Journal articles: 'Glutathion peroxidasa'

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Brenot, Audrey, Katherine Y. King, Blythe Janowiak, Owen Griffith, and Michael G. Caparon. "Contribution of Glutathione Peroxidase to the Virulence of Streptococcus pyogenes." Infection and Immunity 72, no. 1 (January 2004): 408–13. http://dx.doi.org/10.1128/iai.72.1.408-413.2004.

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ABSTRACT Glutathione peroxidases are widespread among eukaryotic organisms and function as a major defense against hydrogen peroxide and organic peroxides. However, glutathione peroxidases are not well studied among prokaryotic organisms and have not previously been shown to promote bacterial virulence. Recently, a gene with homology to glutathione peroxidase was shown to contribute to the antioxidant defenses of Streptococcus pyogenes (group A streptococcus). Since this bacterium causes numerous suppurative diseases that require it to thrive in highly inflamed tissue, it was of interest to determine if glutathione peroxidase is important for virulence. In this study, we report that GpoA glutathione peroxidase is the major glutathione peroxidase in S. pyogenes and is essential for S. pyogenes pathogenesis in several murine models that mimic different aspects of streptococcal suppurative disease. In contrast, glutathione peroxidase is not essential for virulence in a zebrafish model of streptococcal myositis, a disease characterized by the absence of an inflammatory cell infiltrate. Taken together, these data suggest that S. pyogenes requires glutathione peroxidase to adapt to oxidative stress that accompanies an inflammatory response, and the data provide the first demonstration of a role for glutathione peroxidase in bacterial virulence. The fact that genes encoding putative glutathione peroxidases are found in the genomes of many pathogenic bacterial species suggests that glutathione peroxidase may have a general role in bacterial pathogenesis.

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Missall, Tricia A., Jocie F. Cherry-Harris, and Jennifer K. Lodge. "Two glutathione peroxidases in the fungal pathogen Cryptococcus neoformans are expressed in the presence of specific substrates." Microbiology 151, no. 8 (August 1, 2005): 2573–81. http://dx.doi.org/10.1099/mic.0.28132-0.

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Glutathione peroxidases catalyse the reduction of peroxides by reduced glutathione. To determine if these enzymes are important for resistance to oxidative stress and evasion of the innate immune system by the fungal pathogen Cryptococcus neoformans, two glutathione peroxidase homologues, which share 38 % identity, were identified and investigated. In this study, these peroxidases, Gpx1 and Gpx2, their localization, their contribution to total glutathione peroxidase activity, and their importance to the oxidative and nitrosative stress resistance of C. neoformans are described. It is shown that the two glutathione peroxidase genes are differentially expressed in response to stress. While both GPX1 and GPX2 are induced during t-butylhydroperoxide or cumene hydroperoxide stress and repressed during nitric oxide stress, only GPX2 is induced in response to hydrogen peroxide stress. Deletion mutants of each and both of the glutathione peroxidases were generated, and it was found that they are sensitive to various peroxide stresses while showing wild-type resistance to other oxidant stresses, such as superoxide and nitric oxide. While the glutathione peroxidase mutants are slightly sensitive to oxidant killing by macrophages, they exhibit wild-type virulence in a mouse model of cryptococcosis.

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WILKINSON, Shane R., David J. MEYER, and John M. KELLY. "Biochemical characterization of a trypanosome enzyme with glutathione-dependent peroxidase activity." Biochemical Journal 352, no. 3 (December 8, 2000): 755–61. http://dx.doi.org/10.1042/bj3520755.

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In most eukaryotes, glutathione-dependent peroxidases play a key role in the metabolism of peroxides. Numerous studies have reported that trypanosomatids lack this activity. Here we show that this is not the case, at least for the American trypanosome Trypanosoma cruzi. We have isolated a single-copy gene from T. cruzi with the potential to encode an 18kDa enzyme, the sequence of which has highest similarity with glutathione peroxidases from plants. A recombinant form of the protein was purified following expression in Escherichia coli. The enzyme was shown to have peroxidase activity in the presence of glutathione/glutathione reductase but not in the presence of trypanothione/trypanothione reductase. It could metabolize a wide range of hydroperoxides (linoleic acid hydroperoxide and phosphatidylcholine hydroperoxide> cumene hydroperoxide>t-butyl hydroperoxide), but no activity towards hydrogen peroxide was detected. Enzyme activity could be saturated by glutathione when both fatty acid and short-chain organic hydroperoxides were used as substrate. For linoleic acid hydroperoxide, the rate-limiting step of this reaction is the reduction of the peroxidase by glutathione. With lower-affinity substrates such as t-butyl hydroperoxide, the rate-limiting step is the reduction of the oxidant. The data presented here identify a new arm of the T. cruzi oxidative defence system.

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Iturbe-Ormaetxe, Iñaki, Manuel A. Matamoros, Maria C. Rubio, David A. Dalton, and Manuel Becana. "The Antioxidants of Legume Nodule Mitochondria." Molecular Plant-Microbe Interactions® 14, no. 10 (October 2001): 1189–96. http://dx.doi.org/10.1094/mpmi.2001.14.10.1189.

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The mitochondria of legume root nodules are critical to sustain the energy-intensive process of nitrogen fixation. They also generate reactive oxygen species at high rates and thus require the protection of antioxidant enzymes and metabolites. We show here that highly purified mitochondria from bean nodules (Phaseolus vulgaris L. cv. Contender × Rhizobium leguminosarum bv. phaseoli strain 3622) contain ascorbate peroxidase primarily in the inner membrane (with lesser amounts detected occasionally in the matrix), guaiacol peroxidases in the outer membrane and matrix, and manganese superoxide dismutase (MnSOD) and an ascorbate-regenerating system in the matrix. This regenerating system relies on homoglutathione (instead of glutathione) and pyridine nucleotides as electron donors and involves the enzymes monodehy-droascorbate reductase, dehydroascorbate reductase, and homoglutathione reductase. Homoglutathione is synthesized in the cytosol and taken up by the mitochondria and bacteroids. Although bacteroids synthesize glutathione, it is not exported to the plant in significant amounts. We propose a model for the detoxification of peroxides in nodule mitochondria in which membrane-bound ascorbate peroxidase scavenges the peroxide formed by the electron transport chain using ascorbate provided by L-galactono-1,4-lactone dehydrogenase in the inner membrane. The resulting monodehydroascorbate and dehydroascorbate can be recycled in the matrix or cytosol. In the matrix, the peroxides formed by oxidative reactions and by MnSOD may be scavenged by specific isozymes of guaiacol peroxidase, ascorbate peroxidase, and catalase.

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Porter, M., D. J. Pearson, V. J. Suarez-Mendez, and A. D. Blann. "Plasma, platelet and erythrocyte glutathione peroxidases as risk factors in ischaemic heart disease in man." Clinical Science 83, no. 3 (September 1, 1992): 343–45. http://dx.doi.org/10.1042/cs0830343.

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1. Plasma, platelet and erythrocyte glutathione peroxidase activities and serum lipid concentrations were measured in patients with ischaemic heart disease and matched control subjects. 2. Mean plasma and platelet glutathione peroxidase activities were significantly lower in the patients with ischaemic heart disease. Erythrocyte glutathione peroxidase activities and serum lipid concentrations were similar in patients with ischaemic heart disease and control subjects. 3. No correlations between plasma, platelet and erythrocyte glutathione peroxidase activities were observed. 4. The combination of plasma and platelet glutathione peroxidase activities provided an 86% discrimination between patients with ischaemic heart disease and matched control subjects. 5. Our data suggest that plasma and platelet glutathione peroxidases may be significant risk factors for ischaemic heart disease. Plasma glutathione peroxidase is a previously unrecognized risk factor.

