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Results for “CATALASE”

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PubMed1979

Studies on rat liver catalase. X. Effect of hemin and an inhibitor on the translation of catalase messenger RNA1.

Rat liver catalase mRNA was translated in a rabbit reticulocyte lysates and wheat germ cell-free system in the presence or absence of hemin and/or a translational inhibitor prepared from reticulocytes, liver cells, and wheat germs. Failure to add hemin to the lysates, or the addition of a hemin-regulated translational inhibitor (HRI) to the hemin-supplemented lysates caused a repressed translation. A preparation of inhibitor from rat liver showed activity similar to that of HRI for this translating system. The translation repression by rat liver inhibitor was reversed by eIF-2 (initiation factor) or GTP, but ATP enhanced the repression. The translation of catalase mRNA in the wheat germ system was not affected by the addition of hemin. An inhibitor prepared from wheat germ extracts, as well as the rat liver inhibitor, markedly decreased the rate of translation. eIF-2, GTP, and ATP behaved in the manner described above. Catalase synthesis in a cell-free system derived from rat liver (using endogenous mRNA) was not influenced by either hemin or the inhibitor. The possibilities are discussed that the synthesis of catalase in liver cells is controlled by a translational inhibitor at the level of chain initiation, and that the formation of the inhibitor from its inactive proinhibitor is regulated by the amount of heme.

Adenosine Triphosphate↗

PubMed1998

Changes in catalase activity and hydrogen peroxide level in rat ovary during estrous cycle and induction of catalase in rat ovary by estradiol-17 beta.

Catalase activity in the whole ovary homogenate and hydrogen peroxide level in the differentially centrifuged fractions of the ovary homogenate during each stage of estrous cycle were measured. The highest catalase activity was observed in the metestrous which declined in the estrous and proestrous and was lowest in the diestrous. An inverse relationship was found between catalase activity and hydrogen peroxide production. Treatment of immature (28-29 days old) female rats with estradiol-17 beta (5 micrograms in 0.2 ml oil/animal/day for consecutive 3 days, s.c.) increased the ovarian catalase activity. The findings indicate that the free radical-scavanger system may have functional role in the ovary.

Animals↗

PubMed1993

Characterization of a catalase-deficient strain of Neisseria gonorrhoeae: evidence for the significance of catalase in the biology of N. gonorrhoeae.

We obtained a catalase-deficient (Kat-) strain of Neisseria gonorrhoeae isolated from a patient who had been unsuccessfully treated with penicillin. Quantitative enzyme assays and electrophoresis of cell extracts on native polyacrylamide gels subsequently stained for catalase and peroxidase activities failed to detect both enzymes. The strain exhibited no growth anomalies or unusual requirements when grown under ordinary laboratory conditions. However, the Kat- strain proved extremely sensitive to exogenous hydrogen peroxide, and analysis of the bacterial DNA after such exposure showed extensive single-strand breakage in both chromosomal and plasmid DNAs. Partial characterization of the gonococcal catalase from a Kat+ laboratory strain revealed that the enzyme had the physical and chemical properties of both catalase and peroxidase.

Acatalasia↗

PubMed1979

Catalase anabolism in yeast: loss of regulation by oxygen of catalase apoprotein synthesis after mutation.

A mutant of Saccharomyces cerevisiae which displays catalase activity when grown under strictly anaerobic conditions has been selected on solid media. Although some preformed holoenzyme has accumulated in anaerobic cells, a sharp increase of activity is still measured during adaptation to oxygen in glucose-buffer; however, a striking difference with the wild-type strain is that in the mutant, catalase formation is observed in the presence of cycloheximide that totally inhibits cytoplasmic translation. It is concluded that kat 80 mutant has lost the regulatory control by oxygen of apocatalase synthesis; the later precursor, characterized as apocatalase synthesis; the latter precursor, characterized as apocatalase T, is thought to be activated in vivo, under aerobic conditions, by inclusion of prosthetic group. Regulation of enzyme synthesis by catabolite repression (glucose erfect) persists, unmodified by reference to the wild-type parental strain. Mutation kat 80 specifically hits catalase anabolism, as no significant variations were observed for the edification of the respiratory system and (apo)cytochrome c peroxidase production. Genetic analysis shows that kat 80 phenotype, recessive in heterozygotes, results from a single nuclear mutation.

Anaerobiosis↗

PubMed2003

Cloning and characterization of katA, encoding the major monofunctional catalase from Xanthomonas campestris pv. phaseoli and characterization of the encoded catalase KatA.

