A cDNA for thylakoid-bound ascorbate peroxidase of pumpkin was cloned and characterized. Thylakoid-bound ascorbate peroxidase had a high similarity to cytosolic ascorbate peroxidases, and the precursor contained a transit peptide to chloroplasts at its ammo-terminus and a putative membrane-spanning region at its carboxy-terminus.. ...

The ionic strength dependence of the reduction of cytochrome c peroxidase compound I by horse cytochrome c has been studied, using stopped-flow technigue, in pH 7.5, potassium phosphate/nitrate buffer. The temperature was set at 25 ± 1° C. The wavelength was monitored at 4 32 nm, an isobestic point for ferri-/ferrocytochrome c, so only the absorbance change of the reduction of cytochrome c peroxidase compound I to compound II can be observed. The observed rate constant, kobs, as a function of the concentration of ferrocytochrome c shows a non-linear increase with increasing ionic strength. A two-parameter eguation is needed to fit the data at low ionic strength, 20 mM to 40 mM, while a three-parameter equation is needed at high ionic strength, 65 mM and above. The maximum rates of these reductions also show two different types of ionic strength dependence. At 20 mM to 40 mM ionic strength, the maximum rate of reduction decreases slightly, within experimental error, with increasing ionic ...

We previously demonstrated that manganese peroxidase from the white-rot fungus Phanerochaete chrysosporium was very susceptible to thermal inactivation due to the loss of calcium from the enzyme [Sutherland & Aust (1996) Arch. Biochem. Biophys. 332, 128-134]. The structural changes that occur during thermal inactivation and the release of calcium from manganese peroxidase have now been characterized. Thermal inactivation caused distinct alterations in the heme environment and slight changes in the overall protein structure, both of which were reversed upon reactivation of the enzyme with calcium. The absorption spectrum of inactivated manganese peroxidase was similar to that of low-spin ferric heme proteins, indicating that a sixth ligand had bound to the distal side of the heme iron. Consistent with disruption of the distal heme environment, thermally inactivated manganese peroxidase did not react with hydrogen peroxide to form compound I. The inactive enzyme exhibited a pH-dependent absorption

TY - JOUR. T1 - Crystal structure of lignin peroxidase. AU - Edwards, Steven L.. AU - Raag, Reetta. AU - Wariishi, Hiroyuki. AU - Gold, Michael H.. AU - Poulos, Thomas L.. PY - 1993/1/15. Y1 - 1993/1/15. N2 - The crystal structure of lignin peroxidase (LiP) from the basidiomycete Phanerochaete chrysosporium has been determined to 2.6 Å resolution by using multiple isomorphous replacement methods and simulated annealing refinement. Of the 343 residues, residues 3-335 have been accounted for in the electron density map, including four disulfide bonds. The overall three-dimensional structure is very similar to the only other peroxidase in this group for which a high-resolution crystal structure is available, cytochrome c peroxidase, despite the fact that the sequence identity is only ≈20%, LiP has four disulfide bonds, while cytochrome c peroxidase has none, and LiP is larger (343 vs. 294 residues). The basic helical fold and connectivity defined by 11 helical segments with the heme sandwiched ...

Species of the genus Pleurotus are among the most efficient natural species in lignin degradation belonging to the subclass of ligninolytic organisms that produce laccase (Lac), Mn-dependent peroxidase (MnP), versatile peroxidase (VP), and the H2O2-generating enzyme aryl-alcohol oxidase, but not lignin peroxidases. Production of Lac and oxidation of 2,6-dimethoxyphenol (DMP) in the presence and absence of Mn2+ were detected both in submerged fermentation (SF) of dry ground mandarine peels and in solid-state fermentation (SSF) of grapevine sawdust in all investigated Pleurotus species and strains. Evidence of cultivation methods having a distinct influence on the level of enzyme activities has been demonstrated. Most of the species and strains had higher Lac activity under SSF conditions than under SF conditions. DMP oxidation in the presence and absence of Mn2+ was detected in all investigated species and strains, but was lower under SF conditions than under SSF conditions for most of ...them. ...

Additional file 19: of Genome-wide and evolutionary analysis of the class III peroxidase gene family in wheat and Aegilops tauschii reveals that some members are involved in stress responses

Author(s): Smith, Martyn T.; Yager, J; Steinmetz, K; Eastmond, D | Abstract: The metabolism of two of benzenes phenolic metabolites, phenol and hydroquinone, by peroxidase enzymes has been studied in detail. Studies employing horseradish peroxidase and human myeloperoxidase have shown that in the presence of hydrogen peroxide phenol is converted to 4,4-diphenoquinone and other covalent binding metabolites, whereas hydroquinone is converted solely to 1,4-benzoquinone. Surprisingly, phenol stimulates the latter conversion rather than inhibiting it, an effect that may play a role in the in vivo myelotoxicity of benzene. Indeed, repeated coadministration of phenol and hydroquinone to B6C3F1 mice results in a dramatic and significant decrease in bone marrow cellularity similar to that observed following benzene exposure. A mechanism of benzene-induced myelotoxicity is therefore proposed in which the accumulation and interaction of phenol and hydroquinone in the bone marrow and the peroxidase-dependent

Mitochondrial swelling and membrane protein thiol oxidation associated with mitochondrial permeability transition induced by Ca2+ and inorganic phosphate are inhibited in a dose-dependent manner either by catalase, the thiol-specific antioxidant enzyme (TSA), a protein recently demonstrated to present thiol peroxidase activity, or ebselen, a selenium-containing heterocycle which also possesses thiol peroxidase activity. This inhibition of mitochondrial permeability transition is due to the removal of mitochondrial-generated H2O2, which can easily diffuse to the extramitochondrial space. Whereas ebselen required the presence of reduced glutathione as a reductant to grant its protective effect, TSA was fully reduced by mitochondrial components. Decrease in the oxygen concentration of the reaction medium also inhibits mitochondrial permeabilization and membrane protein thioloxidation, in a concentration-dependent manner. The results presented in this report confirm that mitochondrial permeability ...