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Gutowicz, Marzena. "Antioxidant and detoxycative mechanisms in central nervous system." Postępy Higieny i Medycyny Doświadczalnej 74 (February 19, 2020): 1–11. http://dx.doi.org/10.5604/01.3001.0013.8548.

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Since the brain contains a large amount of polyunsaturated fatty acids, consumes up to 20% of oxygen used by the whole body and exhibits low antioxidants activity, it seems to be especially vulnerable to oxidative stress. The most important antioxidant enzymes are superoxide dismutase (SOD), which catalyze the dismutation of superoxide anion to hydrogen peroxide, catalase (CAT), which converts toxic hydrogen peroxide to water and oxygen, and glutathione peroxidase (Se-GSHPx), which reduces hydrogen peroxide and organic peroxides with glutathione as the cofactor. Among other detoxifying enzymes, the most significant is glutathione transferase (GST), which shows detoksyvarious catalytic activities allowing for removal of xenobiotics, reducing organic peroxides and oxidized cell components. One of the most important brain nonenzymatic antioxidants is reduced glutathione (GSH), which (individually or in cooperation with peroxidases) participates in the reduction of free radicals, repair of oxidative damage and the regeneration of other antioxidants, such as ascorbate or tocopherol. Glutathione as a cosubstrate of glutathione transferase scavenges toxic electrophilic compounds. Although the etiology of the major neurodegenerative diseases are unknown, numerous data suggest that reactive oxygen species play an important role. Even a small change in the level of antioxidants can leads to the many disorders in the CNS.

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Miller, Charles D., Drauzio Rangel, Gilberto UL Braga, Stephan Flint, Sun-Il Kwon, Claudio L. Messias, Donald W. Roberts, and Anne J. Anderson. "Enzyme activities associated with oxidative stress in Metarhizium anisopliae during germination, mycelial growth, and conidiation and in response to near-UV irradiation." Canadian Journal of Microbiology 50, no. 1 (January 1, 2004): 41–49. http://dx.doi.org/10.1139/w03-097.

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Metarhizium anisopliae isolates have a wide insect host range, but an impediment to their commercial use as a biocontrol agent of above-ground insects is the high susceptibility of spores to the near-UV present in solar irradiation. To understand stress responses in M. anisopliae, we initiated studies of enzymes that protect against oxidative stress in two strains selected because their spores differed in sensitivity to UV-B. Spores of the more near-UV resistant strain in M. anisopliae 324 displayed different isozyme profiles for catalaseperoxidase, glutathione reductase, and superoxide dismutase when compared with the less resistant strain 2575. A transient loss in activity of catalaseperoxidase and glutathione reductase was observed during germination of the spores, whereas the intensity of isozymes displaying superoxide dismutase did not change as the mycelium developed. Isozyme composition for catalaseperoxidases and glutathione reductase in germlings changed with growth phase. UV-B exposure from lamps reduced the activity of isozymes displaying catalaseperoxidase and glutathione reductase activities in 2575 more than in 324. The major effect of solar UV-A plus UV-B also was a reduction in catalaseperoxidases isozyme level, a finding confirmed by measurement of catalase specific activity. Impaired growth of M. anisopliae after near-UV exposure may be related to reduced abilities to handle oxidative stress.Key words: catalaseperoxidase, germination, glutathione reductase, Metarhizium anisopliae, near-UV, protein oxidation, superoxide dismutase.

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8

Shigeoka, S., T. Takeda, and T. Hanaoka. "Characterization and immunological properties of selenium-containing glutathione peroxidase induced by selenite in Chlamydomonas reinhardtii." Biochemical Journal 275, no. 3 (May 1, 1991): 623–27. http://dx.doi.org/10.1042/bj2750623.

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The selenite-induced glutathione peroxidase in Chlamydomonas reinhardtii has been purified about 323-fold with a 10% yield, as judged by PAGE. The native enzyme had an Mr of 67,000 and was composed of four identical subunits of Mr 17,000. Glutathione was the only electron donor, giving a specific activity of 193.6 mumol/min per mg of protein. L-Ascorbate, NADH, NADPH, pyrogallol, guaiacol and o-dianisidine did not donate electrons to the enzyme. In addition to H2O2, organic hydroperoxides were reduced by the enzyme. The Km values for glutathione and H2O2 were 3.7 mM and 0.24 mM respectively. The enzyme reaction proceeded by a Ping Pong Bi Bi mechanism. Cyanide and azide had no effect on the activity. The enzyme contained approx. 3.5 atoms of selenium per mol of protein. On immunoprecipitation, Chlamydomonas glutathione peroxidase was precipitated and its activity was inhibited about 90% by the antibody raised against bovine erythrocyte glutathione peroxidase. The antibody also cross-reacted with the subunits of Chlamydomonas glutathione peroxidase in Western blotting SDS/PAGE. In terms of enzymic, physico-chemical and immunological properties, the experimental results demonstrate clearly that Chlamydomonas glutathione peroxidase resembles other well-characterized glutathione peroxidases from animal sources that contain selenium.

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Gaetani, GF, AM Ferraris, M. Rolfo, R. Mangerini, S. Arena, and HN Kirkman. "Predominant role of catalase in the disposal of hydrogen peroxide within human erythrocytes." Blood 87, no. 4 (February 15, 1996): 1595–99. http://dx.doi.org/10.1182/blood.v87.4.1595.bloodjournal8741595.

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Purified enzymes were mixed to form a cell-free system that simulated the conditions for removal of hydrogen peroxide within human erythrocytes. Human glutathione peroxidase disposed of hydrogen peroxide (H2O2) at a rate that was only 17% of the rate at which human catalase simultaneously removed hydrogen peroxide. The relative rates observed were in agreement with the relative rates predicted from the kinetic constants of the two enzymes. These results confirm two earlier studies on intact erythrocytes, which refuted the notion that glutathione peroxidase is the primary enzyme for removal of hydrogen peroxide within erythrocytes. The present findings differ from the results with intact cells, however, in showing that glutathione peroxidase accounts for even less than 50% of the removal of hydrogen peroxide. A means is proposed for calculating the relative contribution of glutathione peroxidase and catalase in other cells and species. The present results raise the possibility that the major function of glutathione peroxidase may be the disposal of organic peroxides rather than the removal of hydrogen peroxide.

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Bhowmick, Debasish, and Govindasamy Mugesh. "Insights into the catalytic mechanism of synthetic glutathione peroxidase mimetics." Organic & Biomolecular Chemistry 13, no. 41 (2015): 10262–72. http://dx.doi.org/10.1039/c5ob01665g.

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This review focuses on the variation of the catalytic mechanisms of synthetic glutathione peroxidase (GPx) mimics depending on their structures and reactivities towards thiols and peroxides. Compounds of different categories follow a characteristic mechanism for the reduction of peroxides.

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Vinita, Thakur. "Role of Superoxide Dismutase and Glutathione Peroxidase in Infertility." International Journal of Scientific Research 2, no. 11 (June 1, 2012): 353–54. http://dx.doi.org/10.15373/22778179/nov2013/112.

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12

George, Joseph. "Determination of selenium during pathogenesis of hepatic fibrosis employing hydride generation and inductively coupled plasma mass spectrometry." Biological Chemistry 399, no. 5 (April 25, 2018): 499–509. http://dx.doi.org/10.1515/hsz-2017-0260.

