Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Both nitric oxide (NO) and superoxide are generated by macrophages, neutrophils and endothelial cells. It has been postulated that the generation of these two radicals under physiological conditions can lead to the formation of peroxynitrite and (as a result of the homolytic lysis of this molecule) the production of hydroxyl radicals. We have used 3-morpholinosydnonimine N-ethylcarbamide (SIN-1), a sydnonimine capable of generating both NO and superoxide simultaneously, to test this hypothesis. SIN-1 (1 mM) generated superoxide and NO at rates of 7.02 microM/min and 3.68 microM/min respectively in phosphate-buffered saline, pH 7.2, at 37 degrees C. Incubation of SIN-1 with both deoxyribose and sodium benzoate resulted in the formation of malondialdehyde (MDA). In addition, the incubation of SIN-1 with sodium benzoate resulted in the production of compounds with fluorescence emission spectra characteristic of hydroxylated products. Both the production of MDA and the generation of fluorescent compounds were inhibited by the hydroxyl radical scavenger mannitol. In all the above respects, SIN-1 mimicked the production of hydroxyl radicals from the ascorbate-driven Fenton reaction. Catalase had no effect on the SIN-1-dependent generation of MDA, and superoxide dismutase was partially inhibitory. SIN-1 produces an oxidant with the properties of the hydroxyl radical by a mechanism clearly different to that of the Fenton reaction. We conclude that the simultaneous production of NO and superoxide from SIN-1 results in the formation of hydroxyl radicals.
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PMID:Production of hydroxyl radicals from the simultaneous generation of superoxide and nitric oxide. 131 May 95

Nitric oxide (NO) induces a covalent modification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from various tissues. This phenomenon, which has previously been interpreted as an auto-ADP-ribosylation, is in fact a covalent binding of NAD+ to the enzyme. In the present study, we show that 3-morpholino-sydnonimine (SIN-1) is much more efficient than sodium nitroprusside (SNP) in stimulating the covalent labelling of GAPDH from cultured striatal neurones in the presence of [adenylate-32P]NAD+ (877 +/- 110 and 266 +/- 33% increase in NAD(+)-labelling induced by maximally effective concentrations of SIN-1 and SNP respectively). The difference in the efficacy of both NO-generating compounds could be due to the additional release of superoxide by SIN-1, since superoxide dismutase and the nitrone 5,5'-dimethyl pyrroline-1-oxide markedly inhibited the SIN-1-induced covalent binding of NAD+ to GAPDH. Catalase and selective scavengers of hydroxyl radicals, mannitol and dimethyl sulphoxide, did not alter the SIN-1-induced covalent modification of GAPDH, ruling out the involvement of hydroxyl radicals in this phenomenon. Supporting further a role of oxygen free radicals in the NAD+ linkage to GAPDH, pyrogallol, a superoxide generator, which alone was ineffective, potentiated the SNP-evoked response. The NAD+ linkage to neuronal GAPDH measured in the presence of NO and superoxide probably involves sulphydryl groups, since the radiolabelling of the protein was reversed by exposure to HgCl2 and prevented by pretreatment with the alkylating agent N-ethylmaleimide. Moreover, the NO-induced inhibition of GAPDH activity was enhanced by pyrogallol, which was ineffective alone. In conclusion, the present study indicates that superoxide anions potentiate NO-induced covalent NAD(+)-linkage to GAPDH and enzyme inactivation.
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PMID:Oxygen free radicals enhance the nitric oxide-induced covalent NAD(+)-linkage to neuronal glyceraldehyde-3-phosphate dehydrogenase. 763 7

