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Oxygen metabolism of catalase-negative and catalase-positive strains of Lactobacillus plantarum.

Two catalase-negative strains of Lactobacillus plantarum and a strain producing the atypical, nonheme catalase were studied to determine if the ability to produce the atypical catalase conferred any growth advantage upon the producing strain. Both catalase-negative strains grew more rapidly than the catalase-positive strain under aerobic or anaerobic conditions in a glucose-containing, complex medium. Upon exhaustion of glucose from the medium, all three strains continued growth under aerobic but not under anaerobic conditions. The continued aerobic growth was accompanied by production of acetic acid in addition to the lactic acid produced during growth on glucose. Oxygen was taken up by exponential phase-cell suspensions grown on glucose when glucose or glycerol were used as substrates. Cells harvested from glucose-exhausted medium oxidized glucose, glycerol, and pyruvate. Oxygen utilization by a catalase-negative strain increased as did the specific activity of reduced nicotinamide adenine dinucleotide peroxidase during late growth in the glucose-exhausted medium. The catalase-positive strain and the catalase-negative strain tested both possessed low but readily detectable levels of superoxide dismutase throughout growth. The growth responses are discussed in terms of the presence of enzymes which would allow the cells to remove potentially damaging reduction products of O2.

Acetates↗

Purification and characterization of a catalase-peroxidase and a typical catalase from the bacterium Klebsiella pneumoniae.

The bacterium Klebsiella pneumoniae synthesizes three different types of catalase: a catalase-peroxidase, a typical catalase and an atypical catalase, designated KpCP, KpT and KpA, respectively (Goldberg, I. and Hochman, A. (1989) Arch. Biochem. Biophys. 268, 124-128). KpCP, but not the other two enzymes, in addition to the catalatic activity, catalyzes peroxidatic activities with artificial electron donors, as well as with NADH and NADPH. Both KpCP and KpT are tetramers, with heme IX as a prosthetic group, and they show a typical high-spin absorption spectrum which is converted to low-spin when a cyanide complex is formed. The addition of dithionite to KpCP causes a shift in the absorption maxima typical of ferrous heme IX. KpCP has a pH optimum of 6.3 for the catalatic activity and 5.2-5.7 for the peroxidatic activity, and relatively low 'Km' values: 6.5 mM and 0.65 H2O2 for the catalatic and peroxidatic activities, respectively. The activity of the catalase-peroxidase is inhibited by azide and cyanide, but not by 3-amino-1,2,4-triazole. KpT has wide pH optimum: 5-10.5 and a 'Km' of 50 mM H2O2, it is inhibited by incubation with 3-amino-1,2,4-triazole and by the acidic forms of cyanide and azide. A significant distinction between the typical catalase and the catalase-peroxidase is the stability of their proteins: KpT is more stable than KpCP to H2O2, temperature, pH and urea.

Catalase↗

Effect of catalase-specific inhibitor 3-amino-1,2,4-triazole on yeast peroxisomal catalase in vivo.

3-Amino-1,2,4-triazole (3-AT) is known as an inhibitor of catalase to whose active center it specifically and covalently binds. Subcellular fractionation and immunoelectronmicroscopic observation of the yeast Candida tropicalis revealed that, in 3-AT-treated cells in which the 3-AT was added to the n-alkane medium from the beginning of cultivation, catalase transported into peroxisomes was inactivated and was present as insoluble aggregated forms in the organelle. The aggregation of catalase in peroxisomes occurred only in these 3-AT-treated cells and not in cells in which 3-AT was added at the late exponential growth phase. Furthermore, 3-AT did not affect the transportation of catalase into peroxisomes. The appearance of aggregation only in cells to which 3-AT was added from the beginning of cultivation suggests that, in the process of catalase transportation into yeast peroxisomes, some conformational change may take place and that correct folding may be inhibited by the binding of 3-AT to the active center of catalase. Accordingly, 3-AT will be an interesting compound for investigation of the transport machinery of the peroxisomal tetrameric catalase.

