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At least 865 records · Page 48Linked to original sources
PubMed2001

Catalase-peroxidase from synechocystis is capable of chlorination and bromination reactions.

Catalase-peroxidases (KatGs) are multifunctional heme peroxidases exhibiting an overwhelming catalase activity and a substantial peroxidase activity of broad specificity. Here, we show that catalase-peroxidases are also haloperoxidases capable of oxidizing chloride, bromide, and iodide in a peroxide- and enzyme-dependent manner. Recombinant KatG and the variants R119A, W122F, and W122A from the cyanobacterium Synechocystis PCC 6803 have been tested for their halogenation activity. Halogenation of monochlorodimedon (MCD), formation of triiodide and tribromide, and bromide- and chloride-mediated oxidation of glutathione have been tested. Halogenation of MCD by chloride, bromide, and iodide was shown to be catalyzed by wild-type KatG and the variant R119A. Generally, rates of halogenation increased in the order Cl(-) < Br(-) < I(-) and/or by decreasing pH. The halogenation activity of R119A was about 7-9% that of the wild-type enzyme. Upon exchange of the distal Trp122 by Phe and Ala, both the catalase and halogenation activities were lost but the overall peroxidase activity was increased. The findings suggest that the same redox intermediate is involved in H(2)O(2) and halide oxidation and that distal Trp122 is involved in both two-electron reactions. That halides compete with H(2)O(2) for the same redox intermediate is also emphasized by the fact that the polarographically measured catalase activity is influenced by halides, with bromide being more effective than chloride.

Alanine↗
PubMed1996

Lung CuZn-superoxide dismutase and catalase gene expression in premature rabbits treated intratracheally with antioxidant-surfactant liposomes.

Tolerance to hyperoxia usually depends on an increase in lung antioxidant enzyme activity. Antioxidant-surfactant liposomes, encapsulating the antioxidant enzymes CuZn-superoxide dismutase (CuZnSOD) and catalase in synthetic surfactant lipids, increase lung antioxidant activity following intratracheal instillation in premature and term rabbits. We investigated whether the exogenous antioxidant enzymes encapsulated in these liposomes inhibit the endogenous antioxidant enzyme synthesis in the premature rabbit lung. Premature rabbits, delivered at 28 days of gestation, were treated intratracheally with antioxidant-surfactant liposomes, surfactant liposomes without antioxidant enzymes, or air placebo at birth and exposed to hyperoxia for 24 h. A comparison group was killed after breathing room air at birth. The right lungs of the pups were assayed for CuZnSOD and catalase activities and DNA content, the left lungs of the same pups were used to quantitate the concentrations of CuZnSOD and catalase mRNA using cRNA probes. Lung CuZnSOD and catalase mRNA quantities increased during exposure to hyperoxia, but were not affected by exogenous antioxidant enzymes. These data suggest that intratracheal instillation of CuZnSOD and catalase does not down-regulate mRNA transcription of these antioxidant enzymes in the premature rabbit lung.

Animals↗
PubMed2000

The effects of exhaustive exercise on the activity levels of catalase in various tissues of male and female rats.

The effects of exhaustive exercise on the activity levels of catalase (EC 1.11.1.6) in various tissues of male and female Sprague-Dawley rats (Rattus norvegicus) were investigated. Both the male and female rats were subdivided into an experimental group and a control group consisting of eight rats each. One group of each sex was subjected to a swimming session of 1 h (experimental group) while the other group of each sex served as sedentary control groups. The tissues investigated were liver, heart, kidney and lung. The activity levels of catalase in all the tissues investigated were significantly (P< 0.05) elevated in both male and female rats as a result of exercise. The average increase in the activity levels of catalase in the various tissues investigated for both male and female rats was 417% (males 404%; females 430%). The male and female rats exhibited comparable activity levels of catalase in all the tissues investigated. The higher activity levels of catalase as a result of exercise might be indicative of a compensatory measure to counteract the possible detrimental effects associated with oxidative stress.

Animals↗
PubMed2002

Catalase and alpha-tocopherol attenuate blood-brain barrier breakdown in pentylenetetrazole-induced epileptic seizures in acute hyperglycaemic rats.

