Utilization Of Peroxide Research Articles

The Impact of Myeloperoxidase and Activated Macrophages on Metaphase II Mouse Oocyte Quality.

Myeloperoxidase (MPO), an abundant heme-containing enzyme present in neutrophils, monocytes, and macrophages, is produced in high levels during inflammation, and associated with poor reproductive outcomes. MPO is known to generate hypochlorous acid (HOCl), a damaging reactive oxygen species (ROS) utilizing hydrogen peroxide (H2O2) and chloride (Cl-). Here we investigate the effect of activated immune cells and MPO on oocyte quality. Mouse metaphase II oocytes were divided into the following groups: 1) Incubation with a catalytic amount of MPO (40 nM) for different incubation periods in the presence of 100 mM Cl- with and without H2O2 and with and without melatonin (100 μM), at 37°C (n = 648/648 total number of oocytes in each group for oocytes with and without cumulus cells); 2) Co-cultured with activated mouse peritoneal macrophage and neutrophils cells (1.0 x 106 cells/ml) in the absence and presence of melatonin (200 μM), an MPO inhibitor/ROS scavenger, for different incubation periods in HTF media, at 37°C (n = 200/200); 3) Untreated oocytes incubated for 4 hrs as controls (n = 73/64). Oocytes were then fixed, stained and scored based on the microtubule morphology and chromosomal alignment. All treatments were found to negatively affect oocyte quality in a time dependent fashion as compared to controls. In all cases the presence of cumulus cells offered no protection; however significant protection was offered by melatonin. Similar results were obtained with oocytes treated with neutrophils. This work provides a direct link between MPO and decreased oocyte quality. Therefore, strategies to decrease MPO mediated inflammation may influence reproductive outcomes.

Paper-based membraneless hydrogen peroxide fuel cell prepared by micro-fabrication

A paper-based membraneless single-compartment hydrogen peroxide power source prepared by micro-electromechanical systems (MEMS) technology is reported. The cell utilizes hydrogen peroxide as both fuel and oxidant in a low volume cell fabricated on paper. The fabrication method used is a simple method where precise, small-sized patterns are produced which include the hydrophilic paper bounded by hydrophobic resin. Open circuit potentials of 0.61 V and 0.32 V are achieved for the cells fabricated with Prussian Blue as the cathode and aluminium/nickel as the anode materials, respectively. The power produced by the cells is 0.81 mW cm−2 at 0.26 V and 0.38 mW cm−2 at 0.14 V, respectively, even after the cell is bent or distorted. Such a fuel cell provides an easily fabricated, environmentally friendly, flexible and cost saving power source. The cell may be integrated within a self-sustained diagnostic system to provide the on-demand power for future bio-sensing applications.

Hyaluronidase-incorporated hyaluronic acid–tyramine hydrogels for the sustained release of trastuzumab

We developed an injectable hydrogel system for the sustained release of protein drugs that incorporated both protein drugs and hyaluronidase. Trastuzumab and hyaluronidase were incorporated in hydrogels composed of hyaluronic acid–tyramine (HA–Tyr) conjugates through the enzymatic crosslinking utilizing hydrogen peroxide (H2O2) and horseradish peroxidase (HRP). Through electrostatic interactions with the HA, trastuzumab was retained in the hydrogel to minimize its burst release. Hyaluronidase was incorporated in the hydrogel to release trastuzumab from the hydrogels. The hydrogels were degraded and showed sustained release of trastuzumab in phosphate buffer over four weeks in vitro. Both the rates of drug release and gel degradation were controlled by the concentration of hyaluronidase. Trastuzumab released from the hydrogels inhibited the proliferation of BT-474 cells in vitro. In an animal model, the single subcutaneous injection of a mixture solution of HA–Tyr conjugates, H2O2, HRP, trastuzumab and hyaluronidase inhibited tumor growth significantly, whereas injection of trastuzumab alone at the same dose failed to do so. Compared to trastuzumab alone, the hyaluronidase-incorporated HA–Tyr hydrogels improved the pharmacokinetic profile of trastuzumab in the plasma of mice. Furthermore, they were fully degraded over two weeks, and the formation of fibrous capsules was not observed in mice.

