Showing papers on "Catalase published in 1978"

The biology of oxygen radicals

Abstract: The reactive superoxide radical, O2-, formerly of concern only to radiation chemists and radiobiologists, is now understood to be a normal product of the biological reduction of molecular oxygen. An unusual family of enzymes, the superoxide dismutases, protect against the deleterious actions of this radical by catalyzing its dismutation to hydrogen peroxide plus oxygen.

Oxygen toxicity in neonatal and adult animals of various species

Abstract: Neonatal and adult animals of five species were exposed to 95+% O2. Survival time and changes in lung antioxidant enzyme activity (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase...

Lignin synthesis: The generation of hydrogen peroxide and superoxide by horseradish peroxidase and its stimulation by manganese (II) and phenols.

Abstract: The enzyme horseradish peroxidase (EC 1.11.1.7) catalyses oxidation of NADH. NADH oxidation is prevented by addition of the enzyme superoxide dismutase (EC 1.15.1.1) to the reaction mixture before adding peroxidase but addition of dismutase after peroxidase has little inhibitory effect. Catalase (EC 1.11.1.6) inhibits peroxidase-catalysed NADH oxidation when added at any time during the reaction. Apparently the peroxidase uses hydrogen peroxide (H2O2) generated by non-enzymic breakdown of NADH to catalyse oxidation of NADH to a free-radical, NAD., which reduces oxygen to the superoxide free-radical ion, O2 .-. Some of the O2 .- reacts with peroxidase to give peroxidase compound III, which is catalytically inactive in NADH oxidation. The remaining O2 .- undergoes dismutation to O2 and H2O2. O2 .- does not react with NADH at significant rates. Mn2+ or lactate dehydrogenase stimulate NADH oxidation by peroxidase because they mediate a reaction between O2 .- and NADH. 2,4-Dichlorophenol, p-cresol and 4-hydroxycinnamic acid stimulate NADH oxidation by peroxidase, probably by breaking down compound III and so increasing the amount of active peroxidase in the reaction mixture. Oxidation in the presence of these phenols is greatly increased by adding H2O2. The rate of NADH oxidation by peroxidase is greatest in the presence of both Mn2+ and those phenols which interact with compound III. Both O2 .- and H2O2 are involved in this oxidation, which plays an important role in lignin synthesis.

Biogenesis of peroxisomes: intracellular site of synthesis of catalase and uricase

Abstract: The intracellular site of synthesis of two peroxisomal enzymes of rat liver, uricase (urate:oxygen oxidoreductase, EC 1.7.3.3) and catalase (hydrogen peroxide:hydrogen peroxide oxidoreductase, EC 1.11.1.6), has been localized on free ribosomes and not membrane-bound ribosomes. Free polysomes and membrane-bound polysomes, prepared by classical cell fractionation techniques from rat liver, were incubated for protein synthesis in a cell-free system derived from rabbit reticulocytes. Characterization of the total translation products by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, as well as by immunoprecipitation with anti-rat albumin anti-serum, confirmed that good separation of the two polysome classes was achieved. Uricase and catalase were immunoprecipitable from translation products directed by free polysomes or phenol-extracted free polysomal mRNA but not from products of membrane-bound polysomes. Furthermore, unlike albumin, nascent uricase and catalase were not cotranslationally segregated by dog pancreas microsomal membranes. The results indicate that uricase and catalase are transferred to the interior of peroxisomes by a post-translational mechanism; an hypothesis is formulated here for the biogenesis of peroxisomes.

Hydrogen peroxide in hepatic microsomes.