Amitrole↗

Protein coordination to manganese determines the high catalytic rate of dimanganese catalases. Comparison to functional catalase mimics.

Catalysis of hydrogen peroxide dismutation by the dimanganese catalase from Thermus thermophilus has been measured and found to obey Michaelis-Menton kinetics with no evidence for substrate inhibition at concentrations up to 0.45 M H2O2. Comparison among three dimanganese catalases (Thermus thermophilus, Thermoleophilium album, and Lactobacillus plantarum) reveals that their apparent second-order rate constants, Kcat/Km, differ by at most a factor of 5, even though the individual kinetic constants differ by as much as a factor of 20. This similarity suggests that all three enzymes may have the same rate-determining step. For T. thermophilus catalase we find that kcat/Km approximately kbi, the bimolecular rate constant at limiting substrate concentrations. Thus, the rate of the rate-determining step is unaltered over the entire range of substrate concentrations, unlike T. album and L. plantarum catalases where substrate inhibition has been reported. Comparison to structurally characterized dimanganese complexes and dimetalloproteins (arginase, hemerythrin), which are functional, albeit kinetically slow, catalase mimics, reveals that high catalase activity correlates with a greater number of stronger sigma-ligand donors like anionic carboxylatos vs neutral histidines that stabilize the oxidized Mn2(III,III) state over reduced Mn2(II,II). A critical feature for enzymatic functionality in vivo is suppression of one-electron chemistry leading to formation of the mixed-valence forms, Mn2(III,IV) and Mn2(II,III), which are kinetically inactive or precursors to inactive species, respectively. Evidence is presented from model compounds suggesting that the mu-carboxylato bridge between Mn ions in catalase may play the key role in suppressing formation of these detrimental oxidation states through destabilization of these one-electron redox processes.

Catalase↗

Cloning and genetic characterization of Helicobacter pylori catalase and construction of a catalase-deficient mutant strain.

The N-terminal sequence of a protein, originally described as an adhesin of Helicobacter pylori, was used in an oligonucleotide-based screening procedure of an H. pylori plasmid library in Escherichia coli. Five independent plasmid clones were isolated, all mapping to the same chromosomal region and encoding the H. pylori catalase. The gene, designated katA, comprises 1,518 nucleotides and encodes a putative protein of 505 amino acids with a predicted Mr of 58,599. A second open reading frame, orf2, encoding a putative 32,715-Da protein of unknown function, follows katA. The transcriptional start site of katA mRNA was determined, but no typical consensus promoter sequence was present. A potential binding site for the Fur protein is located upstream of katA. When introduced into the catalase-deficient E. coli double-mutant UM255, the cloned gene readily complemented E. coli for catalase activity. H. pylori KatA is highly homologous to catalases in both prokaryotes and eukaryotes, with the highest homology being shown to Bordetella pertussis (64.9%), Bacteroides fragilis (59.8%), and Haemophilus influenzae (57.9%) catalases. Transposon insertion mutants were generated in three independent H. pylori strains by TnMax5-mediated transposon shuttle mutagenesis. In contrast to the wild-type strains, no significant catalase-specific enzymatic activity could be detected in the mutant strains, consistent with the fact that no additional katA-homologous gene copies were found in the H. pylori chromosome. No significant difference between wild-type and mutant strains for binding to epithelial cells was apparent, suggesting that KatA is not involved in H. pylori adhesion. The cloning and genetic characterization of katA are essential steps for further investigation of the role of catalase in the defense of H. pylori against oxygen-dependent killing mechanisms by polymorphonuclear granulocytes, a process not well understood for this chronically persisting pathogen.

Amino Acid Sequence↗

Human erythrocyte catalase, isolation with an improved method, characterization and comparison to bovine liver catalase.