Poole, L.B., and Ellis, H.R. (1996) Flavin-dependent alkyl hydroperoxide reductase from Salmonella typhimurium. 1. Purification and enzymatic activities of overexpressed AhpF and AhpC proteins. Biochemistry 35, 56-64. PDF of article Poole, L.B. (1996) Flavin-dependent alkyl hydroperoxide reductase from Salmonella typhimurium. 2. Cystine disulfides involved in catalysis of peroxide reduction. Biochemistry 35, 65-75. PDF of article Poole, L.B., Chae, H.Z., Flores, B.M., Reed, S.L., Rhee, S.G., and Torian, B.E. (1997) Peroxidase activity of a TSA-like antioxidant protein from a pathogenic amoeba. Free Radical Biol. Med. 23, 955-959. PDF of article Li Calzi, M., and Poole, L.B. (1997) Requirement for the two AhpF cystine disulfide centers in catalysis of peroxide reduction by alkyl hydroperoxide reductase. Biochemistry 36, 13357-13364. PDF of article Ellis, H. R., and Poole, L.B. (1997) Roles for the two cysteine residues of AhpC in catalysis of peroxide reduction by alkyl hydroperoxide reductase ...

1C8I: Direct binding of hydroxylamine to the heme iron of Arthromyces ramosus peroxidase. Substrate analogue that inhibits compound I formation in a competetive manner.

thyroid peroxidase - MedHelps thyroid peroxidase Center for Information, Symptoms, Resources, Treatments and Tools for thyroid peroxidase. Find thyroid peroxidase information, treatments for thyroid peroxidase and thyroid peroxidase symptoms.

Kangasjärvi, Saijaliisa; Lepistö, Anna; Hannikainen, Kati; Piippo, Mirva; Luomala, Eeva-Maria; Aro, Eva-Mari; Rintamäki, Eevi (2008 ...

Lactoperoxidase is a peroxidase enzyme secreted from mammary, salivary, and other mucosal glands that functions as a natural antibacterial agent. Lactoperoxidase is a member of the heme peroxidase family of enzymes. In humans, lactoperoxidase is encoded by the LPO gene. Lactoperoxidase catalyzes the oxidation of a number of inorganic and organic substrates by hydrogen peroxide. These substrates include bromide and iodide and therefore lactoperoxidase can be categorised as a haloperoxidase. Another important substrate is thiocyanate. The oxidized products produced through the action of this enzyme have potent bactericidal activities. Lactoperoxidase together with its inorganic ion substrates, hydrogen peroxide, and oxidized products is known as the lactoperoxidase system. The lactoperoxidase system plays an important role in the innate immune system by killing bacteria in milk and mucosal (linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion) ...

en] The cloning and sequencing of the rbpa gene coding for a versatile peroxidase from a novel Bjerkandera strain is hereby reported. The 1777 bp isolated fragment contained a 1698 bp peroxidase-encoding gene, interrupted by 11 introns. The 367 amino acid-deduced sequence includes a 27 amino acid-signal peptide. The molecular model, built via homology modelling with crystal structures of four fungal peroxidases, highlighted the amino acid residues putatively involved in manganese binding and aromatic substrate oxidation. The potential heme pocket residues (R44, F47, H48, E79, N85, H177, F194 and D239) include both distal and proximal histidines (H48 and H177). RBP possesses potential calcium-binding residues (D49, G67, D69, S71, S178, D195, T197, I200 and D202) and eight cysteine residues (C3, C15, C16, C35, C121, C250, C286, C316). In addition, RIBP includes residues involved in substrate oxidation: three acidic residues (E37, E41 and D183)-putatively involved in manganese binding and H83 and ...

A picture of substrate binding for small, aromatic substrates at the δ-heme edge emerged largely from chemical modification work (reviewed in [5,6,14,15]), although NMR also played an important role [16-23]. A few structures appeared at the end of the 1990s for horseradish peroxidase and Arthromyces ramosus peroxidase in complex with various small organic molecules [1-3], showing binding at the δ-heme edge, and there is now a collection of other crystal structures in which binding of various organic compounds has been observed at the same site (not all of which are genuine substrates) [1-3,12,13,24-27]. For CcP, there was a general consensus of opinion that small substrates were bound close to the δ-site [7,28-30]. The actual binding site for guaiacol has never been identified, although there is a report of phenol binding to an artificially created cavity in CcP [31].. In our structure, we observed guaiacol binding at two sites, close to Phe68 and Ile40. Guaiacol was not seen bound at the ...

TY - JOUR. T1 - Unfolding and pH studies on manganese peroxidase. T2 - Role of heme and calcium on secondary structure stability. AU - Banci, Lucia. AU - Bartalesi, Ilaria. AU - Ciofi-Baffoni, Simone. AU - Tien, Ming. PY - 2003/1/25. Y1 - 2003/1/25. N2 - The present study characterizes the unfolding and folding processes of recombinant manganese peroxidase. This enzyme contains five disulfide bonds, two calcium ions, and one heme prosthetic group. Circular dichroism in the far UV was used to monitor global changes of the protein secondary structure, whereas UV-visible spectroscopy of the Soret band provided information about local changes in the heme cavity. The effects of reducing agents, oxidizing agents, and denaturants on this process were investigated. In addition to affecting the secondary structure content, these factors also affect the binding of the heme and the calcium ions, both of which have a significant effect on the folding process. Our results also show that denaturants induce ...

