Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.11.1.6 (catalase)
55,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prooxidant effect of chemotherapeutic agents is of significant interest in connection with activation of oxidative stress in cancer cells. Role of development of adaptive antioxidant response to the rise of resistance to cytotoxical effect of doxorubicin (DOX) has been studied in human erythroleukemia K562 cells. Growth of resistance to DOX caused enhancement of antioxidant enzymes (Cu, Zn-SOD, Mn-SOD, catalase) elevation of Mn-SOD activity being predominant. Additional increasing of antioxidant level was elevation of GSH maintenance and level of GST-related enzymes (glutathione peroxidase, glutathione S-transferase, glutathione reductase) in resistance K562/DOX cells. The enhancement of antioxidant system prevented activation of lipid peroxidation. Furthermore, the antioxidant growth caused decrease of level of proteintyrosine kinases, thioredoxin, thioredoxin reductase in contrary to elevation of glutaredoxin activity. Increasing of Bcl-2 and suppression of p53 levels was found to be caused by the change of redox state of K562DOX cells. The data support the suggestion that adaptive antioxidant response to prooxidant effect of DOX promotes the development of cellular drug resistance.
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PMID:[Role of the antioxidant system and redox-dependent regulation of transcription factors bcl-2 and p53 in forming resistance of human K562 erythroleukemia cells to doxorubicin]. 1178 3

Levels of Escherichia coli thioredoxin 1 (Trx1), Trx2, glutaredoxin 1 (Grx1), Grx2, and Grx3 have been determined by novel sensitive sandwich enzyme-linked immunosorbent assay. In a wild type strain, levels of Trx1 increased from the exponential to the stationary phase of growth (1.5-fold to 3400 ng/mg), as did levels of Grx2 (from approximately 2500 to approximately 8000 ng/mg). Grx3 and Trx2 levels were quite stable during growth ( approximately 4500 and approximately 200 ng/mg, respectively). Grx1 levels decreased from approximately 600 ng/mg at the exponential phase to approximately 285 ng/mg at the stationary phase. A large elevation of Grx1 (20-30-fold), was observed in null mutants for the thioredoxin system whereas levels of the other redoxins in all combinations of examined null mutants barely exceeded a 2-3-fold increase. Measurements of thymidine incorporation in newly synthesized DNA suggested that mainly Grx1 and, to a lesser extent, Trx1 contribute to the reduction of ribonucleotides. All glutaredoxin species were elevated in catalase-deficient strains, implying an antioxidant role for the glutaredoxins. Trx1, Trx2, and Grx1 levels increased after exposure to hydrogen peroxide and decreased after exposure to mercaptoethanol. The levels of Grx2 and Grx3 behaved exactly the opposite, suggesting that the transcription factor OxyR does not regulate their expression.
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PMID:Protein levels of Escherichia coli thioredoxins and glutaredoxins and their relation to null mutants, growth phase, and function. 1189 49

Neutrophils have a short half-life and high tendency to undergo apoptosis. One feature that may influence these characteristics is the antioxidant/oxidant balance of these cells. There are few studies on the levels of antioxidant enzymes in human neutrophils. We have analyzed by immunohistochemistry of paraffin-embedded cells and from cytospin preparations the most important antioxidant proteins in human neutrophils, and compared their levels with those in blood monocytes. Neutrophils showed moderate to high catalase, weak to moderate extracellular superoxide dismutase, and weak copper zinc superoxide dismutase and gamma-glutamylcysteine synthetase immunoreactivities. There were no detectable levels of manganese superoxide dismutase, thioredoxin, and heme oxygenase 1. Some differences were observed between the samples prepared by embedding in paraffin or by cytospin. These results, in combination with a recent study from this laboratory, suggest that a prominent feature in neutrophils is their high catalase activity but lower level of glutathione-dependent antioxidant enzymes. The differences in antioxidant profiles in neutrophils and monocytes may have important effects on the life span of human neutrophils, in both healthy and diseased tissues.
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PMID:Antioxidant defense mechanisms in human neutrophils. 1197 Aug 40

Singlet oxygen ((1)O(2)) is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules. A soluble protein from Saccharomyces cerevisiae specifically provides protection against a thiol-containing metal-catalyzed oxidation system (thiol/Fe(3+)/O(2)) but not against an oxidation system without thiol. This 25 kDa protein acts as a peroxidase but requires the NADPH-dependent thioredoxin system or a thiol-containing intermediate, and was named thioredoxin peroxidase (TPx). The role of TPx in the cellular defense against oxidative stress induced by singlet oxygen was investigated in Escherichia coli containing an expression vector with a yeast genomic DNA fragment that encodes TPx and mutant in which the catalytically essential amino acid cysteine (Cys-47) has been replaced with alanine by a site-directed mutagenesis. Upon exposure to methylene blue and visible light, which generates singlet oxygen, there was a distinct difference between the two strains in regard to growth kinetics, viability, the accumulation of oxidized proteins and lipids, and modulation of activities of superoxide dismutase and catalase. The results suggest that TPx may play an important protective role in a singlet oxygen-mediated cellular damage.
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PMID:Yeast thioredoxin peroxidase expression enhances the resistance of Escherichia coli to oxidative stress induced by singlet oxygen. 1218 53

