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At least 1,531 records · Page 85Linked to original sources
PubMed1984

Use of superoxide dismutase and catalase to protect catecholamines from oxidation in tissue culture studies.

A new enzymatic approach for the prevention of catecholamine oxidation that is particularly useful for studies with cultured cells is described. Catecholamine oxidation was assayed by acid alumina chromatography using a modified procedure that yields greater than or equal to 90% column recovery of catecholamine concentrations as low as 1.0 nM. Addition of superoxide dismutase and catalase (10-25 micrograms/ml each) results in virtually complete inhibition of catecholamine oxidation under a variety of experimental conditions. Although superoxide dismutase could prevent catecholamine oxidation, addition of catalase helped prevent the cytotoxicity of oxidative products. When used together, these enzymes have no effect on cell growth, hormonal response, or radioligand binding to membrane beta-adrenergic receptors in the murine S49 lymphoma cell, a widely used model system for studying catecholamine action. Combined use of superoxide dismutase and catalase offers nonperturbing, long-lasting protection of catecholamines in studies with cells in vitro. This method provides a useful alternative to ascorbic acid, chelators, or reducing agents which have previously been used to prevent catecholamine oxidation but which may have other effects on cultured cells and on membrane proteins.

Animals↗
PubMed1984

On the role of catalase in the oxidation of tissue fatty acids.

The role of catalase in lipid metabolism has been studied by means of a comparison of the turnover characteristics of the major lipid classes in the normal mouse with those of animals in which the catalase activity had been inhibited and blocked by aminotriazole and allylisopropylacetamide. Double isotope ratios were determined in the lipid fractions of several tissues following the injection of labeled glycerol, and a number of significant differences were identified between these treatments. Since catalase is recognized as an integral component of the peroxisomal pathway of fatty acid oxidation, these results may be taken as indicating that interruption of the process of peroxisomal beta-oxidation in this manner cause extensive perturbations of lipid metabolism in the living animal, and these perturbations extend well beyond those tissues where the predominant localization of these organelles occurs. The concept which derives from these data--that of a significant regulatory role of peroxisomes in relation to the overall balance of lipid metabolism in the animal body--is described and discussed.

Adipose Tissue↗
PubMed1985

Catalases HPI and HPII in Escherichia coli are induced independently.

Three strains of Escherichia coli differing only in the catalase locus mutated by transposon Tn10 were constructed. These strains produced only catalase HPI (katE::Tn10 and katF::Tn10 strains) or catalase HPII (katG::Tn10). HPI levels increased gradually about twofold during logarithmic growth but did not increase during growth into stationary phase in rich medium. HPII levels, which were initially threefold lower than HPI levels, did not change during logarithmic growth but did increase tenfold during growth into stationary phase. HPI levels increased in response to ascorbate or H2O2 being added to the medium but HPII levels did not. In minimal medium, any carbon source derived from the tricarboxylic acid cycle caused five- to tenfold higher HPII levels during logarithmic growth but had very little effect on HPI levels. Active electron transport did not affect either HPI or HPII levels.

Ascorbic Acid↗
PubMed1988

NADPH mediates the inactivation of bovine liver catalase by monochloroamine.

Bovine liver catalase suffered a biphasic inactivation when exposed to NH2Cl. A rapid and irreversible phase of activity loss was followed by a much slower and reversible inactivation. Removal of tightly bound NADPH from the enzyme decreased the extent of the rapid phase; whereas addition of NADPH augmented it. The catalase from Aspergillus niger, which does not contain bound NADPH, was not nearly as sensitive toward NH2Cl as was the liver enzyme and was not sensitized by added NADPH. NADPH is oxidized by NH2Cl, as evidenced by loss of the 340-nm absorption band, but the product of this oxidation was not NADP+. The rapid inactivation of liver catalase by NH2Cl was accompanied by some bleaching of the bands in the visible, while the slow inactivation was coincident with the appearance of a new band at 570 nm. A tentative explanation for these observations is proposed.

