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PubMed1985

Linkage map of the short arm of human chromosome 11: location of the genes for catalase, calcitonin, and insulin-like growth factor II.

The following order of genes on the short arm of human chromosome 11 (11p) was determined previously: parathyroid hormone (PTH)-the beta-globin gene cluster (HBBC)-HRAS1/insulin. Although it is generally agreed that HRAS1 (formerly termed c-Ha-ras-1) and the insulin gene are close to each other [1-4 centimorgans (cM)], their order on chromosome 11p is still in question. We have now added three other genes, those for catalase, calcitonin, and insulin-like growth factor II (IGF-II), to this map of chromosome 11p by use of restriction site polymorphisms adjacent to these genes in classical linkage analysis. Most importantly, we find no evidence of linkage between the catalase and HBBC loci. In addition, our data indicate that the calcitonin gene is located between the catalase gene and the PTH gene. Our best estimate of the distance between the catalase and calcitonin gene is approximately 16 cM, while that between the calcitonin and PTH genes is approximately equal to 8 cM. In agreement, very loose linkage was found between the catalase and PTH loci (approximately 26 cM). Since the catalase locus has been mapped to 11p13, these data support the view that the PTH, HBBC, HRAS1, and insulin loci are located on the distal short arm of chromosome 11. The IGF-II gene is tightly linked to both the HRAS1 oncogene and the insulin gene since no recombinants were observed between the IGF-II and the HRAS1/insulin loci. Thus, based on our linkage analysis we propose that the most likely gene order for the short arm of chromosome 11 is centromere-catalase-calcitonin-PTH-HBBC-HRAS1/insulin-tel ome re and that the IGF-II gene is very close to both the HRAS1 and the insulin genes.

Calcitonin↗
PubMed1993

Autocrine production of extracellular catalase prevents apoptosis of the human CEM T-cell line in serum-free medium.

CCRF-CEM is a human T-cell line originally isolated from a child with acute lymphoblastic leukemia. At cell densities > 2 x 10(5) cells per ml, CEM cells grow in serum-free medium, but at lower cell densities the cultures rapidly undergo apoptosis, or programmed cell death. The viability of low-density CEM cells could be preserved by supplementing the serum-free medium with "conditioned" medium from high-density CEM cultures, but a variety of known growth factors and lymphokines were ineffective. Fractionation of conditioned medium by sequential chromatography on DEAE-cellulose, propyl agarose, chromatofocusing, and hydrophobic-interaction HPLC resulted in the isolation of a 60-kDa protein capable of sustaining CEM growth in the absence of serum. The active protein was identified as human catalase based on its amino acid sequence and composition and was subsequently shown to exhibit catalase activity and to be replaceable by human erythrocyte catalase or bovine liver catalase. Comparison of the level of intracellular catalase activity with the amount released into the culture medium demonstrated that the latter accounted for < 3% of the total catalase activity present in the cell culture. These findings show that, despite its low amount, the catalase released by CEM cells, and perhaps by T cells in general, provides a critical first line of defense against hydrogen peroxide (H2O2) present in the extracellular milieu.

Amino Acid Sequence↗
PubMed1998

Adeno-associated viral-mediated catalase expression suppresses optic neuritis in experimental allergic encephalomyelitis.

Suppression of oxidative injury by viral-mediated transfer of the human catalase gene was tested in the optic nerves of animals with experimental allergic encephalomyelitis (EAE). EAE is an inflammatory autoimmune disorder of primary central nervous system demyelination that has been frequently used as an animal model for the human disease multiple sclerosis (MS). The optic nerve is a frequent site of involvement common to both EAE and MS. Recombinant adeno-associated virus containing the human gene for catalase was injected over the right optic nerve heads of SJL/J mice that were simultaneously sensitized for EAE. After 1 month, cell-specific catalase activity, evaluated by quantitation of catalase immunogold, was increased approximately 2-fold each in endothelia, oligodendroglia, astrocytes, and axons of the optic nerve. Effects of catalase on the histologic lesions of EAE were measured by computerized analysis of the myelin sheath area (for demyelination), optic disc area (for optic nerve head swelling), extent of the cellular infiltrate, extravasated serum albumin labeled by immunogold (for blood-brain barrier disruption), and in vivo H2O2 reaction product. Relative to control, contralateral optic nerves injected with the recombinant virus without a therapeutic gene, catalase gene inoculation reduced demyelination by 38%, optic nerve head swelling by 29%, cellular infiltration by 34%, disruption of the blood-brain barrier by 64%, and in vivo levels of H2O2 by 61%. Because the efficacy of potential treatments for MS are usually initially tested in the EAE animal model, this study suggests that catalase gene delivery by using viral vectors may be a therapeutic strategy for suppression of MS.

