme plane, and Phe140 at the entrance to the active site pocket. Three mutant forms TOP F140Y, T151W and F140Y/T151W have been expressed in Escherichia coli, and reactivated to yield active enzymes. Single-point mutations introducing additional aromatic amino acid residues at the surface of TOP exhibit a significant effect on the enzyme catalytic activity and stability as judged by the results of steady-state and transient kinetics studies. TOP T151W is up to 4-fold more active towards a number of aromatic substrates including luminol, whereas TOP F140Y is 2-fold more stable against thermal inactivation and 8-fold more stable in the reaction course. These steady-state observations have been rationalized with the help of transient kinetic studies on the enzyme reaction with hydrogen peroxide in a single turnover regime. The stopped-flow data reveal (a) an increased stability of F140Y Compound I towards hydrogen peroxide, and thus, a higher operational stability as compared to the wild-type enzyme, and (b) a lesser leakage of oxidative equivalents from TOP T151W Compound I resulting in the increased catalytic activity. The results obtained show that TOP unique properties can be further improved for practical applications by site-directed mutagenesis.

  8. Association of mercury and selenium with altered glutathione metabolism and oxidative stress in diving ducks from the San Francisco Bay region

    USGS Publications Warehouse

    Hoffman, D.J.; Ohlendorf, H.M.; Marn, C.M.; Pendleton, G.W.

    1998-01-01

    Adult male greater scaup (Aythya marila) (GS), surf scoters (Melanitta perspicillata)(SS), and ruddy ducks (Oxyura jamaicensis) (RD) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic selenium (Se) concentrations were highest in GS (geometric mean = 67 ppm, dw) and SS (119 ppm) in Suisun Bay, whereas hepatic mercury (Hg) was highest (19 ppm) in GS and SS from Tomales Bay. Hepatic Se and Hg were lower in RD and did not differ between locations. Hepatic supernatants were assayed for enzymes related to glutathione metabolism and antioxidant activity including: glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase (GSH-peroxidase), glutathione reductase (GSSG-reductase), and glutathione-S-transferase (GSH-transferase). GSH-peroxidase activity was higher in SS and RD, and G-6-PDH higher in GS and SS from Suisun Bay than Tomales Bay. GSSG-reductase was higher in SS from Suisun Bay. The ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) was greater in all species from Tomales Bay. The following significant relationships were found in one or more species with increasing hepatic Hg concentration: lower body, liver and heart weights; decreased hepatic GSH concentration, G-6-PDH and GSH-peroxidase activities; increased ratio of GSSG to GSH, and increased GSSG-reductase activity. With increasing hepatic Se concentration, GSH-peroxidase increased but GSH decreased. It is concluded that measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. Concentrations of mercury and selenium and variable affected have been associated with adverse effects on reproduction and neurological function in experimental studies with mallards.

  9. [Total Peroxidase and Catalase Activity of Luminous Basidiomycetes Armillaria borealis and Neonothopanus nambi in Comparison with the Level of Light Emission].

    PubMed

    Mogil'naya, O A; Ronzhin, N O; Medvedeva, S E; Bondar, V S

    2015-01-01

    The peroxidase and catalase activities in the mycelium of luminous basidiomycetes Armillaria borealis and Neonothopanus nambi in normal conditions and under stress were compared. An increase in the luminescence level was observed under stress, as well as an increase in peroxidase and catalase activities. Moreover, the peroxidase activity in extracts of A. borealis mycelium was found to be almost one and a half orders of magnitude higher, and the catalase activity more than two orders of magnitude higher in comparison with the N. nambi mycelium. It can be suggested that the difference between the brightly luminescent and dimly luminescent mycelium of N. nambi is due to the content of H2O2 or other peroxide compounds.

  10. Depollution potential of three macrophytes: exudated, wall-bound and intracellular peroxidase activities plus intracellular phenol concentrations.

    PubMed

    Larue, Camille; Korboulewsky, Nathalie; Wang, Runying; Mévy, Jean-Philippe

    2010-10-01

    The aim of this study was to investigate the potential role of three macrophyte species (Iris pseudacorus, Typha latifolia and Phragmites australis) for detoxication of xenobiotics, and to study their variations with seasons or concentrations of sewage sludge from the food industry. For this purpose, some aspects of the green liver concept were explored through peroxidase measurements in three compartments in roots: intracellular, cell wall and extracellular. In addition, phenol concentrations were also measured in order to assess heavy metal detoxication potential. Enzyme activities and phenol concentrations were overall lower in winter according to the phenological stages and some sludge effects occurred. Results show that P. australis roots exuded and contained more peroxidase in all seasons: 17 U/g (1373 U/g protein), 0.8 U/g (613 U/g protein) and 4.8 U/g (1329 U/g protein) in intracellular compartments, cell wall and exudates, respectively. In contrast, the highest phenol concentration was found in I. pseudacorus roots: 3.58 mg eq. [corrected] gallic acid/g. Hence, in constructed wetlands, P. australis is suitable for organic waste water treatment, while I. pseudacorus should be used in the case of waters highly charged with heavy metals.