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Abstract Serum and liver selenium levels were studied during the pathogenesis of N-nitrosodimethylamine (NDMA) induced hepatic fibrosis in rats. The degree of fibrosis was assessed with Masson’s trichrome staining and quantifying collagen content in the liver. Lipid peroxides were measured in blood and liver samples and total glutathione and glutathione peroxidase were assayed in the liver tissue to evaluate oxidative stress. Interleukin-6 (IL-6) and transforming growth factor-β1 (TGF-β1) were measured in the serum. Selenium levels were determined using inductively coupled plasma-mass spectrometry (ICP-MS) after acid digestion and hydride generation of selenium. Serial administrations of NDMA produced well-developed fibrosis and early cirrhosis in the liver with 4-fold increase of total collagen content and deposition of collagen fibers. Blood and hepatic lipid peroxides, serum IL-6 and TGF-β1 were significantly increased. There was significant reduction in hepatic glutathione and glutathione peroxidase levels. Serum and liver selenium were remarkably decreased on all the days studied. The results suggest that decreased selenium and glutathione peroxidase contribute to the impairment of cellular antioxidant defense, which in turn results in oxidative stress and trigger pathogenesis of hepatic fibrosis. The study further demonstrated that ICP-MS with hydride generation technique is a reliable and sensitive method for determination of selenium in biological samples.

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Banerjee, Manisha, Anand Ballal, and Shree K. Apte. "A novel glutaredoxin domain-containing peroxiredoxin ‘All1541’ protects the N2-fixing cyanobacterium Anabaena PCC 7120 from oxidative stress." Biochemical Journal 442, no. 3 (February 24, 2012): 671–80. http://dx.doi.org/10.1042/bj20111877.

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Prxs (peroxiredoxins) are ubiquitous thiol-based peroxidases that detoxify toxic peroxides. The Anabaena PCC 7120 genome harbours seven genes/ORFs (open reading frames) which have homology with Prxs. One of these (all1541) was identified to encode a novel Grx (glutaredoxin) domain-containing Prx by bioinformatic analysis. A recombinant N-terminal histidine-tagged All1541 protein was overexpressed in Escherichia coli and purified. Analysis with the protein alkylating agent AMS (4-acetamido-4′-maleimidyl-stilbene-2,2′-disulfonate) showed All1541 to form an intra-molecular disulfide bond. The All1541 protein used glutathione (GSH) more efficiently than Trx (thioredoxin) to detoxify H2O2. Deletion of the Grx domain from All1541 resulted in loss of GSH-dependent peroxidase activity. Employing site-directed mutagenesis, the cysteine residues at positions 50 and 75 were identified as peroxidatic and resolving cysteine residues respectively, whereas both the cysteine residues within the Grx domain (positions 181 and 184) were shown to be essential for GSH-dependent peroxidase activity. On the basis of these data, a reaction mechanism has been proposed for All1541. In vitro All1541 protein protected plasmid DNA from oxidative damage. In Anabaena PCC 7120, all1541 was transcriptionally activated under oxidative stress. Recombinant Anabaena PCC 7120 strain overexpressing All1541 protein showed superior oxidative stress tolerance to H2O2 as compared with the wild-type strain. The results suggest that the glutathione-dependent peroxidase All1541 plays an important role in protecting Anabaena from oxidative stress.

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Johnson, Robert M., Gerard Goyette, Yaddanapudi Ravindranath, and Ye-Shih Ho. "Red cells from glutathione peroxidase-1–deficient mice have nearly normal defenses against exogenous peroxides." Blood 96, no. 5 (September 1, 2000): 1985–88. http://dx.doi.org/10.1182/blood.v96.5.1985.

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Abstract The role of glutathione peroxidase in red cell anti-oxidant defense was examined using erythrocytes from mice with a genetically engineered disruption of the glutathione peroxidase-1 (GSHPx-1) gene. Because GSHPx-1 is the sole glutathione peroxidase in the erythrocyte, all red cell GSH peroxidase activity was eliminated. Oxidation of hemoglobin and membrane lipids, using the cis-parinaric acid assay, was determined during oxidant challenge from cumene hydroperoxide and H2O2. No difference was detected between wild-type red cells and GSHPx-1–deficient cells, even at high H2O2 exposures. Thus, GSHPx-1 appears to play little or no role in the defense of the erythrocyte against exposure to peroxide. Simultaneous exposure to an H2O2 flux and the catalase inhibitor 3-amino-1,2,4-triazole supported this conclusion. Hemoglobin oxidation occurred only when catalase was depleted. Circulating erythrocytes from the GSHPx-1–deficient mice exhibited a slight reduction in membrane thiols, indicating that high exposure to peroxides might occur naturally in the circulation.

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Johnson, Robert M., Gerard Goyette, Yaddanapudi Ravindranath, and Ye-Shih Ho. "Red cells from glutathione peroxidase-1–deficient mice have nearly normal defenses against exogenous peroxides." Blood 96, no. 5 (September 1, 2000): 1985–88. http://dx.doi.org/10.1182/blood.v96.5.1985.h8001985_1985_1988.

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The role of glutathione peroxidase in red cell anti-oxidant defense was examined using erythrocytes from mice with a genetically engineered disruption of the glutathione peroxidase-1 (GSHPx-1) gene. Because GSHPx-1 is the sole glutathione peroxidase in the erythrocyte, all red cell GSH peroxidase activity was eliminated. Oxidation of hemoglobin and membrane lipids, using the cis-parinaric acid assay, was determined during oxidant challenge from cumene hydroperoxide and H2O2. No difference was detected between wild-type red cells and GSHPx-1–deficient cells, even at high H2O2 exposures. Thus, GSHPx-1 appears to play little or no role in the defense of the erythrocyte against exposure to peroxide. Simultaneous exposure to an H2O2 flux and the catalase inhibitor 3-amino-1,2,4-triazole supported this conclusion. Hemoglobin oxidation occurred only when catalase was depleted. Circulating erythrocytes from the GSHPx-1–deficient mice exhibited a slight reduction in membrane thiols, indicating that high exposure to peroxides might occur naturally in the circulation.

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Park, Jinah, Sunmi Lee, Sanghyuk Lee, and Sang Won Kang. "2-Cys Peroxiredoxins: Emerging Hubs Determining Redox Dependency of Mammalian Signaling Networks." International Journal of Cell Biology 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/715867.

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Mammalian cells have a well-defined set of antioxidant enzymes, which includes superoxide dismutases, catalase, glutathione peroxidases, and peroxiredoxins. Peroxiredoxins are the most recently identified family of antioxidant enzymes that catalyze the reduction reaction of peroxides, such as H2O2. In particular, typical 2-Cys peroxiredoxins are the featured peroxidase enzymes that receive the electrons from NADPH by coupling with thioredoxin and thioredoxin reductase. These enzymes distribute throughout the cellular compartments and, therefore, are thought to be broad-range antioxidant defenders. However, recent evidence demonstrates that typical 2-Cys peroxiredoxins play key signal regulatory roles in the various signaling networks by interacting with or residing near a specific redox-sensitive molecule. These discoveries help reveal the redox signaling landscape in mammalian cells and may further provide a new paradigm of therapeutic approaches based on redox signaling.