과산화수소 제독 과정에서의 탄저균 전사체 분석

Decontamination of biological agents utilizes hydrogen peroxide(<TEX>$H_2O_2$</TEX>) for its effectiveness and safeness. Bacillus anthracis is a major target for <TEX>$H_2O_2$</TEX> decontamination. To assess the effect of <TEX>$H_2O_2$</TEX> on B. anthracis and identify biomarkers for decontamination, whole transcriptomic profiling of <TEX>$H_2O_2$</TEX>-treated B. anthracis was performed. Here we identified deregulation in stress response genes, transcription factors and cellular homeostasis genes. We also found that expression of antisense RNAs increased in B. anthracis during decontamination. We postulate that B. anthracis prioritizes survival and adaptation in response to <TEX>$H_2O_2$</TEX> treatment by changing its gene expression pattern.

Selective Photooxidation of a Mustard‐Gas Simulant Catalyzed by a Porphyrinic Metal–Organic Framework

AbstractThe photooxidation of a mustard‐gas simulant, 2‐chloroethyl ethyl sulfide (CEES), is studied using a porphyrin‐based metal–organic framework (MOF) catalyst. At room temperature and neutral pH value, singlet oxygen is generated by PCN‐222/MOF‐545 using an inexpensive and commercially available light‐emitting diode. The singlet oxygen produced by PCN‐222/MOF‐545 selectively oxidizes CEES to the comparatively nontoxic product 2‐chloroethyl ethyl sulfoxide (CEESO) without formation of the highly toxic sulfone product. In comparison to current methods, which utilize hydrogen peroxide as an oxidizing agent, this is a more realistic, convenient, and effective method for mustard‐gas detoxification.

Selective Photooxidation of a Mustard-Gas Simulant Catalyzed by a Porphyrinic Metal-Organic Framework.

The photooxidation of a mustard-gas simulant, 2-chloroethyl ethyl sulfide (CEES), is studied using a porphyrin-based metal-organic framework (MOF) catalyst. At room temperature and neutral pH value, singlet oxygen is generated by PCN-222/MOF-545 using an inexpensive and commercially available light-emitting diode. The singlet oxygen produced by PCN-222/MOF-545 selectively oxidizes CEES to the comparatively nontoxic product 2-chloroethyl ethyl sulfoxide (CEESO) without formation of the highly toxic sulfone product. In comparison to current methods, which utilize hydrogen peroxide as an oxidizing agent, this is a more realistic, convenient, and effective method for mustard-gas detoxification.

Ultra-high-throughput screening of an in vitro-synthesized horseradish peroxidase displayed on microbeads using cell sorter.

The C1a isoenzyme of horseradish peroxidase (HRP) is an industrially important heme-containing enzyme that utilizes hydrogen peroxide to oxidize a wide variety of inorganic and organic compounds for practical applications, including synthesis of fine chemicals, medical diagnostics, and bioremediation. To develop a ultra-high-throughput screening system for HRP, we successfully produced active HRP in an Escherichia coli cell-free protein synthesis system, by adding disulfide bond isomerase DsbC and optimizing the concentrations of hemin and calcium ions and the temperature. The biosynthesized HRP was fused with a single-chain Cro (scCro) DNA-binding tag at its N-terminal and C-terminal sites. The addition of the scCro-tag at both ends increased the solubility of the protein. Next, HRP and its fusion proteins were successfully synthesized in a water droplet emulsion by using hexadecane as the oil phase and SunSoft No. 818SK as the surfactant. HRP fusion proteins were displayed on microbeads attached with double-stranded DNA (containing the scCro binding sequence) via scCro-DNA interactions. The activities of the immobilized HRP fusion proteins were detected with a tyramide-based fluorogenic assay using flow cytometry. Moreover, a model microbead library containing wild type hrp (WT) and inactive mutant (MUT) genes was screened using fluorescence-activated cell-sorting, thus efficiently enriching the WT gene from the 1:100 (WT:MUT) library. The technique described here could serve as a novel platform for the ultra-high-throughput discovery of more useful HRP mutants and other heme-containing peroxidases.