Animals↗
PubMed1996

Homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum. A dioxygenase with catalase activity.

Homoprotocatechuate 2,3-dioxygenase (2,3-HPCD) cleaves the aromatic ring of its substrate with insertion of both atoms of oxygen from O2 to form alpha-hydroxy- delta-carboxymethyl cis-muconic semialdehyde. The enzyme has been purified from the Gram-positive bacterium Brevibacterium fuscum and characterized. The enzyme appears to have a range of quaternary structures with predominant components of alpha4 and alpha6 (alpha subunit Mr = 42500 +/- 1500) and binds approximately 1 Fe(II)/subunit. Although the substrate Km values are similar to those of other Fe(II) ring cleaving dioxygenases, the turnover number is lower by 90-97%, and the enzyme exhibits much higher stability to metal chelators and H2O2. The stability to H2O2 is shown to derive from an endogenous catalase activity of 2,3-HPCD (stoichiometry: 2 H2O2 --> 2 H2O + O2) that is novel for dioxygenases. H2O2 is a mixed-type inhibitor of the dioxygenase activity, suggesting that dioxygenase and catalase activities are both catalyzed by the enzyme, but at distinguishable sites. In contrast, catecholic substrates, including homoprotocatechuate and p-nitrocatechol, are nonessential activators of the catalase activity. The plot of 1/vi of catalase activity versus 1/[H2O2] is parabolic in the absence of catecholic substrates and linear in their presence, indicating that these reactions proceed by different mechanisms. A mechanism for catalase activity is proposed in which 2 H2O2 molecules bind simultaneously to the iron to account for the observed parabolic kinetic plot. Electron transfer between the peroxides mediated by the iron would yield 2 H2O and O2. Catecholic substrates are proposed to modify this reaction by excluding one H2O2 from the Fe(II), thereby causing the kinetic plots to appear linear. Electron donation by the catecholic substrates would facilitate O O bond cleavage of H2O2, but outer sphere electron transfer from a second H2O2 in another step would be necessary to complete the reaction. p-Nitrocatechol is shown to bind differently to 2,3-HPCD than to other Fe(II) ring cleavage dioxygenases. Possible explanations for this observation are considered in the context of the proposed catalase and normal dioxygenase mechanisms which may also have bearing on the unique catalase activity and low dioxygenase turnover number of the enzyme.

Amino Acids↗
PubMed1996

Structure of the heme d of Penicillium vitale and Escherichia coli catalases.

A heme d prosthetic group with the configuration of a cis-hydroxychlorin gamma-spirolactone has been found in the crystal structures of Penicillium vitale catalase and Escherichia coli catalase hydroperoxidase II (HPII). The absolute stereochemistry of the two heme d chiral carbon atoms has been shown to be identical. For both catalases the heme d is rotated 180 degrees about the axis defined by the alpha-gamma-meso carbon atoms, with respect to the orientation found for heme b in beef liver catalase. Only six residues in the heme pocket, preserved in P. vitale and HPII, differ from those found in the bovine catalase. In the crystal structure of the inactive N201H variant of HPII catalase the prosthetic group remains as heme b, although its orientation is the same as in the wild type enzyme. These structural results confirm the observation that heme d is formed from protoheme in the interior of the catalase molecule through a self-catalyzed reaction.

Catalase↗
PubMed1996

Suppression of doxorubicin cardiotoxicity by overexpression of catalase in the heart of transgenic mice.