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Johnson, Robert M., Gerard Goyette, Yaddanapudi Ravindranath, and Ye-Shih Ho. "Oxidation of glutathione peroxidase–deficient red cells by organic peroxides." Blood 100, no. 4 (August 15, 2002): 1515–16. http://dx.doi.org/10.1182/blood-2002-04-1124.

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Ganguli, Sayak, and Abhijit Datta. "Prediction of Indels and SNP’s in Coding Regions of Glutathione Peroxidases – An Important Enzyme in Redox Homeostasis of Plants." International Letters of Natural Sciences 7 (December 2013): 49–62. http://dx.doi.org/10.18052/www.scipress.com/ilns.7.49.

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Plant glutathione peroxidases are an important class of enzymes which play key roles in the stress adaptability of plants both in context of biotic and abiotic stress pathways. They have been over the years much studied in animals since the catalytic residues are comprised of selenocysteine a variant amino acid which is ribosomally encoded with the help of an RNA structural element known as SECIS. Various workers over the years have shown that plant glutathione peroxidases play active roles in ROS sequestration, lipid hydroperoxidation as well as regulate glutathione levels. However, each plant has various patterns of glutathione peroxidase expression and action and in some plants certain isoforms have not been detected at all. This work focuses on the prediction and identification of single nucleotide polymorphisms (SNPs) and INDELs in the coding regions of plant glutathione peroxidases, with the help of a Bayesian based algorithm subsequently validated. A large number of informative sites were detected 279 of which had variant frequency of ≥ 50%. This data should be beneficial for future studies involving genetic manipulation and population based breeding experiments

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Rana, Satyawati, Chhinder Pal Sodhi, Saroj Mehta, Kim Vaiphei, Ranjan Katyal, Sarita Thakur, and Satish Kumar Mehta. "Protein-energy malnutrition and oxidative injury in growing rats." Human & Experimental Toxicology 15, no. 10 (October 1996): 810–14. http://dx.doi.org/10.1177/096032719601501003.

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1 Weaning rats were fed ad libitum isocaloric diets containing 5% and 20% casein based proteins. 5% protein diet was protein deficient diet. Pair fed rats with the 5% protein group were maintained simulta neously on 20% protein diet but the amount restricted to the amount taken up by PEM group. 2 Glutathione, antioxidative enzymes, lipid peroxida tion and histopathological studies in liver and only glutathione and antioxidative enzymes in blood were carried out. 3 Rats fed the 5% protein diet developed a severe protein energy malnutrition (PEM) whereas those on pair-fed diet developed mild to moderate PEM. 4 Glutathione related thiols, superoxide dismutase, glutathione peroxidase, catalase and glutathione-S- transferase with (1 Chloro 2,4-dinitro benzene (CDNB) substrate) were decreased in liver with concomitant increase of lipid peroxidation in severe PEM. In blood glutathione, glutathione peroxidase and catalase were decreased while superoxide dismutase was increased in severe PEM group. 5 Mild to moderate PEM (pair-fed group) also resulted in similar changes in liver except glutathione peroxidase, lipid peroxidation in liver and superoxide dismutase in blood. 6 Hepatic injury was detectable only in the severe PEM group. 7 Oxidative-stress and hepatic injury occurred in severe PEM and to a lesser degree in mild to moderate PEM.

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Admoni, Sharon Nina, Daniele Pereira Santos-Bezerra, Ricardo Vesoni Perez, Thiago Andrade Patente, Maria Beatriz Monteiro, Ana Mercedes Cavaleiro, Maria Candida Parisi, et al. "Glutathione peroxidase 4 functional variant rs713041 modulates the risk for cardiovascular autonomic neuropathy in individuals with type 1 diabetes." Diabetes and Vascular Disease Research 16, no. 3 (January 1, 2019): 297–99. http://dx.doi.org/10.1177/1479164118820641.

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Cardiac autonomic neuropathy is a neglected diabetic chronic complication for which genetic predictors are rarely reported. Oxidative stress is implicated in the pathogenesis of microvascular complications, and glutathione peroxidase 4 is involved in the detoxification of peroxides and of reactive oxygen species. Thus, the association of a functional variant in the gene encoding glutathione peroxidase 4 (rs713041) with this diabetic complication was investigated in 341 individuals with type 1 diabetes evaluated for cardiac autonomic neuropathy status (61.7% women, 34 [27–42] years old; diabetes duration: 21 [15–27] years; HbA1c: 8.3% [7.4–9.4]; as median [interquartile interval]). Cardiac autonomic neuropathy was present in 29% of the participants. There was an inverse association of the minor T allele of rs713041 with cardiac autonomic neuropathy (odds ratio = 0.39; 95% confidence interval = 0.17–0.90; p = 0.0271) after adjustment for potential confounders. The functional glutathione peroxidase 4 variant rs713041 modulated the risk for cardiac autonomic neuropathy in the studied population with type 1 diabetes.

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Shahnaj, Sharifun, Rimpy Chowhan, Potshangbam Meetei, Pushpa Kakchingtabam, Khundrakpam Herojit Singh, Laishram Rajendrakumar Singh, Potshangbam Nongdam, Aron Fisher, and Hamidur Rahaman. "Hyperoxidation of Peroxiredoxin 6 Induces Alteration from Dimeric to Oligomeric State." Antioxidants 8, no. 2 (February 2, 2019): 33. http://dx.doi.org/10.3390/antiox8020033.

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Peroxiredoxins(Prdx), the family of non-selenium glutathione peroxidases, are important antioxidant enzymes that defend our system from the toxic reactive oxygen species (ROS). They are thiol-based peroxidases that utilize self-oxidation of their peroxidatic cysteine (Cp) group to reduce peroxides and peroxidized biomolecules. However, because of its high affinity for hydrogen peroxide this peroxidatic cysteine moiety is extremely susceptible to hyperoxidation, forming peroxidase inactive sulfinic acid (Cys-SO2H) and sulfonic acid (Cys-SO3H) derivatives. With the exception of peroxiredoxin 6 (Prdx6), hyperoxidized sulfinic forms of Prdx can be reversed to restore peroxidase activity by the ATP-dependent enzyme sulfiredoxin. Interestingly, hyperoxidized Prdx6 protein seems to have physiological significance as hyperoxidation has been reported to dramatically upregulate its calcium independent phospholipase A2 activity. Using biochemical studies and molecular dynamic (MD) simulation, we investigated the roles of thermodynamic, structural and internal flexibility of Prdx6 to comprehend the structural alteration of the protein in the oxidized state. We observed the loosening of the hydrophobic core of the enzyme in its secondary and tertiary structures. These changes do not affect the internal dynamics of the protein (as indicated by root-mean-square deviation, RMSD and root mean square fluctuation, RMSF plots). Native-PAGE and dynamic light scattering experiments revealed the formation of higher oligomers of Prdx6 under hyperoxidation. Our study demonstrates that post translational modification (like hyperoxidation) in Prdx6 can result in major alterations of its multimeric status.

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Gutyj, B. V., D. F. Gufriy, V. Y. Binkevych, R. O. Vasiv, N. V. Demus, K. Y. Leskiv, O. M. Binkevych, and O. V. Pavliv. "Influence of cadmium loading on glutathione system of antioxidant protection of the bullocks’bodies." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 20, no. 92 (December 10, 2018): 34–40. http://dx.doi.org/10.32718/nvlvet9207.