Endogenous peroxidase activity has been demonstrated in sections of rat liver fixed briefly by glutaraldehyde perfusion and incubated in Graham and Karnovskys medium for cytochemical demonstration of peroxidase activity (29). In 25-40% of sinusoidal cells, an electron-opaque reaction product is localized in segments of the endoplasmic reticulum, including the perinuclear cisternae, a few Golgi vesicles and saccules and in some large membrane-bounded granules. This staining is abolished after prolonged fixation or boiling of tissue sections in glutaraldehyde, and in the absence of H2O2 or DAB from the incubation medium. Furthermore, the reaction is inhibited completely by sodium azide and high concentrations of H2O2, and partially by KCN and aminotriazole. Among the different cells in hepatic sinusoids, the nonphagocytic fat-storing cells (39) are always peroxidase negative, whereas the lining cells in process of erythrophagocytosis are consistently peroxidase positive. The possible biological ...

The plasma membrane-bound peroxidases (PRX) zmprx01, zmprx66 and zmprx70 and the respiratory burst oxidase homologs (RBOH) rbohA, rbohB, rbohC and rbohD were analysed in this study. The distribution of the genes inside the roots was investigated by real-time qPCR. Therefor four different segments (root tip, elongation zone, differentiation zone and lateral roots) were in focus of the analyses. It could be observed that the genes are differently distributed in the root. The peroxidases were predominantly expressed in the elongation zone and almost not in the root tip. The rboh genes were more inhomogeneous distributed. For each RBOH a specific expression pattern could be detected. rbohA was mostly expressed in the differentiation zone. rbohB was more even expressed in the root. rbohC was even distributed as well but predominantly in the elongation zone. rbohD was mostly expressed in the differentiation zone. For a further investigation of the peroxidases plants were exposed to cadmium (short term and

Reactive oxygen species (ROS), such as O2 and H2O2, play a key role in plant metabolism, cellular signaling, and defense. In leaf cells, the chloroplast is considered to be a focal point of ROS metabolism. It is a major producer of O2 and H2O2 during photosynthesis, and it contains a large array of ROS-scavenging mechanisms that have been extensively studied. By contrast, the function of the cytosolic ROS-scavenging mechanisms of leaf cells is largely unknown. In this study, we demonstrate that in the absence of the cytosolic H2O2-scavenging enzyme ascorbate peroxidase 1 (APX1), the entire chloroplastic H2O2-scavenging system of Arabidopsis thaliana collapses, H2O2 levels increase, and protein oxidation occurs. We further identify specific proteins oxidized in APX1-deficient plants and characterize the signaling events that ensue in knockout-Apx1 plants in response to a moderate level of light stress. Using a dominant-negative approach, we demonstrate that heat shock transcription factors play a ...

A dye-decolorizing peroxidase (DyP) from Pleurotus ostreatus (PosDyP4) catalyzes the oxidation of Mn2+ to Mn3+, in the presence of H2O2, with an efficiency similar to the well-known manganese peroxidases and versatile peroxidases from this and other white-rot fungi. PosDyP4 has been overexpressed in Escherichia coli as an active enzyme, and its crystal structure has been solved at 1.56 Å resolution. A combination of substrate diffusion simulations on the solved structure using the PELE software, electron paramagnetic resonance, and site-directed mutagenesis led to identification of the residues involved in Mn2+ oxidation. The oxidation site in PosDyP4 is different than the conserved site in the other Mn-oxidizing peroxidases mentioned above, and it includes four acidic residues (three aspartates and one glutamate) located at the surface of the protein. Moreover, since the Mn2+ ion is not in direct contact with the heme propionates, a tyrosine residue participates in the electron transfer to the ...

The basidiomycete isolate b19, originally identified by morphological characteristics of the fruiting body as Nematoloma frowardii, efficiently produces manganese peroxidase (MNP) and is used for degradation of natural, persistent aromatic polymers (lignin, humic acids and brown coal components). The N. frowardii MNP has shown good activity in conversion of xenobiotic compounds such as polycyclic hydrocarbons and trinitrotoluene. However, this biotechnologically promising fungus has not previously been studied at the molecular biology level. We show here that according to the molecular characterization of its main MNP isozyme, Nf b19 MNP2, and partial sequencing of its MNP3-, three lignin peroxidase- and two laccase-encoding genes, and the gene encoding the ribosomal SSU 18S RNA, that the fungus has a close phylogenetic relationship to the white-rot basidiomycete Phlebia radiata (Fr.). Ribosomal internal transcribed spacer (ITS) sequence (ITS1+5.8S+ITS2) phylogeny reclassifies Nf b19 as a possible

TY - JOUR. T1 - Metal free MoS2 2D sheets as a peroxidase enzyme and visible-light-induced photocatalyst towards detection and reduction of Cr(vi) ions. AU - Borthakur, Priyakshree. AU - Boruah, Purna K.. AU - Das, Manash R.. AU - Artemkina, Sofya B.. AU - Poltarak, Pavel A.. AU - Fedorov, Vladimir E.. PY - 2018/10/21. Y1 - 2018/10/21. N2 - Two-dimensional molybdenum disulphide (MoS2) sheets were prepared by using simple thermal decomposition method. The synthesized sheets were characterized by different analytical tools including FTIR, XRD, XPS, Raman spectroscopy, HRTEM and FESEM analyses. The synthesized sheets exhibited outstanding peroxidase mimicking activity towards the peroxidase oxidation of chromogenic probe molecule 3,3′,5,5′-tetramethyl benzidine (TMB), producing a blue coloured solution of 3,3′,5,5′-tetramethylbenzidine diimine (TMBDI) in an acidic medium (pH 4). Based on this peroxidase mimicking activity it was utilized for colorimetric determination of toxic Cr(vi) ions ...