The first cloning and characterization of the gene katA, encoding the major catalase (KatA), from Xanthomonas is reported. A reverse genetic approach using a synthesized katA-specific DNA probe to screen a X. campestris pv. phaseoli genomic library was employed. A positively hybridizing clone designated pKat29 that contained a full-length katA was isolated. Analysis of the nucleotide sequence revealed an open reading frame of 1,521 bp encoding a 507-amino acid protein with a theoretical molecular mass of 56 kDa. The deduced amino acid sequence of KatA revealed 84% and 78% identity to CatF of Pseudomonas syringae and KatB of P. aeruginosa, respectively. Phylogenetic analysis places Xanthomonas katA in the clade I group of bacterial catalases. Unexpectedly, expression of katA in a heterologous Escherichia coli host resulted in a temperature-sensitive expression. The KatA enzyme was purified from an overproducing mutant of X. campestris and was characterized. It has apparent K(m) and V(max) values of 75 m M [H(2)O(2)] and 2.55 x 10(5) micromol H(2)O(2) micromol heme(-1) s(-1), respectively. The enzyme is highly sensitive to 3-amino-1,2,4-triazole and NaN(3), has a narrower optimal pH range than other catalases, and is more sensitive to heat inactivation.

Catalase↗

PubMed2001

A common functional C-T substitution polymorphism in the promoter region of the human catalase gene influences transcription factor binding, reporter gene transcription and is correlated to blood catalase levels.

Oxidative stress is implicated in disease and aging. In order to obtain molecular genetic tools that can be used to determine the potential impact of oxidative stress we examined the human catalase gene promoter for possible variation. Genomic DNA isolated from 10 individuals was screened for polymorphisms in the 5'-flanking region by direct sequence analysis of PCR products (nt -307 to -46 from the transcription start site). A common C/T polymorphism -262 base pairs from the transcription start site was detected. Computer analysis indicated that the two variants bound different transcription factors. Indeed, gel retardation analysis revealed different protein binding patterns to the two variants. Expression studies with reporter constructs showed significantly higher transcriptional activity of the T variant in HepG2 and K562 cells (1.5-fold,p <.05 Wilcoxon test). Thus a higher expression in human liver and blood cells is possible. In order to test this hypothesis, catalase levels in red blood cells were determined in 29 donors. The corresponding genotype was determined with a restriction enzyme-based assay. It was found that catalase levels were significantly higher in donors carrying the T allele in comparison to donors homozygous for the C allele (p <.03). In conclusion, we report here the first common (allele frequency in a Swedish population, 28%) genetic variant in a fundamental oxidative stress protection gene with a defined phenotype.

Alleles↗

PubMed2005

(salen)MnIII compounds as nonpeptidyl mimics of catalase. Mechanism-based tuning of catalase activity: a theoretical study.

We present the results of the first theoretical investigation of salen-manganese complexes as synthetic catalytic scavengers of hydrogen peroxide molecules that mimic catalase enzymes. Catalase mimics can be used as therapeutic agents against oxidative stress in treatment of many diseases, including Alzheimer's disease, stroke, heart disease, aging, and cancer. A ping-pong mechanism approach has been considered to describe the H2O2 dismutation reaction. The real compounds reacting with a peroxide molecule were utilized in our BP density functional calculations to avoid uncertainties connected with using incomplete models. Part I of the dismutation reaction-converting a peroxide molecule into a water molecule with simultaneous oxidation of the metal atom of the catalyst-can be done quite effectively at the Mn catalytic center. To act as catalytic scavengers of hydrogen peroxide, the oxomanganese salen complexes have to be deoxidized during part II of the dismutation reaction. It has been shown that there are two possible reaction routes for the second part of the dismutation reaction: the top and the side substrate approach routes. Our results suggest that the catalyst could be at least temporarily deactivated (poisoned) in the side approach reaction route due to the formation of a kinetically stable intermediate. Overall, the side approach reaction route for the catalyst recovery is the bottleneck for the whole dismutation process. On the basis of the detailed knowledge of the mode of action of the (salen)MnIII catalase mimics, we suggest and rationalize structural changes of the catalyst that should lead to better therapeutic properties. The available experimental data support our conclusions. Our findings on the reaction dismutation mechanism could be the starting point for further improvement of salen-manganese complexes as synthetic catalytic scavengers of reactive oxygen species.

Catalase↗

PubMed2005

A molecular switch and electronic circuit modulate catalase activity in catalase-peroxidases.

The catalase reaction of catalase-peroxidases involves catalase-specific features built into a peroxidase core. An arginine, 20 A from the active-site heme, acts as a molecular switch moving between two conformations, one that activates heme oxidation and one that activates oxoferryl heme reduction by H(2)O(2), facilitating the catalatic pathway in a peroxidase. The influence of the arginine is imparted to the heme through its association with or dissociation from a tyrosinate that modulates reactivity through a Met-Tyr-Trp crosslinked adduct and a pi electron interaction of the heme with the adduct Trp.

