Publications

• Purification and characterization of an intracellular catalase-peroxidase from Penicillium simplicissimum.

  Fraaije M.W., Roubroeks H.P., Hagen W.R., Van Berkel W.J.

  The first dimeric catalase-peroxidase of eucaryotic origin, an intracellular hydroperoxidase from Penicillium simplicissimum which exhibited both catalase and peroxidase activities, has been isolated. The enzyme has an apparent molecular mass of about 170 kDa and is composed of two identical subun ... >> More

  The first dimeric catalase-peroxidase of eucaryotic origin, an intracellular hydroperoxidase from Penicillium simplicissimum which exhibited both catalase and peroxidase activities, has been isolated. The enzyme has an apparent molecular mass of about 170 kDa and is composed of two identical subunits. The purified protein has a pH optimum for catalase activity at 6.4 and for peroxidase at 5.4. Both activities are inhibited by cyanide and azide whereas 3-amino-1,2,4-triazole has no effect. 3,3'-Diaminobenzidine, 3,3'-dimethoxybenzidine, guaiacol, 2,6-dimethoxyphenol and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) all serve as substrates. The optical spectrum of the purified enzyme shows a Soret band at 407 nm. Reduction by dithionite results in the disappearance of the Soret band and formation of three absorption maxima at 440, 562 and 595 nm. The prosthetic group was identified as a protoheme IX and EPR spectroscopy revealed the presence of a histidine residue as proximal ligand. In addition to the catalase-peroxidase, an atypical catalase which is active over a broad pH range was also partially purified from P. simplicissimum. This catalase is located in the periplasm and contains a chlorin-type heme as prosthetic group. << Less

  Eur J Biochem 235:192-198(1996) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Intracellular catalase/peroxidase from the phytopathogenic rice blast fungus Magnaporthe grisea: expression analysis and biochemical characterization of the recombinant protein.

  Zamocky M., Furtmuller P.G., Bellei M., Battistuzzi G., Stadlmann J., Vlasits J., Obinger C.

  Phytopathogenic fungi such as the rice blast fungus Magnaporthe grisea are unique in having two catalase/peroxidase (KatG) paralogues located either intracellularly (KatG1) or extracellularly (KatG2). The coding genes have recently been shown to derive from a lateral gene transfer from a (proteo)b ... >> More

  Phytopathogenic fungi such as the rice blast fungus Magnaporthe grisea are unique in having two catalase/peroxidase (KatG) paralogues located either intracellularly (KatG1) or extracellularly (KatG2). The coding genes have recently been shown to derive from a lateral gene transfer from a (proteo)bacterial genome followed by gene duplication and diversification. Here we demonstrate that KatG1 is expressed constitutively in M. grisea. It is the first eukaryotic catalase/peroxidase to be expressed heterologously in Escherichia coli in high amounts, with high purity and with almost 100% haem occupancy. Recombinant MagKatG1 is an acidic, mainly homodimeric, oxidoreductase with a predominant five-co-ordinated high-spin haem b. At 25 degrees C and pH 7.0, the E(0)' (standard reduction potential) of the Fe(III)/Fe(II) couple was found to be -186+/-10 mV. It bound cyanide monophasically with an apparent bimolecular rate constant of (9.0+/-0.4)x10(5) M(-1).s(-1) at pH 7.0 and at 25 degrees C and with a K(d) value of 1.5 muM. Its predominantly catalase activity was characterized by a pH optimum at 6.0 and k(cat) and K(m) values of 7010 s(-1) and 4.8 mM respectively. In addition, it acts as a versatile peroxidase with a pH optimum in the range 5.0-5.5 using both one-electron [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) o-dianisidine, pyrogallol or guaiacol] and two-electron (Br(-), I(-) or ethanol) donors. Structure-function relationships are discussed with respect to data reported for prokaryotic KatGs, as is the physiological role of MagKatG1. Phylogenetic analysis suggests that (intracellular) MagKatG1 can be regarded as a typical representative for catalase/peroxidase of both phytopathogenic and saprotrophic fungi. << Less

  Biochem. J. 418:443-451(2009) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

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

  Hochman A., Goldberg I.

  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 ... >> More

  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. << Less

  Biochim Biophys Acta 1077:299-307(1991) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Mechanisms of catalase activity of heme peroxidases.

  Vlasits J., Jakopitsch C., Bernroitner M., Zamocky M., Furtmuller P.G., Obinger C.

  In the absence of exogenous electron donors monofunctional heme peroxidases can slowly degrade hydrogen peroxide following a mechanism different from monofunctional catalases. This pseudo-catalase cycle involves several redox intermediates including Compounds I, II and III, hydrogen peroxide reduc ... >> More

  In the absence of exogenous electron donors monofunctional heme peroxidases can slowly degrade hydrogen peroxide following a mechanism different from monofunctional catalases. This pseudo-catalase cycle involves several redox intermediates including Compounds I, II and III, hydrogen peroxide reduction and oxidation reactions as well as release of both dioxygen and superoxide. The rate of decay of oxyferrous complex determines the rate-limiting step and the enzymes' resistance to inactivation. Homologous bifunctional catalase-peroxidases (KatGs) are unique in having both a peroxidase and high hydrogen dismutation activity without inhibition reactions. It is demonstrated that KatGs follow a similar reaction pathway as monofunctional peroxidases, but use a unique post-translational distal modification (Met+-Tyr-Trp adduct) in close vicinity to the heme as radical site that enhances turnover of oxyferrous heme and avoids release of superoxide. Similarities and differences between monofunctional peroxidases and bifunctional KatGs are discussed and mechanisms of pseudo-catalase activity are proposed. << Less

  Arch Biochem Biophys 500:74-81(2010) [PubMed] [EuropePMC]