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It was presented the results of studies of the cadmium effect loading on the activity of the glutathione system of antioxidant protection in young cattle, namely on the activity of glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, the level of reduced glutathion. It was established that feeding of cadmium chloride to bullocks at a dose of 0.03 and 0.05 mg/kg body weight contributed to a decrease in both the enzyme and non-enzyme link of the glutathione antioxidant defense system. The toxic effect of cadmium contributes to a change in stationary concentrations of radical metabolites. О2˙ˉ, ˙ОН, НО2˙, which, in turn, initiate lipid peroxidation processes. The lowest level of glutathione indexes of the antioxidant defense system in the blood of young cattle was established on the sixteenth and twenty fourth day of the experiment, it was associated with enhanced activation of lipoperoxidation and an imbalance between the activity of the antioxidant system and the intensity of lipid peroxidation. The feeding of cadmium chloride to bullocks at a dose of 0.03 and 0.05 mg/kg of animal weight did not affect the activity of the glutathione antioxidant defense system in their blood. It was established that the greater the amount of cadmium chloride in the feed, the lower the activity of the glutathione system of the antioxidant defense of the body of bulls. Thus, cadmium chloride suppresses the antioxidant protection system, in particular, by reducing the activity of the enzyme link: glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, and non-enzyme link: reduced glutathione.

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Wingler, Kirstin, and Regina Brigelius-Flohé. "Gastrointestinal glutathione peroxidase." BioFactors 10, no. 2-3 (1999): 245–49. http://dx.doi.org/10.1002/biof.5520100223.

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Blanchflower, William J., Desmond A. Rice, and William B. Davidson. "Blood glutathione peroxidase." Biological Trace Element Research 11, no. 1 (December 1986): 89–100. http://dx.doi.org/10.1007/bf02795527.

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Sandström, B. E., and S. L. Marklund. "Effects of variation in glutathione peroxidase activity on DNA damage and cell survival in human cells exposed to hydrogen peroxide and t-butyl hydroperoxide." Biochemical Journal 271, no. 1 (October 1, 1990): 17–23. http://dx.doi.org/10.1042/bj2710017.

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The selenium-dependent glutathione peroxidase activities of two human cell lines, the colon carcinoma HT29 and the mesothelioma P31, cultured in medium containing 2% serum, increased from 195 to 541 and from 94 to 361 units/mg of protein respectively after supplementation with 100 nM-selenite. The catalase activity remained unchanged by this treatment. The effects of the obtained variation in glutathione peroxidase activities were investigated by exposing cells to H2O2 and t-butyl hydroperoxide. Selenite supplementation resulted in a decrease in H2O2-induced DNA single-strand breaks in both HT29 and P31 cells. A small, but significant, decrease in the number of DNA single-strand breaks for low doses (10-50 microM) of t-butyl hydroperoxide was found only in P31 cells and not in HT29 cells. We could detect neither induction of double-strand breaks (detection limit approx. 1000 breaks per cell) nor DNA-protein cross-links after exposing the cells to the two peroxides. In spite of the apparent protective effect of increased glutathione peroxidase activity on DNA single-strand break formation, there were no differences between selenite-supplemented and non-supplemented cells in cell survival after exposure to peroxide.

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Brigelius-Flohé, Regina, and Matilde Maiorino. "Glutathione peroxidases." Biochimica et Biophysica Acta (BBA) - General Subjects 1830, no. 5 (May 2013): 3289–303. http://dx.doi.org/10.1016/j.bbagen.2012.11.020.

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OHNISHI, Tsukasa, Tsuyoshi KASAMA, Hisashi NOGUCHI, Hiroaki NAKAJIMA, Hirotsugu IDE, Terumi TAKAHASHI, and Yukie NIWA. "Lipid Peroxides, Superoxide Dismutase, Catalase and Glutathione Peroxidase in Lung Carcinoma Tissue." Showa University Journal of Medical Sciences 1, no. 1-2 (1989): 65–70. http://dx.doi.org/10.15369/sujms1989.1.65.

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Zaets, Iryna, Sergij Kramarev, and Natalia Kozyrovska. "Inoculation with a bacterial consortium alleviates the effect of cadmium overdose in soybean plants." Open Life Sciences 5, no. 4 (August 1, 2010): 481–90. http://dx.doi.org/10.2478/s11535-010-0025-1.

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AbstractInoculating plants that have inefficient antioxidant systems with plant-associated bacteria allows them to overcome heavy metal intoxication. We monitored protein oxidation, the activity of plant defense system enzymes, and the phenolics content in soybean (Glycine max L.) during a prolonged exposure to cadmium (Cd). The assistance of the bacterial consortium reduced the bioavailability of Cd in a soil containing 10 times the metal’s Standard Maximum Value (SMV). This reduced the accumulation of Cd in the soybeans’ roots and seeds. At 100 SMV, bacterial inoculation resulted in increased Cd bioavailability, which enhanced cadmium uptake by the soybean plants. At both Cd concentrations, oxidative stress was more prolonged in the soybean’s roots than its leaves. In cadmium-polluted soil, glutathion peroxidase activity changed more rapidly in the roots of plants when they had been inoculated. Inhibition of the peroxidases’ activities strengthened the activity of glutathione-S-transferase; increased the phenolics content in plant roots; and alleviated stress in inoculated soybean plants compared to untreated plants. The bacterial consortium may be recommended for a plant protection at 10 SMV Cd in the soil, and for phytostabilization at 100 SMV.

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Zhang, Jie, Yan Wang, Hong Fei Yang, and Jian Long Li. "The Improvement of Thermotolerance in Tall Fescue and Perennial Ryegrass by Activating the Antioxidative System." Advanced Materials Research 610-613 (December 2012): 249–53. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.249.

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The effect of hydrogen peroxide (H2O2) of low concentration on thermotolerance of tall fescue (Festuca arundinacea cv. Barlexas) and perennial ryegrass (Lolium perenne cv. Accent) was studied following a foliar pretreatment with 10 mM H2O2. Antioxidative enzymes activities and antioxidant content were measured in both cool-season turfgrass cultivars under heat stress (38/30 °C, day/night) and control normal temperature (26/15 °C, day/night). While activities of catalase(CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione-dependent peroxidases (GPX) were enhanced by H2O2pretreatment during heat stress. APX, GR and GPX activities were significantly enhanced during heat stress. These were likely the most important antioxidative enzymes in tall fescue and perennial ryegrass protecting plants against heat stress. The thermotolerance was also concomitant with an increased glutathione pool, as evaluated by the significant increase of the total glutathione pool in two pretreated cultivars. The increase of POD, CAT, APX, GR activities and significant increase of GPX activity prior to the initiation of heat stress in pre-treatment plants suggested a possible role for H2O2as a signaling molecule protecting them against the subsequent heat-induced damage.

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Saudrais, Elodie, Nathalie Strazielle, and Jean-François Ghersi-Egea. "Choroid plexus glutathione peroxidases are instrumental in protecting the brain fluid environment from hydroperoxides during postnatal development." American Journal of Physiology-Cell Physiology 315, no. 4 (October 1, 2018): C445—C456. http://dx.doi.org/10.1152/ajpcell.00094.2018.

