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PubMed1982

Hepatocytes with extraperoxisomal catalase in rats fed 3'-methyl-4-dimethylaminoazobenzene.

Histochemical and cytochemical studies were done to further characterize the preneoplastic hepatocytes with extraperoxisomal catalase (EPC-cells) that were found in the livers of rats fed 3'-methyl-4-dimethylaminoazobenzene. Catalase activity was demonstrated cytochemically to be localized in nuclear matrices, hyaloplasm, and peroxisomal matrices of EPC-cells. It is suggested that an impairment of peroxisome formation is involved in the altered intracellular distribution of catalase. Administration of clofibrate increased the catalase activity in EPC-cells. To examine the preneoplastic nature of EPC-cells, activities of glucose-6-phosphatase (G6Pase) and gamma-glutamyl transpeptidase (GGT) were examined, since changes in the activities of these enzymes have been used as markers of putative preneoplastic cells. In the present study, neither weak G6Pase activity nor positive GGT activity was considered to be a consistent feature of EPC-cells. However, available evidence suggests that EPC-cells are one of the carcinogen-induced cell populations with altered phenotypes.

Animals↗

PubMed1980

Glucose and dietary vitamin E protection against catalase inactivation in the red cells of rats.

One-month-old male Sprague-Dawley rats were fed a basal vitamin E deficient diet with or without 50 ppm vitamin E supplementation for 7 months. The washed red cells were suspended in a saline-phosphate buffer, pH 7.4, that contained either 0, 0.011 or 0.055 M glucose and were incubated at 37 C with constant shaking. Catalase activity in the red cells of vitamin E deficient rats was decreased 74% (P less than 0.001) at the end of the 22-hour incubation, and only 9% of the initial value was retained at the end of 46 hours. In the red cells of the vitamin E supplemented group, 82% and 48% of catalase activity was retained at the end of 22 and 46 hours, respectively. Glucose in the medium significantly increased catalase activity during the early hours of incubation and retarded the enzyme inactivation at the end of 22 and 46 hours in both groups of animals. The activities of superoxide dismutase and glutathione peroxidase were not significantly altered by the presence of glucose or by the status of dietary vitamin E during the incubation. The results suggest that both glucose and dietary vitamin E provide protection against inactivation of catalase under the experimental conditions.

Animals↗

PubMedDate not supplied

[Stability of Penicillium vitale immobilized catalase in continuous decomposition of hydrogen peroxide].

The process of hydrogen peroxide continuous decomposition by the preparation of the fungus Penicillium vitale catalase immobilized by aminoorganosilica which were activated by glutaric aldehyde, cyanuric chloride or 2,4-toluylene diisocyanate. Catalase with an oxidized carbohydrate component was used as well. Such a modified enzyme was directly bound with the surface of aminocontaining silica and alumina. It is shown that in the process of H2O2 decomposition the preparations of immobilized catalase are inactivated. The decrease in its activity is described by a model which suggests that rates of hydrogen peroxide decomposition and enzyme inactivation are described by the first order equations. A method for calculation and prediction of mean time of continuous operation of columns with bound catalase and other immobilized enzymes is suggested in terms of the given model.

Catalase↗

PubMedDate not supplied

[Oxidation of nitrous oxide during decomposition of hydrogen peroxide by catalase].

Possible involvement of the catalase mechanism in the elimination of nitrous oxide was studied in model experiments. The concentration of N2O in the gaseous phase was found to decrease due to the decomposition of hydrogen peroxide by catalase. The concentration of NO increased accompanying the removal of N2O from the gaseous phase in the pressure of H2O2 and catalase. Though the observed effect is slight, the oxidation of nitrous oxide during the decomposition of H2O2 by catalase might be one of the mechanisms for biological elimination of N2O under the oxidating conditions.

Catalase↗

PubMed1994

Role of oxyradicals in cardiovascular depression and cellular injury in hemorrhagic shock and reinfusion: effect of SOD and catalase.

