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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the biochemical mechanism of EDU protection against ozone injury, peroxidase, ascorbate-dependent peroxidase, and catalase activities, and the contents of ascorbic acid, dehydroascorbic acid, malondialdehyde and soluble protein were measured in Phaseolus vulgaris L. cv. Lit exposed to ozone and ethylenediurea (EDU) in open-top chambers. Plants not treated with EDU showed foliar bronzing due to ozone, while EDU-treated plants were not affected. EDU application modified the reaction of biochemical parameters to ozone. Soluble protein content was elevated by EDU. Peroxidase activity increased with ozone exposure in untreated plants only, while ascorbate-dependent peroxidase activity was lower in EDU treated plants. Catalase activity decreased in EDU-untreated plants. The ratio of ascorbic acid to dehydroascorbic acid was significantly increased in EDU treated plants. These results suggest that EDU might induce ascorbic acid synthesis and therefore provide the plant with a very potent antioxidant. Or the content of hydrogen peroxide was reduced due to other unknown processes and caused a delay in foliar senescence, regardless of whether these processes were ozone-induced or due to natural aging processes.
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PMID:Effects of ethylenediurea and ozone on the antioxidative systems in beans (Phaseolus vulgaris L.). 1509 6

Piper species, commonly used in diet and traditional medicine were assessed for their antioxidant potential. Catalase activity was predominated in Piper longum, followed by Piper cubeba, green pepper, Piper brachystachyum and Piper nigrum. P. nigrum was richest in glutathione peroxidase and glucose-6-phosphate dehydrogenase, green pepper was richest in peroxidase and vitamin C while vitamin E was more in P. longum and P. nigrum. P. brachystachyum and P. longum were rich sources of vitamin A. All the Piper species had GSH content of around 1 to 2 nM/g tissue. The antioxidant components of Piper species constitute a very efficient system in scavenging a wide variety of reactive oxygen species. Antioxidant potential of Piper species was further confirmed by their ability to curtail in vitro lipid peroxidation by around 30-50% with concomitant increase in GSH content.
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PMID:Enzymatic and non-enzymatic antioxidants in selected Piper species. 1525 5

Diabetes is a multifactorial disease that has now been recognized to involve overproduction of reactive oxygen species and pro-inflammatory cytokines. Peroxisomes are subcellular organelles with several important metabolic functions, and their role in the regulation of cellular oxidative stress is now well established. Despite having their own antioxidant system, peroxisomes undergo functional alterations during various conditions that are associated with free radical production such as inflammation, ischemia-reperfusion, carcinogenesis and diabetes. In this study we investigated the effect of diabetes on peroxisomal functions in rat kidneys and show for the first time that experimental diabetes induces redox-sensitive enhancement of peroxisomal activities. Streptozotocin-induced diabetes significantly increased (p < 0.01) beta-oxidation of lignoceric acid and the enzymic activity of acyl coenzyme A oxidase. Catalase activity was significantly reduced (p < 0.01) in the kidneys of diabetic rats, whereas the enzymic activity of DHAPATase (dihydroxyacetone phosphate acyltransferase) was not markedly affected by diabetes. Treatment of diabetic rats with antioxidants, thiocetic acid and vitamin C attenuated the diabetes-induced modulation of peroxisomal functions. The present study shows that the diabetes-induced effects on kidney peroxisomal functions are redox sensitive, and antioxidants might prove useful tools to alleviate nephropathy in diabetes.
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PMID:Antioxidants attenuate diabetes-induced activation of peroxisomal functions in the rat kidney. 1531 30