Weak antioxidant capacity, particularly low catalase activity in the heart, may be a factor responsible for the high sensitivity of this organ to doxorubicin-induced oxidative damage. To test this hypothesis, a heart-specific promoter was used to drive the expression of murine catalase cDNA in transgenic mice. Fifteen healthy transgenic mouse lines were produced. Cardiac catalase activity was constitutively overexpressed in both atrium and ventricule, ranging from 2- to 630-fold higher than normal. This enzyme activity was not altered in liver, kidneys, lungs, and skeletal muscles. Other antioxidant components, including glutathione, glutathione peroxidase, glutathione reductase, metallothionein, and superoxide dismutase, were not altered in the catalase-overexpressing heart. Mice (7 weeks old) from several transgenic lines and from nontransgenic controls were treated intraperitoneally with doxorubicin at a single dose of 20 mg/kg and sacrificed on the 4th day after treatment. As compared to normal controls, transgenic lines expressing catalase activity 60- or 100-fold higher than normal exhibited a significant resistance to doxorubicin-induced cardiac lipid peroxidation, elevation of serum creatine phosphokinase, and functional changes in the isolated atrium. Interestingly, 200-fold or greater elevation of catalase activity did not provide protection. The results provide direct evidence for the role of catalase in doxorubicin cardiotoxic responses.

Animals↗
PubMed1996

Salicylic acid is a modulator of tobacco and mammalian catalases.

Salicylic acid (SA) plays a key role in the establishment of resistance to microbial pathogens in many plants. The discovery that SA inhibits catalase from tobacco led us to suggest that H2O2 acts as second messenger to activate plant defenses. Detailed analyses of SA's interaction with tobacco and mammalian catalases indicate that SA acts as an electron donor for the peroxidative cycle of catalase. When H2O2 fluxes were relatively low (1 microM/min or less), SA inhibited catalase, consistent with its suggested signaling function via H2O2. However, significant inhibition was only observed at 100 microM SA or more, a level reached in infected, but not in uninfected, leaves. This inhibition was probably due to siphoning catalase into the slow peroxidative reaction. Surprisingly, SA was also able to protect catalase from inactivation by damaging levels of H2O2 (lower millimolar range), which is generally assumed to reflect accumulation of inactive ferro-oxy intermediates. SA did so by supporting or substituting for the protective function of catalase-bound NADPH. These results add new features to SA's interaction with heme enzymes and its in vivo redox properties. Thus, SA, in addition to its proposed signaling function, may also have an important antioxidant role in containing oxidative processes associated with plant defense responses.

Animals↗
PubMed1998

Oxidation of catalase by singlet oxygen.

Different bands of catalase activity in zymograms (Cat-1a-Cat-1e) appear during Neurospora crassa development and under stress conditions. Here we demonstrate that singlet oxygen modifies Cat-1a, giving rise to a sequential shift in electrophoretic mobility, similar to the one observed in vivo. Purified Cat-1a was modified with singlet oxygen generated from a photosensitization reaction; even when the reaction was separated from the enzyme by an air barrier, a condition in which only singlet oxygen can reach the enzyme by diffusion. Modification of Cat-1a was hindered when reducing agents or singlet oxygen scavengers were present in the photosensitization reaction. The sequential modification of the four monomers gave rise to five active catalase conformers with more acidic isoelectric points. The pI of purified Cat-1a-Cat-1e decreased progressively, and a similar shift in pI was observed as Cat-1a was modified by singlet oxygen. No further change was detected once Cat-1e was reached. Catalase modification was traced to a three-step reaction of the heme. The heme of Cat-1a gave rise to three additional heme peaks in a high performance liquid chromatography when modified to Cat-1c. Full oxidation to Cat-1e shifted all peaks into a single one. Absorbance spectra were consistent with an increase in asymmetry as heme was modified. Bacterial, fungal, plant, and animal catalases were all susceptible to modification by singlet oxygen, indicating that this is a general feature of the enzyme that could explain in part the variety of catalases seen in several organisms and the modifications observed in some catalases. Modification of catalases during development and under stress could indicate in vivo generation of singlet oxygen.

Catalase↗
PubMed1999

Mechanisms of protection of catalase by NADPH. Kinetics and stoichiometry.

