Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The range of antioxidant enzyme systems available to Haemonchus contortus for detoxification of hydrogen peroxide was investigated using cDNA cloning of candidate genes. PCR with primers based on conserved amino acid regions and spliced leader sequences was used to obtain full-length sequences for a 2-Cys peroxiredoxin, a catalase, and a selenium-independent glutathione peroxidase, indicating that H. contortus expresses a number of antioxidant systems with the potential to detoxify peroxide (nucleotide sequence data reported in this paper are available in the GenBank, EMBL and DDBJ databases under the accession numbers AY603335, AY603336 and AY603337). Quantitative PCR analysis comparing L3-stage larvae with adult worms showed significantly elevated peroxiredoxin levels in adults, equivalent catalase levels in the two stages, and significantly less glutathione peroxidase in adults, suggesting a significant role for peroxiredoxin in allowing the nematode to detoxify hydrogen peroxide encountered in the parasitic environment. Exposure of L4-stage worms to hydrogen peroxide in vitro (generated using glucose/glucose oxidase) caused no change in mRNA levels for each of the genes, though the exposed worms showed up to eightfold higher catalase activities. The lack of mRNA changes alongside increased catalase enzyme activity indicates that transcript level was not predictive of enzyme activity, suggesting that activity may be regulated in response to oxidative stress by a mechanism other than increased transcription.
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PMID:cDNA cloning and expression patterns of a peroxiredoxin, a catalase and a glutathione peroxidase from Haemonchus contortus. 1536 24

Oral streptococci such as Streptococcus gordonii are facultative anaerobes that initiate biofilm formation on tooth surfaces. An isolated S. gordonii::Tn917-lac biofilm-defective mutant contained a transposon insertion in an open reading frame (ORF) encoding a homolog of NosX of Ralstonia eutropha, a putative maturation factor of nitrous oxide reductase. Located downstream are two genes, qor1 and qor2, predicted to encode two putative NADPH quinone oxidoreductases. These three genes are cotranscribed, forming a putative oxidative stress response (osr) operon in S. gordonii. Inactivation of nosX, qor1, or qor2 resulted in biofilm-defective phenotypes. Expression of nosX, measured by the beta-galactosidase activity of the nosX::Tn917-lac mutant, was growth-phase dependent and enhanced when grown under aerobic conditions or in the presence of paraquat. Real-time reverse transcription-PCR revealed that nosX-specific mRNA levels were increased approximately 8.4 and 3.5 fold in biofilm-derived cells grown on plastic and glass, respectively, when compared to planktonic cells. Expression of nosX increased 19.9 fold in cells grown under aerated aerobic conditions and 4.7 fold in cells grown under static aerobic conditions. Two ORFs immediately adjacent to the osr operon encode a putative NADH oxidase (Nox) and a putative thiol-specific antioxidant enzyme (AhpC, for alkyl hydroperoxide peroxidase C). Expression of nox and ahpC was also significantly increased in cells grown under aerated and static aerobic conditions when compared to anaerobic conditions. In addition, nox expression was increased in biofilm cells compared to planktonic cells. These genes may be part of an island that deals with oxidoreductive response, some of which may be important in S. gordonii biofilm formation.
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PMID:Role of a nosX homolog in Streptococcus gordonii in aerobic growth and biofilm formation. 1557 67