  11. Low Concentration of Silver Nanoparticles Not Only Enhances the Activity of Horseradish Peroxidase but Alter the Structure Also

    PubMed Central

    Karim, Zoheb; Adnan, Rohana; Ansari, Mohd Saquib

    2012-01-01

    Chemical synthesis of Ag-NPs was carried out using reduction method. The reduction mechanistic approach of silver ions was found to be a basic clue for the formation of the Ag-NPs. The nanoparticles were characterized by UV-vis, FT-IR and TEM analysis. We had designed some experiments in support of our hypothesis, “low concentrations of novel nanoparticles (silver and gold) increases the activity of plant peroxidases and alter their structure also”, we had used Ag-NPs and HRP as models. The immobilization/interaction experiment had demonstrated the specific concentration range of the Ag-NPs and within this range, an increase in HRP activity was reported. At 0.08 mM concentration of Ag-NPs, 50% increase in the activity yield was found. The U.V-vis spectra had demonstrated the increase in the absorbance of HRP within the reported concentration range (0.06–0.12 mM). Above and below this concentration range there was a decrease in the activity of HRP. The results that we had found from the fluorescence spectra were also in favor of our hypothesis. There was a maximum increase in ellipticity and α-helix contents in the presence of 0.08 mM concentration of Ag-NPs, demonstrated by circular dichroism (CD) spectra. Finally, incubation of a plant peroxidase, HRP with Ag-NPs, within the reported concentration range not only enhances the activity but also alter the structure. PMID:22848490

  12. Peroxidase-like activity of gold nanoparticles stabilized by hyperbranched polyglycidol derivatives over a wide pH range

    NASA Astrophysics Data System (ADS)

    Drozd, Marcin; Pietrzak, Mariusz; Parzuchowski, Paweł; Mazurkiewicz-Pawlicka, Marta; Malinowska, Elżbieta

    2015-12-01

    The aim of this work was to carry out comparative studies on the peroxidase-like activity of gold nanoparticles (AuNPs) stabilized with low molecular weight hyperbranched polyglycidol (HBPG-OH) and its derivative modified with maleic acid residues (HBPG-COOH). The influence of the stabilizer to gold precursor ratio on the size and morphology of nanoparticles obtained was checked, and prepared nanoparticles were characterized by means of transmission electron microscopy and UV-Vis spectroscopy. The results indicated the divergent effect of increasing the concentration of stabilizers (HBPG-OH or HBPG-COOH) on the size of the nanostructures obtained. The gold nanoparticles obtained were characterized as having intrinsic peroxidase-like activity and the mechanism of catalysis in acidic and alkaline mediums was consistent with the standard Michaelis-Menten kinetics, revealing a strong affinity of AuNPs with 2, 2‧-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 3, 3‧, 5, 5‧-tetramethylbenzidine (TMB), and significantly lower affinity towards phenol. By comparing the kinetic parameters, a negligible effect of polymeric ligand charge on activity against various types of substrates (anionic or cationic) was indicated. The superiority of steric stabilization via the application of tested low-weight hyperbranched polymers over typical stabilizers in preventing salt-induced aggregation and maintaining high catalytic activity in time was proved. The applied hyperbranched stabilizers provide a good tool for manufacturing gold-based nanozymes, which are highly stable and active over a wide pH range.

  13. Enzymatic changes in phenylalanine ammonia-lyase, cinnamic-4-hydroxylase, capsaicin synthase, and peroxidase activities in capsicum under drought stress.

    PubMed

    Phimchan, Paongpetch; Chanthai, Saksit; Bosland, Paul W; Techawongstien, Suchila

    2014-07-23

    Penylalanine ammonia-lyase (PAL), cinnamic-4-hydroxylase (C4H), capsaicin synthase (CS), and peroxidase (POD) are involved in the capsaicinoid biosynthesis pathway and may be altered in cultivars with different pungency levels. This study clarified the action of these enzymes under drought stress for hot Capsicum cultivars with low, medium,and high pungency levels. At the flowering stage, control plants were watered at field capacity, whereas drought-induced plants were subjected to gradual drought stress. Under drought stress, PAL, C4H, CS, and POD enzyme activities increased as compared to the non-drought-stressed plants. A novel discovery was that PAL was the critical enzyme in capsaicinoid biosynthesis under drought stress because its activities and capsaicinoid increased across the different pungency levels of hot pepper cultivars examined.

  14. Metals content of Glossoscolex paulistus extracellular hemoglobin: Its peroxidase activity and the importance of these ions in the protein stability.