NADPH is known to be tightly bound to mammalian catalase and to offset the ability of the substrate of catalase (H2O2) to convert the enzyme to an inactive state (compound II). In the process, the bound NADPH becomes NADP+ and is replaced by another molecule of NADPH. This protection is believed to occur through electron tunneling between NADPH on the surface of the catalase and the heme group within the enzyme. The present study provided additional support for the concept of an intermediate state of catalase, through which NADPH serves to prevent the formation (rather than increase the removal) of compound II. In contrast, the superoxide radical seemed to bypass the intermediate state since NADPH had very little ability to prevent the superoxide radical from converting catalase to compound II. Moreover, the rate of NADPH oxidation was several times the rate of compound II formation (in the absence of NADPH) under a variety of conditions. Very little NADPH oxidation occurred when NADPH was exposed to catalase, H2O2, or the superoxide radical separately. That the ratio exceeds 1 suggests that NADPH may protect catalase from oxidative damage through actions broader than merely preventing the formation of compound II.

Acetaldehyde↗
PubMed2000

Overexpression of catalase in the mitochondrial or cytosolic compartment increases sensitivity of HepG2 cells to tumor necrosis factor-alpha-induced apoptosis.

The sensitivity of HepG2 cells overexpressing catalase in either the cytosolic or mitochondrial compartment to tumor necrosis factor-alpha (TNF-alpha) and cycloheximide was studied. Cells overexpressing catalase in the cytosol (C33 cells) and especially in mitochondria (mC5 cells) were more sensitive to TNF-alpha-induced apoptosis than were control cells (Hp cells). The activities of caspase-3 and -8 were increased by TNF-alpha, with the highest activities found in mC5 cells. Sodium azide, an inhibitor of catalase, reduced the increased sensitivity of mC5 and C33 cells to TNF-alpha to the level of toxicity found with control Hp cells. Azide also decreased the elevated caspase-3 activity of mC5 cells. A pan-caspase inhibitor prevented the TNF-alpha-induced apoptosis and toxicity produced by catalase overexpression. Addition of H(2)O(2) prevented TNF-alpha-induced apoptosis and caspase activation, an effect prevented by simultaneous addition of catalase. TNF-alpha plus cycloheximide increased ATP levels, with higher levels in C33 and mC5 cells compared with Hp cells. TNF-alpha did not produce apoptosis in mC5 cells maintained in a low energy state. TNF-alpha signaling was not altered by the overexpression of catalase, as activation of nuclear factor kappaB and AP-1 by TNF-alpha was similar in the three cell lines. These results suggest that catalase, overexpressed in the cytosolic or especially the mitochondrial compartment, potentiates TNF-alpha-induced apoptosis and activation of caspases by removal of H(2)O(2).

Adenosine Triphosphate↗
PubMed1982

Radiation-induced inhibition of human lymphocyte blastogenesis: the effect of superoxide dismutase and catalase.

Mitogen-induced lymphocyte blastogenesis was measured following X-irradiation (0-4 Gy) in the presence or absence of superoxide dismutase (SOD), under aerobic and anaerobic conditions. There were no significant differences between radiation survival curves under these different conditions, nor did SOD have any radioprotective effect. This demonstrates the lack of oxygen dependence of radiation-induced inhibition of lymphocyte blastogenesis. Following X-irradiation at 2 Gy, neither SOD nor catalase, alone or together, added before or after irradiation, were radioprotective. In comparison to controls, both enzymes depressed lymphocyte proliferation when added at levels as low as 25 microgram catalase or 100 microgram SOD/ml media. When SOD and catalase were added together, the greatest depression of blastogenesis was obtained with increasing levels of SOD relative to increasing levels of catalase, indicating that SOD was largely responsible for this depression. The suppressive effect of administration of SOD (p less than 0.05), catalase (p less than 0.001) and SOD + catalase (p less than 0.001) on lymphocyte division was significantly greater when given prior to X-irradiation. The lack of an oxygen effect and the inability of SOD and catalase to protect human lymphocytes from X-irradiation suggest that 2- and /or H2O2 are not involved in radiation-induced inhibition of lymphocyte blastogenesis.

Aerobiosis↗
PubMed1987

Post-irradiation modification of oxygen-dependent and independent damage by catalase in barley seeds.