In this study, we sought to determine whether the increases in peroxidase activity and electrolyte leakage induced in maize (Zea mays L.) leaves by sodium bisulfite were causally related to the sodium bisulfite-induced increases in sporulation of the pathogen Bipolaris maydis race T on infected maize leaves. Pretreatment of detached leaves of maize inbred W64 A with sodium bisulfite (500 ,ig/ml) for 24 h in the dark at 28°C increased peroxidase activity in the Tms cytoplasm (susceptible) isoline compared with the N cytoplasm (resistant) isoline. No such differences in peroxidase activity between the two isolines were observed when detached leaves were pretreated with double distilled water. The sodium bisulfite-induced increase in peroxidase activity persisted even when leaves pretreated with sodium bisulfite were inoculated with R maydis race T and subsequently incubated for 48 h in the dark at 28° C. Similarly, pretreatment with sodium bisulfite caused a greater increase in electrolyte ...

The ability of plant cells cultivated ,i,in vitro,/i, to metabolize polychlorinated biphenyls (PCBs) was correlated with the morphology of the cultures tested as models for phytoremediation studies. More differentiated cultures showed generally higher transformation capacity. The ability of plant cells to transform PCBs is connected to their viability in the presence of PCBs and their behaviour can be positively correlated with the production of intracellular and extracellular peroxidases. The cultures with high PCB-transforming activity proved to exhibit high peroxidase activity in the presence of PCBs while those with low ability to metabolize PCB showed a decrease of the enzyme activity in the presence of PCBs. Experiments with propylgallate were used to distinguish the ratio of involvement of peroxidases in PCB metabolism. ,p, ...

The protein encoded by this gene is an antioxidant enzyme and belongs to the peroxiredoxin family. The protein is localized to the cytoplasm. Peroxidases of the peroxiredoxin family reduce hydrogen peroxide and alkyl hydroperoxides to water and alcohol with the use of reducing equivalents derived from thiol-containing donor molecules. This protein has been found to play a regulatory role in the activation of the transcription factor NF-kappaB.

Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides.

The surface oxidation site (Trp171) in lignin peroxidase (LiP) which is specific for the reaction with the high redox potential substrate, veratryl alcohol (1.4 V), had been previously engineered in a heme peroxidase that has similar protein fold but lacks this activity. The new Trp site was engineered by introducing a Trp residue in the coprinus cinereus peroxidase (CiP) at the equivalent position to that of the Trp171 in LiP. In order to induce the catalytic activity towards veratryl alcohol in CiP, it was also necessary to reproduce the naturally-occurring negatively-charged microenvironment of the Trp site. Multifrequency EPR spectroscopy characterization of the D179W+R258E+R272D variant of CiP unequivocally showed that, upon reaction of the enzyme with hydrogen peroxide a new Trp radical (g-values of gx = 2.0035(5), gy = 2.0027(5) and gz = 2.0022(1)) was formed after the [Fe(IV)=O Por+] intermediate, as a result of intramolecular electron transfer between Trp179 and the porphyrin. The EPR ...

1CCP: X-ray structures of recombinant yeast cytochrome c peroxidase and three heme-cleft mutants prepared by site-directed mutagenesis.

Article Evaluation of manganese peroxidase (MnP) for its ability to resist the ozonization and thereafter decolorize methyl orange. The goal of this study was to determine whether ozone can be used to suppress bacterial growth in operating a white ro...

Suspension culture of compact callus aggregates (CCA) of Daucus carota (carrot), consisting of yellow, spherical cellular clumps displaying tissue differentiation was established. The production of peroxidase which was detected in trace amounts in dispersed carrot cell cultures was found in high amounts (5.0-14.5 U g(-1) FW) in CCA cultures. Kinetics analysis showed that CCA grew quickly for 4-12 days with a specific growth rate of 0.20 day(-1), while the peroxidase activity increased sharply after day 12. Fungal elicitors were found to effectively induce peroxidase synthesis. Peroxidase activity of 54.0 U g(-1) FW was obtained by adding Aspergillus niger elicitor at day 16 to make its concentration in medium 50 mg l(-1). (C) 1998 Elsevier Science B.V. All rights reserved.; Suspension culture of compact callus aggregates (CCA) of Daucus carota (carrot), consisting of yellow, spherical cellular clumps displaying tissue differentiation was established. The production of peroxidase which was ...

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The effect of NaCl on total peroxidase activity, induction of isoperoxidases and lipid peroxidation in 5-day-old seedlings of two contrasting genotypes of Setaria italica L. (Prasad, a salt tolerant cultivar and Lepakshi, a salt susceptible cultivar), was studied. Total peroxidase activity increased under NaCl salinity and the degree of elevation in the activity was salt concentration dependent. Nevertheless, a greater activity was recorded in the tolerant cultivar (cv Prasad) compared to the susceptible (cv Lepakshi) one in all days of sampling. Further, the pattern of isoperoxidases was modified during stress conditions as evident from the electrophoregrams. Although, five acidic isoforms were detected in both cultivars, differences were found between the cultivars. Furthermore, it was observed that acidic isoperoxidases were strongly expressed and an acidic isoperoxidase, A(3p) (27 kDa) is specifically found in the tolerant cultivar (cv Prasad) under NaCl stress. This isoform was partially ...