We investigated the effects of hemorrhagic shock and reinfusion on the cardiac function and contractility, plasma CK and CK-MB activity and lactate concentration, oxyradical-producing activity of polymorphonuclear leukocytes (PMNL-CL), cardiac chemiluminescence (LV-CL), antioxidant enzymatic activity [superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px)], and malondialdehyde (MDA) concentration in anesthetized dogs, to determine the role of oxyradicals in cardiac depression and cellular injury in hemorrhagic shock and reinfusion. The dogs were assigned to four groups: group I (sham), 4 hrs duration; group II, 4 hr of shock; group III, 2 hr of shock, followed by reinfusion for 2 hr; and group IV, as in group III, but pretreated with SOD and catalase. Hemorrhagic shock was produced by withdrawing blood to maintain the mean arterial pressure at 50 +/- 5 mm Hg. Cardiac function and contractility were depressed during hemorrhagic shock. Plasma CK; CK-MB and lactate; and cardiac MDA, Mn-SOD, and CuZn-SOD increased, while catalase activity decreased during shock. Following reinfusion after 2 hr of shock, hemodynamic parameters and plasma lactate tended to return toward control values. Plasma CK and CK-MB, PMNL-CL and cardiac MDA, total SOD, Mn- and CuZn-SOD increased further, while LV-CL and GSH-Px decreased. In spite of the increased antioxidant reserve, oxidative damage was noted. Pretreatment with SOD and catalase attenuated the deleterious effects of shock and reinfusion on the cardiovascular function, plasma CK, CK-MB, and lactate, PMNL-CL, cardiac MDA and SOD, and LV-CL. Protection was incomplete for cardiovascular function and plasma CK and CK-MB. These results suggest that oxyradicals (O2-, H2O2) may be partly involved in the deterioration of cardiovascular function and cellular injury during hemorrhagic shock and reinfusion.

Animals↗

PubMed1993

Superoxide dismutase (SOD)-catalase conjugates. Role of hydrogen peroxide and the Fenton reaction in SOD toxicity.

Superoxide dismutase (SOD) has been championed as an effective antioxidant for the treatment of ischemia-reperfusion injury in a wide variety of tissues. Unfortunately a bell-shaped dose-response curve has been observed, whereby SOD at higher concentrations loses its effectiveness and may even enhance the extent of reperfusion injury. Using the xanthine/xanthine oxidase reaction to generate superoxide radicals, we have attempted to examine the role of the Fenton reaction in SOD toxicity observing that high SOD levels along with micromolar concentrations of Fe2+ greatly increased the production of the highly toxic hydroxyl radical. The production of superoxide radicals and their conversion to hydroxyl radicals were measured by using the spin-trapping agent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and electron spin resonance (ESR). Attempts to counter the toxicity of SOD involved the covalent conjugation of SOD to catalase in an effort to lower the available free H2O2 and thus minimize the extent of the Fenton reaction. The conjugate was tested in both the xanthine/xanthine oxidase system and a rat heart model of ischemia-reperfusion. In the xanthine/xanthine oxidase model, the combination of SOD and Fe2+ results in an enhanced production of hydroxyl radicals which is inhibited by the inclusion of catalase. In reperfused ischemic hearts, working at levels of free SOD which were either toxic or failed to give any protection against reperfusion injury, an equivalent amount of SOD conjugated to catalase resulted in an 80% return to normal mechanical function of the reperfused hearts. We attribute the toxicity of free SOD in hearts subjected to ischemia-reperfusion injury to the production of hydroxyl radicals as a result of the increased Fenton reaction. This reaction is inhibited by the presence of catalase conjugated to SOD.

Animals↗

PubMed1993

Role of catalase and heat shock protein on recovery of cardiac endothelial and mechanical function after ischemia.