Experimental data indicate that acute hyperglycaemia can aggravate the consequences of epileptic seizures on the permeability of the blood-brain barrier (BBB). The purpose of this study was to examine the effects of chronic administration of alpha -tocopherol (vitamin E) and acute catalase administration on the disrupted BBB during experimentally pentylenetetrazole-induced status epilepticus in acute hyperglycaemic rats. The integrity of the BBB was tested using the Evans Blue (EB) dye extravasation. The concentration of EB dye was measured in four regions of the brain. Epileptic seizures induced a significant increase in EB dye extravasation in the brain regions compared with that of the groups of rats treated with saline, glucose, catalase and alpha -tocopherol (P< 0.01). The content of EB dye in the brain regions of animals in the acute hyperglycaemia plus epileptic group was higher than that of the saline, glucose, catalase, alpha -tocopherol and epileptic groups (P< 0.01). The increased EB dye transfer from blood to the brain in status epilepticus and acute hyperglycaemia plus status epilepticus was attenuated by the treatment with catalase and alpha -tocopherol. These data suggest that a partial reduction in the production of reactive oxygen species by catalase and alpha -tocopherol contributes to decreases in the content of EB dye across the BBB during pentylenetetrazole-induced status epilepticus in acute hyperglycaemic rats.

Acute Disease↗
PubMed1993

Molecular evolutionary analysis based on the amino acid sequence of catalase.

Heme-containing catalase sequences from 20 different organisms representing prokaryotes, fungi, animals, and plants have been compiled for phylogenetic reconstruction. Phylogenies based on distance and parsimony analysis show that fungal and animal catalases can be derived from one ancestor, whereas bacterial catalases fail to form a monophyletic group. Plant catalases appear to form a second class of catalases that arose independently from a possible prokaryotic ancestor.

Amino Acid Sequence↗
PubMed1988

Catalase activity measured in rats naive to ethanol correlates with later voluntary ethanol consumption: possible evidence for a biological marker system of ethanol intake.

Catalase activity in blood collected from young rats naive to ethanol (65 days) was significantly and positively correlated with later voluntary consumption of ethanol. Catalase activity levels were also correlated with catalase activity in brain and blood sampled after exposure to ethanol. The results obtained in the present study extend and confirm earlier findings (Aragon et al. 1985c) that brain catalase activity and voluntary ethanol intake are unidirectionally and causally related. The results also suggest that brain catalase activity may be part of an enzymatic system controlling the production and elimination of acetaldehyde in brain. This system may be a biological marker system mediating the affinity of organisms to ingest ethanol.

Alcohol Drinking↗
PubMed1988

On the compartmentalization of catalase, fatty acyl-CoA oxidase and urate oxidase in mammalian livers, and the influence of clofibrate treatment on this microlocalization.

The compartmentalization of catalase, fatty acyl-CoA oxidase and urate oxidase was examined in the livers of mice, rats and guinea pigs, using the technique of digitonin extraction in order to avoid the trauma associated with centrifugation procedures. The results are interpreted as indicating that an appreciable proportion of catalase activity occurs in the cytoplasmic compartment of these cells. Following treatment of the animals with clofibrate, the specific activity in both peroxisomal and cytoplasmic compartments was increased, with a higher proportion of cytoplasmic catalase being evident in mice. The results for catalase were compared with those for fatty acyl-CoA oxidase and urate oxidase both of which were indicated as showing a closer association with the peroxisomal compartment than was the case for catalase. These data have been discussed in relation to their significance on present understanding of peroxisomal structure and function.

Acyl-CoA Oxidase↗
PubMed1978

Evidence of the presence of extraperoxisomal catalase in chloragogen cells of the earthworm, Lumbricus terrestris L.

The DAB reactivity of the midintestine of the earthworm, consisting of epithelial layer, muscle layer, and chloragogen tissue, was examined electron microscopically. Besides the mitochondrial membranes of the examined cell types and the hemoglobin content of the blood vessels and chloragogen cells, a considerable DAB reactivity was found in the whole cytosol of the chloragocytes. The DAB reaction of the cytosol was more intensive when incubation medium for catalase, less intensive when incubation medium for peroxidase, was used and did not occur when H2O2 was omitted. Cytosol of the chloragogen cells was isolated and preliminary assay of catalase and peroxidase activities was made. Cytosol samples showed moderate peroxidase activity, but catalase activity measured by the decomposition of hydrogen peroxide showed a very high rate. Catalase and peroxidase activities of the cytosol were heat-sensitive and might have been inhibited by azide and cyanide, respectively. Results prove the assumption that the intensive DAB reactivity of the chloragocyte cytosol is caused by its extraperoxisomal catalase content.