Ammonium Chloride↗
PubMed1989

An electron spin resonance study of oxyradical generation in superoxide dismutase- and catalase-deficient mutants of Escherichia coli K-12.

The response of superoxide dismutase- and catalase-deficient strains of Escherichia coli to redox active compounds was examined by electron spin resonance. Levels of radicals formed in response to pyocyanine in situ were extremely low and were found to be predominantly extracellular, even in a strain completely deficient in both superoxide dismutase and catalase. In cell-free extracts of superoxide dismutase-minus strains incubated with NADPH and pyocyanine, the primary accumulating radical was the superoxide anion (O2-), although low levels of the hydroxyl radical (.OH) were also detected. In contrast, extracts from strains lacking catalase were found to accumulate higher levels of hydroxyl radicals.

Catalase↗
PubMed1989

Three different types of catalases in Klebsiella pneumoniae.

Crude extracts from aerobically grown bacterium Klebsiella pneumoniae contain three different types of catalases, designated KpT, KpCP, and KpA, whose activities in crude extracts are in the ratio 4.1:1:0.3. KpT resembles typical catalases: its molecular weight is 259,000, its activity is independent of pH in the range 5.5-10.5, it is stable at 52 degrees C but loses 80% of its activity when incubated at 60 degrees C for 45 min, and it has hydrophobic properties revealed by binding to phenyl-Sepharose and stability in ethanol-chloroform. KpCP is a catalase-peroxidase with a molecular weight of 278,000, has a sharp pH optimum at 6.3, and is inactivated by treatment at 52 degrees C for 45 min and by ethanol-chloroform. KpA has been reported to be a dimer with molecular weight of 160,000 which contains a chlorin-type heme, has a plateau of maximal activity between pH's 2.8 and 11.8, and is stable to treatment with ethanol-chloroform and to incubation at 70 degrees C. All three enzymes are inhibited by cyanide.

Catalase↗
PubMed1992

The effects of catalase gene overexpression on life span and resistance to oxidative stress in transgenic Drosophila melanogaster.

Oxygen free radicals and hydroperoxides have been postulated to play a causal role in the aging process, implying that antioxidant enzymes may act as longevity determinants. Catalase (H2O2:H2O2 oxidoreductase; EC1.11.1.6) is the sole enzyme involved in the elimination of H2O2 in Drosophila melanogaster; glutathione peroxidase being absent. A genomic fragment containing the Drosophila catalase gene was used to construct transgenic Drosophila lines by means of P element-mediated transformation. Enhanced levels of catalase (up to 80%) did not prolong the life span of flies, nor did they provide improved protection against oxidative stress induced by hyperoxia or paraquat treatment. However, enhanced resistance to hydrogen peroxide was observed in the overexpressors.

Animals↗
PubMed1976

Stimulation of the microsomal alkylglycerol monooxygenase by catalase.

Liver cytosol contains a heat-sensitive nondialyzable soluble factor necessary for maximal activity of the alkylglycerol monooxygenase present in rat liver microsomes. In this report, we demonstrate that the stimulatory component in rat liver supernatant is catalase. Catalase functions to protect the enzyme from inactivation by H2O2 in addition to its documented ability to retard the noenzymatic oxidation of the pterin cofactor. The protective effect of catalase on alkylglycerol monooxygenase and on the aromatic amino acid hydroxylase systems indicates that H2O2 sensitivity is a general feature of pterin-dependent hydroxylases.

Animals↗
PubMed1979

Magnetic circular dichroism studies of bovine liver catalase.