The Dehaloperoxidase Paradox: How Nature Juggles Oxygen Transport, Peroxidase, and Peroxygenase Activities at a Single Heme Active Site

Dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata is the first oxygen-binding globin that possesses a biologically relevant peroxidase activity. The two known isoforms of DHP, A and B, have been shown to oxidize trihalophenols to dihaloquinones in a dehalogenation reaction that utilizes hydrogen peroxide as the oxidant. More recently, however, we have shown that DHP possesses both peroxygenase and oxidase activities using a new class of substrate, haloindoles, in addition to its previously identified O2-binding and peroxidase functions. Using 5-Br-indole as a representative substrate, the major monooxygenated products were found to be 5-Br-2-oxindole and 5-Br-3-oxindolenine. Isotope 18O-labeling studies confirmed that the oxygen atom incorporated was derived exclusively from H2 18O2, indicative of a previously unreported peroxygenase activity for DHP. Peroxygenase activity could be initiated from either the ferric or oxyferrous states with equivalent substrate conversion and product distribution. It was found that 5-Br-3-oxindole, a precursor of the product 5-Br-3-oxindolenine, readily reduced the ferric enzyme to the oxyferrous state, demonstrating an unusual product-driven reduction of the enzyme. As such, DHP returns to the globin-active oxyferrous form after peroxygenase activity ceases. Reactivity with 5-Br-3-oxindole in the absence of H2O2 also yielded 5,5’-Br2-indigo above the expected reaction stoichiometry under aerobic conditions, and O2-concentration studies demonstrated dioxygen consumption. Non-enzymatic and anaerobic controls both confirmed the requirements for DHP and molecular oxygen in the catalytic generation of 5,5’-Br2-indigo, and together suggest a newly identified oxidase activity for DHP. Preliminary data also suggest that DHP is able to catalyze the oxidation of 2,3-dimethylindole by a previously unreported oxygenase activity. The two major products were identified by HPLC and LC-MS analysis to be the dioxygenated product o-acetamidoacetophenone and the monooxygenated product 3-hydroxy-2,3-dimethylindole. Isotope labeling studies verified that the oxygen atom incorporation into the products were derived exclusively from molecular oxygen. Consistent with these results, the reaction did not proceed under anaerobic conditions, and was also decreased in the presence of radical scavengers. Our initial studies suggest that the observed radical-based oxygenase activity of DHP is reminiscent of lipoxygenase, a non-heme dioxygenase. The breadth of chemical reactivity demonstrated by DHP not only expands our current understanding of this multifunctional enzyme, but also highlights the plasticity of a single heme active site within a globin-fold to function as an oxygen-transport center, as a peroxidase for phenolic substrate oxidation, and as a peroxygenase for indolic substrate oxygenation. Figure 1

Kinetics, mechanistic and synergistic studies of Alpha lipoic acid with hydrogen peroxide

Alpha lipoic acid (ALA) holds redox behavior that was observed in the presence of different metals utilizing hydrogen peroxide (H2O2) as a strong oxidizing agent. The effects of different parameters like temperature, pH and concentrations were also monitored.ALA in the presence of hydrogen peroxide (H2O2) showed oxidation as well as degradation processes. To monitor the oxidation kinetics of ALA in the presence of different essential metals to find its reaction pathway using salt affect parameters.The redox behavior of Alpha lipoic acid (ALA) was found to be significant at pH ranging from 4 to 10, at 29°C in a given pseudo first order reaction conditions. The values of the rate constant in the presence of different essential metals such as Mo, Se, Co, Cr, Fe, and Zn were also obtained. Furthermore, synergistic effects were observed in the presence of Mo6+ and Fe2+ at all applied conditions.Activation energy of ALA oxidation is 36.7kJ whereas in the presence of Fe2+ its activation energy went up to 48kJ; however, in the presence of Mo6+ the activation energy drops to 18.3kJ. In the presence of Fe2+ and Mo6+ the synergistic effect works and its activation energy became 36.5kJ. The reaction mechanism was also proposed.