Abstract: Publisher Summary This chapter talks about the hydrogen peroxide in hepatic microsomes. H 2 O 2 determination in microsomes is dependent on a method that fulfills some requirements. Those requirements are (1) it is sensitive enough to permit determination of 1 μM H 2 O 2 without interfering with monooxygenase-dependent hydroxylation reactions, (2) allows to eliminate the influence of various substrates or products of mixed-function oxidation reactions, (3) permits inhibition of contaminating catalase so that during an incubation period measurements not only of small steady-state concentrations, but also of rate and extent of H 2 O 2 formation are possible, and (4) allows to determine possible degradation of H 2 O 2 by residual catalase-, peroxidase-, or NADPH-dependent mixed-function oxygenase activity. The reason that in the presence of sodium azide H 2 O 2 accumulates and is subjected to further metabolism by pathways other than catalase, for example NADPH-dependent mixed-function oxygenase, the trapping of H 2 O 2 as HCHO by the addition of exogenous catalase and methanol avoids such degradation. Under circumstances where H 2 O 2 accumulates, the measurements of rate and extent of H 2 O 2 formation in microsomes can vary depending on the method applied.

Virulence and Resistance to Superoxide, Low pH and Hydrogen Peroxide among Strains of Mycobacterium tuberculosis

Abstract: Six strains of Mycobacterium tuberculosis of different virulence in guinea-pigs were compared with regard to their resistance to low pH, to hydrogen peroxide (2O2) at different pH values and to superoxide (·O2-). Low virulence was associated with susceptibility to H2O2 in native and isoniazid-resistant strains but not in laboratory-attenuated strain H37Ra. H2O2 resistance was only partly related to catalase content. Low virulence was not associated with susceptibility to an acid environment but the tuberculocidal effect of H2O2 was significantly increased at low pH. The strains were uniformly resistant to ·O2- and contained similar amounts of superoxide dismutase. The implications of these observations are discussed in the context of mechanisms of host defence in tuberculosis.

Factors Related to the Oxygen Tolerance of Anaerobic Bacteria

Abstract: The effect of atmospheric oxygen on the viability of 13 strains of anaerobic bacteria, two strains of facultative bacteria, and one aerobic organism was examined. There were great variations in oxygen tolerance among the bacteria. All facultative bacteria survived more than 72 h of exposure to atmospheric oxygen. The survival time for anaerobes ranged from less than 45 min for Peptostreptococcus anaerobius to more than 72 h for two Clostridium perfringens strains. An effort was made to relate the degree of oxygen tolerance to the activities of superoxide dismutase, catalase, and peroxidases in cell-free extracts of the bacteria. All facultative bacteria and a number of anaerobic bacteria possessed superoxide dismutase. There was a correlation between superoxide dismutase activity and oxygen tolerance, but there were notable exceptions. Polyacrylamide gel electropherograms stained for superoxide dismutase indicated that many of the anaerobic bacteria contained at least two electrophoretically distinct enzymes with superoxide dismutase activity. All facultative bacteria contained peroxidase, whereas none of the anaerobic bacteria possessed measurable amounts of this enzyme. Catalase activity was variable among the bacteria and showed no relationship to oxygen tolerance. The ability of the bacteria to reduce oxygen was also examined and related to enzyme content and oxygen tolerance. In general, organisms that survived for relatively long periods of time in the presence of oxygen but demonstrated little superoxide dismutase activity reduced little oxygen. The effects of medium composition and conditions of growth were examined for their influence on the level of the three enzymes. Bacteria grown on the surface of an enriched blood agar medium generally had more enzyme activity than bacteria grown in a liquid medium. The data indicate that superoxide dismutase activity and oxygen reduction rates are important determinants related to the tolerance of anaerobic bacteria to oxygen.

Endoplasmic reticulum marker enzymes in Golgi fractions--what does this mean?

Abstract: NADPH cytochrome c (cyt c) reductase and glucose-6-phosphatase, two enzymes thought to be restricted to the endoplasmic reticulum (ER) and widely used as ER markers, are present in isolated Golgi fractions assayed immediately after their isolation. Both enzymes are rapidly inactivated in fractions stored at 0 degrees C in 0.25 M sucrose, conditions which do not affect the activity of other enzymes in the same preparation. The inactivation process was shown to be dependent on time and protein concentration and could be prevented by EDTA and catalase. Morphological evidence shows that extensive membrane damage occurs parallel with the inactivation. Taken together with the immunological data in the companion paper, the findings indicate that the enzymes NADPH cyt c reductase and probably glucose-6-phosphate are indigenous components of Golgi membranes.