Absorption, circular dichroism (CD) and magnetic circular dichroism (MCD) spectra of beef liver catalase at pH 5.0 and 6.9, and its complexes with NaF, KCNO, NaCNS, NaN3 and NaCN, have been measured between 250 nm and 700 nm at room temperature. The pH 6.9 native catalase MCD shows the presence of several additional transitions not resolved in the absorption spectrum. While these bands can be seen in the spectra of all the derivatives, with the exception of the cyanide, their relative intensities changes considerably between complexes. Of special interest in the MCD of ferric hemes is the signal intensity at about 400 nm and 620 nm. The data indicate that the MCD intensity at 620 nm increases as the high spin iron porphyrin fraction increases, reaching a maximum with the fluoride complex. The 430 nm band intensity increases as the proportion of low spin iron increases, reaching a maximum with the cyanide complex. The MCD spectra also indicate clearly the existence of spin mixtures in the complexes with CNO-, CNS-, and N3-, where both the 430 nm and 620 nm bands have appreciable intensity. It is significant that despite almost identical absorption spectra the CNS- complex has higher fraction of low spin iron than either the CNO- or the N3- species. The differences between the pH 5 and 6.9 MCD spectra of the native catalase suggest that the environment of the heme centre is sensitive to protonation.

Animals↗
PubMed1987

Superoxide dismutase and catalase protect cultured hepatocytes from the cytotoxicity of acetaminophen.

Superoxide dismutase, catalase and mannitol prevent the killing of cultured hepatocytes by acetaminophen in the presence of an inhibitor of glutathione reductase, BCNU. Under these conditions, the cytotoxicity of acetaminophen depends upon its metabolism, since beta-naphthoflavone, an inhibitor of mixed function oxidation, prevents the cell killing. In hepatocytes made resistant to acetaminophen by pretreatment with the ferric iron chelator, deferoxamine, addition of ferric or ferrous iron restores the sensitivity to acetaminophen. In such a situation, both superoxide dismutase and catalase prevent the killing by acetaminophen in the presence of ferric iron. By contrast, catalase, but not superoxide dismutase, prevents the cell killing dependent upon addition of ferrous iron. These results document the participation of both superoxide anion and hydrogen peroxide in the killing of cultured hepatocytes by acetaminophen and suggest that hydroxyl radicals generated by an iron catalyzed Haber-Weiss reaction mediate the cell injury.

Acetaminophen↗
PubMed1987

The distinct role of catalase and DNA repair systems in protection against hydrogen peroxide in Escherichia coli.

The katEkatG mutant of E. coli, UM1, had no assayable catalase activities in the extract and showed increased (about 20 fold) sensitivity to killing by H2O2 when compared with its parental strain CSH7. The mutant strain was able to reactivate H2O2-damaged lambda phage. On the other hand, recA and polA mutants were also highly sensitive to H2O2, but they had normal level of catalase activities. RecA derivatives of UM1 were much more sensitive to H2O2 than UM1 and recA strains. The induction of umu operon occurred in UM1 at lower (1/10-1/20) doses of H2O2 than in CSH7. From the results it is concluded that the lethal effect of H2O2 is due to DNA damage induced by it and that catalase and DNA repair systems have a distinct role in protection against H2O2 in E. coli.

Bacteriophage lambda↗
PubMed1989

Ubiquitous formation of catalase compound II in hemoglobin-free perfused rat liver and detection of novel spectral species.

Spectral examinations of hemoglobin-free perfused rat livers with a high-sensitivity reflectance spectrophotometer have revealed an accumulation of catalase Compound II to an amount comparable to that of Compound I under the aerobic steady state. This finding is in contrast to a recent proposal that NADPH associated with catalase both prevents and reverses the accumulation of Compound II (Kirkman, H. N., Galiano, S., and Gaetani, G.F. (1987) J. Biol. Chem. 262, 660-666). Furthermore, spectral species with a broad peak extending from 550 to 600 nm were observed in a time range between the methanol-induced decays of Compound I and Compound II. When rats were treated with 3-amino-1,2,4-triazole, catalase Compound I was not detected but spectral species with peaks at 570, 556 and 530 nm were observed. These novel spectral profiles suggest contributions from "peroxy" and "ferryl" forms of cytochrome oxidase.