TY - JOUR. T1 - Structure-function studies of cytochrome c peroxidase from ps. nautica. AU - Alves, T.. AU - Besson, S.. AU - Pereira, A. S.. AU - Pettigrew, G. W.. AU - Moura, José J. G.. AU - Moura, I.. PY - 2001/8. Y1 - 2001/8. M3 - Meeting Abstract. VL - 86. SP - 122. EP - 122. JO - Journal of Inorganic Biochemistry. JF - Journal of Inorganic Biochemistry. SN - 0162-0134. IS - 1. ER - ...

297283835 - EP 0898620 B1 2002-11-06 - ASSAY OF PEROXIDASE ACTIVITY - [origin: WO9739142A1] Chemiluminescent detection of molecules of synthetic or natural origin such as proteins and nucleic acids (DNA and RNA), as well as other biologic molecules, is increasingly replacing radioactive detection as the method of choice where sensitivity is critical. In such assays, luminescence is customarily achieved by the oxidation of a luminol or isoluminol substrate in the presence of an oxidizing agent such as hydrogen peroxide or hydrogen peroxide source, such as perborate, and a peroxidase catalyst such as horseradish peroxidase. To obtain useful levels of luminescence (e.g., detectable levels) by customary techniques, a luminescent enhancer is also present during oxidation. It has been found in the practice of the present invention that azine enhancers have contained an impurity which reduces the properties of the chemiluminescent assay working solutions. The present invention describes a working solution, a

Cold acclimation in woody perennials is a metabolically intensive process, but coincides with environmental conditions that are not conducive to the generation of energy through photosynthesis. While the negative effects of low temperatures on the photosynthetic apparatus during winter have been well studied, less is known about how this is reflected at the level of gene and metabolite expression, nor how the plant generates primary metabolites needed for adaptive processes during autumn. The MapMan tool revealed enrichment of the expression of genes related to mitochondrial function, antioxidant and associated regulatory activity, while changes in metabolite levels over the time course were consistent with the gene expression patterns observed. Genes related to thylakoid function were down-regulated as expected, with the exception of plastid targeted specific antioxidant gene products such as thylakoid-bound ascorbate peroxidase, components of the reactive oxygen species scavenging cycle, and the

Cold acclimation in woody perennials is a metabolically intensive process, but coincides with environmental conditions that are not conducive to the generation of energy through photosynthesis. While the negative effects of low temperatures on the photosynthetic apparatus during winter have been well studied, less is known about how this is reflected at the level of gene and metabolite expression, nor how the plant generates primary metabolites needed for adaptive processes during autumn. The MapMan tool revealed enrichment of the expression of genes related to mitochondrial function, antioxidant and associated regulatory activity, while changes in metabolite levels over the time course were consistent with the gene expression patterns observed. Genes related to thylakoid function were down-regulated as expected, with the exception of plastid targeted specific antioxidant gene products such as thylakoid-bound ascorbate peroxidase, components of the reactive oxygen species scavenging cycle, and the

Catalase-peroxidases are bifunctional enzymes that catalyze the removal of hydrogen peroxide by two distinct pathways (catalase and peroxidase). They are central to antibiotic resistance in Mycobacterium tuberculosis and may be virulence factors in several dangerous human pathogens. These enzymes also hold much promise for engineering new enzymes to combat long-standing problems (e.g., environmental contamination by toxic pollutants). Currently, understanding of catalase-peroxidase structure and function is lacking to facilitate new drug development and enzyme engineering. The purpose of the research described in this dissertation is to understand the molecular basis for the unique catalytic abilities of catalase-peroxidases to fully capitalize on their potential. The versatile catalytic abilities of these enzymes arise from an active site that is normally restricted to one activity (i.e., peroxidase). This is facilitated by three structures which are quite distant from the active site: a ...

peroxidase and IAA oxidase activities. Protein concentration was determined by the method of Bradford (1976) using bovine serum albumin (BSA) as protein standard.. IAA oxidase assay IAA oxidase activity was measured by the spectrophotometric method described by Beffa et al. (1990). Reaction mixtures contained 0.76 ml of 50 mM phosphate buffer (KH2PO4/Na2HPO4, pH 6.0), 0.01 ml of 5 mM MnCl2, 0.01 ml of 5 mM 2,4-dichlorophenol (DCP), 0.02 ml of 14.3 mM IAA and 0.2 ml of enzyme extract. The final volume of the reaction mixtures was 1 ml. Assays were conducted at 25.0 0.5 C for 1 h. Salkowski reagent was used to determine IAA destruction at the wavelength of 535 nm after 1 h. One unit of IAA oxidase activity is equivalent to a DA535 of 1.0 for 1 mg of protein in 1 h. Each value represented the mean of three replicates.. Peroxidase assay Peroxidase (EC 1.11.1.7) activity was determined spectrophotometrically by measuring the increase in absorbance at 470 nm after 30 min incubation at 30.0 0.5 C ...

The report gives the research-based overview of on Global Horseradish Peroxidase (HRP) Market 2019 size, industry status and forecast, competition landscape and growth opportunity. This research report categorizes the global horseradish peroxidase (hrp) market by companies, region, type and end-use industry. It als...