Mechanisms of Attachment of Neutrophils to Candida albicans Pseudohyphae in the Absence of Serum, and of Subsequent Damage to Pseudohyphae by Microbicidal Processes of Neutrophils In Vitro

Abstract: Mechanisms were studied that might explain the attachment and damage to Candida albicans pseudohyphae by neutrophils in the absence of serum. Attachment of neutrophils to pseudo hyphae was inhibited by Candida mannans (1-10 mg/ml), but not by mannose, dextran, chitin, conconavalin A, or highly charged polyamino acids. Contact was also inhibited by pretreatment of Candida before incubation with neutrophils with chymotrypsin, but not trypsin or several inhibitors of proteases. Similar results were obtained with pretreatment of neutrophils, except that trypsin was inhibitory. When pseudohyphae were killed with ultraviolet light, proteinpolysaccharide complexes of mol wt <10,000 were released which appeared to bind to the surfaces of neutrophils and inhibit contact between neutrophils and Candida, as well as other fungi. Damage to Candida by neutrophils was inhibited by agents known to act on neutrophil oxidative microbicidal mechanisms, including sodium cyanide, sodium azide, catalase, superoxide dismutase, and 1, 4 diazobicyclo (2, 2, 2) octane, a singlet oxygen quencher. Neutrophils from a patient with chronic granulomatous disease did not damage Candida at all. However, the hydroxyl radical scavengers mannitol and benzoate were not inhibitory. Cationic proteins and lactoferrin also did not appear to play a major role in this system. Low concentrations of lysozyme which did not damage Candida in isotonic buffer solutions damaged pseudohyphae in distilled water. Isolated neutrophil granules damaged pseudohyphae only with added hydrogen peroxide and halide, and damage occurred only with granule fractions known to contain myeloperoxidase. These findings suggest that neutrophils recognized a molecule on the Candida surface which has a chymotrypsin sensitive protein component, and which may be liberated from the cell surface upon death of organism. The neutrophil receptors for Candida appear to be sensitive to trypsin and chymotrypsin. Damage to Candida by neutrophils occurred primarily by oxidative mechanisms, including the production of superoxide and hydrogen peroxide interacting with myeloperoxidase and halide, as well as singlet oxygen, but did not appear to involve hydroxyl radical. Lysozyme might have an accessory role, under some conditions.

Identification of hydrogen peroxide as a photoproduct toxic to human cells in tissue-culture medium irradiated with "daylight" fluorescent light

Abstract: Hydrogen peroxide, lethal for human cells, is produced in Dulbecco's modified Eagle's tissue culture medium when exposed to “daylight” fluorescent light. Addition of pure H2O2 and use of the enzyme catalase demonstrate that about 40% of the toxicity in irradiated medium is due to generated peroxide. Riboflavin and tryptophan, or riboflavin and tyrosine, are the components necessary for formation of lethal levels of H2O2 during light exposure.

Synthesis of catalase in two cell-free protein-synthesizing systems and in rat liver.

Abstract: Rat liver polysomal RNA was translated in the rabbit reticulocyte lysate and in the wheat germ cell-free protein-synthesizing systems, using [35S]methionine as label. The catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase, EC 1.11.1.6) that was synthesized was isolated by immunoprecipitation and characterized by electrophoresis in sodium dodecyl sulfate/polyacrylamide gels followed by fluorography. The catalase made in both systems migrated more slowly during electrophoresis than did purified peroxisomal catalase. By comparison with standards of known molecular mass, the cell-free products were estimated to be about 4000 daltons larger than the purified enzyme. We also investigated the biosynthesis of catalase in vivo by injecting [35S]methionine into rats. The precursor of catalase known to be synthesized in liver and found in the high-speed supernatant 8 min later [Lazarow, P. B. & de Duve, C. (1973) J. Cell Biol. 59, 491-506] was isolated immunochemically. For comparison, 1-day-old completed catalase was immunoprecipitated from peroxisomes. The migrations in sodium dodecyl sulfate gels of the 8-min-old precursor and the subunit of the day-old enzyme were indistinguishable and approximately the same as the migration of the cell-free products. These results indicate that catalase's apparent size does not change when it enters peroxisomes but rather decreases during the chemical purification procedure.