Amitrole↗
PubMed1992

Ethanol metabolism in rat brain homogenates by a catalase-H2O2 system.

Homogenates of perfused rat brains incubated in the presence of ethanol (50-100 mM) and glucose (10 mM) were found to oxidize ethanol to acetaldehyde. The addition of glucose oxidase, a known hydrogen peroxide generator, to the incubation medium, significantly (P less than 0.05) increased the generation of acetaldehyde. The presence in the incubation medium of metyrapone, an inhibitor of cytochrome P450, or pyrazole, an alcohol dehydrogenase inhibitor, did not affect the levels of acetaldehyde obtained. Conversely, the presence of 3-amino-1,2,4-triazole, a known catalase inhibitor, induced a concentration-dependent reduction of the amount of acetaldehyde generated after incubation, even in the presence of glucose oxidase. Homogenates of perfused brains of rats treated with 3-amino-1,2,4-triazole or cyanamide (another H2O2-dependent catalase blocker) also showed a dose-dependent reduction of the acetaldehyde obtained. These findings support the notion that a catalase-mediated oxidation of ethanol is present in rat brain homogenates. It is suggested that this local oxidation of ethanol may have important biological implications. The data of both studies increase support for the notion that acetaldehyde is produced directly in the brain and that it may be the agent mediating some of the psychopharmacological properties of ethanol and be one of the factors determining the propensity of an animal to voluntarily consume ethanol.

Acetaldehyde↗
PubMed1993

Development and characterization of hydrogen peroxide-resistant Chinese hamster ovary cell variants--I. Relationship between catalase activity and the induction/stability of the oxidant-resistant phenotype.

Hydrogen peroxide (H2O2)-resistant sublines of Chinese hamster ovary (CHO) cells were isolated by in vitro exposure to the oxidant (treatment for 1 hr followed by 3 days of growth in peroxide-free medium). Stepwise increase in low level H2O2 concentrations produced variants which were progressively more resistant to the growth inhibitory effect elicited by the oxidant. Removal from H2O2 decreased resistance and the curve describing this process was biphasic in nature. In addition, the rate of loss of the H2O2-resistant phenotype was more rapid for the toxicity elicited by low concentrations of hydrogen peroxide, compared to that produced by high concentrations. Changes in total cell proteins were found to parallel the variations in sensitivity to the oxidant, since the protein content constantly increased during the adaptation process and decreases upon removal from H2O2. Catalase activity did not show large variations in resistant sublines with respect to the parental cell line, and these changes were at least partially related to differences in cell size/amount of total cell proteins of the sublines. In addition, the minor changes observed for catalase activity did not correlate with the degree of resistance to growth inhibition elicited by the oxidant. It may therefore be suggested that the H2O2-resistant phenotype of mammalian cells, initially adapted to low--then gradually increased--concentrations of the oxidant, is the result of a complex phenomenon which only partially involves over-expression of catalase.

Animals↗
PubMed1991

Developmental immunohistochemistry of catalase in the human brain.

The immunohistochemical studies on a peroxisomal enzyme, catalase, were done on brains from human fetuses to adults. The catalase-positive neurons appeared in the basal ganglia, thalamus and cerebellum at 27-28 weeks of gestation, and in the frontal cortex at 35 weeks. They then increased in number with gestational age. The extent of immunopositive staining increased with enlargement of perikaryonal size. However, the extent gradually decreased with postnatal age. On the other hand, catalase-positive glia appeared in the deep white matter at 31-32 weeks of gestation, their appearance shifting from the deep to the superficial white matter with increasing age. These results suggest that peroxisomes are closely related to neuronal growth and myelinogenesis in the human brain during development.

Adolescent↗
PubMed1994

Superoxide dismutase and catalase prevent the formation of reactive oxygen species during reduction of cyclized dopa ortho-quinone by DT-diaphorase.