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Hydrogen peroxide, released at low physiological concentration, is involved in different cell signaling pathways during brain development. When released at supraphysiological concentrations in brain fluids following an inflammatory, hypoxic, or toxic stress, it can initiate lipid peroxidation, protein, and nucleic acid damage and contribute to long-term neurological impairment associated with perinatal diseases. We found high glutathione peroxidase and glutathione reductase enzymatic activities in both lateral and fourth ventricle choroid plexus tissue isolated from developing rats, in comparison to the cerebral cortex and liver. Consistent with these, a high protein expression of glutathione peroxidases 1 and 4 was observed in choroid plexus epithelial cells, which form the blood-cerebrospinal fluid barrier. Live choroid plexuses isolated from newborn rats were highly efficient in detoxifying H2O2 from mock cerebrospinal fluid, illustrating the capacity of the choroid plexuses to control H2O2 concentration in the ventricular system of the brain. We used a differentiated cellular model of the blood-cerebrospinal fluid barrier coupled to kinetic and inhibition analyses to show that glutathione peroxidases are more potent than catalase to detoxify extracellular H2O2 at concentrations up to 250 µM. The choroidal cells also formed an enzymatic barrier preventing blood-borne hydroperoxides to reach the cerebrospinal fluid. These data point out the choroid plexuses as key structures in the control of hydroperoxide levels in the cerebral fluid environment during development, at a time when the protective glial cell network is still immature. Glutathione peroxidases are the main effectors of this choroidal hydroperoxide inactivation.

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Maser, Robin L., Dianne Vassmer, Brenda S. Magenheimer, and James P. Calvet. "Oxidant Stress and Reduced Antioxidant Enzyme Protection in Polycystic Kidney Disease." Journal of the American Society of Nephrology 13, no. 4 (April 2002): 991–99. http://dx.doi.org/10.1681/asn.v134991.

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ABSTRACT. Oxidative stress has been implicated in the pathogenesis of both acquired and hereditary polycystic kidney disease. Mechanisms of oxidant injury in C57BL/6J-cpk mice and Han:SPRD-Cy rats with rapidly or slowly progressive polycystic kidney disease were explored. Expression of heme oxygenase-1 mRNA, an inducible marker of oxidative stress, was shown to be increased in cystic kidneys of mice and rats in a pattern that reflected disease severity. By contrast, there was a decrease in mRNA expression of the antioxidant enzymes extracellular glutathione peroxidase, superoxide dismutase, catalase, and glutathioneS-transferase during disease progression. Renal mRNA levels of these enzymes were strikingly reduced in rapidly progressive disease in homozygous cystic mice and rats. In slowly progressive disease in heterozygous rats, renal antioxidant mRNA levels were decreased to a greater extent in cystic males than in the less severely affected females. Protein levels for extracellular glutathione peroxidase were also reduced in plasma and in cystic kidneys of mice and rats. Plasma extracellular glutathione peroxidase enzymatic activity was also decreased, whereas the lipid peroxidation products malondialdehyde and 4-hydroxy-2(E)-nonenal were increased in kidneys and blood plasma of cystic mice. Reduced antioxidant enzyme protection and increased oxidative damage represent general mechanisms in the pathogenesis of polycystic kidney disease.

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Adhikari, Aniket, and Madhusnata De. "Study of Glutathione Peroxidase GPX Activity Among Betel Quid Chewers of Indian Population." International Journal of Trend in Scientific Research and Development Volume-3, Issue-3 (April 30, 2019): 70–73. http://dx.doi.org/10.31142/ijtsrd21619.

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Saccoccia, Fulvio, Francesco Angelucci, Giovanna Boumis, Gianni Desiato, Adriana E. Miele, and Andrea Bellelli. "Selenocysteine robustness versus cysteine versatility: a hypothesis on the evolution of the moonlighting behaviour of peroxiredoxins." Biochemical Society Transactions 42, no. 6 (November 17, 2014): 1768–72. http://dx.doi.org/10.1042/bst20140212.

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Peroxiredoxins (Prxs) and glutathione peroxidases (Gpxs) provide the majority of peroxides reducing activity in the cytoplasm. Both are peroxidases but differences in the chemical mechanism of reduction of oxidative agents, as well as in the reactivity of the catalytically active residues, confer peculiar features on them. Ultimately, Gpx should be regarded as an efficient peroxides scavenger having a high-reactive selenocysteine (Sec) residue. Prx, by having a low pKa cysteine, is less efficient than Gpx in reduction of peroxides under physiological conditions, but the chemistry of the sulfur together with the peculiar structural arrangement of the active site, in typical Prxs, make it suitable to sense a redox environment and to switch-in-function so as to exert holdase activity under redox-stress conditions. The complex macromolecular assembly would have evolved the chaperone holdase function and the moonlighting behaviour typical of many Prxs.

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Knoblauch, A. L., A. Paky, J. R. Michael, M. E. Kutner, E. Cadenas, H. Sies, N. F. Adkinson, and G. H. Gurtner. "Hydroperoxide-induced chemiluminescence in rabbit lungs: role of arachidonic acid enzymes." Journal of Applied Physiology 65, no. 3 (September 1, 1988): 1340–50. http://dx.doi.org/10.1152/jappl.1988.65.3.1340.

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Low-level chemiluminescence (C) is thought to be an index of oxidant stress. We measured the relationship between low-level C, pulmonary arterial pressure, and perfusate concentration of thromboxane B2 (TxB2) in isolated perfused rabbit lungs during challenge with tert-butyl hydroperoxide (t-bu-OOH). We also measured glutathione release as another index of oxidant stress. We found that C was correlated with each variable, suggesting that oxidant stress measured by C and by glutathione release stimulated TxB2 production and pulmonary vasoconstriction. We also investigated the contribution of active O2 metabolites produced by prostaglandin (PG) peroxidase to oxidant stress by studying the effects of t-bu-OOH before and after the use of cyclooxygenase and lipoxygenase inhibitors. We found that C was augmented after inhibition, perhaps due to metabolism of t-bu-OOH by peroxidases of both arachidonic acid (AA) metabolic pathways in the absence of their normal substrates. We studied phenylbutazone, thought to inhibit peroxidases, and AA. C during t-bu-OOH administration was not augmented after phenylbutazone and was markedly inhibited after AA administration perhaps because AA competes with t-bu-OOH. To further study the role of peroxidases we pretreated the lungs with the antioxidant dithiothreitol, which inhibits peroxidases involved in both the cyclooxygenase and lipoxygenase pathways. Dithiothreitol nearly abolished C produced by t-bu-OOH and also prevented the increased light caused by eicosatetrynoic acid. We directly tested the hypothesis that C occurred as a result of the interaction of t-bu-OOH and the cyclooxygenase and lipoxygenase enzymes; we measured C when t-bu-OOH was added to purified PGH2 synthase or soybean lipoxygenase. The combination of t-bu-OOH with PGH2 synthase or lipoxygenase led to C that was inhibited by dithiothreitol and by the antioxidant phenol. These results suggest that enzymes involved in AA metabolism can interact with t-bu-OOH and that the action of these enzymes on t-bu-OOH leads to C. The results may mean that lipid peroxides can indirectly contribute to tissue oxidant stress due to production of active O2 metabolites as by-products of their metabolism by AA peroxidases.

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LUOMA, P. V., J. STENGÅRD, H. KORPELA, A. RAUTIO, E. A. SOTANIEMI, E. SUVANTO, and J. MARNIEMI. "Lipid peroxides, glutathione peroxidase, high density lipoprotein subfractions and apolipoproteins in young adults." Journal of Internal Medicine 227, no. 4 (April 1990): 287–89. http://dx.doi.org/10.1111/j.1365-2796.1990.tb00161.x.

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NAKANO, T., M. SATO, and M. TAKEUCHI. "Glutathione Peroxidase of Fish." Journal of Food Science 57, no. 5 (September 1992): 1116–19. http://dx.doi.org/10.1111/j.1365-2621.1992.tb11276.x.