Activity of ascorbate peroxidase (APX) (A), glutathione reductase (GR) (B), dehydroascorbate reductase (DR) (C), and monodehydroascorbate reductase (MR) (D) in

Anti-Mouse IgG3 (Gamma 3 chain) (Peroxidase Conjugated) Secondary Antibody, Rabbit Polyclonal, Peroxidase (Horseradish) validated in WB, E, IC (ASR3057), Abgent

Anti-Human IgG (gamma chain) (Peroxidase Conjugated) Secondary Antibody, Rabbit Polyclonal, Peroxidase (Horseradish) validated in WB, E, IC (ASR3050), Abgent

GPX1 encodes a member of the glutathione peroxidase family, which contains important antioxidant enzymes and helps detoxify hydrogen peroxide with glutathione, and thereby protect cells against oxidative damage (R). It protects the hemoglobin in red blood cells from oxidative breakdown.. H2O2 is also essential for growth-factor mediated signal transduction, mitochondrial function, and maintenance of antioxidant balance; therefore, by limiting H2O2 accumulation, glutathione peroxidases are also involved in modulating these processes.. It is also a selenoprotein, requiring selenium to function.. Associated with risk for breast cancer (R). ...

Eosinophil peroxidase is an enzyme found within the eosinophil granulocytes, innate immune cells of humans and mammals. This oxidoreductase protein is encoded by the gene EPX, expressed within these myeloid cells. EPO shares many similarities with its orthologous peroxidases, myeloperoxidase (MPO), lactoperoxidase (LPO), and thyroid peroxidase (TPO). The protein is concentrated in secretory granules within eosinophils. Eosinophil peroxidase is a heme peroxidase, its activities including the oxidation of halide ions to bacteriocidal reactive oxygen species, the cationic disruption of bacterial cell walls, and the post-translational modification of protein amino acid residues. The major function of eosinophil peroxidase is to catalyze the formation of hypohalous acids from hydrogen peroxide and halide ions in solution. For example: H2O2 + Cl− → HOCl + H2O Hypohalous acids formed from halides or pseudohalides are potent oxidizing agents. The open reading frame of human eosinophil peroxidase was ...

TY - JOUR. T1 - Oxidation of 1,2,4,5-tetramethoxybenzene by lignin peroxidase of Phanerochaete chrysosporium. AU - Koduri, Rao S.. AU - Whitwam, Ross E.. AU - Barr, David. AU - Aust, Steven D.. AU - Tien, Ming. PY - 1996/2/15. Y1 - 1996/2/15. N2 - We have reinvestigated the lignin peroxidase-catalyzed oxidation of 1,2,4,5-tetramethoxybenzene (TMB) by using presteady-state and steady-state kinetic methods. Our presteady-state kinetic results show that the reaction of compound I with TMB obeyed second order kinetics with a rate constant of 1.1 x 107 M-1 s-1. The reaction of compound II with TMB exhibits a hyperbolic concentration dependence with a K(d) of 16 μM and k = 24 s-1. The stoichiometry of TMB oxidation during steady state is two TMB cation radicals formed per H2O2 consumed. These results clearly show that TMB is a good substrate for both compounds I and II of lignin peroxidase.. AB - We have reinvestigated the lignin peroxidase-catalyzed oxidation of 1,2,4,5-tetramethoxybenzene (TMB) by ...

TY - JOUR. T1 - Human myeloperoxidase and thyroid peroxidase, two enzymes with separate and distinct physiological functions, are evolutionarily related members of the same gene family. AU - Kimura, Shioko. AU - Ikeda-Saito, Masao. PY - 1988/1/1. Y1 - 1988/1/1. N2 - Human myeloperoxidase and human thyroid peroxidase nucleotide and amino acid sequences were compared. The global similarities of the nucleotide and amino acid sequences are 46% and 44%, respectively. These similarities are most evident within the coding sequence, especially that encoding the myeloperoxidase functional subunits. These results clearly indicate that myeloperoxidase and thyroid peroxidase are members of the same gene family and diverged from a common ancestral gene. The residues at 416 in myeloperoxidase and 407 in thyroid peroxidase were estimated as possible candidates for the proximal histidine residues that link to the iron centers of the enzymes. The primary structures around these histidine residues were compared ...

Peroxiredoxins are ubiquitously expressed proteins that reduce hydroperoxides using disulfur-reducing compounds as electron donors. Peroxiredoxins (Prxs) have been classified in two groups dependent on the presence of either one (1-Cys Prx) or two (2-Cys Prx) conserved cysteine residues. Moreover, 2-Cys Prxs, also named thioredoxin peroxidases, have peroxide reductase activity with the use of thioredoxin as biological electron donor. However, the biological reducing agent for the 1-Cys Prx has not yet been identified. We report here the characterization of a 1-Cys Prx from yeast Saccharomyces cerevisiae that we have named Prx1p. Prx1p is located in mitochondria, and it is overexpressed when cells use the respiratory pathway, as well as in response to oxidative stress conditions. We show also that Prx1p has peroxide reductase activity in vitro using the yeast mitochondrial thioredoxin system as electron donor. In addition, a mutated form of Prx1p containing the absolutely conserved cysteine as ...

Peroxidase (E.C. 1.11.1.7., hydrogen donor oxidoreductase) is widely distributed and has been isolated from many higher plants (1). The wide distribution of the enzyme suggests that it could be of great biological importance. However the role that it plays in metabolism is not clear due to the large number of reactions it catalyzes and the considerable number of isozymic species (2). In tomato plants, Evans and Aldridge (3) separated out six isoperoxidases and in a later paper Evans reported 12 isoperoxidases from tomato shoots (4). A homogeneous tomato fruit peroxidase isozyme was obtained by Jen et al. (5) using hydrophobic chromatography. Isozymes were not detected in Euphorbia characias peroxidase (6), in Ipomoea batatas peroxidase (7) and in Hordeum vulgare peroxidase (8). The simultaneous presence of Cu (II) amine oxidase and peroxidase in cell walls suggests that the peroxide generated on oxidation of the amines could be utilized by the peroxidase (6,8,9). In the graminea Oryza sativa, ...