Animals↗
PubMed1993

Increased serum catalase activity in rats subjected to thermal skin injury.

We found that rats subjected to thermal skin injury (burn) had increased serum hydrogen peroxide (H2O2) scavenging activity, serum catalase activity, erythrocyte (RBC) fragility, and edematous lung injury (lung leak) when compared to sham-treated rats. Serum H2O2 scavenging activity was inhibited by addition of sodium azide, a catalase inhibitor. Treatment of rats with the oxygen radical scavenger, dimethylthiourea (DMTU), decreased RBC fragility and lung leak but did not alter increased H2O2 scavenging or catalase activity of serum from rats subjected to skin burn. We conclude that increased serum catalase activity is a consequence of thermal skin injury and that increased serum catalase activity may be a mechanism that modulates H2O2-dependent processes following skin burn.

Animals↗
PubMed1995

Complete amino acid sequence of Proteus mirabilis PR catalase. Occurrence of a methionine sulfone in the close proximity of the active site.

The catalase of Proteus mirabilis PR, a peroxide-resistant (PR) mutant of Proteus mirabilis, binds strongly NADPH, which is a unique property among known bacterial catalases. The enzyme subunit consists of 484 amino acid residues for a mass of 55,647 daltons. The complete amino acid sequence was resolved through the combination of protein sequencing, mass spectrometry, and nucleotide sequencing of a PCR fragment. The sequence obtained was compared with that of other known catalases. Amino acids of the active site are all conserved as well as essential residues involved in NADPH binding. Among the amino acids interacting with the heme, a methionine sulfone was found at position 53, in place of a valine in most other catalases. The origin of oxidation of this methionine is unknown, but the presence of this modification could change iron accessibility by large substrates or inhibitors. This posttranslational modification was also demonstrated in the wild-type P. mirabilis catalase.

Amino Acid Sequence↗
PubMed1988

Serum antibodies to Aspergillus fumigatus catalase in patients with cystic fibrosis.

Seven to ten percent of patients with cystic fibrosis had serum antibodies to the catalase antigen of Aspergillus fumigatus in three cross-sectional surveys between 1977 and 1984. A total of 208 patients participated at least once, and the cumulated frequency of catalase antibodies in 94 patients included in all three surveys was 16%. The titre range was 1 to 16. The prevalence rate of Aspergillus fumigatus in sputum was 50% for a 2.5-year observation period. Catalase antibodies were strongly associated with the occurrence of Aspergillus fumigatus in sputum (p = 0.003), and the microorganism was more numerous in colonized patients with catalase antibodies than in those without such antibodies (p = 0.004). Patients with Aspergillus fumigatus in sputum and a positive catalase antibody test tended to have an adverse development as regards lung function compared to both carriers without antibodies and non-carriers. The observed differences could not, however, be related to different rates of chronic Pseudomonas aeruginosa infection.

Adolescent↗
PubMed2006

Cardiac overexpression of catalase rescues cardiac contractile dysfunction induced by insulin resistance: Role of oxidative stress, protein carbonyl formation and insulin sensitivity.

AIMS/HYPOTHESIS: Insulin resistance leads to oxidative stress and cardiac dysfunction. This study examined the impact of catalase on insulin-resistance-induced cardiac dysfunction, oxidative damage and insulin sensitivity. METHODS: Insulin resistance was initiated in FVB and catalase-transgenic mice by 12 weeks of sucrose feeding. Contractile and intracellular Ca2+ properties were evaluated in cardiomyocytes including peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90), half-width duration (HWD), maximal velocity of shortening/relengthening (+/-dL/dt), fura-fluorescence intensity change (DeltaFFI) and intracellular Ca2+ clearance rate (tau). Reactive oxygen species (ROS) and protein damage were evaluated with dichlorodihydrofluorescein and protein carbonyl formation. RESULTS: Sucrose-fed mice displayed hyperinsulinaemia, impaired glucose tolerance and normal body weight. Myocytes from FVB sucrose-fed mice exhibited depressed PS and +/-dL/dt, prolonged TR90 and tau, and reduced DeltaFFI associated with normal TPS and HWD compared with those from starch-fed control mice. ROS and protein carbonyl formation were elevated in FVB sucrose-fed mice. Insulin sensitivity was reduced, evidenced by impaired insulin-stimulated 2-deoxy-D: -[3H]glucose uptake. Western blot analysis indicated that sucrose feeding: (1) inhibited insulin-stimulated phosphorylation of insulin receptor and Akt; (2) enhanced protein-tyrosine phosphatase 1B (PTP1B) expression; and (3) suppressed endothelial nitric oxide synthase (eNOS) and Na+-Ca2+ exchanger expression without affecting peroxisome proliferator-activated receptor gamma (PPARgamma), sarco(endo)plasmic reticulum Ca2+-ATPase isozyme 2a and phospholamban. Catalase ablated insulin-resistance-induced mechanical dysfunction, ROS production and protein damage, and reduced eNOS, but not insulin insensitivity. Catalase itself decreased resting FFI and enhanced expression of PTP1B and PPARgamma. CONCLUSIONS/INTERPRETATION: These data indicate that catalase rescues insulin-resistance-induced cardiac dysfunction related to ROS production and protein oxidation but probably does not improve insulin sensitivity.