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Maiorino, M., A. Roveri, and F. Ursini. "PHOSPHOLIPID HYDROPEROXIDE GLUTATHIONE PEROXIDASE." Phosphorus and Sulfur and the Related Elements 38, no. 1-2 (July 1988): 41–48. http://dx.doi.org/10.1080/03086648808079699.

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Stiborová, Marie, Heinz H. Schmeiser, and Eva Frei. "To the Mechanism of 2-Nitroanisole Carcinogenicity: in vitro Metabolism of 2-Nitroanisole Mediated by Peroxidasesand Xanthine Oxidase." Collection of Czechoslovak Chemical Communications 63, no. 6 (1998): 857–69. http://dx.doi.org/10.1135/cccc19980857.

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The in vitro enzymatic metabolism of carcinogenic 2-nitroanisole was investigated using peroxidases (horseradish peroxidase and prostaglandin H synthase) and xanthine oxidase catalyzing oxidative and reductive reactions, respectively. The oxidation of 2-nitroanisole catalyzed by horseradish peroxidase exhibits the Michaelis-Menten kinetics. The Michaelis constant (Km) and the maximal velocity (Vmax) values for this substrate were determined at pH 5.0, 7.0, 7.6 and 8.0. At optimal pH (7.6), the Km and Vmax values are 0.219 μmol/l and 34.45 pmol/min per nmol peroxidase, respectively. The oxidation of 2-nitroanisole is inhibited by radical trapping agents (NADH, ascorbate, glutathione and nitrosobenzene). This indicates that the peroxidase-mediated oxidation of 2-nitroanisole proceeds via a radical mechanism. Active oxygen species are formed during the horseradish peroxidase-catalyzed reactions in the presence of NADH, hydrogen peroxide and 2-nitroanisole. 2-Nitroanisole is also oxidized by mammalian prostaglandin H synthase. Using the nuclease P1-enhanced variation of the 32P-postlabelling assay, the formation of DNA adducts was detected in DNA treated with 2-nitroanisole and xanthine oxidase. No DNA binding was detected after oxidation of 2-nitroanisole with horseradish peroxidase and prostaglandin H synthase. The results presented (the formation of DNA adducts after 2-nitroanisole activation by xanthine oxidase and that of radicals and/or superoxide radicals during the reactions with peroxidases) strongly suggest the participation of 2-nitroanisole both in the initiation and in the promotion phases of carcinogenesis.

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Batist, G., A. G. Katki, V. J. Ferrans, and C. E. Myers. "The Role of Selenium Compounds in Cancer Therapy." Journal of the American College of Toxicology 5, no. 1 (January 1986): 87–93. http://dx.doi.org/10.3109/10915818609140739.

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Experimental evidence is presented that demonstrates the impact of selenium on the effects of a variety of anticancer treatments, including chemotherapy and radiation. Selenium-dependent glutathione peroxidase can detoxify organic peroxides resulting from some of these treatments. Selenium deficiency has also been associated with significant changes in liver enzymes that activate some drugs and contribute to detoxification. Some forms of free selenium have cytotoxicity against a variety of tumor cell lines, both murine and human. Experimental data suggest that catalytic oxidation of cellular glutathione and reduction of molecular oxygen are part of the mechanism of this antitumor activity. This provides provocative possibilities for the inclusion of selenium into cancer therapy regimens.

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Ramming, Thomas, and Christian Appenzeller-Herzog. "Destroy and Exploit: Catalyzed Removal of Hydroperoxides from the Endoplasmic Reticulum." International Journal of Cell Biology 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/180906.

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Peroxidases are enzymes that reduce hydroperoxide substrates. In many cases, hydroperoxide reduction is coupled to the formation of a disulfide bond, which is transferred onto specific acceptor molecules, the so-called reducing substrates. As such, peroxidases control the spatiotemporal distribution of diffusible second messengers such as hydrogen peroxide (H2O2) and generate new disulfides. Members of two families of peroxidases, peroxiredoxins (Prxs) and glutathione peroxidases (GPxs), reside in different subcellular compartments or are secreted from cells. This review discusses the properties and physiological roles of PrxIV, GPx7, and GPx8 in the endoplasmic reticulum (ER) of higher eukaryotic cells where H2O2and—possibly—lipid hydroperoxides are regularly produced. Different peroxide sources and reducing substrates for ER peroxidases are critically evaluated. Peroxidase-catalyzed detoxification of hydroperoxides coupled to the productive use of disulfides, for instance, in the ER-associated process of oxidative protein folding, appears to emerge as a common theme. Nonetheless,in vitroandin vivostudies have demonstrated that individual peroxidases serve specific, nonoverlapping roles in ER physiology.

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Steven Esworthy, R., Fong-Fong Chu, Raymond J. Paxton, Steven Akman, and James H. Doroshow. "Human plasma glutathione peroxidase is a distinct protein from intracellular glutathione peroxidase." Free Radical Biology and Medicine 9 (January 1990): 3. http://dx.doi.org/10.1016/0891-5849(90)90177-k.

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Zatorska, Agnieszka, Janusz Maszewski, and Zofia Jóźwiak. "Changes in GSH-antioxidant system induced by daunorubicin in human normal and diabetic fibroblasts." Acta Biochimica Polonica 50, no. 3 (September 30, 2003): 825–35. http://dx.doi.org/10.18388/abp.2003_3674.

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We investigated the effect of daunorubicin on glutathione content and activity of GSH-related enzymes in cultured normal and diabetic human fibroblasts. Cells were incubated with 4 microM daunorubicin (DNR) for 2 h followed by culture in drug-free medium for up to 72 h. Treatment of diabetic cells with the drug caused a time-dependent depletion of intracellular GSH and a decrease of the GSH to total glutathione ratio. GSH depletion was accompanied by apoptotic changes in morphology of the nucleus. Analysis of GSH-related enzymes showed a significant increase of the activities of Se-dependent and Se-independent peroxidases and glutathione S-transferase. In contrast, glutathione reductase activity was reduced by 50%. Significant differences between normal and diabetic cells exposed to DNR were observed in the level of GST and Se-dependent glutathione peroxidase activities. These findings indicated that daunorubicin efficiently affects the GSH antioxidant defense system both in normal and diabetic fibroblasts leading to disturbances in glutathione content as well as in the activity of GSH-related enzymes.

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Eshdat, Yuval, Doron Holland, Zehava Faltin, and Gozal Ben-Hayyim. "Plant glutathione peroxidases." Physiologia Plantarum 100, no. 2 (June 1997): 234–40. http://dx.doi.org/10.1034/j.1399-3054.1997.1000204.x.

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Eshdat, Yuval, Doron Holland, Zehava Faltin, and Gozal Ben-Hayyim. "Plant glutathione peroxidases." Physiologia Plantarum 100, no. 2 (June 1997): 234–40. http://dx.doi.org/10.1111/j.1399-3054.1997.tb04779.x.

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45

Arthur, J. R. "The glutathione peroxidases." Cellular and Molecular Life Sciences 57, no. 13 (February 2001): 1825–35. http://dx.doi.org/10.1007/pl00000664.

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Shigeoka, S., T. Onishi, Y. Nakano, and S. Kitaoka. "Characterization and physiological function of glutathione reductase in Euglena gracilis z." Biochemical Journal 242, no. 2 (March 1, 1987): 511–15. http://dx.doi.org/10.1042/bj2420511.