Plants resistant to the fungal pathogen Leptosphaeria maculans were generated by an interspecific cross between the highly susceptible Brassica napus (canola) and the highly resistant Brassica carinata. Changes in the leaf protein profiles of these lines were investigated in order to understand the biochemical basis for the observed resistance. Two-dimensional electrophoresis followed by tandem mass spectrometry led to the identification of proteins unique to the susceptible (5 proteins) and resistant genotypes (7 proteins) as well those that were differentially expressed in the resistant genotype 48 h after challenge with the pathogen (28 proteins). Proteins identified as being unique in the resistant plant material included superoxide dismutase, nitrate reductase, and carbonic anhydrase. Photosynthetic enzymes (fructose bisphosphate aldolase, triose phosphate isomerase, sedoheptulose bisphosphatase), dehydroascorbate reductase, peroxiredoxin, malate dehydrogenase, glutamine synthetase, N-glyceraldehyde-2-phosphotransferase, and peptidyl-prolyl cis-trans isomerase were observed to be elevated in the resistant genotype upon pathogen challenge. Increased levels of the antioxidant enzyme superoxide dismutase were further validated and supported by spectrophotometric and in-gel activity assays. Other proteins identified in this study such as nitrate reductase and peptidylprolyl isomerase have not been previously described in this plant-pathogen system, and their potential involvement in an incompatible interaction is discussed.
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PMID:Proteome-level investigation of Brassica carinata-derived resistance to Leptosphaeria maculans. 1565 67

We report the cloning, expression and characterization of a cDNA encoding the antioxidant enzyme peroxiredoxin (Prx) from the mole cricket, Gryllotalpa orientalis. The G. orientalis Prx (GoPrx) cDNA contains an open reading frame of 660 bp encoding 220 amino acid residues and possesses one cysteine residue that is characteristic of the 1-Cys subgroup of the peroxiredoxin family. The deduced amino acid sequence of the GoPrx cDNA showed 69% identity to Drosophila melanogaster DPx-2540, 50% to D. melanogaster DPx-6005, and 47% to Glossina morsitans morsitans Prx. Phylogenetic analysis further confirmed a closer relationship of the deduced amino acid sequences of the GoPrx gene to the DPx-2540 within the 1-Cys Prx cluster. The cDNA encoding GoPrx was expressed as a 27-kDa polypeptide in baculovirus-infected insect Sf9 cells. The purified recombinant GoPrx was shown to reduce H(2)O(2) in the presence of electrons donated by dithiothreitol, but did not show the activity in the presence of thioredoxin as electron donor. Northern blot analysis revealed the presence of GoPrx transcripts in all tissues examined. When H(2)O(2) was injected into the body cavity of G. orientalis adult, GoPrx mRNA expression was up-regulated in the fat body tissues. Furthermore, the expression levels of GoPrx mRNA in the fat body were particularly high when G. orientalis adult was exposed at low (4 degrees C) and high (37 degrees C) temperatures, suggesting that the GoPrx seems to play a protective role against oxidative stress caused by temperature shock.
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PMID:Molecular cloning and characterization of a peroxiredoxin gene from the mole cricket, Gryllotalpa orientalis. 1576 13

Peroxiredoxin 6 (Prdx6), a bifunctional 25-kDa protein with both GSH peroxidase and phospholipase A2 activities, is the only mammalian 1-Cys member of the peroxiredoxin superfamily and is expressed in all major organs, with a particularly high level in lung. Prdx6 uses GSH as an electron donor to reduce H2O2 and other hydroperoxides including phospholipid hydroperoxides at approximately 5 micromol/mg protein/min with K1 approximately 3 x 10(6) M(-1) s(-1). Oxidation of the Cys47 to a sulfenic acid during catalysis requires piGST-catalyzed glutathionylation and reduction with GSH to complete the enzymatic cycle. Prdx6 stably overexpressed in cells protected against oxidative stress, whereas antisense treatment resulted in oxidant stress and apoptosis. Adenoviral-mediated overexpression of Prdx6 in mouse lungs protected against the toxicity of hyperoxia, whereas Prdx6-null mice were more sensitive to the effects of hyperoxia or paraquat. We postulate that Prdx6 functions in antioxidant defense mainly by facilitating repair of damaged cell membranes via reduction of peroxidized phospholipids. The PLA2 activity of Prdx6 is Ca2+ independent and maximal at acidic pH. Inhibition of PLA2 activity results in alterations of lung surfactant phospholipid synthesis and turnover. Thus, Prdx6, a unique mammalian peroxiredoxin, is an important antioxidant enzyme and has a major role in lung phospholipid metabolism.
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PMID:Peroxiredoxin 6, a 1-Cys peroxiredoxin, functions in antioxidant defense and lung phospholipid metabolism. 1589 Jun 16