Mono- and Stereopictres of 5.0 Angstrom coordination sphere of Arsenic atom in PDB 3fmu: Crystal Structure Analysis of Fungal Versatile Peroxidase From Pleurotus Eryngii

Lignin decomposition involves a series of enzymes that oxidize phenolic] and non-phenolic lignin units. The first step in lignin decomposition produces aromatic radicals by oxidizing the lignin polymer. Laccases and lignin peroxidases (e.g. lignin peroxidase, manganese peroxidase) are extracellular enzymes involved in this first step. Laccases directly oxidize phenolic lignin units using molecular oxygen. However, phenolic lignin units comprise less than 10% of the lignin polymer, with non-phenolic units making up to 90% of the polymer. Lignin peroxidase (LiP) degrades non-phenolic lignin units by first being oxidized by hydrogen peroxide (H2O2), then oxidizing aromatic nuclei of soluble lignin units. LiP can be recycled through oxidation by H2O2. The oxidized aromatic radical species are further involved in non-enzymatic radical reactions resulting in polymer cleavages[1][8]. Manganese peroxidase (MnP) oxidizes Mn2+ to Mn3+, Mn2+ being a commonly available element in soils and ...

Different peroxidases, including 2-cysteine (2-Cys) peroxiredoxins (PRXs) and thylakoid ascorbate peroxidase (tAPX), have been proposed to be involved in the water-water cycle (WWC) and hydrogen peroxide (H2O2)-mediated signaling in plastids. We generated an Arabidopsis (Arabidopsis thaliana) double-mutant line deficient in the two plastid 2-Cys PRXs (2-Cys PRX A and B, 2cpa 2cpb) and a triple mutant deficient in 2-Cys PRXs and tAPX (2cpa 2cpb tapx). In contrast to wild-type and tapx single-knockout plants, 2cpa 2cpb double-knockout plants showed an impairment of photosynthetic efficiency and became photobleached under high light (HL) growth conditions. In addition, double-mutant plants also generated elevated levels of superoxide anion radicals, H2O2, and carbonylated proteins but lacked anthocyanin accumulation under HL stress conditions. Under HL conditions, 2-Cys PRXs seem to be essential in maintaining the WWC, whereas tAPX is dispensable. By comparison, this HL-sensitive phenotype was more ...

The reactivity of potassium fluoride with wild-type cytochrome c peroxidase (CcP) and a mutant of cytochrome c peroxidase in which the distal histidine (His-52) is replaced with leucine [CcP(H52L)] has been studied from pH 4 to 8 in phosphate buffer at 0.1 M ionic strength. The spectrum of the fluoride complex of CcP(H52L) has been characterized. The kinetics of fluoride binding and the equilibrium constant for complex formation for both wild-type CcP and CcP(H52L) have been determined as a function of pH. The results of this study indicate that HF binds to wild-type CcP when the distal histidine is unprotonated. However, the association rate constant for fluoride binding to CcP(H52L) is only a factor of ten slower than binding to CcP at pH 5.5 and about the same at pH 8.0. A possible explanation is that another group, such as Arg-48 or the heme-bound hydroxide group in CcP(H52L), provides a function similar to that of His-52 in wild-type CcP. A major effect of the H52L mutation is to increase ...

An eco-friendly treatment of industrial effluents is a major environmental concern of the modern world in the face of stringent environmental legislations. By keeping in mind the extensive industrial applications of ligninolytic enzymes, this study was performed to purify, and immobilize the manganese peroxidase (MnP) produced from an indigenous strain of Ganoderma lucidum. The present study was also focused on investigating the capability of immobilized MnP for decolorization of dye containing textile effluents. A large magnitude of an indigenous MnP (882±13.3 U/mL) was obtained from white rot fungal strain G. lucidum in solid state bio-processing of wheat straw under optimized fermentation conditions (moisture, 50%; substrate, 5 g; pH, 5.5; temperature, 30°C; carbon source, 2% fructose; nitrogen source, 0.02% yeast extract; C: N ratio, 25:1; fungal spore suspension, 5 mL and fermentation time period, 4 days). After ammonium sulfate fractionation and Sephadex-G-100 gel filtration chromatography, MnP

TY - JOUR. T1 - Cross-linking of tyrosine-containing peptides by hydrogen peroxide-activated Coprinus Cinereus peroxidase. AU - Steffensen, C.L.. AU - Mattinen, Maija-Liisa. AU - Andersen, Henrik Jørgen. AU - Kruus, Kristiina. AU - Buchert, Johanna. AU - Holm Nielsen, Jacob. PY - 2008. Y1 - 2008. N2 - Hydrogen peroxide-activated Coprinus Cinereus peroxidase (CIP) can initiate polymerization of tyrosine-containing peptides via initial formation of an intermediate tyrosyl radical, which for the first time has been identified by spin trap electron spin resonance spectroscopy as located on carbon 1 in the aromatic ring, and subsequent formation of either dityrosine or isodityrosine bonds through a net elimination of two hydrogen atoms between peptides. The rate and degree of polymerization were found to depend on peptide size and the amino acid adjacent to tyrosine, as longer peptides and amino acids with bulky side groups were less reactive. In the forwarded hypothesis for the reaction mechanism ...