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The purified glutathione reductase was homogeneous on polyacrylamide-gel electrophoresis. It had an Mr of 79,000 and consisted of two subunits with a Mr of 40,000. The activity was maximum at pH 8.2 and 52 degrees C. It was specific for NADPH but not for NADH as the electron donor; the reverse reaction was not observed. The Km values for NADPH and GSSG were 14 and 55 microM respectively. The enzyme activity was markedly inhibited by thiol inhibitors and metal ions such as Hg2+, Cu2+ and Zn2+. Euglena cells contained total glutathione at millimolar concentration. GSH constituted more than 80% of total glutathione in Euglena under various growth conditions. Glutathione reductase was located solely in cytosol, as were L-ascorbate peroxidase and dehydroascorbate reductase, which constitute the oxidation-reduction cycle of L-ascorbate [Shigeoka et al. (1980) Biochem. J. 186, 377-380]. These results indicate that glutathione reductase functions to maintain glutathione in the reduced form and to accelerate the oxidation-reduction of L-ascorbate, which scavenges peroxides generated in Euglena cells.

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Rotaru, Luciana Teodora, Renata Maria Varut, Mihai Banicioiu Covei, Irina Iuliana Costache, Marius Novac, Oana Nicolaescu, Cristina Florescu, Alina Petrica, Roxana Kostici, and Daniela Ciobanu. "Determination of Antioxidant Components and Activity of Tamarix ramosissima Comparative with Vaccinium myrtillus on Streptozotocin-diabetic Mice." Revista de Chimie 69, no. 7 (August 15, 2018): 1860–65. http://dx.doi.org/10.37358/rc.18.7.6432.

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Tamarix ramosissima (Tamaricaceae) is a small tree that grows spontaneously in Europe and Asia, being considered an invasive species in geographical areas with warm climates. The chemical composition is partially elucidated, being empirically used for antiinflammatory, analgesic, antibacterial and antioxidant effect. Our study aimed to evaluate the total polyphenol and flavonoid content of vegetal extracts and to test in vivo antioxidant therapeutic effect of it, comparative with Vaccinium myrtillus, using streptozotocin-induced diabetic mice. After five weeks the animals were sacrificed and we determined erythrocyte activities of superoxide dismutase, glutathione peroxidase, glutathione reductase and level of lipid peroxides as thiobarbituric acid reactive substances. Antioxidant enzymes had highest activities in mice treated with T. ramosissima extract and the level of lipid peroxides was the lowest. The tested extract had higher content of polyphenols comparative with V. myrtillus. Our results sustain the efficiency of T. ramosissima extracts on normalizing the effects of oxidative stress in diabetes.

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González, Ricardo, Cheyla Romay, Aluet Borrego, Frank Hernández, Nelson Merino, Zullyt Zamora, and Enis Rojas. "Lipid Peroxides and Antioxidant Enzymes in Cisplatin-Induced Chronic Nephrotoxicity in Rats." Mediators of Inflammation 2005, no. 3 (2005): 139–43. http://dx.doi.org/10.1155/mi.2005.139.

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Cisplatin (CDDP), an anticancer drug, induces remarkable toxicity in the kidneys of animals and humans and it has been well documented that reactive oxygen species and the renal antioxidant system are strongly involved in acute renal damage induced by CDDP. The aim of the present study was to investigate whether or not the renal antioxidant system plays also an important role in chronic renal damage induced by repeated doses of CDDP (1 mg/kg intraperitoneally twice weekly during 10 weeks in rats). In order to elucidate it, serum creatinine and urea levels, renal glutathione and thiobarbituric acid-reactive substances (TBARS) content, as well as renal superoxide dismutase and glutathione peroxidase activities were measured in the kidney homogenates of chronically CDDP-treated rats and additionally histological studies were performed in the rat kidneys. The chronic treatment with CDDP induced a significant increase in creatinine and urea levels in serum, but the other parameters mentioned above were not significantly modified as compared to the values in nontreated rats. Taking into account these results, we conclude that chronic CDDP administration induces also severe nephrotoxicity, in contrast to CDDP acute application, without any significant modification in the activity of relevant antioxidant enzymes such as superoxide dismutase and glutathione peroxidase, renal glutathione and lipid peroxides, by which the role of the antioxidant system in chronic nephrotoxicity induced by CDDP in rats is uncertain.

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Schlecker, Tanja, Marcelo A. Comini, Johannes Melchers, Thomas Ruppert, and R. Luise Krauth-Siegel. "Catalytic mechanism of the glutathione peroxidase-type tryparedoxin peroxidase of Trypanosoma brucei." Biochemical Journal 405, no. 3 (July 13, 2007): 445–54. http://dx.doi.org/10.1042/bj20070259.

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Trypanosoma brucei, the causative agent of African sleeping sickness, encodes three nearly identical genes for cysteine-homologues of the selenocysteine-containing glutathione peroxidases. The enzymes, which are essential for the parasites, lack glutathione peroxidase activity but catalyse the trypanothione/Tpx (tryparedoxin)-dependent reduction of hydroperoxides. Cys47, Gln82 and Trp137 correspond to the selenocysteine, glutamine and tryptophan catalytic triad of the mammalian selenoenzymes. Site-directed mutagenesis revealed that Cys47 and Gln82 are essential. A glycine mutant of Trp137 had 13% of wild-type activity, which suggests that the aromatic residue may play a structural role but is not directly involved in catalysis. Cys95, which is conserved in related yeast and plant proteins but not in the mammalian selenoenzymes, proved to be essential as well. In contrast, replacement of the highly conserved Cys76 by a serine residue resulted in a fully active enzyme species and its role remains unknown. Thr50, proposed to stabilize the thiolate anion at Cys47, is also not essential for catalysis. Treatment of the C76S/C95S but not of the C47S/C76S double mutant with H2O2 induced formation of a sulfinic acid and covalent homodimers in accordance with Cys47 being the peroxidative active site thiol. In the wild-type peroxidase, these oxidations are prevented by formation of an intramolecular disulfide bridge between Cys47 and Cys95. As shown by MS, regeneration of the reduced enzyme by Tpx involves a transient mixed disulfide between Cys95 of the peroxidase and Cys40 of Tpx. The catalytic mechanism of the Tpx peroxidase resembles that of atypical 2-Cys-peroxiredoxins but is distinct from that of the selenoenzymes.

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Rajasekaran, Muthiah. "Nephroprotective effect of Costus pictus extract against doxorubicin-induced toxicity on Wistar rat." Bangladesh Journal of Pharmacology 14, no. 2 (May 14, 2019): 93–100. http://dx.doi.org/10.3329/bjp.v14i2.39992.

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The present study was conducted to evaluate the nephroprotective effect of a medicinal herb Costus pictus against doxorubicin-induced toxicity. Rats were divided into six groups and treated with doxorubicin and ethanol extract of the C. pictus. Doxorubicin was administered intraperitoneally with a single dose (4 mg/kg) per week for three weeks. The extract (200 or 400 mg/kg) was administered orally for 4 weeks to two doxorubicin groups. Significant changes of the serum kidney markers, albumin, urea, uric acid and creatinine, and glutathione peroxidase, glutathione–S-transferase, catalase, superoxide dismutase, reduced glutathione and lipid peroxides in the kidney of doxorubicin-treated rat were observed. Histological features were also severely affected. However, biochemical and histological changes in the extract-treated rat were non-significant, showing that the herb is nephroprotective. The effects were comparable to the anti-oxidant vitamin E.

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Journal articles on the topic 'Glutathion peroxidasa'

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