UNIPROT:P30044 - FACTA Search

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Query: UNIPROT:P30044 (antioxidant enzyme)
8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic hyperglycemia in diabetes determines the overproduction of free radicals, and evidence is increasing that these contribute to the development of diabetic complications. It has recently been reported that dehydroepiandrosterone possesses antioxidant properties; this study evaluates whether, administered daily for three weeks per os, it may provide antioxidant protection in tissues of rats with streptozotocin-induced diabetes. Lipid peroxidation was evaluated on liver, brain and kidney homogenates from diabetic animals, measuring both steady-state concentrations of thiobarbituric acid reactive substances and fluorescent chromolipids. Hyperglycemic rats had higher thiobarbituric acid reactive substances formation and fluorescent chromolipids levels than controls. Dehydroepiandrosterone-treatment (4 mg/day for 3 weeks) protected tissues against lipid peroxidation: liver, kidney and brain homogenates from dehydroepiandrosterone-treated animals showed a significant decrease of both thiobarbituric acid reactive substances and fluorescent chromolipids formation. The effect of dehydroepiandrosterone on the cellular antioxidant defenses was also investigated, as impaired antioxidant enzyme activities were considered proof of oxygen-dependent toxicity. In kidney and liver homogenates, dehydroepiandrosterone treatment restored to near-control values the cytosolic level of reduced glutathione, as well as the enzymatic activities of superoxide-dismutase, glutathione-peroxidase, catalase. In the brain, only an increase of catalase activity was evident (p < .05), which reverted with dehydroepiandrosterone treatment. The results demonstrate that DHEA treatment clearly reduces oxidative stress products in the tissues of streptozotocin-treated rats.
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PMID:Dehydroepiandrosterone protects tissues of streptozotocin-treated rats against oxidative stress. 1040 10

It was studied the relation between activities of ferments an antioxidant system: of superoxide dismutase, catalase and GSH-peroxidase in the homogenates of livers, lungs and cerebrum of intact rats. When activities were brought to identical units of measurement, it was determined that relation of activities can see with a point to view of chemical kinetics laws for consecutively-parallel reactions. It is followed from the result that the activity of catalase livers can be explained by the participation of catalases in other reactions, which were connected with forming a hydrogen peroxide. From the relations between ferments of antioxidant system it was discovered that GSH-peroxidase is the most important antioxidant enzyme for the cerebrum. Data of the relation of activities ferments of antioxidant system are stipulated by the tissues particularities and they are reflected a contribution of every biocatalyst in that system.
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PMID:[Relationship between values of antioxidant enzyme system activity in various tissues of intact rats]. 1040 49

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.
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PMID:Characterisation of Fasciola hepatica cytochrome c peroxidase as an enzyme with potential antioxidant activity in vitro. 1040 59

Metallothionein (MT) is a protein involved in heavy metal homeostasis and detoxification. According to several studies, MT could be involved in the antioxidant defense system, in which glutathione (GSH) is an essential component. The aim of this study was to verify the implication of MT in the antioxidant defense system in isolated rat hepatocytes. For this purpose, hepatocyte cultures were exposed to treatments known to modify MT or GSH levels. Zinc (Zn) was used as an inducer of MT while diethyl maleate (DEM) and buthionine sulfoximine (BSO) were used as GSH depletors. GSH, MT, and antioxidant enzyme activities were measured under conditions of MT induction and GSH depletion. Induction of MT synthesis through an 18-hour exposure to Zn (20 microM), did not result in any significant change in GSH levels or in activities of the antioxidant enzymes, glutathione-peroxidase (GSH-Px), catalase, and superoxide dismutase (SOD). DEM caused GSH depletion in cells, whether they were exposed to Zn or not, that lasted one h; after that time, GSH rose back to basal levels. BSO also caused GSH-depletion in cells exposed or unexposed to Zn, and no recovery in GSH levels was detectable during the entire period of exposure (12 h). However, GSH depletion induced by both DEM or BSO was attenuated in Zn-treated hepatocytes. Moreover, DEM and BSO exposures led to a depletion of MT levels in Zn-treated hepatocytes, indicating a link between GSH and MT metabolism. In cells unexposed to either Zn, DEM or BSO, there was an increase in GSH-Px and SOD activities after 6 and 12 h of incubation, respectively. Under the same conditions, catalase activity was inhibited after 6 h of incubation and returned to the activity found at t = 0 after 12 h of incubation. DEM and BSO treatments had no significant effect on GSH-Px or SOD activities although they led to inhibition of catalase activity. Taken together, our data indicate that MT induction, which creates a new pool of thiol groups in the cell cytosol, can attenuate GSH depletion induced by DEM or BSO. It appears that catalase is most sensitive to oxidative stress and that MT induction can antagonize the deleterious effects of such stress on the enzyme. This study supports the view that MT is part of the hepatocyte antioxidant-defense-system.
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PMID:Metallothionein induction attenuates the effects of glutathione depletors in rat hepatocytes. 1041 75