3-Morpholinosydnonimine (SIN-1) is widely used to generate nitric oxide (NO(x).) and superoxide radical (O2-.). The effect of SOD on the toxicity of SIN-1 is complex, depending on what is the ultimate species responsible for toxicity. SIN-1 (< 1 mM) was only slightly toxic to HepG2 cells. Copper, zinc superoxide dismutase (Cu,Zn-SOD) or manganese superoxide dismutase (Mn-SOD) increased the toxicity of SIN-1. Catalase abolished, while sodium azide potentiated, this toxicity, suggesting a key role for H2O2 in the overall mechanism. Depletion of GSH from the HepG2 cells also potentiated the toxicity of SIN-1 plus SOD. Although Me2SO, sodium formate, and mannitol had no protective effect, iron chelators, thiourea and urate protected the cells against the SIN-1 plus Cu,Zn-SOD-mediated cytotoxicity. The cytotoxic effect of Cu,Zn-SOD but not Mn-SOD, showed a biphasic dose response being most pronounced at lower concentrations (10-100 units/ml). In the presence of SIN-1, Mn-SOD increased accumulation of H2O2 in a concentration-dependent manner. In contrast, Cu,Zn-SOD increased H2O2 accumulation from SIN-1 at low but not high concentrations of the enzyme, suggesting that high concentrations of the Cu,Zn-SOD interacted with the H2O2. EPR spin trapping studies demonstrated the formation of hydroxyl radical from the decomposition of H2O2 by high concentrations of the Cu,Zn-SOD. The cytotoxic effect of the NO donors SNAP and DEA/NO was only slightly enhanced by SOD; catalase had no effect. Thus, the oxidants responsible for the toxicity of SIN-1 and SNAP or DEA/NO to HepG2 cells under these conditions are different, with H2O2 derived from O2-. dismutation playing a major role with SIN-1. These results suggest that the potentiation of SIN-1 toxicity by SOD is due to enhanced production of H2O2, followed by site-specific damage of critical cellular sites by a transition metal-catalyzed reaction. These results also emphasize that the role of SOD as a protectant against oxidant damage is complex and dependent, in part, on the subsequent fate and reactivity of the generated H2O2.
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PMID:Increased cytotoxicity of 3-morpholinosydnonimine to HepG2 cells in the presence of superoxide dismutase. Role of hydrogen peroxide and iron. 767 15

The reactivity and toxicity of nitric oxide is modest in comparison to oxidants derived from nitric oxide. Exposure of Escherichia coli to 1 mM nitric oxide under aerobic or anaerobic conditions did not decrease viability of the bacteria. Peroxynitrite (1 mM), the reaction product of superoxide and nitric oxide, was completely bactericidal after 5 s. The nitrovasodilator, 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1), slowly decomposes to release both nitric oxide and superoxide and thereby produces peroxynitrite. SIN-1 killed E. coli in direct proportion to its concentration with an LD50 of 0.5 mM. Copper, zinc superoxide dismutase (50-400 units/ml) provided substantial but not complete protection against SIN-1 killing. Catalase (500-10,000 units/ml) partially protected in direct proportion to its concentration, while inactivated catalase was not protective. Superoxide dismutase and catalase together completely protected E. coli against SIN-1 toxicity. Oxy-hemoglobin eliminated both SIN-1 and peroxynitrite toxicity. The bactericidal activity of SIN-1 was further enhanced by pterin plus xanthine oxidase. Pterin plus xanthine oxidase alone or together with Fe3+ ethylenediamine tetraacetate produced no significant decrease in E. coli viability. Hydrogen peroxide was not directly toxic to the bacteria, but E. coli pretreated with hydrogen peroxide were more susceptible to peroxynitrite, SIN-1, and the aerobic oxidation products of nitric oxide. Hydrogen peroxide pretreatment did not increase significantly the toxicity of nitric oxide under anaerobic conditions. Our results suggest that peroxynitrite is far more toxic to E. coli than nitric oxide or its by products from aerobic oxidation.
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PMID:The comparative toxicity of nitric oxide and peroxynitrite to Escherichia coli. 784 Jun 33