Disruption of heme-peptide covalent cross-linking in mammalian peroxidases by hypochlorous acid

Myeloperoxidase (MPO), lactoperoxidase (LPO) and eosinophil peroxidase (EPO) play a central role in oxidative damage in inflammatory disorders by utilizing hydrogen peroxide and halides/pseudo halides to generate the corresponding hypohalous acid. The catalytic sites of these enzymes contain a covalently modified heme group, which is tethered to the polypeptide chain at two ester linkages via the methyl group (MPO, EPO and LPO) and one sulfonium bond via the vinyl group (MPO only). Covalent cross-linking of the catalytic site heme to the polypeptide chain in peroxidases is thought to play a protective role, since it renders the heme moiety less susceptible to the oxidants generated by these enzymes. Mass-spectrometric analysis revealed the following possible pathways by which hypochlorous acid (HOCl) disrupts the heme-protein cross-linking: (1) the methyl-ester bond is cleaved to form an alcohol; (2) the alcohol group undergoes an oxygen elimination reaction via the formation of an aldehyde intermediate or undergoes a demethylation reaction to lose the terminal CH2 group; and (3) the oxidative cleavage of the vinyl-sulfonium linkage. Once the heme moiety is released it undergoes cleavage at the carbon-methyne bridge either along the δ–β or a α–γ axis to form different pyrrole derivatives. These results indicate that covalent cross-linking is not enough to protect the enzymes from HOCl mediated heme destruction and free iron release. Thus, the interactions of mammalian peroxidases with HOCl modulates their activity and sets a stage for initiation of the Fenton reaction, further perpetuating oxidative damage at sites of inflammation.

Effects of Hydrogen Peroxide on Foam Concrete Performances

This paper reports the effects of hydrogen peroxide in surface morphology, strength, density, thermal conductivity of foam concrete and hydrogen peroxide utilization efficiency. The results show that these foam concretes are new and innovative building materials with interesting properties: low mass density and high strength when the addition amount of hydrogen peroxide is in 5%~6% range. Responsible for these properties are the macro-and microporosity. Macropores are created by adding hydrogen peroxide in different addition amount. It is also found that the utilization efficiency of hydrogen peroxide is higher when the addition amount of hydrogen peroxide is in the range of 5%~6%.

Comparison of different solvents for isolation of antioxidant compounds of horseradish

Horseradish (Armoracia rusticana) is a perennial herb belonging to the Brassicaceae family and contains biologically active substances. Since horseradish has long been used as a spice for meat and fish products, the Food and Drug Administration (FDA) approved it as seasoning, spice, and flavoring and affirmed it as Generally Recognized As Safe (GRAS). Scientists are interested in horseradish because it is a rich source of peroxidase, a heme-containing enzyme that utilizes hydrogen peroxide to oxidize a wide variety of organic and inorganic compounds. Also horseradish is rich in other valuable substances – vitamins, minerals, phenolic compounds and also isothiocyanates. The aim of the current research was to determine best solvent for extraction of phenolic compounds from horseradish roots showing high antiradical activity. From horseradish roots were extracted with four different ratio of solvent: ethanol/ water (80/20, 70/30, 60/40, 50/50 v/v) using conventional methods and then concentrated to rotary evaporator. Preliminary tests showed that the best solvent ethanol/ water (80/20 v/v) solutions can be chosen.