The aim of this study was to investigate the roles of heat shock proteins and catalase after heat shock stress in the recovery of cardiac mechanical and endothelial function following a prolonged ischemic, cardioplegic arrest. Isolated working rat hearts were subjected to an ischemic cardioplegic arrest for 4 hours at 4 degrees C. Six groups, each of 6 hearts, were studied: control; control treated with 3-aminotriazole, an inhibitor of catalase; sham; sham + 3-aminotriazole; heat-shocked rats; heat shocked rats + 3-aminotriazole. Postischemic recovery of cardiac output and endothelial function (as % of preischemic control values) were respectively 54.6 +/- 1.9 and 21.2 +/- 3.0 in the control group; 52.3 +/- 2.9 and 19.1 +/- 3.9 in the control + 3-aminotriazole group; 72.2 +/- 2.7 and 54.2 +/- 7.6 in the heat shocked group; and 68.0 +/- 4.0 and 21.0 +/- 5.8 in the heat shocked + 3-aminotriazole group. SDS PAGE and western blotting showed induction of heat shock proteins in the heat stressed animals. Measurement of catalase activity showed significant inhibition in the 3-aminotriazole treated groups. It is concluded that, following heat shock stress, the enhanced endothelial recovery after prolonged ischemic cardioplegic arrest is dependent on catalase activity but that this does not apply to the recovery of mechanical functional.

Amitrole↗

PubMed1993

Protection of rabbit retina from ischemic injury by superoxide dismutase and catalase.

PURPOSE: To provide evidence that free radical damage is a component of postischemic retinal injury; to determine whether antioxidant enzymes, superoxide dismutase (SOD) and catalase, can protect the retina from ischemic injury. METHODS: Total retinal ischemia for 60 or 75 min was produced in Dutch rabbits by raising intraocular pressure. Retinal recovery was monitored with the electroretinogram. Enzymes were administered as an intravenous bolus dose 2-3 min before restoration of circulation. RESULTS: In eyes subjected to 60 min ischemia, the amplitude of the a-wave 4 hours after reperfusion averaged 114.9% of baseline value in control rabbits and 126.5% in SOD-treated animals. The b-wave amplitude at this time was 79.3% and 106.8% in control rabbits and SOD-treated rabbits, respectively. After an ischemic insult of 75 min, at 4 hours the a-wave amplitude was 89.2% of baseline in control eyes, 108.8% in SOD-treated eyes, 159.6% in eyes that received a combination of SOD and catalase, and 149.8% in catalase-treated eyes. The amplitude of the b-wave was reduced to 47.8% in control eyes and 44.8% in SOD-treated eyes, but recovered to 92.3% in rabbits that received the combination therapy and 98.8% in animals that received catalase alone. CONCLUSIONS: These findings suggest that free radical generation is involved in ischemic tissue damage. The fact that antioxidant enzymes can be protective has implications for the treatment of acute ischemic diseases of the retina.

Animals↗

PubMed1996

A modified catalase assay suitable for a plate reader and for the analysis of brain cell cultures.

The enzyme catalase is present in relatively small amounts in neural tissue. A standard spectrophotometric assay for catalase has been modified to make it suitable both for automated assay with a plate reader and for the analysis of neural cell cultures. Catalase activity is determined by measuring residual hydrogen peroxide after incubation with the enzyme. Ferrous ions and thiocyanate are used for the spectrophotometric determination of hydrogen peroxide. The stable visible absorption of ferrithiocyanate can be measured either with a plate reader or a spectrophotometer. The method assays catalase activity from single wells of a tissue culture plate containing 2-3 mg of embryonic rat mesencephalon.

Animals↗

PubMed1997

Modification of catalase by chondroitin sulfate.

Catalase was chemically modified by sodium chondroitin sulfate using the benzoquinone binding method. Thus, 40-42% of the catalase preparation was modified. Treatment of catalase and superoxide dismutase with benzoquinone-activated chondroitin sulfate results in a bienzymic conjugate with electrophoretically heterogenous composition. The yield of the products and their residual catalytic activity indicate that the method can be used for the preparation of modified catalase and the bienzymic conjugate to study their efficiency in vivo.

Benzoquinones↗

PubMed1997

The effects of temperature and pH on the kinetics of reactions between catalase and its suicide substrate hydrogen peroxide.