Animals↗
PubMed2002

Ethanol-stimulated behaviour in mice is modulated by brain catalase activity and H2O2 rate of production.

RATIONALE: Over the last few years, a role for the brain catalase-H(2)O(2) enzymatic system has been suggested in the behavioural effects observed in rodents after ethanol administration. This role seems to be related to the ability of cerebral catalase to metabolise ethanol to acetaldehyde using H(2)O(2)as a co-substrate. On the other hand, it has been shown that normobaric hyperoxia increases the rate of cerebral H(2)O(2) production in rodents in vivo. Thus, substrate-level changes could regulate brain catalase activity, thereby modulating the behavioural effects of ethanol. OBJECTIVES: The aim of the present study was to assess if the enhancement of cerebral H(2)O(2) production after hyperoxia exposure results in a boost of ethanol-induced locomotion in mice. METHODS: CD-1 mice were exposed to air or 99.5% O(2) inhalation (for 15, 30, or 45 min) and 0, 30, 60 or 120 min after this treatment, ethanol-induced locomotion was measured. The H(2)O(2)-mediated inactivation of endogenous brain catalase activity following an injection of 3-amino-1,2,4-triazole was used as a measure of the rate of cerebral H(2)O(2) production. RESULTS: Hyperoxia exposure (30 or 45 min) potentiated the locomotor-stimulating effects of ethanol (2.5 or 3.0 g/kg), whereas cocaine (4 mg/kg) or caffeine (15 mg/kg)-induced locomotion and blood ethanol levels were unaffected. Moreover, the results also confirmed brain H(2)O(2) overproduction in mice. CONCLUSIONS: The present results suggest that an increase in brain H(2)O(2) production potentiates ethanol-induced locomotion. Therefore, this study provides further support for the notion that the brain catalase-H(2)O(2) system, and by implication centrally formed acetaldehyde, plays a key role in the mediation of ethanol's psychopharmacological effects.

Amitrole↗
PubMed2005

Production of catalases by Aspergillus niger isolates as a response to pollutant stress by heavy metals.

Isolates of Aspergillus niger, selected from the coal dust of a mine containing arsenic (As; 400 mg/kg) and from the river sediment of mine surroundings (As, 1651 mg/kg, Sb, 362 mg/kg), growing in minimal nitrate medium in the phase of hyphal development and spore formation, exhibited much higher levels of total catalase activity than the same species from the culture collection or a culture adapted to soil contaminated with As (5 mg/L). Electrophoretic resolution of catalases in cell-free extracts revealed three isozymes of catalases and production of individual isozymes was not significantly affected by stress environments. Exogenously added stressors (As(5+), Cd(2+), Cu(2+)) at final concentrations of 25 and 50 mg/L and H(2)O(2) (20 or 40 mM) mostly stimulated production of catalases only in isolates from mines surroundings, and H(2)O(2) and Hg(2+) caused the disappearance of the smallest catalase I. Isolates exhibited a higher tolerance of the toxic effects of heavy metals and H(2)O(2), as monitored by growth, than did the strain from the culture collection.

Aspergillus niger↗
PubMed2006

The expression and diversity of catalases in isolates of genus Comamonas in response to the oxidative stress of a polluted environment.