    PubMed

    Caruso, Celia S; Biazin, Ezer; Carvalho, Francisco A O; Tabak, Marcel; Bachega, José F R

    2016-08-01

    In this work we investigate the presence of divalent cations bound to the Glossoscolex paulistus (HbGp) hemoglobin and their effect over the protein stability and the peroxidase (POD) activity. Atomic absorption studies show that the HbGp iron content is consistent with the presence of 144 ions per protein. Moreover, using iron as a reference, the content of calcium was estimated as 30±4 ions per protein, independently of the EDTA pre-treatment or not prior to the acidic treatment performed in the protein digestion. The zinc content was 14±2 ions in the absence of EDTA pre-treatment, and 3±1 ions per protein in the presence of EDTA pre-treatment, implying the presence of one zinc ion per protomer (1/12 of the whole molecule). Finally, the copper concentration is negligible. Different from the vertebrate hemoglobins, where the effectors are usually organic anions, the hexagonal bilayer hemoglobins have as effectors inorganic cations that increase the oxygen affinity and stabilize the structure. Previous studies have suggested that the presence of divalent cations, such as copper and zinc, is related to the different types of antioxidant enzymatic activities as the superoxide dismutase (SOD) activity shown by giant hemoglobin from Lumbricus terrestris (HbLt). Recently, studies on HbGp crystal structure have confirmed the presence of Zn(2+) and Ca(2+) binding sites. The Ca(2+) sites are similar as observed in the HbLt crystal structure. Otherwise, the Zn(2+) sites have no relation with those observed in Cu/Zn SODs. Our peroxidase assays with guaiacol confirm the POD activity and the effect of the zinc ions for HbGp. Our present results on HbGp metal content and their stability effects is the first step to understand the role of these cations in HbGp function in the future. PMID:27221949

  15. Dynamics of glutathione regulation in Schistosoma mansoni: correlations with the acute effects of oltipraz

    SciTech Connect

    Morrison, D.D.

    1984-01-01

    Glutathione is present in adult Schistosoma mansoni (0.336 +/- 0.012 nmol/mg protein) at significantly lower levels than uninfected host tissues (1.051 +/- 0.013 nmol/mg protein, liver; 0.627 +/- 0.013 nmol/mg protein, kidney). Host hepatic glutathione levels decline significantly during the course of infection, while renal cortical glutathione levels are unaffected. Of the enzymes regulating glutathione utilization, glutathione reductase in the male parasite exhibits a specific activity of 10.3 +/- 4.2 nmol/mg protein, 15% of hepatic values. The apparent glutathione S-transferase activity was 26 +/- 7 ..mu..mol conjugate formed/min/mg protein with p-nitrobenzyl chloride as substrate (13% of hepatic values) and 526 +/- 18 ..mu..mol conjugate formed/min/mg protein with 1-chloro-2,4-dinitrobenzene as substrate (43% of hepatic values). Male schistosomes exhibited negligible glutathione peroxidase activity. Oltipraz, an antischistosomal compound, effected a significant depletion of parasite and host glutathione levels within 1 h of exposure in vivo and in vitro (at 250 mg/kg and 10 ..mu..M, respectively). Host tissue glutathionine levels returned to, or above, control levels by 6 h after oltipraz administration, while parasite glutathione levels remained significantly depressed. Uptake of (/sup 35/S) cysteine or (/sup 35/S) cystine by schistosomes was inhibited by oltipraz. However, the drug did not alter the relative distribution of label once incorporated into the parasite, indicating that the enzymes of glutathione synthesis were not directly inhibited.

  16. Endurance Training and Glutathione-Dependent Antioxidant Defense Mechanism in Heart of the Diabetic Rats

    PubMed Central

    Gül, Mustafa; Atalay, Mustafa; Hänninen, Osmo

    2003-01-01

    Regular physical exercise beneficially influences cardiac antioxidant defenses in normal rats. The aim of this study was to test whether endurance training can strengthen glutathione-dependent antioxidant defense mechanism and decrease lipid peroxidation in heart of the streptozotocin-induced diabetic rats. Redox status of glutathione in blood of diabetic rats in response to training and acute exercise was also examined. Eight weeks of treadmill training increased the endurance in streptozotocin-induced diabetic rats. It did not affect glutathione level in heart tissue at rest and also after exercise. On the other hand, endurance training decreased glutathione peroxidase activity in heart, while glutathione reductase and glutathione S-transferase activities were not affected either by acute exhaustive exercise or endurance training. Reduced and oxidized glutathione levels in blood were not affected by either training or acute exercise. Conjugated dienes levels in heart tissue were increased by acute exhaustive exercise and also 8 weeks treadmill training. Longer duration of exhaustion in trained group may have contributed to the increased conjugated dienes levels in heart after acute exercise. Our results suggest that endurance type exercise may make heart more susceptible to oxidative stress. Therefore it may be wise to combine aerobic exercise with insulin treatment to prevent its adverse effects on antioxidant defense in heart in patients with diabetes mellitus. PMID:24616611