Variation of initial (intact) activity (ai), inactivation rate constant (ki) and the partition ratio (r) of bovine liver catalase in the reaction with its suicide substrate, hydrogen peroxide, were determined in workable ranges of temperature (17-42 degrees C) or pH (5-10.5), using the data of progress curves. The changes of temperature had a slight effect on ai, giving a Q10 of 1.15 for the enzymatic breakdown of H2O2, corresponding to an improved value for its activation energy of 8.8 +/- l kJ.mol-1. In contrast, the ki was greatly increased by elevation of temperature, giving a Q10 of 2.1 for the suicide inactivation reaction of catalase. Consequently, a significant decrease of r was observed by increasing of temperature. In pH studies, decreasing of pH from 7.0 to 5.0 led to reduction of ai whereas the ki value was not effected significantly, possibly due to the parallel changes in affinities to free catalase and compound I for H2O2. Reduction of ki and alpha i were observed at pH > 9.5, where reversible dissociation of tetrameric enzyme into catalytically inactive subunits is possible. The r had a maximum value at pH around 7.5, similar to that of catalase activity. The effect of ionic strength on the above kinetic parameters was studied. There was not an observable influence when the ammonium sulfate concentration was below l M.

Animals↗

PubMed1998

Interaction of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) with catalase and horseradish peroxidase in an aqueous solution and in the reverse micelles of AOT/N-heptane.

Some properties of catalase and horseradish peroxidase entrapped into reverse micelles of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/n-heptane with those in an aqueous solution of AOT are compared. Secondary structure of catalase significantly changes and activity is completely lost in the presence of aqueous micellar solution of AOT. In AOT/n-heptane reverse micelles secondary structure of catalase does not change. AOT has no effect on horseradish peroxidase in aqueous solution. On the other hand slight changes in secondary structure of horseradish peroxidase in AOT/n-heptane reverse micelles appear. It is concluded that electrostatic interactions between catalase or horseradish peroxidase with AOT molecule at neutral pH are not the main factor determining reactivity of investigated enzymes in reverse micelles.

Benzothiazoles↗

PubMedDate not supplied

[Effects of Hirudo therapy on lipid peroxidation and catalase activity of the rabbit retina after light-induced eye injuries].

Effect of Hirudo therapy on the level of lipid peroxidation (LPO) products and catalase activity in the retina and pigmented epithelium (PE) after exposure to intensive illumination is assessed. Light injury to the eye (100,000 lux in 90 min) leads to accumulation of LPO products and suppression of catalase activity. Hirudo therapy after potent light exposure of the eye decreased the level of hydroperoxide and malonic dialdehyde and normalized retinal and PE catalase activity, thus exerting a therapeutic antioxidant effect. Hirudo therapy before illumination did not notably protect the eye as regards the content of LPO products and catalase activity.

Animals↗

PubMed1997

Purification and characterization of a homodimeric catalase-peroxidase from the cyanobacterium Anacystis nidulans.

Cytosolic extracts of the cyanobacterium Anacystis nidulans exhibit both catalase and o-dianisidine peroxidase activity. Native polyacrylamide gel electrophoresis demonstrates one distinct enzyme, which has been purified to essential homogeneity and found to be composed of two identical subunits of equal size (80.5 kDa). The isoelectric point is at pH 4.7. It is a very efficient catalase with a broad pH optimum between 6.5 and 7.5 and a Km for H2O2 of 4.3 mM, a calculated turnover number of 7200 s(-1), and an overall-rate constant of 3.5 x 10(6) M(-1) s(-1). The behaviour of this protoheme-enzyme is typical of the class of prokaryotic catalase-peroxidases, which is sensitive to cyanide (Ki = 27.2 microM) and insensitive to the eukaryotic catalase inhibitor 3-amino-1,2,4-triazole. The enzyme accepts electrons from o-dianisidine, but not from ascorbate, glutathione, and NADH. With hydrogen peroxide in steady-state conditions the enzyme is mainly in the ferric state indicating that Compound I is much faster reduced by H2O2 than it is formed. The native enzyme is in the high-spin state, which is transformed to low-spin upon addition of cyanide. With peroxoacetic acid Compound I is formed at a rate of 5.9 x 10(4) M(-1) s(-1) at pH 7.0 and 25 degrees C with about 50% hypochromicity, a Soret-maximum at 405 nm and isosbestic points at 354 and 427 nm.