Dopa was oxidized by Mn(3+)-pyrophosphate complex to the corresponding o-quinone, accompanied by the cyclization of the amino chain to form cyclized dopa ortho-quinone (cDoQ) with absorption maxima at wavelengths of 305 and 475 nm. The cyclization was found to proceed in a single step from DoQ to cDoQ without formation of cDoQH2 and oxygen consumption. DT-diaphorase catalyzes the reduction of cDoQ to the corresponding hydroquinone (cDoQH2), which was found to be unstable in the presence of oxygen. The autoxidation of the cDoQH2 was followed by recording the constant oxidation of NADH and oxygen consumption and reduction of cDoQ at a wavelength of 475 nm. It was found that three different oxidizing agents were involved in autoxidation of cDoQH2. The addition of DETAPAC resulted in a strong inhibition of NADH oxidation (65% inhibition) during the reduction of cDoQ by DT-diaphorase, suggesting that manganese was responsible for 65% of the autoxidation of cDoQH2. The addition of SOD to the incubation mixture resulted in the inhibition of NADH oxidation (79%) during the reduction of cDoQ by DT-diaphorase. In the presence of DETAPAC, the addition of SOD inhibited NADH oxidation during cDoQH2 autoxidation 75%, suggesting that superoxide radicals are responsible for 75% of the oxygen-dependent autoxidation. The remaining NADH oxidation, which was not inhibited by DETAPAC and SOD, was accompanied by a constant oxygen consumption, suggesting that this autoxidation of cDoQH2 proceeds by reducing oxygen to superoxide radical. The effect of SOD and catalase in the presence of DETAPAC was also studied. A nearly complete inhibition (90%) of oxygen consumption during the reduction of cDoQ by DT-diaphorase was observed when SOD alone or SOD and catalase were added to the incubation mixture containing DETAPAC. We conclude that SOD and catalase constitute a protective cellular system against formation of reactive oxygen species during reduction of cDoQ by DT-diaphorase.

Animals↗
PubMed1988

Further evaluation of the effects of laminin, testosterone, ganglioside GM 1, and catalase on early growth in rat nerve regeneration chambers.

We present here the results of an extended series of experiments on the effects of exogenous biochemical agents on nerve regeneration. They were applied by multiple injection into in vivo nerve regeneration chambers developed in this laboratory for rat sciatic nerve. Previously, a mixture of laminin, testosterone, ganglioside GM 1, and catalase at a defined concentration was shown to substantially advance the progress and maturation of regeneration in 16-day chambers, out of a variety of numerous other agents screened. In this study, an attempt is made to further clarify the contribution of the single ingredients used in combination. None of the agents proved to be able to mimic the previously observed effects by themselves (to their full extent). The best results were obtained by application of laminin; catalase treatment revealed results apparently worse than those in controls. Therefore, a redefined combination of the described agents, catalase now being omitted, was also tested. These results appeared to be grossly similar to those we recently reported.

Animals↗
PubMed1988

Hepatic ethanol metabolism is mediated predominantly by catalase-H2O2 in the fasted state.

Methanol and butanol were employed as selective substrates for catalase-H2O2 and alcohol dehydrogenase (ADH), respectively, in the perfused rat liver. As expected, rates of butanol metabolism accounted for over 85% of overall rates of alcohol oxidation indicating that ADH was the predominant pathway of alcohol metabolism in both the fed or fasted state in the absence of added substrate. In the fasted state, however, addition of oleate (1 mM) diminished butanol oxidation 20-25% yet increased rates of methanol oxidation over 4-fold. Under these conditions, methanol uptake accounted for nearly two-thirds of overall rates of alcohol oxidation. These data demonstrate that catalase-H2O2 is the predominant pathway of alcohol oxidation in the fasted state in the presence of fatty acids. Accordingly, it is concluded that diet and nutritional state play important roles in the contribution of the ADH and catalase pathways to alcohol oxidation.

Alcohol Dehydrogenase↗