Dominant mutations in the copper/zinc superoxide dismutase (SOD1) gene have been observed in 15-20% of familial amyotrophic lateral sclerosis (FALS) cases. The mechanism by which SOD1 mutations result in motor neuron degeneration in FALS mice partly involves oxidative damage and an increased peroxidase activity of the mutant SOD1. A new therapeutic approach designed to eliminate the substrate of this peroxidase activity was examined in two lines of transgenic mice expressing the FALS-linked mutation glycine to alanine (G93A). We investigated the ability of putrescine-modified catalase (PUT-CAT), an antioxidant enzyme that removes hydrogen peroxide and has increased permeability at the blood-brain barrier, to modify the time course of the SOD1 mutation-induced motor neuron disease in these FALS mice. Continuous, subcutaneous administration of PUT-CAT significantly delayed the age at which onset of clinical disease occurred (indicated by loss of splay and/or tremors of hindlimbs) in a high-expressor line of FALS transgenic mice. Intraperitoneal injection of PUT-CAT given two times per week also significantly delayed the onset of clinical disease in a low-expressor line of FALS mice. PUT-CAT also significantly delayed the age at which clinical weakness developed (quantified by measuring the shortening of stride length) in both lines of FALS animals. No significant changes were observed in the survival times of the high-expressor FALS mice in any of the treatment groups. However, a trend toward a prolongation of survival was observed in the PUT-CAT-treated low-expressor FALS mice. These results support the role of free radical-mediated damage in the cascade of events leading to motor neurodegeneration in FALS and indicate that PUT-CAT interacts with a critical step in this cascade to delay the onset of clinical disease as well as the development of clinical weakness in FALS transgenic mice.
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PMID:Therapeutic benefits of putrescine-modified catalase in a transgenic mouse model of familial amyotrophic lateral sclerosis. 1048 88

We have isolated the cDNAs encoding human and mouse homologues of a yeast protein, termed peroxisomal membrane protein 20 (PMP20). Comparison of the amino acid sequences of human (HsPMP20) and mouse (MmPMP20) PMP20 proteins revealed a high degree of identity (93%), whereas resemblance to the yeast Candida boidinii PMP20A and PMP20B (CbPMP20A and CbPMP20B) was less (30% identity). Both HsPMP20 and MmPMP20 lack transmembrane regions, as do CbPMP20A and CbPMP20B. HsPMP20 mRNA expression was low in human fetal tissues, especially in the brain. In adult tissues, HsPMP20 mRNA was expressed in the majority of tissues tested. HsPMP20 and MmPMP20 contained the C-terminal tripeptide sequence Ser-Gln-Leu (SQL), which is similar to the peroxisomal targeting signal 1 utilized for protein import into peroxisomes. HsPMP20 bound directly to the human peroxisomal targeting signal 1 receptor, HsPEX5. Mutagenesis analysis showed that the C-terminal tripeptide sequence, SQL, of HsPMP20 is necessary for its binding to HsPEX5. Subcellular fractionation of HeLa cells, expressing epitope-tagged PMP20, revealed that HsPMP20 is localized in the cytoplasm and in a particulate fraction containing peroxisomes. Double-staining immunofluorescence studies showed colocalization of HsPMP20 and thiolase, a bona fide peroxisomal protein. The amino acid sequence alignment of HsPMP20, MmPMP20, CbPMP20A, and CbPMP20B displayed high similarity to thiol-specific antioxidant proteins. HsPMP20 exerted an inhibitory effect on the inactivation of glutamine synthetase in the thiol metal-catalyzed oxidation system but not in the nonthiol metal-catalyzed oxidation system, suggesting that HsPMP20 possesses thiol-specific antioxidant activity. In addition, HsPMP20 removed hydrogen peroxide by its thiol-peroxidase activity. These results indicate that HsPMP20 is imported into the peroxisomal matrix via PEX5p and may work to protect peroxisomal proteins against oxidative stress. Because some portion of PMP20 might also be present in the cytosol, HsPMP20 may also have a protective effect in the cytoplasm.
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PMID:Characterization of human and murine PMP20 peroxisomal proteins that exhibit antioxidant activity in vitro. 1051 71