Amitrole↗

PubMed1998

Adsorption of Catalase on Hydroxyapatite.

The adsorption of catalase on calcium hydroxyapatite is reported in this study. In all the solutions investigated, catalase adsorption takes place under conditions where the adsorbent and the adorbate are both negatively charged and is accompanied by the release of phosphate ions. This suggests that electrostatic attraction does not play a leading role in the adsorption process. However, electrostatic repulsion does play a role as evidenced by the influence of the solution composition on the maximum amount adsorbed. In fact, the amount adsorbed increases when the surface charge tends to be less negative (decrease of pH and phosphate concentration, presence of calcium) or when the electrical charges are screened as a result of the ionic strength increase. This was confirmed by the electrophoretic mobility which becomes more negative after protein adsorption. The rate of catalase adsorption is extremely low; the time required to reach a stationary concentration is 60 and 125 h in potassium nitrate and phosphate solution, respectively. The reversibility of catalase was examined with respect to changes in the bulk solution concentration. No significant desorption was obtained after several days of observation. The adsorption, desorption, and kinetic aspects have been discussed in relation to changes in the the protein structure upon interaction and to the microstructural characteristics of the mineral. Copyright 1998 Academic Press.

Journal Article↗

PubMed1989

Morphometric cytochemistry of diminution of catalase-containing peroxisomes in copper-loaded liver.

The density of hepatocellular catalase-containing peroxisomes was quantified, utilizing a computer-aided image analysing technique, on 1-micron thick diaminobenzidine-stained sections. Hepatic copper accumulation following intraperitoneal injection of cupric chloride resulted in a dose-dependent reduction in the density of catalase-containing peroxisomes. A significant correlation between the density of peroxisomes and the activity of hepatic catalase indicated that computer-aided image analysis of peroxisomes stained by the diaminobenzidine technique provided a useful estimate of catalase activity in liver injured by copper. Slight treatment-related differences in the mean diameter of peroxisomes were detected in high-dose but not low-dose rats.

Animals↗

PubMed2001

A catalase-peroxidase from a newly isolated thermoalkaliphilic Bacillus sp. with potential for the treatment of textile bleaching effluents.

A new thermoalkaliphilic bacterium was isolated from a textile wastewater drain and identified as a new Bacillus sp. (Bacillus SF). Because of its high pH stability and thermostability, a catalase-peroxidase (CP) from this strain has potential for the treatment of textile bleaching effluents. The CP from Bacillus SF was purified to more than 70.3-fold homogeneity using fractionated ammonium sulfate precipitation, hydrophobic interaction, and anion-exchange and gel-filtration chromatography. The native CP had a molecular mass of 165 kDa and was composed of two identical subunits. The isoelectric point of the protein was at pH 6.0. Peptide mass mapping using matrix-assisted laser desorption ionization-mass spectrometry showed a homology between the CP from Bacillus SF and the CP from Bacillus stearothermophilus. The apparent Km value of the catalase activity for H2O2 was 2.6 mM and the k(cat) value was 11,475 s(-1). The enzyme showed high catalase activity and an appreciable peroxidase activity with guaiacol and o-dianisidine. The enzyme was stable at high pH, with a half-life of 104 h at pH 10 and 25 degrees C and 14 h at 50 degrees C. The enzyme was inhibited by azide and cyanide, in a competitive manner, but not by the catalase-specific inhibitor 3-amino-1,2,4-triazole.

Bacillus↗

PubMed1991

Heme-dependent catalase activity of lactobacilli.

The heme-dependent catalase in Lactobacillus pentosus, L. sake, L. delbrueckii and Enterococcus faecalis was studied. The catalase was formed by cells grown aerobically in the presence of hematin or for lactobacilli when grown without added hematin, after incubation of buffered cells in the presence of hematin. The kinetics of the production of catalase revealed maximum activity for L. pentosus and E. faecalis at late stationary and late logarithmic growth phase, respectively. The physiological role of catalase was studied with L. sake. The presence of hematin allows higher growth yields, since it protects the cells against hydrogen peroxide formed endogenously up to concentrations of 4.6 mmol/l.

Culture Media↗