Fatty acid beta-oxidation system in microbodies of n-alkane-grown Candida tropicalis.

Abstract: Localization of fatty acid beta-oxidation system in microbodies of Candida tropicalis cells growing on n-alkanes was studied. Microbodies isolated from the yeast cells showed palmitate-dependent activities of NAD reduction, acetyl-CoA formation and oxygen consumption. When sodium azide, an inhibitor of catalase, was added to the system, palmitate-dependent formation of hydrogen peroxide was observed. Stoichiometric study revealed that two moles of NAD were reduced per one mole of oxygen consumed in the absence of sodium azide and the presence of the inhibitor doubled the oxygen consumption by microbodies without an appreciable change in NAD reduction. These results indicate that the yeast microbodies contain beta-oxidation system of fatty acid, and that catalase located in the organelles participates in the degradation of hydrogen peroxide to be formed at the step of dehydrogenation of acyl-CoA.

Conversion of L-thyroxine to triiodothyronine in rat kidney homogenate.

Abstract: Rat kidney homogenates, in phosphate-EDTA buffer, consistently catalyzed the formation of T3 from added L-thyroxine (T4). The formation of T3 was assessed by both paper chromatography and RIA of T3. Conversion of T4 to T3 appeared to be enzymatic, showing pH and temperature optima (pH 7.0 and 37 C, respectively) and tissue and time dependence. Formation of T3 was unaffected by azide, cyanide, or catalase, nor was it dependent upon oxygen; indeed, under anaerobic conditions conversion of T4 to T3 was enhanced. Dialyzed homogenate retained full activity, and no cofactor requirement was demonstrated. A role of iron and thiol groups in the enzymatic formation of T3 from T4 was suggested by the inhibitory action of iron chelators and thiol-blocking reagents. The capacity of kidney for T3 formation was considerable and increased with increasing T4 concentrations, being approximately 2 nmol/g tissue/h at very high T4 levels. The apparent Km was estimated to be 3 x 10(-6) M. The conversion of T4 to T3 was inhibited by propylthiouracil at micromolar concentrations whereas methimazole, iodide, and lithium salts were without effect. The enzymatic activity of the homogenates was associated with its particulate components, the readily sedimenting fractions corresponding to plasma membranes and mitochondria being most active, and was absent from nuclei and cytosol.

Phagocyte-produced free radicals: roles in cytotoxicity and inflammation.

Abstract: The production of superoxide free radical, O2-, by metabolically activated phagocytes results in damage to the phagocyte which is manifested by the premature death of the cell in vitro The cytotoxic agent appears to be formed by the reaction of superoxide with hydrogen peroxide, and is thought to be hydroxyl radical or a secondary radical thereof In vivo two animal models of induced inflammation also appear to be largely dependent on superoxide production by phagocytes for the development of tissue damage manifested as oedema Intravenously administered superoxide dismutase shows anti-inflammatory activity in these models, but only when so derivatized that it can remain in the circulation for longer periods of time Catalase, or a catalase derivative, on the other hand, shows no anti-inflammatory activity in vivo

Reactive forms of oxygen and chemiluminescence in phagocytizing rabbit alveolar macrophages.