  17. Serum Specific IgE to Thyroid Peroxidase Activates Basophils in Aspirin Intolerant Urticaria.

    PubMed

    Shin, Yoo Seob; Suh, Dong-Hyeon; Yang, Eun-Mi; Ye, Young-Min; Park, Hae-Sim

    2015-06-01

    Thyroid antibodies are frequently observed in urticaria patients, but their roles in urticaria are not clearly elucidated. We investigated the role of serum specific IgE to thyroid peroxidase (TPO) in patients with aspirin intolerant acute urticaria (AIAU) and aspirin intolerant chronic urticaria (AICU). We recruited 59 AIAU and 96 AICU patients with 69 normal controls (NC). Serum specific IgE to TPO was measured by manual direct ELISA, and CD203c expressions on basophil with additions of TPO were measured to prove a direct role of TPO in effector cells. The prevalences of serum specific IgE to TPO were significantly higher in AIAU (15.2%) and AICU groups (7.5%) compared to NC (0%, P=0.018: P=0.013, respectively). Flow cytometry showed CD203c induction in a dose dependent manner with serial additions of TPO in some AIAU and AICU patients having high specific IgE to TPO. Our findings show that the prevalence of serum specific IgE to TPO was significantly higher in both AIAU and AICU patients than in NC. It is suggested that specific IgE to TPO play a pathogenic role in AIAU and AICU. PMID:26028921

  18. Insight into the mechanism revealing the peroxidase mimetic catalytic activity of quaternary CuZnFeS nanocrystals: colorimetric biosensing of hydrogen peroxide and glucose

    NASA Astrophysics Data System (ADS)

    Dalui, Amit; Pradhan, Bapi; Thupakula, Umamahesh; Khan, Ali Hossain; Kumar, Gundam Sandeep; Ghosh, Tanmay; Satpati, Biswarup; Acharya, Somobrata

    2015-05-01

    Artificial enzyme mimetics have attracted immense interest recently because natural enzymes undergo easy denaturation under environmental conditions restricting practical usefulness. We report for the first time chalcopyrite CuZnFeS (CZIS) alloyed nanocrystals (NCs) as novel biomimetic catalysts with efficient intrinsic peroxidase-like activity. Novel peroxidase activities of CZIS NCs have been evaluated by catalytic oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). CZIS NCs demonstrate the synergistic effect of elemental composition and photoactivity towards peroxidase-like activity. The quaternary CZIS NCs show enhanced intrinsic peroxidase-like activity compared to the binary NCs with the same constituent elements. Intrinsic peroxidase-like activity has been correlated with the energy band position of CZIS NCs extracted using scanning tunneling spectroscopy and ultraviolet photoelectron spectroscopy. Kinetic analyses indicate Michaelis-Menten enzyme kinetic model catalytic behavior describing the rate of the enzymatic reaction by correlating the reaction rate with substrate concentration. Typical color reactions arising from the catalytic oxidation of TMB over CZIS NCs with H2O2 have been utilized to establish a simple and sensitive colorimetric assay for detection of H2O2 and glucose. CZIS NCs are recyclable catalysts showing high efficiency in multiple uses. Our study may open up the possibility of designing new photoactive multi-component alloyed NCs as enzyme mimetics in biotechnology applications.Artificial enzyme mimetics have attracted immense interest recently because natural enzymes undergo easy denaturation under environmental conditions restricting practical usefulness. We report for the first time chalcopyrite CuZnFeS (CZIS) alloyed nanocrystals (NCs) as novel biomimetic catalysts with efficient intrinsic peroxidase-like activity. Novel peroxidase activities of CZIS NCs have been

  19. Glutathione S-transferase activity in follicular fluid from women undergoing ovarian stimulation: role in maturation.

    PubMed

    Meijide, Susana; Hernández, M Luisa; Navarro, Rosaura; Larreategui, Zaloa; Ferrando, Marcos; Ruiz-Sanz, José Ignacio; Ruiz-Larrea, M Begoña

    2014-10-01

    Female infertility involves an emotional impact for the woman, often leading to a state of anxiety and low self-esteem. The assisted reproduction techniques (ART) are used to overcome the problem of infertility. In a first step of the in vitro fertilization therapy women are subjected to an ovarian stimulation protocol to obtain mature oocytes, which will result in competent oocytes necessary for fertilization to occur. Ovarian stimulation, however, subjects the women to a high physical and psychological stress, thus being essential to improve ART and to find biomarkers of dysfunction and fertility. GSH is an important antioxidant, and is also used in detoxification reactions, catalysed by glutathione S-transferases (GST). In the present work, we have investigated the involvement of GST in follicular maturation. Patients with fertility problems and oocyte donors were recruited for the study. From each woman follicles at two stages of maturation were extracted at the preovulatory stage. Follicular fluid was separated from the oocyte by centrifugation and used as the enzyme source. GST activity was determined based on its conjugation with 3,4-dichloronitrobenzene and the assay was adapted to a 96-well microplate reader. The absorbance was represented against the incubation time and the curves were adjusted to linearity (R(2)>0.990). Results showed that in both donors and patients GST activity was significantly lower in mature oocytes compared to small ones. These results suggest that GST may play a role in the follicle maturation by detoxifying xenobiotics, thus contributing to the normal development of the oocyte. Supported by FIS/FEDER (PI11/02559), Gobierno Vasco (Dep. Educación, Universiades e Investigación, IT687-13), and UPV/EHU (CLUMBER UFI11/20 and PES13/58). The work was approved by the Ethics Committee of the UPV/EHU (CEISH/96/2011/RUIZLARREA), and performed according to the UPV/EHU and IVI-Bilbao agreement (Ref. 2012/01). PMID:26461371