Glutathione Peroxidase 7 Utilizes Hydrogen Peroxide Generated by Ero1α to Promote Oxidative Protein Folding

Ero1 flavoproteins catalyze oxidative folding in the endoplasmic reticulum (ER), consuming oxygen and generating hydrogen peroxide (H2O2). The ER-localized glutathione peroxidase 7 (GPx7) shows protein disulfide isomerase (PDI)-dependent peroxidase activity in vitro. Our work aims at identifying the physiological role of GPx7 in the Ero1α/PDI oxidative folding pathway and at dissecting the reaction mechanisms of GPx7. Our data show that GPx7 can utilize Ero1α-produced H2O2 to accelerate oxidative folding of substrates both in vitro and in vivo. H2O2 oxidizes Cys57 of GPx7 to sulfenic acid, which can be resolved by Cys86 to form an intramolecular disulfide bond. Both the disulfide form and sulfenic acid form of GPx7 can oxidize PDI for catalyzing oxidative folding. GPx7 prefers to interact with the a domain of PDI, and intramolecular cooperation between the two redox-active sites of PDI increases the activity of the Ero1α/GPx7/PDI triad. Our in vitro and in vivo evidence provides mechanistic insights into how cells consume potentially harmful H2O2 while optimizing oxidative protein folding via the Ero1α/GPx7/PDI triad. Cys57 can promote PDI oxidation in two ways, and Cys86 emerges as a novel noncanonical resolving cysteine. GPx7 promotes oxidative protein folding, directly utilizing Ero1α-generated H2O2 in the early secretory compartment. Thus, the Ero1α/GPx7/PDI triad generates two disulfide bonds and two H2O molecules at the expense of a single O2 molecule.

Biological Fenton’s Oxidation of Pentachlorophenol by Aquatic Plants

This study proposes a new treatment method to decompose persistent chemicals such as pentachlorophenol (PCP) in water, utilizing hydrogen peroxide present in aquatic plants to proceed the biological Fenton reaction. PCP was not effectively removed by aquatic plants. However, by adding 2.8mM of Fe(2+), there was a rapid removal of PCP while at the same time consumption of endogenous hydrogen peroxide occurred. It was observed the increase of chloride ions formation in water-confirming the complete degradation of PCP. These results demonstrated that PCP was oxidized through a biological Fenton reaction, and hydrogen peroxide in aquatic plants was a key endogenous substance in treatment of refractory toxic pollutants.

GW24-e2914 Involvement of vascular peroxidase 1 in the endothelial dysfunction in hypertension

ObjectivesVascular peroxidase 1 (VPO1) is a new heme-containing peroxidase, which can utilise hydrogen peroxide (H2O2) generated from co-expressed NADPH oxidase (NOX) to produce hypochlorous acid (HOCl) and catalyse peroxidative reactions....

GW24-e3020 Involvement of vascular peroxidase 1 in angiotensin II-induced H9c2 cells hypertrophy

ObjectivesOxidative stress induces hypertrophic gene expression and collagen deposition that mediates cardiac hypertrophy and myocardial fibrosis. Vascular peroxidase 1 (VPO1) is a new heme-containing peroxidase, which can utilise hydrogen peroxide...

GW24-e3078 Vascular peroxidase 1 is involved in pulmonary arterial hypertension via mediate pulmonary arterial smooth cells proliferation

ObjectivesHypoxia could induce pulmonary arterial smooth muscle cells (PASMCs) proliferation via hydrogen peroxide (H2O2)-induced oxidative stress. Our previous research had demonstrated that vascular peroxidase 1 (VPO1) could utilise hydrogen peroxide...