The observation that purified yeast glutamine synthetase is rapidly inactivated in a thiol-containing buffer yet retains activity in crude extracts containing the same thiol led to our discovery of an enzyme that protects against oxidation in a thiol-containing system. This novel antioxidant enzyme was shown to reduce hydroperoxides and, more recently, peroxynitrite with the use of electrons provided by a physiological thiol like thioredoxin. It defined a family of proteins, present in organisms from all kingdoms, that was named peroxiredoxin (Prx). All Prx enzymes contain a conserved Cys residue that undergoes a cycle of peroxide-dependent oxidation and thiol-dependent reduction during catalysis. Mammalian cells express six isoforms of Prx (Prx I to VI), which are classified into three subgroups (2-Cys, atypical 2-Cys, and 1-Cys) based on the number and position of Cys residues that participate in catalysis. The relative abundance of Prx enzymes in mammalian cells appears to protect cellular components by removing the low levels of peroxides produced as a result of normal cellular metabolism. During catalysis, the active site cysteine is occasionally overoxidized to cysteine sulfinic acid. Contrary to the general belief that oxidation to the sulfinic state is an irreversible process in cells, studies on the fate of the overoxidized Prx species revealed a mechanism by which the catalytically active thiol form is recovered. This sulfinic reduction is a slow, ATP-dependent process that is specific to 2-Cys Prx isoforms. This reversible overoxidation may represent an adaptation unique to eukaryotic cells that accommodates the intracellular messenger function of H(2)O(2), but experimental validation of such speculation is yet to come.
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PMID:Peroxiredoxins: a historical overview and speculative preview of novel mechanisms and emerging concepts in cell signaling. 1591 83

Thermophilic bacterium Bacillus stearothermophilus TLS33, isolated from a hot spring in Chiang Mai, Thailand, usually produces many enzymes that are very useful for industrial applications. However, the functional properties and mechanisms of this bacterium under stress conditions are rarely reported and still need more understanding on how the bacterium can survive in stress environments. In this study, we examined the oxidative stress induced proteins of this bacterium by proteomic approach combining two-dimensional electrophoresis and mass spectrometry. When the bacterium encountered oxidative stress, peroxiredoxin, as an antioxidant enzyme, is one of the interesting stressed proteins which appeared to be systematically increased with different pI. There are four isoforms of peroxiredoxin, denoted as Prx I, Prx II, Prx III and Prx IV, which are observed at the same molecular weight of 27 kDa but differ in pI values of 5.0, 4.87, 4.81 and 4.79, respectively. The H2O2 concentration directly increased Prx II, Prx III and Prx IV intensities, but decreased Prx I intensity. These shifting of peroxiredoxin isoforms may occur by a post-translational modification. Otherwise, the longer time of oxidative stress had not affected the expression level of peroxiredoxin isoforms. Therefore, this finding of peroxiredoxin intends to know the bacterial adaptation under oxidative stress. Otherwise, this protein plays an important role in many physiological processes and able to use in the industrial applications.
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PMID:Proteomics viewed on stress response of thermophilic bacterium Bacillus stearothermophilus TLS33. 1612 33

