The role of hydroxyl radicals in irreversible inactivation of lactoperoxidase by excess H2O2

Jenzer, Herbert; Köhler, H.; Broger, Clemens

doi:10.1016/0003-9861(87)90359-6

Cited by 42 publications

(20 citation statements)

References 65 publications

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“…Oxidative modification by HOOH or lipid peroxides has been shown to inactivate various hemoproteins, including myoglobin (1-3), hemoglobin (1, 4), cytochrome P450 (5-8), prostaglandin H synthase (9, 10), catalase (11), myeloperoxidase (12), horseradish peroxidase (13), and lactoperoxidase (14,15). The mechanism by which this occurs is unknown, although it is generally thought to involve destruction of the heme moiety (1-8, 10, 14-19).…”

Section: Introductionmentioning

confidence: 99%

Oxidative modification by low levels of HOOH can transform myoglobin to an oxidase.

Osawa

Korzekwa

1991

Proc. Natl. Acad. Sci. U.S.A.

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It is generally thought that the oxidative modification of hemoproteins leads to their inactivation. In the current study, however, a transiently activated form of myoglobin was shown to be formed when the prosthetic heme group became covalently bound to the polypeptide during the reaction of myoglobin with low levels of HOOH. In the presence of an enzymatic metmyoglobin reducing system containing diaphorase and methylene blue with excess NADH, this HOOHaltered myoglobin catalyzed NADH oxidation and oxygen consumption; the overall stoichiometry indicated a twoelectron reduction of oxygen to HOOH. This reaction was not catalyzed by iron released from heme, as desferrioxamine had no effect on the activity. Stoichiometric amounts of HOOH were sufficient to produce the activated oxidase state of myoglobin, whereas larger amounts of HOOH lead to heme destruction, iron release, and inactivation of the oxidase activity.The alteration of myoglobin to an enzyme that can form toxic oxygen metabolites may have pathological importance, especially in myocardial injury caused by ischemia and reperfusion, where myoglobin is present in large amounts and HOOH is formed. Furthermore, the oxidase form may be involved in the mechanism of destruction of the heme seen with oxidative treatment of myoglobin.Oxidative modification by HOOH or lipid peroxides has been shown to inactivate various hemoproteins, including myoglobin (1-3), hemoglobin (1, 4), cytochrome P450 (5-8), prostaglandin H synthase (9, 10), catalase (11), myeloperoxidase (12), horseradish peroxidase (13), and lactoperoxidase (14,15). The mechanism by which this occurs is unknown, although it is generally thought to involve destruction of the heme moiety (1-8, 10, 14-19).We report, however, that treatment of myoglobin with 1-2.5 equivalents of HOOH results in crosslinking of an intact heme moiety to the protein and gives rise to an altered hemoprotein with oxidase activity. Inactivation occurs only when larger amounts of HOOH, which lead to multiple catalytic events, are used to treat myoglobin.MATERIALS AND METHODS Materials. Diaphorase was purchased from Sigma. Catalase was obtained from Fluka. Superoxide dismutase and NADH were purchased from Calbiochem. HOOH and methylene blue were from Fisher Scientific. Desferrioxamine mesylate was from Ciba. Sperm whale and horse heart myoglobin were obtained from United States Biochemical.Formation of Heme-Derived Adducts from the Reaction of HOOH with Myoglobin. In a previous study (20) on characterization of the protein-bound heme adduct, myoglobin was treated with HOOH at pH 4.7 or 7.4. We have found that HOOH treatment at either pH gives an altered myoglobin with oxidase activity. In this study only acidic conditions were used because these conditions more closely represent the environment of the myocardium under ischemia (21).Specifically, myoglobin (130 AM) was treated with HOOH (330 AM) in a total volume of 2.0 ml of 25 mM sodium acetate, pH 4.7, for 60 min at room temperature. The reaction mixture was placed on i...

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Section: Introductionmentioning

confidence: 99%

Oxidative modification by low levels of HOOH can transform myoglobin to an oxidase.

Osawa

Korzekwa

1991

Proc. Natl. Acad. Sci. U.S.A.