Novel Structured Catalysts for Hydrogen Peroxide Decomposition in Monopropellant and Hybrid Rockets

This paper describes the development of a novel catalytic system capable of decomposing hydrogen peroxide. The system is based on ceramic honeycombs in yttria-stabilized zirconia, with manganese oxides as the active phase. The effectiveness of different catalyst preparation procedures, entirely developed in house, has been evaluated using a plug-flow reactor operating with diluted hydrogen peroxide vapors. A monopropellant test bench has been then assembled to verify the performance of a selected number of catalytic samples in a test environment closer to the actual operating conditions of a space propulsion system: the catalysts have demonstrated decomposition efficiencies exceeding 90%. The concept has been finally scaled up to a hybrid configuration based on the utilization of hydrogen peroxide as the oxidizer and high-density polyethylene as the fuel: the possibility to ignite and reignite the fuel grain has been demonstrated and propulsive efficiencies close to 90% have been measured.

First Crystal Structure of a Fungal High-redox Potential Dye-decolorizing Peroxidase: SUBSTRATE INTERACTION SITES AND LONG-RANGE ELECTRON TRANSFER

Dye-decolorizing peroxidases (DyPs) belong to the large group of heme peroxidases. They utilize hydrogen peroxide to catalyze oxidations of various organic compounds. AauDyPI from Auricularia auricula-judae (fungi) was crystallized, and its crystal structure was determined at 2.1 Å resolution. The mostly helical structure also shows a β-sheet motif typical for DyPs and Cld (chlorite dismutase)-related structures and includes the complete polypeptide chain. At the distal side of the heme molecule, a flexible aspartate residue (Asp-168) plays a key role in catalysis. It guides incoming hydrogen peroxide toward the heme iron and mediates proton rearrangement in the process of Compound I formation. Afterward, its side chain changes its conformation, now pointing toward the protein backbone. We propose an extended functionality of Asp-168, which acts like a gatekeeper by altering the width of the heme cavity access channel. Chemical modifications of potentially redox-active amino acids show that a tyrosine is involved in substrate interaction. Using spin-trapping experiments, a transient radical on the surface-exposed Tyr-337 was identified as the oxidation site for bulky substrates. A possible long-range electron transfer pathway from the surface of the enzyme to the redox cofactor (heme) is discussed.

RECOMBINANT HORSERADISH PEROXIDASE FOR ANALYTICAL APPLICATIONS

86 Horseradish peroxidase isoenzyme C (HRP, EC 1.11.1.7), a hemeand Ca-contai ning glycoprotein, is a member of the superfa mily of plant peroxidases [1–3] that are able to utilize hydrogen peroxide to catalyze the one electron oxidation of a wide variety of organic and inorganic substrates. Whereas plant pe roxidases find interest for applications in va rious biotechnological processes, like bleaching and degradation of organic compounds (e.g. phenols and lignin), HRP specifically is used in analytical biochemistry and biotechnology as a marker enzyme for antibodies, DNA and low molecular mass analytes. Broad substrate specificity and high catalytic activity and stability determined the world-wide application of HRP in bioand immunosensors, chemiluminescent, fluorescent and electrochemical detection systems, DNA microarrays and biochips with HRP-based colori metric detection [4–6, 14, 56]. Progress made in peroxidase gene hetero logous expression opened up the prospect to study structure-function relationships by means of genetic engineering. The baculovirus expression system allowed production of recombinant HRP in soluble, active and glycosylated form [7], however, this system is laborious and not as wide spread as expression in E. coli. Expression of HRP in yeast indicated only very low expression of active enzyme [8]. Up to date for the production of wild-type as well as mutant recombinant HRP the E. coli expression system is mostly used [9, 10]. Recombinant HRP forms inclusion bodies containing only traces of heme if expressed in bacterial cytoplasm. Multistep refolding and reactivation of recombinant apo-peroxidase with the prosthetic heme group is complex as the protein contains four disulfide bonds and in addition must bind two Ca-ions per molecule. Moreover, the plant-derived enzyme contains 18% carbohydrates via 8 glycosylation sites. Crystal structure of recombinant HRP has been solved, revealing the presence of two domains formed by a total of ten α-helices [11]. Among of the factors leading to the formation of inclusion bodies upon expression of UDK 543.645.6:665.123