We have previously used the comet assay to demonstrate that the nitric oxide donor 3-morpholinosydnonimine (SIN-1) produces DNA damage in rat islets of Langerhans and in the SV40-transformed insulin-secreting hamster cell line, HIT-T15. Damage is not prevented by the addition of superoxide dismutase (SOD). In the present study, we have compared SIN-1, which generates nitric oxide, superoxide anion and hydrogen peroxide, with two other nitric oxide donors, S-nitrosoglutathione (GSNO) and the tetra-iron-sulphur cluster nitrosyl, Roussin's black salt (RBS). We have used the comet assay as a highly sensitive method to measure DNA-damaging ability, and also measured inhibition of DNA synthesis and inhibition of insulin secretion. We have examined the effect of SOD and catalase on each of these endpoints in HIT-T15 cells following a 30-min exposure to the compounds (24 h for DNA synthesis). All compounds produced a significant dose-dependent increase in strand-breakage formation and all inhibited DNA synthesis and glucose-stimulated insulin secretion. RBS was the most potent. SOD did not reduce the responses observed with any of the compounds. Catalase largely prevented DNA strand breakage, inhibition of DNA synthesis and inhibition of insulin secretion by SIN-1, but had no effect on responses to GSNO or RBS. Addition of SOD together with catalase gave no greater protection against SIN-1 than catalase alone. The nitric oxide and superoxide anion produced by SIN-1 are though to combine to form highly reactive peroxynitrite. In addition, H2O2 may be formed in the presence of SIN-1 and may form hydroxyl radical in the presence of a transition metal, such as Fe2+. It appears that in insulin-secreting cells, the effects of SIN-1 are largely mediated by this latter mechanism. In contrast, GSNO and RBS appear to act by a different mechanism, not overtly involving reactive oxygen species. GSNO and H2O2 show no significant interaction in the induction of DNA strand breaks. Both nitric oxide and H2O2 are effective, directly or indirectly, as DNA strand-breaking agents, inhibitors of DNA synthesis and inhibitors of insulin secretion.
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PMID:Use of the comet assay to investigate possible interactions of nitric oxide and reactive oxygen species in the induction of DNA damage and inhibition of function in an insulin-secreting cell line. 920 24

The cytotoxicity of the superoxide anion radical- and nitric oxide-releasing compound SIN-1 to L929 cells was studied in Krebs-Henseleit buffer. pH 7.4, in the presence and absence of Hepes. SIN-1 cytotoxicity was significantly higher in the presence of Hepes than in the absence of Hepes. The available amount of peroxynitrite formed from SIN-1, however, was significantly decreased by Hepes as indicated by decreased oxidation of dihydrorhodamine 123. On the other hand, Hepes largely increased the formation of H2O2 from SIN-1. Catalase protected the L929 cells from SIN-1 cytotoxicity in the buffer with Hepes. In the buffer without Hepes catalase did not have any protective effect. In contrast, tyrosine and tryptophan provided significant protection against SIN-1 cytotoxicity independent of the presence of Hepes. These results demonstrate that the immediate toxic agent formed from SIN-1 decisively depends on the presence of Hepes. In its absence cytotoxicity is most likely mediated by peroxynitrite while in the presence of Hepes, cytotoxicity is conveyed by co-operative action of hydrogen peroxide and reactive nitrogen species.
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PMID:The critical role of Hepes in SIN-1 cytotoxicity, peroxynitrite versus hydrogen peroxide. 955 63