Catalase enzyme was purified from human erythrocytes. The modified procedure of Mörikofer-Zwez et. al. [Eur. J. Biochem. 11: 49-57, 1969] yielded erythrocyte catalase with high specific activity and with one band on SDS polyacrylamide gel. Its other characteristics (isoelectric point; E405/280, E1%1cm at 280 nm and 405 nm) were in agreement with previously described findings. The results obtained for molecular mass, electrophoretic mobility, chromatographic behaviour on CM-Sepadex gel, addition test, and change of electrophoretic mobility in human serum showed differences between human erythrocyte catalase and bovine liver catalase. These results suggest that human erythrocyte catalase and bovine liver catalase are two distinct catalase forms.

Animals↗

Protection of human neutrophils by endogenous catalase: studies with cells from catalase-deficient individuals.

To investigate the importance of catalase as a protecting enzyme against oxidative damage in phagocytic leukocytes, we have tested the functional capacity of neutrophils from two individuals homozygous for Swiss-type acatalasemia and from two individuals heterozygous for this deficiency. In the former cells, 25-30% of residual activity of catalase was present. In the latter cells, the values were close to normal. Chemotaxis towards casein, release of lysosomal enzymes and hydrogen peroxide during phagocytosis of zymosan, and intracellular killing of Staphylococcus aureus were normal in all cells tested. Inhibition of heme enzymes with azide (2 mM) enhanced the respiration and hexose monophosphate shunt activity of normal, but not of homozygous acatalasemic, neutrophils. This indicates that the enhancement in normal cells is, at least in part, due to catalase inhibition. After 15 min preincubation with an H(2)O(2)-generating system (glucose plus glucose oxidase), the respiratory response to zymosan phagocytosis was strongly depressed in the homozygous acatalasemic and in normal, azide-treated neutrophils, but not in normal, untreated cells. Under these conditions, the release of lysosomal enzymes was depressed and that of lactate dehydrogenase enhanced, in catalase-deficient and in catalase-inhibited, but not in normal, neutrophils. During prolonged incubation with the H(2)O(2)-generating system (30-60 min), the reduction level of intracellular glutathione remained high and the hexose monophosphate shunt continued to operate normally in all cells tested. Thus, although the function of neutrophils without catalase activity was depressed by extracellular hydrogen peroxide, the H(2)O(2) degradation via the glutathione redox system remained operative. The results indicate that the glutathione redox system by itself efficiently protects phagocytosing neutrophils against their own oxidative products. During heavy external oxidative stress, however, both catalase and the glutathione redox system are needed for adequate protection.

Catalase↗

Diminished synthesis of catalase due to the decrease in catalase mRNA in Japanese-type acatalasemia.

In order to characterize the genetic defect in Japanese-type acatalasemia, we examined catalase synthesis in the cultured fibroblasts isolated from a patient suffering from this disease. The transcript of the mutant catalase gene was also analyzed by Northern blotting. It was demonstrated that the severe reduction in catalase protein in the acatalasemic patient is due to the defective synthesis of the enzyme caused by the lack of catalase mRNA. Using Southern blotting, we did not detect large deletion, insertion or rearrangement in the mutant catalase gene as compared with the normal one. We conclude that Japanese-type acatalasemia in this study is resulted by a small mutation in the non-coding region of catalase gene which affects some step in the catalase mRNA metabolism.

Acatalasia↗

Catalase activities of Phanerochaete chrysosporium are not coordinately produced with ligninolytic metabolism: catalases from a white-rot fungus.

Phanerochaete chrysosporium uses hydrogen peroxide as a substrate in its ligninolytic phase. To determine how the fungus protects itself against detrimental effects of reactive oxygen species, catalase activity was examined. The fungus produced up to four different catalase isozymes, Cat A to D. Isozyme CatC was the dominant activity in all growth conditions. A minor catalase, CatD, was apparent in low-carbon culture and upon exposure of mycelium grown on high-nitrogen medium with 5-50 mm of hydrogen peroxide. In low-nitrogen culture, an increase in catalase-specific activity preceded the onset of ligninolysis by 3 days. In low-carbon culture, catalase was produced at an even higher level without development of ligninolysis. Thus, catalase activity was not coordinately produced with ligninolytic metabolism.