Four main vascular effects of hydrogen peroxide (H2O2) were studied in intact and rubbed aortic rings from WKY rats. In rings partially precontracted with phenylephrine: 1-30 microM H2O2 induced an increase of tone, 100 microM H2O2 produced a transient contraction followed by a fast-developing endothelium-independent relaxation, and 0.3 mM H2O2 induced a fast-developing relaxation followed by a slow-developing endothelium-independent relaxation. Superoxide dismutase (SOD) or dimethyl sulfoxide (DMSO)/manitol did not significantly modify the H2O2 effects, while catalase suppressed them. Indomethacin abolished the increase of tone elicited by H2O2 and revealed a small endothelium-dependent relaxation, which was suppressed by N(G)-nitro-L-arginine (L-NA), high K+ or tetraethylammonium (TEA). TEA strongly inhibited the fast-developing relaxation while indomethacin, glybenclamide, 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), cafeic acid or eicosatriynoic acid (ETI) did not affect the relaxation. In rings precontracted with 70 mM KCl, 1-100 microM H2O2 induced a small increase of tone and 0.3 mM a slow-developing relaxation. Catalase or Fe2+-EDTA/vitamin C suppressed the slow-developing relaxation while deferoxamine did not modify it. In rings partially precontracted with arachidonic acid, 1-30 microM H2O2 induced higher contractile effects than in rings partially precontracted with phenylephrine. H2O2 at 0.3 mM for one hour induced a persistent impairment on the reactivity of the rings and the release of lactate dehydrogenase. In summary, H2O2 produces: (1) contractions mediated by direct activation of cyclooxygenase; 2) endothelium-dependent relaxations related to activation of endothelial K+ channels and NO synthesis; 3) reversible endothelium-independent relaxations mediated by activation of smooth muscle K+ channels; and 4) irreversible endothelium-independent relaxations related to cellular damage, caused by H2O2 but not by hydroxyl radicals.
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PMID:Characterization of four different effects elicited by H2O2 in rat aorta. 1599 30

Ascorbic acid (AA) is one of the most important endogenous reducing agents and can participate in a variety of cellular events. In vitro, AA can act as a potent oxidant agent in the presence of free metals, promote modifications in protein structures and form reactive oxygen species during its oxidation. We have observed that AA (above 6 mmol/l) inactivates delta-aminolevulinate dehidratase (delta-ALA-D), a sulfhydryl-containing enzyme and that the inhibitory action was considerably decreased when 3-morpholinepropanesulfonic acid buffer (MOPS - pH: 6.8; 100 mmol/l) was used in the delta-ALA-D activity assay instead of potassium phosphate buffer (PB - pH: 6.8; 100 mmol/l). delta-ALA-D inhibition, probably, is mediated by the oxidation of -SH groups caused by the auto-oxidation of AA promoted by metals or another oxidizing system present in liver supernatants. This hypothesis was confirmed by studying dithiothreitol (DTT - 400 micromol/l) oxidation, as a model of enzyme thiols, where we observed that the mechanism underlying DTT and delta-ALA-D oxidation caused by ascorbate is the same. The difference observed between different buffers may be related to the oxidation of Fe(II) to Fe(III) that was more accentuated in PB than in MOPS buffer. The presence of ethilenediamintetraacetic acid (EDTA - 100 micromol/l) and Fe(III) (5 micromol/l) stimulated DTT oxidation more in PB than in MOPS buffer. Deferroxamine (DF - 100 micromol/l) considerably decreased DTT oxidation. Catalase (0.4 mg/ml) and Superoxide dismutase (SOD - 300 U/ml) had only a modest effect on DTT oxidation. The present results suggest that delta-ALA-D inhibition by AA is mediated primarily by the oxidized form of AA and reactive oxygen species play only a modest role in the process.
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PMID:Oxidation of delta-ALA-D and DTT mediated by ascorbic acid: modulation by buffers depends on free iron. 1607 98