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“…However, observations that Cu,Zn-SOD and Fe-SOD but not Mn-SOD are oxidatively inactivated suggests that Fenton chemistry might occur in an enzyme active site; manganese cannot act as a Fenton catalyst (Beyer and Fridovich, 1987). The auto-inactivation of lactoperoxidase was proposed to involve heme iron in the ferrous state acting as a Fenton catalyst (Jenzer et al, 1987). It has been suggested (Hodgson and Fridovich, 1975;Matheson and Travis, 1985) that "free" OH• (formed external to the active site) is not responsible for inactivation of SOD and myeloperoxidase, but rather that either a caged OH• or a metal coordinated OH• (in the active site) causes inactivation of these enzymes.…”

Section: Discussionmentioning

confidence: 99%

“…We suggested that penta-coordinate ferrous heme in the active site is able to act as a Fenton catalyst in the conversion of H202 to OH•. Oxidative inactivation in other enzymes can involve OH• attack on an amino acid or the heme (Matheson and Travis, 1985;Beyer and Fridovich, 1987;Jenzer et al, 1987).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it was speculated that inactivation may be due to uncoupling of CYP1A and formation of ROS (White et al, 1997a). A number of enzymes (CYP2B, Cu,Zn-superoxide dismutase (SOD), Fe-SOD, lactoperoxidase, myeloperoxidase, xanthine oxidase) that use or produce H202 and that contain· a metal ion undergo oxidative auto-inactivation (Loosemore et al, 1980;Matheson and Travis, 1985;Beyer and Fridovich, 1987;Jenzer et al, 1987;Karuzina and Archakov, 1994).…”

Section: Introductionmentioning

confidence: 99%

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Involvement of Cytochrome P450 1A in the toxicity of aryl hydrocarbon receptor agonists : alteration arachidonic acid metabolism and production of reactive oxygen species

Schlezinger¹

1998

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“…Thus, Compound I11 should represent an inactive form of the enzyme. Compound 111 also has been implicated as a precursor to irreversible loss of activity of l a c t o p e r~x i d a s e .~~-~ Jenzer et al 44 consider lactoperoxidase Compound 111 to be a labile complex of ferrous heme iron and molecular oxygen. They propose that hydrogen peroxide displaces oxygen and reacts with the ferrous iron to form hydroxyl radical, which then reacts with the apoprotein in a manner leading to covalent binding of porphyrin and release of iron to solution.…”

Section: Peroxide-dependent Inactivationmentioning

confidence: 98%

Stability testing of ligninase and Mn‐peroxidase from Phanerochaete chrysosporium

Aitken

Irvine

1989

Biotech & Bioengineering

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The white-rot fungus Phanerochaete chrysosporium produces extracellular peroxidases (ligninase and Mn-peroxidase) believed to be involved in lignin degradation. These extracellular enzymes have also been implicated in the degradation of recalcitrant pollutants by the organism. Commercial application of ligninase has been proposed both for biomechanical pulping of wood and for wastewater treatment. In vitro stability of lignin degrading enzymes will be an important factor in determining both the economic and technical feasibility of application for industrial uses, and also will be critical in optimizing commercial production of the enzymes. The effects of a number of variables on in vitro stability of ligninase and Mn-peroxidase are presented in this paper. Thermal stability of ligninase was found to improve by increasing pH and by increasing enzyme concentration. For a fixed pH and enzyme concentration, ligninase stability was greatly enhanced in the presence of its substrate veratryl alcohol (3,4-dimethoxybenzyl alcohol). Ligninase also was found to be inactivated by hydrogen peroxide in a second-order process that is proposed to involve the formation of the unreactive peroxidase intermediate Compound III. Mn-peroxidase was less susceptible to inactivation by peroxide, which corresponds to observations by others that Compound III of Mn-peroxidase forms less readily than Compound III of ligninase.

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The role of hydroxyl radicals in irreversible inactivation of lactoperoxidase by excess H2O2

Cited by 42 publications

References 65 publications

Oxidative modification by low levels of HOOH can transform myoglobin to an oxidase.

Oxidative modification by low levels of HOOH can transform myoglobin to an oxidase.

Involvement of Cytochrome P450 1A in the toxicity of aryl hydrocarbon receptor agonists : alteration arachidonic acid metabolism and production of reactive oxygen species

Stability testing of ligninase and Mn‐peroxidase from Phanerochaete chrysosporium

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