2,7-Dichlorodihydrofluorescein (DCDHF), commonly known as dichlorofluorescin, and dihydrorhodamine 123 (DHR) are often used to detect the production of reactive nitrogen and oxygen species in cells via oxidation to their respective fluorescent products. To determine which biological oxidants might be involved, DCDHF and DHR were exposed to a number of oxidants in vitro to determine which are capable of oxidizing these compounds. Formation of dichlorofluorescein (DCF) and rhodamine is typically monitored by measuring their intrinsic fluorescence, however, absorbance can also be utilized (epsilon500 nm = 59,500 and 78,800 M(-1) cm(-1) for DCF and rhodamine, respectively). Peroxynitrite (ONOO-) readily oxidized both compounds with an efficiency equal to 38% of added ONOO- for DCDHF and 44% for DHR. Addition of nitric oxide (NO) to a superoxide-generating system resulted in DCDHF and DHR oxidation which was inhibitable by superoxide dismutase (SOD). SIN-1-mediated oxidation of DCDHF and DHR was also SOD-inhibitable, suggesting that peroxynitrite is the primary oxidant formed from SIN-1 decomposition. Aerobic addition of NO resulted in DCDHF oxidation in a manner consistent with nitrogen dioxide (.NO2) formation. NO did not oxidize DHR and actually inhibited UV-light-induced DHR oxidation. Simultaneous addition of NO and ONOO- resulted in an apparent inhibition of indicator oxidation; however, subsequent addition of ONOO- alone 20 s later produced a higher than average amount of oxidized indicator. Addition of indicator after NO + ONOO- followed by subsequent ONOO- addition gave similar results, suggesting the formation of a relatively stable, oxidant-activated NO/ONOO- adduct. At pH 7.4, hypochlorous acid was 66% efficient at oxidizing DHR but only 9% with DCDHF. Neither H2O2 (1 mM) nor superoxide flux alone produced significant indicator oxidation. Oxidation of DCDHF by horseradish peroxidase (HRP) plus H2O2 was considerably less efficient than oxidation of DHR. At 20-fold higher concentrations, HRP alone oxidized DHR but the rate was much lower than when H2O2 was present. Catalase largely inhibited HRP-mediated oxidation of DHR but not DCDHF, suggesting a direct effect of the peroxidase on DCDHF. These results reveal that peroxynitrite, hypochlorous acid, and H2O2 plus peroxidase all oxidize DCDHF and DHR to varying degrees but that neither superoxide, H2O2 alone, nor physiological levels of nitric oxide are capable of indicator oxidation. Thus, DCDHF or DHR oxidation in any given cell type may involve more than one oxidant. In cell systems where nitric oxide production occurs, oxidation of either DCDHF or DHR is likely to include a peroxynitrite component. Identification of relevant oxidants will best be achieved with a combined experimental approach which exploits the differential reactivities of DCDHF and DHR and the judicious use of inhibitors and oxidant scavengers.
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PMID:Dichlorodihydrofluorescein and dihydrorhodamine 123 are sensitive indicators of peroxynitrite in vitro: implications for intracellular measurement of reactive nitrogen and oxygen species. 970 Oct 53

1. We report opposite inotropic effects of NO donors in frog cardiac fibres. The negative effect, elicited by either 3-morpholino-sydnonimine (SIN-1) or S-nitroso-N-acetyl-penicillamine (SNAP), involved cyclic GMP (cGMP) production. However, SIN-1, unlike SNAP, could elicit a positive effect, in a superoxide dismutase (SOD)-sensitive manner. SIN-1, unlike SNAP, can release both NO and superoxide anion, the precursors of peroxynitrite (OONO-). The role of these messengers was examined. 2. Catalase did not reduce the positive inotropic effect of SIN-1. Thus, a conversion of superoxide anion into hydrogen peroxide was not involved in this effect. In addition, catalase did not modify the negative effects of SIN-1 plus SOD, or SNAP plus SOD. 3. LY 83583, a superoxide anion generator, elicited a positive inotropic effect, like SIN-1. The effect of LY 83583 was additive to the negative effects of SIN-1 or SNAP, and to the positive effect of SIN-1. Thus, superoxide anion generation, per se, did not account for the positive effect of SIN-1. 4. Authentic peroxynitrite (OONO-), but not mock-OONO- (negative control plus decomposed OONO-), exerted a dramatic positive inotropic effect in cardiac fibres. The effect of OONO- was larger in atrial fibres, as compared with ventricular fibres. 5. The positive effect of OONO- was not additive with that of SIN-1, suggesting a common mechanism of action. In contrast, the effects of either OONO- or SIN-1 were additive with the negative inotropic effect of SNAP. Furthermore, the effect of OONO-, like that of SIN-1, was not antagonized by 1H-[1,2,4]xidiazolo[4, 3-a]quinoxaline-1-one (ODQ; 10 microM), the guanylyl cyclase inhibitor. 6. The positive inotropic effects of SIN-1 and OONO- were not modified by hydroxyl radical scavengers, such as dimethyl-thio-urea (DMTU; 10 mM). 7. The positive inotropic effect of SIN-1 (100 microM) was abolished in sodium-free solutions, a treatment that eliminates the activity of the sodium-calcium exchanger. In contrast, the effect of SIN-1 was unchanged by a potassium channel inhibitor (tetraethyl-ammonium, 20 mM), or a sodium-potassium pump inhibitor (ouabain 10 microM). 8. We conclude that OONO- is a positive inotropic agent in frog cardiac fibres. The generation of OONO- accounts for the positive inotropic effect of SIN-1. OONO- itself was responsible for the positive inotropic effect, and appeared to modulate the activity of the sodium-calcium exchanger.
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PMID:Peroxynitrite is a positive inotropic agent in atrial and ventricular fibres of the frog heart. 1058 9

