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

When Escherichia coli was incubated with xanthine oxidase and acetaldehyde, the killing of E. coli was accelerated by iron-EDTA but inhibited by hematin or hemoglobin. On the other hand, when E. coli was incubated with human neutrophils in the presence of phorbol myristate acetate (PMA), all of these iron species at concentrations of a few micromolar accelerated the inactivation of neutrophils and in so doing protected the E. coli from being killed by the neutrophils. The inactivation of the neutrophils was accompanied by an increase in lipid peroxidation and by a decrease in viability measured with trypan blue. This inactivation was inhibited by scavengers such as deoxyribose, mannitol, or thiourea. Desferrioxamine B and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) both inhibited the inactivation mediated by iron-EDTA, but had no effect on the hematin- or hemoglobin-mediated inactivation. Vanadium (vanadyl ion), an effective Fenton reagent, behaved in the same way as iron-EDTA relative to the effects of DMPO on neutrophil inactivation. These results led us to conclude that neutrophils were inactivated during PMA stimulation by OH radicals in the presence of iron-EDTA and by some other oxidizing species when hematin or Hb is present. Ascorbate enhanced the inactivation of neutrophils mediated by these iron species. Catalase was very effective in inhibiting neutrophil inactivation. Superoxide dismutase was not as effective but the combination with catalase was most effective.
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PMID:The effect of hemoglobin, hematin, and iron on neutrophil inactivation in superoxide generating systems. 813 43

In studies designed to further examine the previously reported involvement of catalase in ethanol-induced effects, we attempted to confirm earlier observations by using normal (C3H-N) and acatalasemic (C3H-A) mice. These mice are identical in every respect and differ only in their catalase activity. Data suggested that the application of 3-amino-1,2,4-triazole (AT), a catalase inhibitor, to both substrains of mice resulted in a proportional decrease in motor activity, thus supporting our earlier observations. We also showed that this effect was specific to ethanol because AT did not have any effect on cocaine-induced motor activity in both substrains. Contrary to the effects of ethanol, these substrains did not differ in motor activity in response to cocaine. In an additional study, we observed that acatalasemic mice differed from the normals in their pattern of voluntary ethanol consumption. Acatalasemic mice consumed more ethanol but only when it was presented in the range of concentrations between 12 and 18%. Finally, we also obtained data suggesting that acatalasemic mice have longer duration of sleep time following ethanol administration compared to normals. Catalase activity was measured in both substrains. Results, once again, confirmed earlier data that the substrains differ in this activity and that AT further decreases brain catalase activity in both mice. Finally, when brain homogenates derived from both substrains were incubated with ethanol significant differences in the amount of generated acetaldehyde were found between the two mice strains. Together, these results provide strong support for the involvement of brain catalase in a variety of ethanol-induced behavioral effects.
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PMID:Differences in ethanol-induced behaviors in normal and acatalasemic mice: systematic examination using a biobehavioral approach. 845 Dec 58

Catalase, superoxide dismutase (SOD) and catalase-superoxide dismutase conjugates with aldehyde dextrans have been prepared in aqueous media and surfactant microemulsions. The catalytic activities of catalase and its conjugates were characterized by first order rate constants in successive cycles of the biocatalysts. The rate constants for catalase and its conjugates inactivation by hydrogen peroxide, kin, and the rate constants for catalase complex I interaction with H2O2, k2, were determined simultaneously from the full kinetic curves for H2O2 decomposition in 1/In[(H2O2)0/[H2O2]t)-1/t coordinates. The kin and k2 values were calculated under variable conditions of the catalase reaction and at varying concentrations of the biocatalysts and hydrogen peroxide as well as in successive cycles of the biocatalysts used for H2O2 decomposition. The utility of the kinetic parameters, kin and k2, for characterizing catalase and its conjugates inactivation and their reactivity in catalase reactions has been demonstrated. The reciprocal action of catalase and SOD on their operational stabilities in enzymatic reactions of H2O2 decomposition is discussed. Catalase conjugation to aldehyde dextrans and SOD in microemulsions enhances the stabilities of the both enzymes.
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PMID:[Operational stability of catalase and its conjugates with aldehyde dextrans and superoxide dismutase]. 872 85