If H2O2 is one of the major mediators of the 'oxygen effect' in biological systems then catalase, which enzymically decomposes H2O2 should have a significant influence on radiation damage, particularly under oxygenated conditions. The post-irradiation (300 Gy gamma rays) effect of catalase was, therefore, assessed on barley seeds of about 4 per cent moisture content under oxygenated and oxygen-free conditions at varying temperatures. Catalase affords concentration-dependent radioprotection under oxygenated condition at both 25 degrees C and 4 degrees C. The level of protection at 4 degrees C is less than at 25 degrees C. This is obviously due to a decrease in catalase activity at low temperature. Under oxygen-free conditions, catalase enhances radiation damage at 4 degrees C while at 25 degrees C it has no effect. This has been substantiated by data on the frequency of chromosomal aberrations and on peroxidase activity. Sodium azide, a catalase inhibitor, was found to eliminate the radioprotective action of catalase. The study supports the view that the 'oxygen effect' is mediated largely through peroxides in irradiated biological systems. However, the observations made particularly at 4 degrees C under oxygen-free condition seem to involve physicochemical reactions.

Azides↗
PubMed1992

Spectral studies of intermediate species formed in one-electron reactions of bovine liver catalase at room and low temperatures. A comparison with peroxidase reactions.

The reactions of native bovine catalase with superoxide and solvated electrons have been investigated using three different methods for generation of these reducing substrates: gamma-radiolysis of oxygenated or deaerated buffer solutions in the presence of an OH radical scavenger; either xanthine or acetaldehyde with xanthine oxidase; and low-temperature (77 K) gamma-radiolysis of buffered ethylene glycol/water solutions with subsequent annealing of samples at 183 K. The first spectral evidence for catalase compound II formation from native catalase via reaction with superoxide was obtained. The results are compared with results for peroxidase compound II or III formation observed under the same experimental conditions. A scheme is proposed to explain these observations involving intermediate formation of catalase compounds I and III and the ferrous enzyme. The one-electron reduction of catalase and peroxidase by radiolytically-generated solvated electrons was compared. In the present study the first absorption spectrum of a high-spin ferrous catalase which has peaks at 561 and 594 nm is reported, in comparison with a hemochromogen low-spin ferrous peroxidase observed under the same experimental conditions (peaks at 527 and 556 nm). Both spectra were recorded at 77 K. Data presented in this work also provide the first spectral evidence indicating the low temperature (183 K) conversion of high-spin ferrous catalase into compound III (oxycatalase) in the presence of dioxygen. Under the same experimental conditions low-spin ferrous peroxidase was converted into the high-spin ferrous form without oxyperoxidase formation.

Animals↗
PubMed1999

Purification of catalase from pea leaf peroxisomes: identification of five different isoforms.

Catalase activity was analyzed in seven organs of pea (Pisum sativum L.) plants: leaves, seeds, flowers, shoots, whole fruits, pods and roots. Leaves showed the highest activity followed by whole fruits and flowers. Catalase was purified from pea leaf peroxisomes. These organelles were isolated from leaves by differential and sucrose density-gradient centrifugation, and catalase was purified by two steps involving anion exchange and hydrophobic chromatography using a Fast Protein Liquid Chromatography system. Pure catalase had a specific activity of 953 mmol H2O2 min(-1) mg(-1) protein and was purified 1000-fold, with a yield of about 19 microg enzyme per kg of pea leaves. Analysis by SDS-PAGE and immunoblot showed that the pea catalase was composed of subunits of 57 kDa. Ultraviolet and visible absorption spectra of the enzyme showed two absorption maxima at 252 and 400 nm with molar extinction coefficients of 2.14 x 10(6) and 7.56 x 10(6) M(-1) cm(-1), respectively. By isoelectric focusing (pH 5-7), five different isoforms were identified and designated as CAT1-5, with isoelectric points of 6.41, 6.36, 6.16, 6.13 and 6.09, respectively. All the catalase isoforms contained a subunit of 57 kDa. Post-embedment, EM immunogold labelling of catalase showed a uniform distribution of the enzyme inside the matrix and core of pea leaf peroxisomes.

Catalase↗
PubMed1990

Failure of benzene and phenol to serve as substrates for the peroxidatic action of catalase.