Oxygen radicals are considered as an important regulator in the pathogenesis of Helicobacter pylori (H. pylori)-induced gastric ulceration and carcinogenesis. Inflammatory genes including inducible nitric oxide synthase (iNOS) may be regulated by oxidant-sensitive transcription factor, nuclear factor-kappaB (NF-kappaB). iNOS induction has been related to gastric apoptosis. We studied the role of NF-kappaB on iNOS expression and apoptosis in H. pylori-stimulated gastric epithelial AGS cells. AGS cells were treated with antisense oligonucleotide (AS ODN) for NF-kappaB subunit p50, an antioxidant enzyme catalase, an inhibitor of NF-kappaB activation pyrrolidine dithiocarbamate (PDTC), iNOS inhibitors N(G)-nitro-L-arginine-methyl ester (L-NAME) and 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), a peroxynitrite donor SIN-1, and a nitric oxide donor NOC-18 in the presence or absence of H. pylori. H. pylori induced cytotocixity time- and dose-dependently, which occurred with induction in iNOS expression and nitrite production. SIN-1 and NOC-18 induced dose-dependent cytotoxicity in AGS cells. Catalase, PDTC, L-NAME, and AMT prevented H. pylori-induced cytotoxicity and apoptosis. It was related to their inhibition on iNOS expression and nitrite production. The cells treated with AS ODN had low levels of p50 and NF-kappaB and inhibited H. pylori-induced cytotoxicity, apoptosis, iNOS expression, and nitrite production. In conclusion, NF-kappaB plays a novel role in iNOS expression and apoptosis in H. pylori-infected gastric epithelial cells.
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PMID:NF-kappaB, inducible nitric oxide synthase and apoptosis by Helicobacter pylori infection. 1146 73

1. In this study, the role of endogenous H(2)O(2) as an endothelium-dependent relaxant factor was characterised in aortas from C57BL/6J and LDL receptor-deficient mice (LDLR(-/-)). 2. Aortic rings from LDLR(-/-) mice showed impaired endothelium-dependent relaxation to acetylcholine (ACh; 0.001-100 micro M) and to the Ca(2+) ionophore A23187 (0.001-3 micro M) compared with aortic rings from control mice. Endothelium-independent relaxation produced by the NO donor, 3-morpholino-sydnonimine (SIN-1) was not different between strains. 3. Pretreatment of vessels with L-NNA (100 micro M) or L-NNA (100 micro M) plus L-NAME (300 micro M) plus haemoglobin (10 micro M) markedly decreased, but did not abolish the relaxation to ACh in control mice. In the aortas from LDLR(-/-) mice treated with L-NNA (100 micro M), ACh induced a contractile effect. Catalase (800 and 2400 U ml(-1)) shifted to the right the endothelium-dependent relaxation to ACh in aortas from control but not from LDLR(-/-) mice. Aminotriazole (50 mM), which inhibits catalase, abolished its effect on control mice. Treatment of vessels with L-NNA and catalase abolished vasorelaxation induced by ACh. Indomethacin (10 micro M) did not modify the concentration-response curve to ACh. Superoxide dismutase (300 U ml(-1)) did not change ACh-induced relaxation in both strains. 4. Exogenous H(2)O(2) produced a concentration-dependent relaxation in endothelium-denuded aortic rings, which was not different between strains. 5. It is concluded that H(2)O(2) greatly contributes to relaxation to ACh in aorta from control mice. Endothelial-dependent relaxation to ACh is impaired in LDLR(-/-) mice. Reduced biosynthesis or increased inactivation of H(2)O(2) is the possible mechanism responsible for endothelial dysfunction in aortas of atherosclerosis-susceptible LDLR(-/-) mice.
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PMID:Endothelium dysfunction in LDL receptor knockout mice: a role for H2O2. 1271 21


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