ATP has been shown to mediate stress responses in the brain. The present study examined the ATP-stimulated stress protein expression of RBA-2 type-2 astrocytes. Our results revealed that ATP stimulated HSP60 expression in a dose- and time-dependent manner. The stimulation requires a minimal ATP concentration of 500 microM and high concentration of extracellular ATP (1 mM) stimulated a significant increase of HSP60 expression from 2 to 24 h. In addition, the ATP-stimulated HSP60 expressions were inhibited by inhibitors for protein kinase C (PKC) and phospholipase D (PLD), and by antioxidants, resveratrol, and catalase. Furthermore, ATP stimulated the expression of Cu/Zn superoxide dismutase (SOD). In addition, ATP and P2X7 receptor selective agonist BzATP also decreased mitochondria membrane potential measured by flow cytometry. To further examine the proteins involving in ATP-mediated stress responses, we conducted proteomic analysis. We found that RBA-2 astrocytes possess abundant peroxiredoxin II (Prx II), an antioxidant enzyme. ATP and exogenous H2O2 stimulated Prx II shifting from oxidized form to reduced form. Thus, we concluded that ATP potentiated the expression of HSP60 and Cu/Zn SOD, and decreased mitochondria membrane potential. In addition, RBA-2 astrocytes expressed Prx II that might also serve as a protective mechanism to control the concentration of reactive oxygen species.
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PMID:Elucidation of ATP-stimulated stress protein expression of RBA-2 type-2 astrocytes: ATP potentiate HSP60 and Cu/Zn SOD expression and stimulates pI shift of peroxiredoxin II. 1617 11

Peroxiredoxin II (Prx II) is a member of antioxidant enzyme family and it plays a protective role against oxidative damage. Constitutive production of endogenous reactive oxygen species was detected in spleen and bone marrow cells lacking Prx II. Here, we investigated the role of Prx II in immune responses. The total number of splenocytes (especially, the population of S-phase cells and CD3(+) T cells) was significantly higher in Prx II(-/-) mice than in wild type. Number of peripheral blood mononuclear cells (PBMCs) in Prx II(-/-) mice was also higher than wild type. Differentiation of Prx II(-/-) mouse bone marrow cells into CD11c-positive dendritic cells was greater than that of wild type. Transplantation of Prx II(-/-) bone marrow cells into wild type mice increased PBMCs in blood and bone marrow-derived dendritic cells. Prx II deletion enhances concanavalin A (ConA)-induced splenocyte proliferation and mixed lymphocyte reaction (MLR) activity of bone marrow-derived CD11c-positive dendritic cells to stimulate recipient splenocytes. Collectively, these data suggest that Prx II inhibits the immune cell responsiveness, which may be regulated by scavenging the low amount of reactive oxygen species (ROS).
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PMID:T lymphocytes and dendritic cells are activated by the deletion of peroxiredoxin II (Prx II) gene. 1629 Feb 4

Oxidative stress is thought to contribute to the initiation and progression of atherosclerosis. As glutathione peroxidase-1 (Gpx1) is an antioxidant enzyme that detoxifies lipid hydroperoxides, we tested the impact of Gpx1 deficiency on atherosclerotic processes and antioxidant enzyme expression in mice fed a high-fat diet (HFD). After 12 weeks of HFD, atherosclerotic lesions at the aortic sinus were of similar size in control and Gpx1-deficient mice. However, after 20 weeks of HFD, lesion size increased further in control but not in Gpx1-deficient mice, even though plasma and aortic wall markers of oxidative damage did not differ between groups. In control mice, the expression of Gpx1 increased and that of Gpx3 decreased at the aortic sinus after 20 weeks of HFD, with no change in the expression of Gpx2, Gpx4, catalase, peroxiredoxin-6, glutaredoxin-1 and -2, or thioredoxin-1 and -2. By comparison, in Gpx1-deficient mice, the expression of antioxidant genes was unaltered except for a decrease in glutaredoxin-1 and an increase in glutaredoxin-2. These changes were associated with increased expression of the proinflammatory marker monocyte chemoattractant protein-1 in control mice but not in Gpx1-deficient mice. In summary, a specific deficiency in Gpx1 was not accompanied by an increase in markers of oxidative damage or increased atherosclerosis in a murine model of HFD-induced atherogenesis.
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PMID:Lack of the antioxidant glutathione peroxidase-1 does not increase atherosclerosis in C57BL/J6 mice fed a high-fat diet. 1650 38


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