  20. JS-K, a glutathione/glutathione S-transferase-activated nitric oxide releasing prodrug inhibits androgen receptor and WNT-signaling in prostate cancer cells

    PubMed Central

    2012-01-01

    Background Nitric oxide (NO) and its oxidative reaction products have been repeatedly shown to block steroid receptor function via nitrosation of zinc finger structures in the DNA-binding domain (DBD). In consequence NO-donors could be of special interest for the treatment of deregulated androgen receptor(AR)-signaling in castration resistant prostate cancer (CRPC). Methods Prostate cancer (PCa) cells were treated with JS-K, a diazeniumdiolate derivate capable of generating large amounts of intracellular NO following activation by glutathione S-transferase. Generation of NO was determined indirectly by the detection of nitrate in tissue culture medium or by immunodetection of nitrotyrosine in the cytoplasm. Effects of JS-K on intracellular AR-levels were determined by western blotting. AR-dimerization was analyzed by mammalian two hybrid assay, nuclear translocation of the AR was visualized in PCa cells transfected with a green fluorescent AR-Eos fusion protein using fluorescence microscopy. Modulation of AR- and WNT-signalling by JS-K was investigated using reporter gene assays. Tumor cell proliferation following JS-K treatment was measured by MTT-Assay. Results The NO-releasing compound JS-K was shown to inhibit AR-mediated reporter gene activity in 22Rv1 CRPC cells. Inhibition of AR signaling was neither due to an inhibition of nuclear import nor to a reduction in AR-dimerization. In contrast to previously tested NO-donors, JS-K was able to reduce the intracellular concentration of functional AR. This could be attributed to the generation of extremely high intracellular levels of the free radical NO as demonstrated indirectly by high levels of nitrotyrosine in JS-K treated cells. Moreover, JS-K diminished WNT-signaling in AR-positive 22Rv1 cells. In line with these observations, castration resistant 22Rv1 cells were found to be more susceptible to the growth inhibitory effects of JS-K than the androgen dependent LNCaP which do not exhibit an active WNT

  1. Colorimetric detection of sulfide based on target-induced shielding against the peroxidase-like activity of gold nanoparticles.

    PubMed

    Deng, Hao-Hua; Weng, Shao-Huang; Huang, Shuang-Lu; Zhang, Ling-Na; Liu, Ai-Lin; Lin, Xin-Hua; Chen, Wei

    2014-12-10

    Colorimetric recognition and sensing of sulfide with high sensitivity was proposed based on target-induced shielding against the peroxidase-like activity of bare gold nanoparticles. Significant features of the new assay system are its simplicity and cost-effectiveness. The recognition of sulfide by bare gold nanoparticles can be fulfilled in a few seconds and the assay can be accomplished in about 10 min. Furthermore, the new assay system does not require surface modification of GNPs to obtain the specificity for sulfide, and a salt-induced aggregation step is not needed. The detection limit of this method for sulfide was 80 nM. These features make this sensor a potentially powerful tool for the quantitative determination of sulfide in water samples. PMID:25441901

  2. The catalytic activity of Ag2S-montmorillonites as peroxidase mimetic toward colorimetric detection of H2O2.

    PubMed

    Liu, Qingyun; Jiang, Yanling; Zhang, Leyou; Zhou, Xinpei; Lv, Xintian; Ding, Yanyuan; Sun, Lifang; Chen, Pengpeng; Yin, Hailiang

    2016-08-01

    Nanocomposites based on silver sulfide (Ag2S) and Ca-montmorillonite (Ca(2+)-MMT) were synthesized by a simple hydrothermal method. The nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectra (FTIR). The as-prepared Ag2S-MMT nanocomposites were firstly demonstrated to possess intrinsic peroxidase-like activity and could rapidly catalytically oxidize the substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue product which can be seen by the naked eye in only one minute. The experimental results revealed that the Ag2S-MMT nanocomposites exhibit higher thermal durance. Based on the TMB-H2O2 catalyzed color reaction, the Ag2S-MMT nanocomposites were exploited as a new type of biosensor for detection and estimation of H2O2 through a simple, cheap and selective colorimetric method. PMID:27157733

  3. Improvement on the thermal stability and activity of plant cytosolic ascorbate peroxidase 1 by tailing hyper-acidic fusion partners.

    PubMed

    Zhang, Mengru; Gong, Ming; Yang, Yumei; Li, Xujuan; Wang, Haibo; Zou, Zhurong

    2015-04-01

    Cytosolic ascorbate peroxidase 1 (APX1) plays a crucial role in regulating the level of plant cellular reactive oxygen species and its thermolability is proposed to cause plant heat-susceptibility. Herein, several hyper-acidic fusion partners, such as the C-terminal peptide tails, were evaluated for their effects on the thermal stability and activity of APX1 from Jatropha curcas and Arabidopsis. The hyper-acidic fusion partners efficiently improved the thermostability and prevented thermal inactivation of APX1 in both plant species with an elevated heat tolerance of at least 2 °C. These hyper-acidified thermostable APX1 fusion variants are of considerable biotechnological potential and can provide a new route to enhance the heat tolerance of plant species especially of inherent thermo-sensitivity.