Catalase↗

Rapid formation of compound II and a tyrosyl radical in the Y229F mutant of Mycobacterium tuberculosis catalase-peroxidase disrupts catalase but not peroxidase function.

Catalase-peroxidases (KatG), which belong to Class I heme peroxidase enzymes, have high catalase activity and substantial peroxidase activity. The Y229F mutant of Mycobacterium tuberculosis KatG was prepared and characterized to investigate the functional role of this conserved residue unique to KatG enzymes. Purified, overexpressed KatG[Y229F] exhibited severely reduced steady-state catalase activity while the peroxidase activity was enhanced. Optical stopped-flow experiments showed rapid formation of Compound (Cmpd) II (oxyferryl heme intermediate) in the reaction of resting KatG[Y229F] with peroxyacetic acid or chloroperoxybenzoic acid, without detectable accumulation of Cmpd I (oxyferryl heme pi-cation radical intermediate), the latter being readily observed in the wild-type enzyme under similar conditions. Facile formation of Cmpd III (oxyferrous enzyme) also occurred in the mutant in the presence of micromolar hydrogen peroxide. Thus, the lost catalase function may be explained in part because of formation of intermediates that do not participate in catalatic turnover. The source of the reducing equivalent required for generation of Cmpd II from Cmpd I was shown by rapid freeze-quench electron paramagnetic resonance spectroscopy to be a tyrosine residue, just as in wild-type KatG. The kinetic coupling of radical generation and Cmpd II formation was shown in KatG[Y229F]. Residue Y229, which is a component of a newly defined three amino acid adduct in catalase-peroxidases, is critically important for protecting the catalase activity of KatG.

Bacterial Proteins↗

The chemical modification of beef liver catalase. V. Ethoxyformylation of histidine and tyrosine residues of catalase with diethylpyrocarbonate.

In order to elucidate the possible roles of histidine and tyrosine residues of catalase [EC 1.11.1.6] in maintaining the quaternary structure and catalatic activity, diethylpyrocarbonate modification experiments were carried out. A method for the estimation of N-ethoxyformyl (EF)-His at pH 5--7 and of O-ethoxyformyl (EF)-Tyr in alkaline solution by measuring A 242 nm (ximM = 3.2) and A278 nm (ximM = 1.16), respectively, was developed. The formation of EF-His and EF-Tyr was an electrophilic reaction and was dependent on pH, exhibiting pK values of 6.8 and 9.9, respectively. The maximal yield of EF-His at pH 6.0 was 49% of the total histidine content, but no inactivation nor unfolding of the enzyme was observed. The formation of 12 EF-Tyr residues per mole of catalase at pH 8.1 did not cause any inactivation, but the formation of 8 more EF-Tyr residues at pH 8.9 resulted in both inactivation and unfolding. Nearly complete inactivation and partial splitting of catalase were observed when 43-46 EF-Tyr residues per mole were produced at pH 10.0. More EF-His residues were formed by the reaction of diethyl pyrocarbonate with cyanoethylated (CE)-catalase monomer (subunit) than with CE-catalase tetramer. The CE-catalase tetramer and monomer were extensively O-ethoxyformylated, reaching 100% EF-Tyr formation. These results indicate that a half of the histidine residues may lie outside the protein core and that three-quarters of the tyrosine residues are probably in the protein core of the enzyme. The production of 2--3 EF-Tyr residues per mole of the monomer by ethoxyformylation at pH 7.0 was accompanied by a decrease in the magnitude of the Soret peak. A possible interaction of those tyrosine residues with porphyrin of the heme group is discussed.

Animals↗

Functional complementation of catalase-defective peroxisomes in a methylotrophic yeast by import of the catalase A from Saccharomyces cerevisiae.