Helicobacter pylori exhibits a complex system of enzymes which serve a range of functions, such as colonization, damage of the host epithelium and provision of essential metabolic substrates. Colonization is favoured by urease and by the action on mucus and the mucosal barrier exerted by phospholipases and proteases, although this latter mechanism is controversial. Toxic effects are effected by urease, alcohol dehydrogenase (ADH), phospholipases and proteolytic enzymes. ADH produces acetaldehyde that is toxic to the mucosal cells, while phospholipases induce generation of products such as lysolecithin, which damage the gastric epithelium. Catalase and sodium dismutase of H. pylori are mainly involved in transforming toxic oxygen metabolites to harmless water; they protect the bacterium from the killing effect of neutrophils. Metabolic enzymes (for example, phosphatases, ATPases) are essential for the generation of energy, for synthesis and transport of cell products and for ion fluxes. In addition, they influence cell growth and the expression of virulence factors.
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PMID:Helicobacter pylori enzymes. 873 Feb 61

To evaluate the possible role of catalase in gastric ethanol metabolism in rats, we studied acetaldehyde formation from ethanol by gastric mucosal homogenate under various in vitro conditions. Homogenized rat gastric mucosa produced significant amounts of acetaldehyde in a time and ethanol concentration-dependent manner, even in the absence of added NAD. Both acetaldehyde formation and catalase activity peaked around the physiological pH, whereas alcohol dehydrogenase (ADH) activity was in that pH range low and reached peak values only at a higher pH of 9 to 10. Catalase inhibitors sodium azide (SA) and 3-amino-1,2,4-triazole (3-AT) had little effect on ADH activity but markedly decreased catalase activity and acetaldehyde formation (1 mM of SA to 56 +/- 13% of control, 5 mM of 3-AT to 67 +/- 3% of control; mean +/- SE). 4-Methylpyrazole decreased ADH activity significantly, but did not affect acetaldehyde formation. Heating of the homogenate at 60 degrees C for 5 min decreased ADH activity only slightly, but totally abolished catalase activity and reduced acetaldehyde formation to 39 +/- 3% of control. Addition of a H2O2 generating system (beta-D(+)-glucose + glucose oxidase] increased acetaldehyde formation in a concentration-dependent manner up to 8-fold of the control value. Our results strongly suggest that, in addition to ADH, catalase may play a significant role in gastric ethanol metabolism in rats.
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PMID:Role of catalase in rat gastric mucosal ethanol metabolism in vitro. 889 20

There is considerable interest in the role of the 1-hydroxyethyl radical (HER) in the toxic effects of ethanol. The goal of this study was to evaluate the effects of HER on classical antioxidant enzymes. The interaction of acetaldehyde with hydroxylamine-o-sulfonic acid has been shown to produce 1, 1'-dihydroxyazoethane (DHAE); this compound appears to be highly unstable, and its decomposition leads to the generation of HER. Addition of DHAE into a solution of PBN led to the appearance of the typical EPR spectra of PBN/HER adduct. No PBN/HER spin adduct was detected when DHAE was incubated with 0.1 M PBN in the presence of GSH. In the absence of PBN, DHAE oxidized ascorbic acid to semidehydroascorbyl radical, presumably via an ascorbate-dependent one-electron reduction of HER back to ethanol. Catalase was progressively inactivated by exposure to DHAE-generated HER in a time and HER concentration-dependent manner. Ascorbic acid and PBN gave full protection to catalase against HER-dependent inactivation. The antioxidants 2-tert-butyl-4-methylphenol, propylgallate, and alpha-tocopherol-protected catalase against inactivation by 84, 88, and 39%, respectively. Other antioxidant enzymes were also sensitive to exposure to HER. Glutathione reductase, glutathione peroxidase, and superoxide dismutase were inactivated by 46, 36, and 39%, respectively, by HER. The results reported here plus previous results showing HER interacts with GSH, ascorbate, and alpha-tocopherol suggest that prolonged generation of HER in cells from animals chronically exposed to ethanol may lower the antioxidant defense status, thereby contributing to mechanisms by which ethanol produces a state of oxidative stress and produces toxicity.
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PMID:Interaction of 1-hydroxyethyl radical with antioxidant enzymes. 1060 Jan 75