  4. Balneotherapy and platelet glutathione metabolism in type II diabetic patients

    NASA Astrophysics Data System (ADS)

    Ohtsuka, Yoshinori; Yabunaka, Noriyuki; Watanabe, Ichiro; Noro, Hiroshi; Agishi, Yuko

    1996-09-01

    Effects of balneotherapy on platelet glutathione metabolism were investigated in 12 type II (non-insulin-dependent) diabetic patients. Levels of the reduced form of glutathione (GSH) on admission were well correlated with those of fasting plasma glucose (FPG; r=0.692, P<0.02). After 4 weeks of balneotherapy, the mean level of GSH showed no changes; however, in well-controlled patients (FPG <150 mg/dl), the level increased ( P<0.01) and in poorly controlled patients (FPG >150 mg/dl), the value decreased ( P<0.05). There was a negative correlation between glutathione peroxidase (GPX) activities and the levels of FPG ( r=-0.430, P<0.05). After balneotherapy, the activity increased in 5 patients, decreased in 3 patients and showed no changes (alteration within ±3%) in all the other patients. From these findings in diabetic patients we concluded: (1) platelet GSH synthesis appeared to be induced in response to oxidative stress; (2) lowered GPX activities indicated that the antioxidative defense system was impaired; and (3) platelet glutathione metabolism was partially improved by 4 weeks balneotherapy, an effect thought to be dependent on the control status of plasma glucose levels. It is suggested that balneotherapy is beneficial for patients whose platelet antioxidative defense system is damaged, such as those with diabetes mellitus and coronary heart disease.

  5. Aluminum induces oxidative burst, cell wall NADH peroxidase activity, and DNA damage in root cells of Allium cepa L.

    PubMed

    Achary, V Mohan M; Parinandi, Narasimham L; Panda, Brahma B

    2012-08-01

    Plants under stress incur an oxidative burst that involves a rapid and transient overproduction of reactive oxygen species (ROS: O(2) (•-) , H(2) O(2) , (•) OH). We hypothesized that aluminum (Al), an established soil pollutant that causes plant stress, would induce an oxidative burst through the activation of cell wall-NADH peroxidase (NADH-PX) and/or plasma membrane-associated NADPH oxidase (NADPH-OX), leading to DNA damage in the root cells of Allium cepa L. Growing roots of A. cepa were treated with Al(3+) (800 μM of AlCl(3) ) for 3 or 6 hr without or with the pretreatment of inhibitors specific to NADH-PX and NADPH-OX for 2 hr. At the end of the treatment, the extent of ROS generation, cell death, and DNA damage were determined. The cell wall-bound protein (CWP) fractions extracted from the untreated control and the Al-treated roots under the aforementioned experimental conditions were also subjected to in vitro studies, which measured the extent of activation of peroxidase/oxidase, generation of (•) OH, and DNA damage. Overall, the present study demonstrates that the cell wall-bound NADH-PX contributes to the Al-induced oxidative burst through the generation of ROS that lead to cell death and DNA damage in the root cells of A. cepa. Furthermore, the in vitro studies revealed that the CWP fraction by itself caused DNA damage in the presence of NADH, supporting a role for NADH-PX in the stress response. Altogether, this study underscores the crucial function of the cell wall-bound NADH-PX in the oxidative burst-mediated cell death and DNA damage in plants under Al stress.

  6. Altering the redox state of skeletal muscle by glutathione depletion increases the exercise‐activation of PGC‐1α

    PubMed Central

    Strobel, Natalie A.; Matsumoto, Aya; Peake, Jonathan M.; Marsh, Susan A.; Peternelj, Tina‐Tinkara; Briskey, David; Fassett, Robert G.; Coombes, Jeff S.; Wadley, Glenn D.

    2014-01-01

    Abstract We investigated the relationship between markers of mitochondrial biogenesis, cell signaling, and antioxidant enzymes by depleting skeletal muscle glutathione with diethyl maleate (DEM) which resulted in a demonstrable increase in oxidative stress during exercise. Animals were divided into six groups: (1) sedentary control rats; (2) sedentary rats + DEM; (3) exercise control rats euthanized immediately after exercise; (4) exercise rats + DEM; (5) exercise control rats euthanized 4 h after exercise; and (6) exercise rats + DEM euthanized 4 h after exercise. Exercising animals ran on the treadmill at a 10% gradient at 20 m/min for the first 30 min. The speed was then increased every 10 min by 1.6 m/min until exhaustion. There was a reduction in total glutathione in the skeletal muscle of DEM treated animals compared to the control animals (P < 0.05). Within the control group, total glutathione was higher in the sedentary group compared to after exercise (P < 0.05). DEM treatment also significantly increased oxidative stress, as measured by increased plasma F2–isoprostanes (P < 0.05). Exercising animals given DEM showed a significantly greater increase in peroxisome proliferator activated receptor γ coactivator‐1α (PGC–1α) mRNA compared to the control animals that were exercised (P < 0.05). This study provides novel evidence that by lowering the endogenous antioxidant glutathione in skeletal muscle and inducing oxidative stress through exercise, PGC‐1α gene expression was augmented. These findings further highlight the important role of exercise induced oxidative stress in the regulation of mitochondrial biogenesis. PMID:25538148

  7. GLUTATHIONE SYNTHESIS

    PubMed Central

    Lu, Shelly C.