We have evaluated the role of monofunctional heme-containing catalase encoded by cat-1 gene from the soil bacterium Comamonas terrigena N3H in the response to various forms of oxidative stress. Our results indicate that this constitutively expressed catalase represents the major source for the defence of Comamonas terrigena cells against toxic peroxides but the cells can express also a second form of catalase that is bigger and its regulation is probably more complicated. The sequence analysis confirmed the presence of highly conserved catalase sequence motifs in two environmental strains of Comamonas terrigena but in those strains that were not exposed to oxidative stress, no such sequence motif could be detected. The results obtained underline the importance of catalase expression in the defence mechanism against oxidative stress in bacterial cells.

Amino Acid Sequence↗
PubMed2006

Cold adapted features of Vibrio salmonicida catalase: characterisation and comparison to the mesophilic counterpart from Proteus mirabilis.

The gene encoding catalase from the psychrophilic marine bacterium Vibrio salmonicida LFI1238 was identified, cloned and expressed in the catalase-deficient Escherichia coli UM2. Recombinant catalase from V. salmonicida (VSC) was purified to apparent homogeneity as a tetramer with a molecular mass of 235 kDa. VSC contained 67% heme b and 25% protoporphyrin IX. VSC was able to bind NADPH, react with cyanide and form compounds I and II as other monofunctional small subunit heme catalases. Amino acid sequence alignment of VSC and catalase from the mesophilic Proteus mirabilis (PMC) revealed 71% identity. As for cold adapted enzymes in general, VSC possessed a lower temperature optimum and higher catalytic efficiency (k (cat)/K (m)) compared to PMC. VSC have higher affinity for hydrogen peroxide (apparent K (m)) at all temperatures. For VSC the turnover rate (k (cat)) is slightly lower while the catalytic efficiency is slightly higher compared to PMC over the temperature range measured, except at 4 degrees C. Moreover, the catalytic efficiency of VSC and PMC is almost temperature independent, except at 4 degrees C where PMC has a twofold lower efficiency compared to VSC. This may indicate that VSC has evolved to maintain a high efficiency at low temperatures.

Adaptation, Physiological↗
PubMed2000

Archaeal promoter-directed expression of the Halobacterium salinarum catalase-peroxidase gene.

The Halobacterium salinarum catalase-peroxidase gene was subcloned into shuttle vectors pWL102 and pWL202 and expressed under the control of different archaeal promoters. When Hbt. salinarum was transformed with the catalase-peroxidase gene under the control of its own promoter, catalase-peroxidase activity increased twofold. Catalase-peroxidase activity increased threefold when Hbt. salinarum was transformed with the catalase-peroxidase gene under the control of a tRNA promoter. This bifunctional enzyme in Hbt. salinarum was not induced by environmental stresses such as H2O2, intense light, darkness, high temperature, low temperature, redox inhibitors, heavy metals, or ions.

Base Sequence↗
PubMed1993

High- and low-dose superoxide dismutase plus catalase does not reduce myocardial infarct size in a subhuman primate model.

Oxygen free radical scavengers have been found to decrease infarct size in dogs subjected to myocardial ischemia-reperfusion injury. A baboon open-chest model was used to determine if superoxide dismutase (SOD), an oxygen free radical scavenger, together with catalase would be equally effective in subhuman primates (baboons). The left anterior descending coronary artery (LAD) was ligated for 2 hours. Before reperfusion, the animals received the following: Group 1 (low-dose SOD/catalase; n = 5) received 15,000 IU/kg of SOD and 55,000 IU/kg of catalase IV over 1 hour, 15 minutes before reperfusion. Group 2 (high-dose human SOD [h-SOD]/catalase; n = 5) received an intraatrial bolus of 400,000 IU of recombinant h-SOD and 27,500 IU/kg of catalase over 30 seconds, followed by 300,000 IU of h-SOD and 55,000 IU/kg of catalase over 1 hour, beginning 15 seconds before reperfusion. Group 3 (n = 8) were control animals. Baboons were put to death 22 hours after reperfusion. Their hearts were excised and sectioned after the perfusion bed distal to the site of ligation was delineated with microvascular dye. The infarct zone was determined histologically. Areas of the perfusion bed and infarct zone were measured by planimetry. Infarct size did not differ significantly between the three groups: control, 66 +/- 7%; low-dose SOD/catalase, 68 +/- 5%; and high-dose h-SOD/catalase, 74 +/- 4%. In this model, high- and low-dose SOD with catalase did not result in any significant reduction in infarct size.

Animals↗