Arginine↗

PubMed1970

Dissociation of catalase. A correlation between changes in sedimentation and spectroscopic properties accompanying dissociation of bacterial catalase in alkaline solution.

1. At high concentrations, in 10mm-phosphate buffer, pH7.0, the sedimentation coefficient of bacterial catalase varies with concentration according to: [Formula: see text] with S(0) (20,w)=11.30S and k(s)=6.29x10(-3)ml mg(-1). Sedimentation-equilibrium experiments yield a molecular weight of 240000. 2. Parallel studies of changes in sedimentation-velocity behaviour and in electronic spectra of bacterial catalase at pH>11 were made. Dissociation is indicated by the appearance of a slow-moving (2.9S) component in sedimentation patterns and this is accompanied by marked changes in absorption spectrum in the Soret region. Values of R=E(406)/E(355) show a theoretically predictable near-linear dependence on alpha, the degree of dissociation calculated from ultracentrifuge data. 3. The Soret absorption of bacterial catalase subunits is much lower than that of the native enzyme, and it is suggested that dissociation produces an environmental constraint on the prosthetic group that results in distortion of the porphyrin ring.

Catalase↗

PubMed2004

Catalase reaction by myoglobin mutants and native catalase: mechanistic investigation by kinetic isotope effect.

The catalase reaction has been studied in detail by using myoglobin (Mb) mutants. Compound I of Mb mutants (Mb-I), a ferryl species (Fe(IV)=O) paired with a porphyrin radical cation, is readily prepared by the reaction with a nearly stoichiometric amount of m-chloroperbenzoic acid. Upon the addition of H2O2 to an Mb-I solution, Mb-I is reduced back to the ferric state without forming any intermediates. This indicates that Mb-I is capable of performing two-electron oxidation of H2O2 (catalatic reaction). Gas chromatography-mass spectroscopy analysis of the evolved O2 from a 50:50 mixture of H2(18)O2/H2(16)O2 solution containing H64D or F43H/H64L Mb showed the formation of 18O2 (m/e = 36) and 16O2 (m/e = 32) but not 16O18O (m/e = 34). This implies that O2 is formed by two-electron oxidation of H2O2 without breaking the O-O bond. Deuterium isotope effects on the catalatic reactions of Mb mutants and catalase suggest that the catalatic reactions of Micrococcus lysodeikticus catalase and F43H/H64L Mb proceed via an ionic mechanism with a small isotope effect of less than 4.0, since the distal histidine residue is located at a proper position to act as a general acid-base catalyst for the ionic reaction. In contrast, other Mb mutants such as H64X (X is Ala, Ser, and Asp) and L29H/H64L Mb oxidize H2O2 via a radical mechanism in which a hydrogen atom is abstracted by Mb-I with a large isotope effect in a range of 10-29, due to a lack of the general acid-base catalyst.

Animals↗

PubMed1989

Pulse radiolysis of catalase in solution. I. Reactions of O2- with catalase and its compound I.

The time-course of absorption changes of oxygen-saturated solutions of bovine-liver catalase after pulse radiolysis have been studied. The rate constant of formation of Compound I due to the reaction of catalase with hydrogen peroxide has been estimated to be 2.0 x 10(7) dm3mol-1s-1. Radiation generated superoxide radicals reduce Compound I to Compound II with a rate constant of 5.0 x 10(6) dm3mol-1s-1. The formation of Compound III in the direct reaction of O2- with catalase has also been observed.

Animals↗

PubMed2004

Catalase immobilization in cellulose acetate beads and determination of its hydrogen peroxide decomposition level by using a catalase biosensor.

Catalase enzyme (EC 1.11.1.6) was immobilized by entrapping in cellulose acetate beads. This organic matrix is highly resistant to mechanical stability and can be used under various conditions. Initial studies were conducted to examine the immobilization ability of catalase on the matrix previously activated with a series of reagent normally and the best results were obtained with the beads activated with Ce(SO4)2. In the optimization studies of the immobilized enzyme optimum pH and temperature were found as pH:7.0 (Tris-HCl, 50 mM) and 35 degrees C. In the characterization studies of the immobilized enzyme some parameters such as storage and thermal stability were investigated. Finally, the immobilized enzyme was used for the decomposition of hydrogen peroxide in milk samples and also by using a catalase biosensor prepared the decomposition level of hydrogen peroxide was detected.