    2012-01-01

    BACKGROUND Glutathione (GSH) is present in all mammalian tissues as the most abundant non-protein thiol that defends against oxidative stress. GSH is also a key determinant of redox signaling, vital in detoxification of xenobiotics, regulates cell proliferation, apoptosis, immune function, and fibrogenesis. Biosynthesis of GSH occurs in the cytosol in a tightly regulated manner. Key determinants of GSH synthesis are the availability of the sulfur amino acid precursor, cysteine, and the activity of the rate-limiting enzyme, glutamate cysteine ligase (GCL), which is composed of a catalytic (GCLC) and a modifier (GCLM) subunit. The second enzyme of GSH synthesis is GSH synthetase (GS). SCOPE OF REVIEW This review summarizes key functions of GSH and focuses on factors that regulate the biosynthesis of GSH, including pathological conditions where GSH synthesis is dysregulated. MAJOR CONCLUSIONS GCL subunits and GS are regulated at multiple levels and often in a coordinated manner. Key transcription factors that regulate the expression of these genes include NF-E2 related factor 2 (Nrf2) via the antioxidant response element (ARE), AP-1, and nuclear factor kappa B (NFκB). There is increasing evidence that dysregulation of GSH synthesis contributes to the pathogenesis of many pathological conditions. These include diabetes mellitus, pulmonary and liver fibrosis, alcoholic liver disease, cholestatic liver injury, endotoxemia and drug-resistant tumor cells. GENERAL SIGNIFICANCE GSH is a key antioxidant that also modulates diverse cellular processes. A better understanding of how its synthesis is regulated and dysregulated in disease states may lead to improvement in the treatment of these disorders. PMID:22995213

  8. Modification of the activity of cell wall-bound peroxidase by hypergravity in relation to the stimulation of lignin formation in azuki bean epicotyls

    NASA Astrophysics Data System (ADS)

    Wakabayashi, Kazuyuki; Nakano, Saho; Soga, Kouichi; Hoson, Takayuki

    Lignin is a component of cell walls of terrestrial plants, which provides cell walls with the mechanical rigidity. Lignin is a phenolic polymer with high molecular mass and formed by the polymerization of phenolic substances on a cellulosic matrix. The polymerization is catalyzed by cell wall-bound peroxidase, and thus the activity of this enzyme regulates the rate of formation of lignin. In the present study, the changes in the lignin content and the activity of cell wall peroxidase were investigated along epicotyls of azuki bean seedlings grown under hypergravity conditions. The endogenous growth occurred primarily in the upper regions of the epicotyl and no growth was detected in the middle or basal regions. The amounts of acetyl bromide-soluble lignin increased from the upper to the basal regions of epicotyls. The lignin content per unit length in the basal region was three times higher than that in the upper region. Hypergravity treatment at 300 g for 6 h stimulated the increase in the lignin content in all regions of epicotyls, particularly in the basal regions. The peroxidase activity in the protein fraction extracted from the cell wall preparation with a high ionic strength buffer also increased gradually toward the basal region, and hypergravity treatment clearly increased the activity in all regions. There was a close correlation between the lignin content and the enzyme activity. These results suggest that gravity stimuli modulate the activity of cell wall-bound peroxidase, which, in turn, causes the stimulation of the lignin formation in stem organs.

  9. Role of peroxidase inhibition by insulin in the bovine thyroid cell proliferation mechanism.

    PubMed

    Krawiec, León; Pizarro, Ramón A; Aphalo, Paula; de Cavanagh, Elena M V; Pisarev, Mario A; Juvenal, Guillermo J; Policastro, Lucía; Bocanera, Laura V