Vitamin K3 (VK3) is a well-known anticancer agent, but its mechanism remains elusive. In the present study, VK3 was found to simultaneously induce cell death, reactive oxygen species (ROS) generation, including superoxide anion (O2*-) and hydrogen peroxide (H2O2) generation, and histone hyperacetylation in human leukemia HL-60 cells in a concentration- and time-dependent manner. Catalase (CAT), an antioxidant enzyme that specifically scavenges H2O2, could significantly diminish both histone acetylation increase and cell death caused by VK3, whereas superoxide dismutase (SOD), an enzyme that specifically eliminates O2*-, showed no effect on both of these, leading to the conclusion that H2O2 generation, but not O2*- generation, contributes to VK3-induced histone hyperacetylation and cell death. This conclusion was confirmed by the finding that enhancement of VK3-induced H2O2 generation by vitamin C (VC) could significantly promote both the histone hyperacetylation and cell death. Further studies suggested that histone hyperacetylation played an important role in VK3-induced cell death, since sodium butyrate, a histone deacetylase (HDAC) inhibitor, showed no effect on ROS generation, but obviously potentiated VK3-induced histone hyperacetylation and cell death. Collectively, these results demonstrate a novel mechanism for the anticancer activity of VK3, i.e., VK3 induced tumor cell death through H2O2 generation, which then further induced histone hyperacetylation.
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PMID:Vitamin K3 triggers human leukemia cell death through hydrogen peroxide generation and histone hyperacetylation. 1625 25

Single-walled carbon nanotubes (SWCNT), nano-cylinders with an extremely small diameter (1-2 nm) and high aspect ratio, have unique physico-chemical, electronic and mechanical properties and may exhibit unusual interactions with cells and tissues, thus necessitating studies of their toxicity and health effects. Manufactured SWCNT usually contain significant amounts of iron that may act as a catalyst of oxidative stress. Because macrophages are the primary responders to different particles that initiate and propagate inflammatory reactions and oxidative stress, we utilized two types of SWCNT: (1) iron-rich (non-purified) SWCNT (26 wt.% of iron) and (2) iron-stripped (purified) SWCNT (0.23 wt.% of iron) to study their interactions with RAW 264.7 macrophages. Ultrasonication resulted in predominantly well-dispersed and separated SWCNT strands as evidenced by scanning electron microscopy. Neither purified nor non-purified SWCNT were able to generate intracellular production of superoxide radicals or nitric oxide in RAW 264.7 macrophages as documented by flow-cytometry and fluorescence microscopy. SWCNT with different iron content displayed different redox activity in a cell-free model system as revealed by EPR-detectable formation of ascorbate radicals resulting from ascorbate oxidation. In the presence of zymosan-stimulated RAW 264.7 macrophages, non-purified iron-rich SWCNT were more effective in generating hydroxyl radicals (documented by EPR spin-trapping with 5,5-dimethyl-1-pyrroline-N-oxide, DMPO) than purified SWCNT. Similarly, EPR spin-trapping experiments in the presence of zymosan-stimulated RAW 264.7 macrophages showed that non-purified SWCNT more effectively converted superoxide radicals generated by xanthine oxidase/xanthine into hydroxyl radicals as compared to purified SWCNT. Iron-rich SWCNT caused significant loss of intracellular low molecular weight thiols (GSH) and accumulation of lipid hydroperoxides in both zymosan-and PMA-stimulated RAW 264.7 macrophages. Catalase was able to partially protect macrophages against SWCNT induced elevation of biomarkers of oxidative stress (enhancement of lipid peroxidation and GSH depletion). Thus, the presence of iron in SWCNT may be important in determining redox-dependent responses of macrophages.
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PMID:Direct and indirect effects of single walled carbon nanotubes on RAW 264.7 macrophages: role of iron. 1652 36