Treatment of the mouse thymoma-derived WEHI7.2 cell line with dexamethasone, a synthetic glucocorticoid, causes the cells to undergo apoptosis. Previous studies have shown that WEHI7.2 cell variants with an increased antioxidant defense exhibit increased resistance to dexamethasone-induced apoptosis, suggesting that oxidative stress may play a role in glucocorticoid-induced apoptosis. In this work we compared metabolic profiles of WEHI7.2 parental cells with those of WEHI7.2 variants with an increased antioxidant defense or overexpressing bcl-2, to determine whether bolstering the antioxidant defense results in altered metabolic parameters that could translate into increased resistance to dexamethasone-induced apoptosis. WEHI7.2 parental cells and cells overexpressing catalase, thioredoxin or bcl-2, or selected for resistance to 200 micro M H(2)O(2) were cultured in low-glucose DMEM medium supplemented with 10% calf serum, and extracted using chloroform-methanol-water (1:1:1). Metabolites contained in the aqueous and organic phases of the extracts were processed separately and subjected to high-resolution (31)P NMR spectroscopy. In most of the steroid-resistant variants, ATP levels and energetic status were decreased compared with the steroid-sensitive parental cell line, while the concentrations of hexose and triose phosphates were increased. Furthermore, the ratio of choline-containing phospholipids to ethanolamine-containing phospholipids was generally reduced in steroid-resistant cells. Phosphatidylethanolamine and its derivatives contain a higher amount of polyunsaturated fatty acids (PUFA) than the choline-containing analogs, and PUFA are readily oxidized by reactive oxygen species. Therefore, an increased initial amount of phosphatidylethanolamine may increase the 'buffering capacity' of this antioxidant and may thus contribute to the steroid resistance of WEHI7.2 variants.
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PMID:Changes in phosphate metabolism in thymoma cells suggest mechanisms for resistance to dexamethasone-induced apoptosis. A 31P NMR spectroscopic study of cell extracts. 1220 27

Hydroxyl radicals may be responsible for oxidative damage during drought or chilling stress. We have shown that the presence of mannitol in chloroplasts can protect plants against oxidative damage by hydroxyl radicals (B. Shen, R.G. Jensen, H.J. Bohnert [1997] Plant Physiol 113: 1177-1183). Here we identify one of the target enzymes that may be protected by mannitol. Isolated thylakoids in the presence of physiological concentrations of Fe2+ generated hydroxyl radicals that were detected by the conversion of phenylalanine into tyrosine. The activity of phosphoribulokinase (PRK), a thiol-regulated enzyme of the Calvin cycle, was reduced by 65% in illuminated thylakoids producing hydroxyl radicals. Mannitol (125 mM) and sodium formate (15 mM), both hydroxyl radical scavengers, and catalase (3000 units mL-1) prevented loss of PRK activity. In contrast, superoxide dismutase (300 units mL-1) and glycine betaine (125 mM) were not effective in protecting PRK against oxidative inactivation. Ribulose-1,5-bisphosphate carboxylase/oxygenase activity was not affected by hydroxyl radicals. We suggest that the stress-protective role of mannitol may be to shield susceptible thiol-regulated enzymes like PRK plus thioredoxin, ferredoxin, and glutathione from inactivation by hydroxyl radicals in plants.
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PMID:Mannitol Protects against Oxidation by Hydroxyl Radicals. 1222 21

We investigated immunohistochemical expression of manganese superoxide dismutase (MnSOD) and three hydrogen peroxide (H(2)O(2)) scavenging pathways, i.e. catalase (CAT), gamma-glutamyl cysteine synthetase (gammaGCS) and thioredoxin (Trx) system in normal bronchial epithelium, bronchial metaplasia and dysplasia and correlated their expression with NF-kappaB activation (p50) and proliferation (Ki67). Normal bronchial epithelium was positive for MnSOD, heavy and light subunits of gammaGCS, CAT and Trx and TrxR. Metaplastic epithelium showed strongest expression of gammaGCSh and Trx, whereas dysplastic epithelium expressed most prominently MnSOD and CAT. There was a significant correlation between expression of gammaGCSh and gammaGCSl (P=0.034) and Trx and TrxR (P=0.037). Trx expression also correlated with gammaGCSh (P<0.001) and gammaGCSl (P=0.012) and TrxR with gammaGCSh (P<0.001) but not with gammaGCSl immunoreactivity (P=0.744). Expression of p50 was highest in metaplastic epithelium while Ki67 was highest in dysplastic lesions. Expression of Trx and gammaGCSh correlated inversely with age of the patients (R=-0.6038, P<0.001 for Trx and R=-0.6162, P<0.001 for gammaGCSh). Changes in the expression of these enzymes in bronchial lesions might be due to alterations of antioxidative mechanisms due to irritation via exogenous toxins and activation of reactive oxygen species (ROS) known to be associated with induction of metaplasia and dysplasia in the bronchial tree.
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PMID:Expression of antioxidant enzymes in bronchial metaplastic and dysplastic epithelium. 1249 89