    2004-07-01

    Monolayer primary cultures of thyroid cells produce, in the presence of insulin, a cytosolic inhibitor of thyroid peroxidase (TPO), lacto peroxidase (LPO), horseradish peroxidase (HRPO) and glutathione peroxidase (GPX). The inhibitor, localized in the cytosol, is thermostable and hydrophylic. Its molecular mass is less than 2 kDa. The inhibitory activity, resistant to proteolytic and nucleolytic enzymes, disappears with sodium metaperiodate treatment, as an oxidant of carbohydrates, supporting its oligosaccharide structure. The presence of inositol, mannose, glucose, the specific inhibition of cyclic AMP-dependent protein kinase and the disappearance of peroxidase inhibition by alkaline phosphatase and alpha-mannosidase in purified samples confirms its chemical structure as inositol phosphoglycan-like. Purification by anionic interchange shows that the peroxidase inhibitor elutes like the two subtypes of inositol phosphoglycans (IPG)P and A, characterized as signal transducers of insulin action. Insulin significantly increases the concentration of the peroxidase inhibitor in a thyroid cell culture at 48 h. The addition of both isolated substances to a primary thyroid culture produces, after 30 min, a significant increase in hydrogen peroxide (H2O2) concentration in the medium, concomitantly with the disappearance of the GPX activity in the same conditions. The presence of insulin or anyone of both products, during 48 h, induces cell proliferation of the thyroid cell culture. In conclusion, insulin stimulates thyroid cell division through the effect of a peroxidase inhibitor, as its second messenger. The inhibition of GPX by its action positively modulates the H2O2 level, which would produce, as was demonstrated by other authors, the signal for cell proliferation.

  10. Effects of Ambient Oxygen and of Fixed Nitrogen on Concentrations of Glutathione, Ascrobate, and Associated Enzymes in Soybean Root Nodules 1

    PubMed Central

    Dalton, David A.; Post, Christopher J.; Langeberg, Lorene

    1991-01-01

    Soybean (Glycine max [L.] Merr.) root nodules contain the enzymes of the ascorbate-glutathione cycle for defense against activated forms of oxygen. Nodulated roots of hydroponically grown soybean plants were exposed to atmospheres containing 2, 21, 50, or alternating 21 and 50 kilopascals of O2. The activities of ascorbate (ASC) peroxidase, monodehydroascorbate (MDHA) reductase, dehydroascorbate (DHA) reductase, and glutathione (GSSG) reductase were higher in nodules exposed to high pO2. Nodule contents of ascorbate and reduced glutathione were also greater in the high pO2 treatments. Treatment of nodulated plants with fixed nitrogen (urea) led to concomitant decreases in acetylene reduction activity, in leghemoglobin content, and in activities of ASC peroxidase, DHA reductase, and GSSG reductase. Activity of MDHA reductase and glutathione concentrations in nodules were not affected by treatment with urea. The enzymes of the ascorbate-glutathione cycle were also detected in uninfected soybean roots, although at levels substantially below those in nodules. These observations indicate that the ascorbate-glutathione cycle can adjust to varying physiological conditions in nodules and that there is a key link between N2 fixation and defenses against activated forms of oxygen. PMID:16668258

  11. Hepatic glutathione and glutathione S-transferase in selenium deficiency and toxicity in the chick

    SciTech Connect

    Kim, Y. S.

    1989-01-01

    First, the hepatic activity of GSH-T{sub CDNB} was increased only under conditions of severe oxidative stress produced by combined Se- and vitamin E (VE)-deficiency, indicating that VE also affects GSH metabolism. Second, the incorporation of {sup 35}S-methionine into GSH and protein was about 4- and 2-fold higher, respectively, in Se- and VE-deficient chick hepatocytes as compared to controls. Third, chicks injected with the glutathione peroxidase (SeGSHpx) inhibitor, aurothioglucose (AuTG), showed increase hepatic GSH-T{sub CDNB} activity and plasma GSH concentration regardless of their Se status. Fourth, the effect of ascorbic acid (AA), on GSH metabolism was studied. Chicks fed 1000 ppm AA showed decreased hepatic GSH concentration compared to chicks fed no AA in a Se- and VE-deficient diet. Fifth, chicks fed excess Se showed increase hepatic activity of GSH-T{sub CDNB} and GSH concentration regardless of VE status.

  12. Covalent attachment of cholesterol oxidase and horseradish peroxidase on perlite through silanization: activity, stability and co-immobilization.

    PubMed

    Torabi, Seyed-Fakhreddin; Khajeh, Khosro; Ghasempur, Salehe; Ghaemi, Nasser; Siadat, Seyed-Omid Ranaei

    2007-08-31

    In the present work, co-immobilization of cholesterol oxidase (COD) and horseradish peroxidase (POD) on perlite surface was attempted. The surface of perlite were activated by 3-aminopropyltriethoxysilane and covalently bonded with COD and POD via glutaraldehyde. Enzymes activities have been assayed by spectrophotometric technique. The stabilities of immobilized COD and POD to pH were higher than those of soluble enzymes and immobilization shifted optimum pH of enzymes to the lower pH. Heat inactivation studies showed improved thermostability of the immobilized COD for more than two times, but immobilized POD was less thermostable than soluble POD. Also activity recovery of immobilized COD was about 50% since for immobilized POD was 11%. The K(m) of immobilized enzymes was found slightly lower than that of soluble enzymes. Immobilized COD showed inhibition in its activity at high cholesterol concentration which was not reported for soluble COD before. Co-immobilized enzymes retained 65% of its initial activity after 20 consecutive reactor batch cycles.

  13. Effects of mercury and selenium on glutathione metabolism and oxidative stress in mallard ducks

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.

    1998-01-01

    Earlier studies reported on the toxicity and related oxidative stress of different forms of Se, incl