Impairment of mitochondrial functions has been found in ethanol-induced liver injury. Ethanol can be oxidized to the 1-hydroxyethyl radical (HER) by rat liver microsomal systems. Experiments were carried out to evaluate the ability of HER to cause mitochondrial swelling as an indicator of the mitochondrial permeability transition (MPT). Electron spin resonance (ESR) spectroscopy was used to detect HER and to study its interaction with mitochondria. The ESR signal intensity of the spin adduct formed from alpha-(4-pyridyl-1-oxide) N-tert-butylnitrone (POBN) and HER generated from either a thermic decomposition of 1,1'-dihydroxyazoethane (DHAE) or a Fenton reaction system containing ethanol was markedly diminished by the addition of mitochondria, indicating an interaction between HER and mitochondria. Exposure of rat liver mitochondria to HER generated from either system caused swelling, as reflected by a decrease in absorbance at 540 nm, in a HER concentration-dependent and a cyclosporin A-sensitive manner. Mitochondrial swelling was also induced in the Fenton reaction system without ethanol. The DHAE-dependent generation of HER in mitochondrial suspension resulted in a decrease of membrane protein thiols and collapse of the membrane potential (delta psi). The swelling induced by HER was prevented by glutathione and vitamin E, but not by superoxide dismutase. Catalase did not prevent the swelling caused by the acetaldehyde/hydroxylamine O-sulfonate (HOS) system, but was inhibitory in the Fenton reaction system with or without ethanol. These results indicate that HER, as well as hydroxyl radical, can induce the MPT, and suggest the possibility that the collapse of delta psi caused by HER may, at least in part, contribute to impairment of mitochondrial function caused by ethanol and in ethanol-induced liver injury.
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PMID:Mitochondrial permeability transition induced by 1-hydroxyethyl radical. 1128 Dec 95

This article presents the proceedings of a symposium at the 2001 RSA Meeting in Montreal, Canada. The organizers and chairs were William J. McBride and Ting-Kai Li. The presentations were (1) Metabolism of ethanol in the brain and the behavioral consequences, by Richard A. Deitrich and Sergey Zimatkin; (2) Catalase production of acetaldehyde as a possible mediator of the psychopharmacological effects of ethanol, by Brian R. Smith; (3) The reinforcing actions of acetaldehyde in the ventral tegmental area, by Zachary A. Rodd-Henricks; and (4) Salsolinol and alcohol addiction, by William J. McBride.
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PMID:Involvement of acetaldehyde in alcohol addiction. 1182 61

Xanthine oxidase reduces molecular oxygen to H2O2 and superoxide radicals during its catalytic action on xanthine, hypoxanthine or acetaldehyde. Ascorbate is catalytically oxidized by the superoxide radicals generated, when present in the reaction solution (Nishikimi 1975). The present study shows that iron ions markedly stimulate the enzyme dependent ascorbate oxidation, by acting as a red/ox-cycling intermediate between the oxidase and ascorbate. An apparent Km-value of 10.8 microM characterized the iron stimulatory effect on the reaction at pH 6.0. Reduced transition-state metals can be oxidized by H2O2 through a Fenton-type reaction. Catalase was found to reduce the effect of iron on the enzyme dependent ascorbate oxidation, strongly suggesting that H2O2, produced during catalysis, is involved in the oxidation of ferrous ions.
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PMID:A kinetic study on iron stimulation of the xanthine oxidase dependent oxidation of ascorbate. 1268 Jul 6

The aim of this work was to study the induction and secretion of interleukin 8 (IL-8) and some oxidative stress parameters after ethanol (EtOH), acetaldehyde (Ac) or lipopolysaccharide (LPS) treatment on HepG2 cells. Cells were treated with 50 mM EtOH, 175 &mgr;M Ac or 1 &mgr;g/ml of LPS. IL-8 induction and secretion were determined in the presence of the toxics, and the effect of antioxidants N-acetyl-L-cysteine and 1,1,3,3-tetramethyl-2-thiourea was evaluated. Further, the effect of adding polyclonal anti-human tumor necrosis factor alpha (TNF-alpha) and H(2)O(2) was studied, and catalase, superoxide dismutase and glutathione peroxidase activities were determined. Lipid peroxidation increased significantly only in Ac-treated cells. All toxics failed to decrease significantly the intracellular levels of reduced GSH. Catalase activity was diminished in all treatments, while other enzyme activities did not present changes. No change in peroxide production was found with any treatment. IL-8 secretion increased in Ac (41%) and in LPS (38%)-treated cells. Antioxidant and anti-TNF-alpha treatments decreased IL-8 secretion. H(2)O(2) (0.25 mM)-treated cells increased IL-8 secretion. IL-8 reverse transcriptase-polymerase chain reaction results correlated with secretion values. Our results show that Ac and LPS treatment produced an increased IL-8 induction and secretion. Oxidative stress and TNF-alpha are mediators in IL-8 response. This observation suggests that in the in vivo liver, the mechanism of ethanol-induced IL-8 production requires ethanol metabolism, and hepatocytes do not require the interaction among different populations of liver cells to respond.
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PMID:Interleukin 8 response and oxidative stress in HepG2 cells treated with ethanol, acetaldehyde or lipopolysaccharide. 1280 41


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