A mutant of the methanol-utilizing yeast Hansenula polymorpha defective in catalase was isolated. It lacks the ability to grow on methanol as the sole source of carbon and energy due to a loss of peroxisomal function that is required for the dissimilation and assimilation of this substrate. Growth of the mutant on glucose or glycerol was not impaired. Transformation of mutant cells with the gene coding for catalase A from Saccharomyces cerevisiae [Cohen, G., Fessl, F., Traczyk, J., Rytka, J. & Ruis, H. (1985) Mol. Gen. Genet. 200, 74-79] conferred constitutive expression of catalase activity. When the gene was placed under control of the regulatory methanol oxidase promoter from H. polymorpha, high levels of activity subject to glucose repression were obtained. In both cases efficient targeting of catalase A to the heterologous peroxisomes and assembly into an active form could be demonstrated. Concomitantly, growth on methanol was restored in the transformed mutant. The results are in line with a high conservation of transport signals on peroxisomal proteins. Expression of a cytosolic catalase in H. polymorpha did not confer the ability to grow on methanol. Therefore, proper localization of the catalase activity is a prerequisite for peroxisomal function.

Alcohol Oxidoreductases↗

The conformer nature of the multiple forms of beef liver catalase as obtained by biochemical and small-angle X-ray scattering experiments. A model for the quaternary structure of the beef liver catalase molecule.

Two of the five multiple forms of beef liver catalase have been extensively studied using biochemical and biophysical analysis techniques. The two molecules, cat I and cat V, have different isoelectric points (pH 6.55 and 5.6), different surface charges (25.8 and 32.7 elementary charges) and display different numbers of primary amino groups on their surfaces. The numbers of tyrosine residues on the surfaces of the two molecules are also different (16 and 10 at pH 10). Since the two forms of catalase can be interconverted, the described changes may be caused by conformational changes of the four protein subunits within the molecule. This mobility of the polypeptide chains is also demonstrated by the different absorption spectra below 390 nm. Using small-angle X-ray scattering, the radii and the volumes of the two catalase forms were shown to be different (cat 1 is smaller than cat V). All five multiple forms of beef liver catalase are concormers of the molecule. A model for the quaternary sturcture of the beef liver catalase are conformers of the molecule. A model for the quaternary structure of the beef liver catalase molecule is suggested. It consists of a regular configuration of four prolate rotational ellipsoids (semiaxes: a = 52 A, b = c = 21 A) in close contact in which the nearest neighbour subunits are shifted by 37 A parallel to each other. Thus the height of the complete molecule is 141 A and the diameter 94 A.

Animals↗

Genetic studies of murine catalase: regulation of multiple molecular forms of kidney catalase.

Starch gel electrophoresis of kidney catalase in inbred strains C3H and C57BL/6, their F1 hybrid, and first and second backcross generations demonstrated that single-component (type A) v. multiple-component (type B) electrophoretic patterns are controlled by a single locus. The type A electrophoretic pattern is dominant. Twenty-five inbred strains of mice were classified according to their kidney catalase electrophoretic pattern. The data indicate that the segregating genetic factor determines a specific substance in the type A kidney which affects the electrophoretic mobility of catalase. A comparison of the F1 hybrid enzyme with a 1:1 mixture of C3H and C57BL/6 enzyme showed that the alteration of electrophoretic mobility is the result of posttranslational modification of the catalase molecule. An association of kidney catalase electrophoretic pattern and the H-2kappa haplotype indicates that the locus controlling the electrophoretic pattern is most likely located on chromosome 17 in close proximity to the H-2 complex.

Animals↗

Characterisation of the katA gene encoding a catalase and evidence for at least a second catalase activity in Staphylococcus xylosus, bacteria used in food fermentation.