Abstract: Chemiluminescence (CL), superoxide anion (O2-) production, and particle uptake were measured to determine the role of antibacterial substances in the chemiluminescent response associated with phagocytosis in rabbit alveolar macrophages (AM). Exposure of AM to zymosan particles induced both CL and the production of extracellular O2-. CL is inhibited by superoxide dismutase, an enzyme which catalyzes the conversion of O2- to hydrogen peroxide (H2O2), by catalase, an enzyme which destroys H2O2, and by the hydroxyl radical (.OH) scavengers, benzoate and ethanol. Superoxide dismutase and catalase probably exert their effects in the extracellular fluid. CL can also be produced by the addition of NaO2 or H2O2 to zymosan in a noncellular system. The chemiluminescent response occurs before particle uptake is complete, which also indicates that CL occurs in the extracellular fluid. These results suggest that CL induced by zymosan in AM is due to the extracellular reaction between various reactive forms of oxygen and zymosan.

Biochemical Properties of Bovine Granulocytes

Abstract: SummaryGranulocyte fractions, containing an average of about 92% neutrophils, were isolated from bovine blood. The electron microscope observation of these fractions showed that neutrophil granules have different shapes, but are all highly and homogeneously electron-dense. With respect to the granulocytes of human blood, bovine cells appear to have a lower content of azurophil enzymes and virtually lack lysozyme. Lysates of bovine granulocytes efficiently kill both E. coli (at pH 6.0 and 7.4) and S. aureus (mainly at pH 7.4). When exposed to opsonized B. mycoides, intact bovine granulocytes exhibit a marked enhancement in oxygen consumption, generation of O2- and H2O2, and glucose oxidation through the hexose monophosphate pathway. About 15% of the total oxygen reduced is recovered extracellularly as O2-. Hydrogen peroxide generated by phagocytizing cells is only partially utilized in reactions catalyzed by catalase and myeloperoxidase, and appears to mainly enter the glutathione cycle.

Degradation of microbodies in relation to activities of alcohol oxidase and catalase in Candida boidinii.

Abstract: Degradation of microbiodies in the methanolutilizing yeastCandida boidinii was mainly studies by electron microscopical observation. The yeast cells precultured on methanol medium contained five to six microbodies per section and showed high activities of alcohol oxidase, catalase, formaldehyde dehydrogenase and formate dehydrogenase. When the precultured cells were transferred into an ethanol medium the number of microbodies and concomitantly the activities of alcohol oxidase and catalase decreased. After 6 h of cultivation microbodies were hardly detected. Also the activity of alcohol oxidase was not measurable and catalase activity was reduced to one tenth, whereas the activities of formaldehyde dehydrogenase and formate dehydrogenase decreased only to about 70%. Experiments with methanol-grown cells transferred into an ethanol medium without nitrogen source indicated that the inactivation of alcohol oxidase and catalase does not require protein synthesis. However, the reappearance of these enzymes is presumably due to de novo protein synthesis as shown by experiments with cycloheximide.

Age-related development of pulmonary antioxidant enzymes in the rat.

Abstract: SummaryThe age-related development of the activity levels of the pulmonary an-tioxidant defense systems: superoxide dismutase, reduced glutathione, glutathione peroxidase, glutathione reductase and catalase, were examined in the rat. All the pulmonary antioxidant enzymes studied showed a lower activity at two days before term than at birth. From day 12 to 70, with the exception of catalase, these enzymes and reduced glutathione generally showed a gradual increase in activity levels with age. Pulmonary catalase activity, however, was lower in the older rats compared to the younger animals. No significant differences were found in the various pulmonary enzyme activities and glutathione levels between male and female rats.

Comparative Investigation of the Action of Several Chlorosis-inducing Herbicides on the Biogenesis of Chloroplasts and Leaf Microbodies.