Cellular defense systems against reactive oxygen species (ROS) include thioredoxin reductase (TrxR) and glutathione reductase (GR). They generate sulfhydryl-reducing systems which are coupled to antioxidant enzymes, the thioredoxin and glutathione peroxidases (TPx and GPx). The fruit fly Drosophila lacks a functional GR, suggesting that the thioredoxin system is the major source for recycling glutathione. Whole genome in silico analysis identified two non-selenium containing putative GPx genes. We examined the biochemical characteristics of one of these gene products and found that it lacks GPx activity and functions as a TPx. Transgene-dependent overexpression of the newly identified Glutathione peroxidase homolog with thioredoxin peroxidase activity (Gtpx-1) gene increases resistance to experimentally induced oxidative stress, but does not compensate for the loss of catalase, an enzyme which, like GTPx-1, functions to eliminate hydrogen peroxide. The results suggest that GTPx-1 is part of the Drosophila Trx antioxidant defense system but acts in a genetically distinct pathway or in a different cellular compartment than catalase.
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PMID:A putative glutathione peroxidase of Drosophila encodes a thioredoxin peroxidase that provides resistance against oxidative stress but fails to complement a lack of catalase activity. 1271 97

This study focuses on the mechanisms for hydrogen peroxide detoxification in Synechococcus sp. strain PCC 7942. To gain better understanding of the role of different routes of hydrogen peroxide detoxification, we inactivated TplA (thioredoxin-peroxidase-like), which we recently identified. In addition, we inactivated the gene encoding catalase-peroxidase and examined the ability to detoxify H(2)O(2) and to survive oxidative stress in both of the single mutants and in the double mutant. Surprisingly, we observed that the double mutant survived H(2)O(2) concentrations that the single catalase-peroxidase mutant could not tolerate. This phenotype correlated with an increased ability of the double mutant to detoxify externally added H(2)O(2) compared to the catalase-peroxidase mutant. Therefore, our studies suggested the existence of a hydrogen peroxide detoxification activity in addition to catalase-peroxidase and thioredoxin-peroxidase. The rate of detoxification of externally added H(2)O(2) was similar in the wild-type and the TplA mutant cells, suggesting that, under these conditions, catalase-peroxidase activity was essential for this process and TplA was dispensable. However, during excessive radiation, conditions under which the cell might experience oxidative stress, TplA appears to be essential for growth, and cells lacking it cannot compete with the wild-type strain. Overall, these studies suggested different physiological roles for various cellular hydrogen peroxide detoxification mechanisms in Synechococcus sp. strain PCC 7942.
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PMID:Oxidative stress in Synechococcus sp. strain PCC 7942: various mechanisms for H2O2 detoxification with different physiological roles. 1277 3

We present the draft genome sequence and its analysis for Fusobacterium nucleatum sub spp. vincentii (FNV), and compare that genome with F. nucleatum ATCC 25586 (FN). A total of 441 FNV open reading frames (ORFs) with no orthologs in FN have been identified. Of these, 118 ORFs have no known function and are unique to FNV, whereas 323 ORFs have functional orthologs in other organisms. In addition to the excretion of butyrate, H2S and ammonia-like FN, FNV has the additional capability to excrete lactate and aminobutyrate. Unlike FN, FNV is likely to incorporate galactopyranose, galacturonate, and sialic acid into its O-antigen. It appears to transport ferrous iron by an anaerobic ferrous transporter. Genes for eukaryotic type serine/threonine kinase and phosphatase, transpeptidase E-transglycosylase Pbp1A are found in FNV but not in FN. Unique ABC transporters, cryptic phages, and three types of restriction-modification systems have been identified in FNV. ORFs for ethanolamine utilization, thermostable carboxypeptidase, gamma glutamyl-transpeptidase, and deblocking aminopeptidases are absent from FNV. FNV, like FN, lacks the classical catalase-peroxidase system, but thioredoxin/glutaredoxin enzymes might alleviate oxidative stress. Genes for resistance to antibiotics such as acriflavin, bacitracin, bleomycin, daunorubicin, florfenicol, and other general multidrug resistance are present. These capabilities allow Fusobacteria to survive in a mixed culture in the mouth.
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PMID:Genome analysis of F. nucleatum sub spp vincentii and its comparison with the genome of F. nucleatum ATCC 25586. 1279 52


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