Using two-dimensional electrophoresis, we have recently identified in human bronchoalveolar lavage fluid a novel protein, termed B166, with a molecular mass of 17 kDa. Here, we report the cloning of human and rat cDNAs encoding B166, which has been renamed AOEB166 for antioxidant enzyme B166. Indeed, the deduced amino acid sequence reveals that AOEB166 represents a new mammalian subfamily of AhpC/TSA peroxiredoxin antioxidant enzymes. Human AOEB166 shares 63% similarity with Escherichia coli AhpC22 alkyl hydroperoxide reductase and 66% similarity with a recently identified Saccharomyces cerevisiae alkyl hydroperoxide reductase/thioredoxin peroxidase. Moreover, recombinant AOEB166 expressed in E. coli exhibits a peroxidase activity, and an antioxidant activity comparable with that of catalase was demonstrated with the glutamine synthetase protection assay against dithiothreitol/Fe3+/O(2) oxidation. The analysis of AOEB166 mRNA distribution in 30 different human tissues and in 10 cell lines shows that the gene is widely expressed in the body. Of interest, the analysis of N- and C-terminal domains of both human and rat AOEB166 reveals amino acid sequences presenting features of mitochondrial and peroxisomal targeting sequences. Furthermore, human AOEB166 expressed as a fusion protein with GFP in HepG2 cell line is sorted to these organelles. Finally, acute inflammation induced in rat lung by lipopolysaccharide is associated with an increase of AOEB166 mRNA levels in lung, suggesting a protective role for AOEB166 in oxidative and inflammatory processes.
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PMID:Cloning and characterization of AOEB166, a novel mammalian antioxidant enzyme of the peroxiredoxin family. 1052 24

In order to investigate the existence of genetic variability in antioxidant enzyme defenses in sunflower, twelve inbred lines, six cytoplasmic male-sterile and six restorer lines, commonly used in breeding programs have been compared with respect to (a) their levels of constitutive superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), glutathione reductase (GR, EC 1.6.4.2) and guaiacol-dependent peroxidase (GPX, EC 1.11.1.7), and (b) their isoenzyme polymorphism in SOD, CAT, and GPX activities. Constitutive levels of antioxidant enzymes in the 2nd leaf pair of 15-20-day-old sunflower plants showed significant differences between lines. The ranges of variation in enzyme activities of the different lines were equivalent to 34.3% (CAT), 38.2% (SOD), 59.5% (APX), 60.0% (GR), and 62.9% (GPX) of the respective maximal values. Isoenzyme profiles of CAT, GPX and SOD revealed the existence in sunflower of at least three, six and four isoforms of these enzymes, respectively. Further characterization of SOD isoenzymes revealed that no isoenzyme corresponded to a Mn-SOD, the faster moving isoform being a Cu/Zn-SOD and the remainder three Fe-SODs. Among the twelve inbred sunflower lines studied there were ample qualitative, and sometimes quantitative too, differences in isoenzyme dotation of CAT, GPX and Fe-SOD.
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PMID:Sunflower (Helianthus annuus) variability in antioxidant enzyme defenses. 1069 64

The study was undertaken to evaluate the role of free oxygen radicals in asphyxiated neonates. Thirty term neonates appropriate for gestational age and with severe birth asphyxia (Apgar score of 3 or less at 1 minute of life) formed the study subjects. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), creatine phosphokinase (CPK) and lipid peroxidase (LPO) in the CSF of these neonates were estimated between 12 and 48 hrs of life. Enzyme estimation was performed by standard methods and the results were analysed statistically using Multivariate Logistic Regression analysis and non parametric tests namely Kruskal Wallis test and Wilcoxon's rank sum test. Out of the thirty babies, 14 were observed to be neurologically normal, 9 had significant morbidity and 7 died. The SOD levels ranged from 12.4 to 140 units/ml, GPx from 128 to 1933 nmol/min/dl, CPK from 2 to 2098 IU/dl and LPO from 5.4 to 30.8 umol/hr/dl. The SOD and GPx levels had an inverse relationship whereas rise in LPO and CPK levels were directly proportional to the extent of neurological damage and ultimate clinical outcome. CPK levels higher than 140 IU/ml were lethal and associated with 100% mortality whereas all normal neonates had CPK below 37 IU/ml. The levels of antioxidant enzymes can reliably and significantly predict mortality and morbidity whereas level of an enzyme cannot confidently confer normalcy. Hence antioxidant enzyme levels with a cut off value can be a useful marker and serve as a prognostic indicator in times to come.
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PMID:Free oxygen radicals--predictors of neonatal outcome following perinatal asphyxia. 1077 93

Mercury content and distribution as well as its effects on growth and oxidative stress were investigated in 30-day-old tomato seedlings (Lycopersicon esculentum Mill.). The content of Hg increased with external Hg concentrations, and was considerably higher in roots than in shoots. Among the leaves, the mature leaves accumulated more. Excess Hg suppressed biomass production of both roots and shoots and reduced chlorophyll content in leaves. Further, substantial increases of H(2)O(2) content, malondialdehyde formation, and antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) were observed in Hg-stressed plants in comparison with controls. The results suggest that the phytotoxic effects of Hg in tomato seedlings may be achieved by an enhanced production of active oxygen species (AOS) and subsequent lipid peroxidation.
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PMID:Mercury-induced oxidative stress in tomato seedlings. 1090

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