Abstract: Seedlings of Triticum aestivum L. and Secale cereale L. were grown in the presence of six different (five having different chemical structures) chlorosis-inducing herbicides: aminotriazole and its derivative SDR 5175, haloxidine, Sandoz 6706, fluometuron, and EMD-IT 5914. Concentrations were applied which allowed the leaves to grow normally and to reach normal total amino nitrogen contents but evoked a complete chlorosis (less than 6% chlorophyll). The effects of the herbicides on the accumulation of several chloroplast constituents and on peroxisomal and mitochondrial marker enzyme activities were compared. Wheat and rye, in general, gave very similar results, wheat being more sensitive to unspecific inhibitory effects. In dark-grown plants, the herbicides had no or only minor effects on the rRNA pattern and on enzyme activities of the leaves. In the light, all herbicides applied prevented the accumulation of carotenoids and of chloroplastic rRNA. Consequently, ribulose-1,5-bisphosphate carboxylase activity was virtually absent. After all herbicide treatments in light, the leaves contained only rather low catalase activity. In the presence of aminotriazole and haloxidine, the chloroplast-specific NADP-glyceraldehyde-3-phosphate dehydrogenase and the peroxisomal enzymes glycolate oxidase and hydroxypyruvate reductase had high or even normal activities, as in untreated leaves. In leaves treated with Sandoz 6706, fluometuron, or EMDIT 5914, the activities of the latter three enzymes were, in parallel, only very low. Some herbicides interfered with enzyme activities in vitro, particularly with those of catalase and of glycolate oxidase. Among mitochondrial enzymes, cytochrome c oxidase activity was either unaffected or lower, while fumarase had considerably higher activities in the herbicide-treated, as compared to untreated leaves. The specific effects on peroxisomal enzymes cannot be explained by the hypothesis of herbicide-induced photodestructions in carotene-deficient plastids. Alternative explanations for the genesis of the chlorosis are discussed.

Regulation of Glyoxysomal Enzymes during Germination of Cucumber: 2. Isolation and Immunological Detection of Isocitrate Lyase and Catalase.

Abstract: The glyoxysomal enzymes isocitrate lyase and catalase have been isolated from etiolated cucumber (Cucumis sativus) cotyledons. The enzymes co-purified through polyethyleneimine precipitation and (NH4)2SO4 precipitation, and were resolved by gel filtration on Sepharose 6B followed by chromatography on diethylaminoethyl-cellulose (isocitrate lyase) or hydroxylapatite (catalase). Purity of the isolated enzymes was assessed by sodium dodecyl sulfate-polyacrylamide electrophoresis, isoelectric focusing, and immunoelectrophoresis. Antibodies raised to both enzymes in rabbits and in tumor-bearing mice were shown to be monospecific by immunoelectrophoresis against total homogenate protein. Isocitrate lyase and catalase represent about 0.56% and 0.1%, respectively, of total extractable cotyledonary protein. Both enzymes appear to be present in a single form. Molecular weights of the native enzymes and its subunits are 225,000 and 54,500 for catalase, and 325,000 and 63,500 for isocitrate lyase. The pH optimum for isocitrate lyase is about 6.75 in morpholinopropane sulfonic acid buffer, but varies significantly with buffer used. The Km for d-isocitrate is 39 micromolar. A double antibody technique (rabbit anti-isocitrate lyase followed by 125I-labeled goat anti-rabbit immunoglobulin G) has been used to visualize isocitrate lyase subunit protein on sodium dodecyl sulfate-polyacrylamide with high specificity and sensitivity.

Effect of molybdenum deficiency on the growth and metabolism of corn plants raised in sand culture

Abstract: Molybdenum deficiency decreased the dry matter yield, tissue concentration of molybdenum, and chlorophyll content of corn (Zea mays L. cv. T.41) plants. Compared with the normal (control) plants, leaves of molybdenum-deficient plants had significantly lower activities of nitrate reductase, catalase, aldolase, and alanine aminotransferase and higher activities of peroxidase, β-glycerophosphatase, and ribonuclease. Within 72 h of supplying molybdenum (50 μM) to molybdenum-deficient plants, chlorophyll concentration, soluble protein, and activities of nitrate reductase, catalase, and alanine aminotransferase showed considerable recovery but the increase in the peroxidase activity was further enhanced. Supply of molybdenum to molybdenum-deficient plants did not significantly affect the activity of aldolase, ribonuclease, and β-glycerophosphatase.