Intercellular fluid (IF) obtained from tomato (Lycopersicon esculentum L.) leaflets colonized by Cladosporium fulvum Cooke contains specific elicitors that induce necrosis in tomato cultivars resistant to the race of C. fulvum used to produce the IF. The responses of cell-suspension cultures produced from tomato lines near-isogenic for resistance genes Cf 4 and Cf 5 to IF produced from leaves infected by races 4 (virulent on Cf 4 but not Cf 5 plants), 2.4.5, and 2.4.5.9 (both virulent on Cf 4 and Cf 5 plants) were used to investigate the possibility that active oxygen (AO) species were involved in the initial host reaction to these elicitors. Concurrently, the same assays were used to determine if the cell lines retained the elicitor specificity of the original plants. An IF/cell combination that gives an incompatible reaction in leaves (race 4 IF and Cf 5 cells) showed reduced oxygen uptake and increases in malonaldehyde (a product of lipid peroxidation); cytochrome c reducing activity, which was inhibited by superoxide dismutase (SOD) (an assay for superoxide); luminol-dependent chemiluminescence (an assay for several AO species); activity of extracellular peroxidases; and extracellular phenolic compounds. In contrast, compatible combinations (IF from races 2.4.5 or 2.4.5.9 and Cf 4 or Cf 5 cells; race 4 IF and Cf 4 cells) did not exhibit any of these changes. The addition of catalase, SOD, ascorbate (a scavenger of superoxide), mannitol (a scavenger of the hydroxyl radical), KCN, or salicyl hydroxamic acid (both inhibitors of peroxidases) prior to IF treatment reduced the IF-induced increases in malonaldehyde and extracellular phenolics. Catalase was an effective inhibitor of the IF-induced changes in oxygen uptake and cytochrome c reducing activity. These results demonstrate the specificity of the IF-induced cell responses and confirm that AO species are involved in the initial cell response.
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PMID:Effect of Specific Elicitors of Cladosporium fulvum on Tomato Suspension Cells : Evidence for the Involvement of Active Oxygen Species. 1666 90

The antioxidant responses of coffee (Coffea arabica L.) cell suspension cultures to cadmium (Cd) were investigated. Cd accumulated very rapidly in the cells and this accumulation was directly correlated with an increase in applied CdCl(2) concentration in the external medium. At 0.05mM CdCl(2), growth was stimulated, but at 0.5mM CdCl(2), the growth rate was reduced. An alteration in activated oxygen metabolism was detected by visual analysis as well as by an increase in lipid peroxidation at the higher CdCl(2) concentration. Catalase (CAT; EC 1.11.1.6), glutathione reductase (GR; EC 1.6.4.2) and superoxide dismutase (SOD; EC 1.15.1.1) activity increased, particularly at the higher concentration of CdCl(2). Ascorbate peroxidase (APX; EC 1.11.1.11) activity was increased at the lower CdCl(2) concentration used, but could not be detected in cells growing in the higher CdCl(2) concentration after 24h of growth, whilst guaiacol peroxidase (GOPX; EC 1.11.1.7) did not show a clear response to Cd treatment. An analysis by non-denaturing PAGE followed by staining for enzyme activity, revealed one CAT isoenzyme, nine SOD isoenzymes and four GR isoenzymes. The SOD isoenzymes were differently affected by CdCl(2) treatment and one GR isoenzyme was shown to specifically respond to CdCl(2). The results suggest that the higher concentrations of CdCl(2) may lead to oxidative stress. The main response appears to be via the induction of SOD and CAT activities for the removal of reactive oxygen species (ROS), and by the induction of GR to ensure the availability of reduced glutathione for the synthesis of Cd-binding peptides, which may also be related to the inhibition of APX activity probably due to glutathione and ascorbate depletion.
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PMID:Antioxidant metabolism of coffee cell suspension cultures in response to cadmium. 1676 93

Cobalt octa-4,5-carboxyphthalocyanine propylenglycol ether proposed for antitumor therapy potentiates the cytotoxic effect of ascorbate on HL-60 human leukemia cells. Combination of these substances caused the formation of H2O2 in the medium and initiated apoptotic death of cells. Catalase abolished the cytotoxic effect of this combination. The results indicate that binary catalytic system of this combination can be regarded as a potential antitumor agent.
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PMID:Apoptotic death of human lympholeukemia HL-60 cells resultant from combined effect of cobalt octa-4,5-carboxyphthalocyanine propylenglycol ether and ascorbate. 1684 38


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