Animals↗

PubMed1986

Temporal variation for the expression of catalase in Drosophila melanogaster: correlations between rates of enzyme synthesis and levels of translatable catalase-messenger RNA.

Two variants that alter the temporal expression of catalase have been isolated from a set of third chromosome substitution lines. Each variant has been mapped to a cytogenetic interval flanked by the visible markers st (3-44.0) and cu (3-50.0) at a map position of 47.0, which is within or near the interval 75D-76A previously identified as containing the catalase structural gene on the bases of dosage responses to segmental aneuploidy. Each variant operates by modulating the rate of enzyme synthesis and the level of translatable catalase-mRNA.

Catalase↗

PubMed1978

Subunit structure of Micrococcus luteus catalase. Dissociation of M. luteus catalase induced by dodecylsulfate, citraconic and 2,3-dimethylmaleic anhydrides and urea.

M. luteus catalase dissociates upon treatment with urea, dodecylsulfate and anhydrides into monomers, the molecular weight of which appears to be 1/4 of that of the native enzyme. The urea-induced dissociation depends upon the incubation time, the urea concentration and the pH of the incubation mixture. Reassociation of the subunits proved to be unsuccessful. Native M. luteus catalase only contains 30% alpha-helix. When fully dissociated in presence of urea, it still retains 15% alpha-helix. Catalase from M. luteus was found to lack cysteine residues.

Catalase↗

PubMed1978

[Catalases of mycobacteria as antigens. I. Isolation, purification and characterization of catalases from different mycobacteria (author's transl)].

Preparations of catalase isolated from the strains M. tuberculosis, M. kansasii and M. bovis BCG are produced for testing their antigenic activity. After desintegration of the bacteria the highest activity remained in the precipitation with 50% saturated ammonium sulphate solution. The further purification of the catalase-fractions occurred with the aid of column chromatography on Sephadex G 200 and DEAE-Sephadex-A 50 after ultrafiltration. In this way the relative activity increased in M. tuberculosis 3- to 4-fold, in M. kansasii 12-fold and in M. bovis BCG 16-fold. The catalase preparations are uniform and nearly free from other protein compounds as indicated by the results of immunoelectrophoresis and Ouchterlony test.

Antigens↗

PubMed1981

Regulation of catalase biosynthesis in Saccharomyces cerevisiae: factor repressing catalase biosynthesis.

A factor which represses the catalase biosynthesis in yeast has been demonstrated in Saccharomyces cerevisiae. This factor can be obtained from yeast cells having both low and normal catalase levels, and is unable to enter the intact cytoplasmic membrane. Moreover, the factor-containing cell extracts obtained either from acatalasemic mutants or normal strains grown in catalase repressive conditions showed higher activity than those obtained from normal strains after being cultured in permissive conditions.

Catalase↗

PubMed2002

Magnetization studies of the active and fluoride-inhibited derivatives of the reduced catalase of Lactobacillus plantarum: toward a general picture of the anion-inhibited and active forms of the reduced dimanganese catalases.

The magnetic properties of the reduced catalase from Lactobacillus plantarum have been studied for the active enzyme and its fluoride complex through variable field/variable temperature magnetization measurements. The magnetic exchange interaction deduced from these experiments [fluoride complex: - J=1.3(1) cm(-1); active enzyme: - J=5.6(5) cm(-1); H=-2 J S(1) S(2)] are similar to those presently obtained in a re-analysis of the data for the corresponding forms of the Thermus thermophilus enzyme (previously published in 1997, Angew Chem Int Ed Engl 36:1626-1628): phosphate complex: - J=2.1(2) cm(-1); active enzyme - J=5.0(3) cm(-1). These results concur to a unified picture for the two enzymes, consistent with the presence of a hydroxide bridge in the reduced active catalases and its replacement by an aqua bridge in the anion-inhibited enzymes as the main mediators of the magnetic exchange.

Anions↗

PubMed2004

Immobilization of catalase by entrapping in alginate beads and catalase biosensor preparation for the determination of hydrogen peroxide decomposition.

In this study, catalase enzyme was immobilized by entrapping in alginate beads in the presence of gelatin. In the optimization studies of the bioactive layer immobilized some parameters such as enzyme amount, alginate, gelatin, and crosslinking agent glutaraldehyde amount were determined as 700 U/mL, 2.0%, 18 mg/mL, and 5.0%, respectively. Effects of pH and temperature on the immobilization were also investigated. In the characterization studies of the immobilized enzyme storage and thermal stability experiments were done. The immobilized enzyme was used for the decomposition of hydrogen peroxide in milk samples and also by using a catalase biosensor prepared by the decomposition level of hydrogen peroxide was detected.

Alginates↗