The catalase gene katA of Staphylococcus xylosus was cloned. It encodes a protein of 494 amino acids with a molecular mass of 56.9 kDa, closely related to monofunctional catalases. A katA mutant still showed a relatively high catalase activity demonstrating that S. xylosus possesses more than one enzyme. By Southern blot analysis using a katA probe, a second genetic locus distinct from katA was detected that probably contained the additional catalase gene. To analyse katA expression, a transcriptional fusion of the katA promoter region to a promoterless beta-galactosidase gene was integrated into the genome of S. xylosus. katA expression is induced upon entry into stationary phase, by oxygen and hydrogen peroxide. Iron and manganese depletion induced katA transcription. Comparing the resistance of S. xylosus wild-type and the katA mutant strain to hydrogen peroxide clearly showed that KatA is essential for S. xylosus to cope with hydrogen peroxide stress. Therefore, S. xylosus has at least two differentially expressed catalases.

Blotting, Southern↗

Molecular and kinetic study of catalase-1, a durable large catalase of Neurospora crassa.

Catalase-1 (Cat-1), one of the two monofunctional catalases of Neurospora crassa, increases during asexual spore formation to constitute 0.6% of total protein in conidia. Cat-1 was purified 170-fold with a yield of 48% from conidiating cultures. Like most monofunctional catalases, Cat-1 is a homotetramer, resistant to inactivation by solvents, fully active over a pH range of 4-12, and inactivated by 3-amino-1,2,4-triazole. Unlike most monofunctional catalases, Cat-1 consists of 88 kDa monomers that are glycosylated with alpha-glucose and/or alpha-mannose, is unusually stable, and is not inactivated or inhibited by hydrogen peroxide. Cat-1 was more resistant than other catalases to heat inactivation and to high concentrations of salt and denaturants. Cat-1 exhibited unusual kinetics: at molar concentrations of hydrogen peroxide the apparent V was 10 times higher than at millimolar concentrations. Inactivation of Cat-1 activity with azide and hydroxylamine was according to first order kinetics, while cyanide at micromolar concentrations was a reversible competitive inhibitor.

Azides↗

Direct voltammetry and catalysis with Mycobacterium tuberculosis catalase-peroxidase, peroxidases, and catalase in lipid films.

Stable films of dimyristoylphosphatidylcholine and M. tuberculosis catalase-peroxidase (KatG), several peroxidases, myoglobin, and catalase showed reversible FeIII/FeII voltammetry on pyrolytic graphite electrodes and catalytic current for hydrogen peroxide and oxygen. Amperometric responses for these films to H2O2 at 0 V are likely to contain significant contributions from catalytic reduction of oxygen produced during the catalytic cycles. Relative apparent turnover rates at pH 6 based on steady-state currents at 0 V versus SCE in the presence of H2O2 were in the order horseradish peroxidase > cytochrome c peroxidase (CcP) > soybean peroxidase > myoglobin > KatG > catalase. Lower currents for the very efficient peroxide scavengers KatG and catalase may be related to the instability of their compounds I in the presence of H2O2. KatG catalyzed the electrochemical reduction of oxygen more efficiently than catalase and CcP but less efficiently than the other peroxidases. DMPC films incorporating glucose oxidase and peroxidases gave good analytical responses to glucose, demonstrating the feasibility of dual enzyme-lipid films for biosensor fabrication.

Bacterial Proteins↗

The catalase-hydrogen peroxide system. A theoretical appraisal of the mechanism of catalase action.

1. The mechanisms of catalase action advanced by Jones & Wynne-Jones (1962) and by Nicholls (1964) are compared in terms of their relative plausibilities and their utility for extension to accommodate more recent experimental information. 2. A revised formal mechanism is advanced that avoids the less satisfactory features of these mechanisms and attempts to account for the roles of catalase sub-units in both reversible and irreversible deactivation phenomena. 3. Theoretical studies of the redox chemistry of peroxides are used to provide the basis for a discussion of the mechanism of the redox act in catalatic action at the molecular level. It is suggested that an important feature of catalase action may be a mediation of the formation of a reactive intermediate by stereospecifically located acid-base functions in the active site. 4. A more detailed statement of this concept is attempted in terms of a hypothetical partial molecular model for the composition and stereochemistry of the active site of catalase. The utility of this model in describing the catalatic and peroxidatic actions of catalase is assessed.

Arginine↗