Evidence from several reports in the literature indicates a possible role for catalase in the metabolism of benzene. To investigate possible peroxidatic activity of catalase on benzene or its major metabolite, phenol, we employed an in vitro assay system that had been used previously to study the peroxidation of ethanol by catalase. Under conditions identical to those used to demonstrate catalase-mediated ethanol peroxidation we observed no peroxidase activity of catalase toward either benzene or phenol. We conclude that catalase is not involved in benzene metabolism and make the observation that, to date, no aromatic compounds have been demonstrated to be substrates for the peroxidatic mode of action of catalase.

Animals↗
PubMed1973

The synthesis and turnover of rat liver of rat liver peroxisomes. IV. Biochemical pathway of catalase synthesis.

Early events in the biosynthesis of liver catalase were studied on female rats receiving [(3)H]leucine or [(3)H]delta-aminolevulinic acid or a mixture of [(3)H]leucine with [(14)C]delta-aminolevulinic acid by intraportal injection. Catalase antigen was selectively separated from homogenates by immunoprecipitation, both without and after partial purification of the enzyme. Label from both precursors appeared first in immunoprecipitable material which was lost upon purification of catalase; the label subsequently became associated with material indistinguishable from catalase. Kinetic analysis of the results indicates that the nonpurifiable material identified by early labeling consists of two distinct biosynthetic intermediates, the first lacking heme and representing about 1.6% of the total catalase content or 13 microg/g liver, the second containing heme and representing about 0.5% of the total catalase content or 4 microg/g liver. The first intermediate migrates at the same rate as catalase upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and therefore has a monomeric molecular weight of about 60,000.

Aminolevulinic Acid↗
PubMed1998

Intron loss and gain during evolution of the catalase gene family in angiosperms.

Angiosperms (flowering plants), including both monocots and dicots, contain small catalase gene families. In the dicot, Arabidopsis thaliana, two catalase (CAT) genes, CAT1 and CAT3, are tightly linked on chromosome 1 and a third, CAT2, which is more similar to CAT1 than to CAT3, is unlinked on chromosome 4. Comparison of positions and numbers of introns among 13 angiosperm catalase genomic sequences indicates that intron positions are conserved, and suggests that an ancestral catalase gene common to monocots and dicots contained seven introns. Arabidopsis CAT2 has seven introns; both CAT1 and CAT3 have six introns in positions conserved with CAT2, but each has lost a different intron. We suggest the following sequence of events during the evolution of the Arabidopsis catalase gene family. An initial duplication of an ancestral catalase gene gave rise to CAT3 and CAT1. CAT1 then served as the template for a second duplication, yielding CAT2. Intron losses from CAT1 and CAT3 followed these duplications. One subclade of monocot catalases has lost all but the 5'-most and 3'-most introns, which is consistent with a mechanism of intron loss by replacement of an ancestral intron-containing gene with a reverse-transcribed DNA copy of a fully spliced mRNA. Following this event of concerted intron loss, the Oryza sativa (rice, a monocot) CAT1 lineage acquired an intron in a novel position, consistent with a mechanism of intron gain at proto-splice sites.

Arabidopsis Proteins↗
PubMed1979

Effect of treatment with hemin on rat liver catalase.

Rats were injected with a single or repeated doses of hemin intraperitoneally, and the effect on liver catalase [EC 1.11.1.6] was studied. A single administration of hemin caused a reduction in the concentration of liver catalase, both in enzymatic activity and in catalase protein determined immunochemically. The reduction occurred a few hours after the hemin injection, and is probably due to stimulated degradation. Disappearance of radioactivity from liver catalase prelabelled with [14C]leucine was enhanced following the administration of hemin. No evidence for a repression in vivo incorporation of [14C]leucine and [3H]sigma-aminolevulinic acid into liver catalase was obtained with hemin-treated rats. When the hemin was given repeatedly at 12-h intervals, the level of liver catalase decreased considerably. However, the impairment in catalase-synthesizing activity of liver cells of rats thus treated was rather slight, when examined in a cell-free system. Some differences were noted between the results in the present study and those in previous investigations with Sedormid-treated rats.

Animals↗