The worldwide Horseradish Peroxidase (HRP) market statistical surveying report is an inescapable research report that contacts the most imperative parts of the Horseradish Peroxidase (HRP) platform that is important to be gotten a handle on by an expert or even a layman. The research covers the current market size of the Global Horseradish Peroxidase (HRP) market and its growth rates based on 5 year history data along with company profile of key players/manufacturers such as TOYOBO, Merck Millipore, Thermo Fisher, BBI Solutions, Enzybel International, Creative Enzymes, Yacoo, Xueman, Worthington, Starbio, Scripps Laboratories. The statistical surveying report illuminates one with respect to few of the imperative perspectives, for example, an outline of the Horseradish Peroxidase (HRP) item, the development factors improving or hampering its advancement, application in the different fields, major ruling organizations, veritable certainties, monetary circumstance, and topographical examination. ...

The binding of substrates to heme enzymes has been widely assumed to occur at the so-called delta-heme edge. Recently, however, a number of examples have appeared in which substrate binding at an alternative site, the gamma-heme edge, is also possible. In previous work [Sharp et al. (2003) Nat. Struct. Biol. 10, 303-307], we showed that binding of ascorbate to ascorbate peroxidase occurred at the gamma-heme edge. Here, we show that the closely related cytochrome c peroxidase enzyme can duplicate the substrate binding properties of ascorbate peroxidase through the introduction of relatively modest structural changes at Tyr36 and Asn184. Hence, crystallographic data for the Y36A/N184R/W191F triple variant of cytochrome c peroxidase shows ascorbate bound to the gamma-heme edge, with hydrogen bonds to the heme propionate and Arg184. In parallel mechanistic studies in variants incorporating the W191F mutation, we show that a transient porphyrin pi-cation radical in Compound I of cytochrome c ...

Ascorbate peroxidase (APX) is known to catalyze the reduction of H2O2 to water and enhance plants tolerance in stress environment. An ascorbate peroxidase protein (BnAPX) was previously isolated from Brassica napus in our laboratory and it was located in the chloroplast. In order to clarify the physiological function of BnAPX in plant response to photooxidative stress, 1562 bp upstream sequence of BnAPX was isolated by genomic walking and searched for cis-element by PROMOTER SCAN software and PLANTCARE website. Many light-responsive cis-elements were revealed in this prediction. Promoter activity analysis of this sequence was operated by transient expression in B. napus protoplasts. Results of promoter deletion analysis indicated that the core promoter element lied in 0.3 kb of BnAPX 5-flanking region. Moreover, our data showed that promoter of BnAPX could be activated by light.. Key words: BnAPX, H2O2, promoter analysis, transient expression, genomic walking, 5-flanking region.. ...

Textile industry represents one prevalent activity worldwide, generating large amounts of highly contaminated and rich in azo dyes wastewater, with severe effects on natural ecosystems and public health. However, an effective and environmentally friendly treatment method has not yet been implemented, while concurrently, the increasing demand of modern societies for adequate and sustainable energy supply still remains a global challenge. Under this scope, the purpose of the present study was to isolate promising species of yeasts inhabiting wood-feeding termite guts, for combined azo dyes and textile wastewater bioremediation, along with biodiesel production. Thirty-eight yeast strains were isolated, molecularly identified and subsequently tested for desired enzymatic activity, lipid accumulation, and tolerance to lignin-derived metabolites. The most promising species were then used for construction of a novel yeast consortium, which was further evaluated for azo dyes degradation, under various culture

The AhpC subunit of the Bacillus subtilis alkyl hydroperoxide reductase was identified as a general stress protein induced in response to heat or salt stress or after entry of the organism into the stationary phase. The ahp operon, encoding the two subunits AhpC and AhpF, was cloned and localized between the gntRKPZ operon and the bglA locus. Two-dimensional gel analyses revealed an especially strong induction of AhpC and AhpF in cells subjected to oxidative stress. Transcriptional studies showed a 3- to 4-fold induction of ahp mRNA after heat or salt stress or starvation for glucose and a 20-fold induction by oxidative stress, thus confirming the protein induction data for AhpC and AhpF. Stress induction occurred at a sigmaA-dependent promoter that overlaps with operator sites similar to the per box. Compared with the wild type, the ahpC mutant was resistant to hydrogen peroxide because of the derepression of the peroxide regulon (N. Bsat, L. Chen, and J. D. Helmann, J. Bacteriol. ...

Page contains details about horseradish peroxidase/anti-alpha fetoprotein monoclonal antibody-grafted gold nanoparticles:horseradish peroxidase/anti-carcino embryonic antigen monoclonal antibody-grafted gold nanoparticles . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com

Using pressure plate and membrane apparatus, irrigation regime of -500kPa was calculated. Forty AM fungal isolates were tested based on their peroxidase activity in soybean plant. Among the AMF, the soybean plants which received UASDAMFS1 (3.86 U mg-1 protein) exhibited less peroxidase activity compared to non mycorhized soybean plants which recorded the highest peroxidase activity (5.06 U mg-1 protein) at irrigation regime of -500 kPa. Total dry matter accumulation in plants was also recorded.

TY - JOUR. T1 - Veratryl alcohol-mediated oxidation of isoeugenyl acetat by lignin peroxidase. AU - ten Have, R.. AU - de Thouars, R.G.. AU - Swarts, H.J.. AU - Field, J.A.. N1 - 234. PY - 1999. Y1 - 1999. M3 - Article. VL - 265. SP - 1008. EP - 1114. JO - European Journal of Biochemistry. JF - European Journal of Biochemistry. SN - 0014-2956. ER - ...

The global Horseradish Peroxidase (HRP) Market report provides an accurate investigation of the different patterns and parameters affecting the industrial growth of the Horseradish Peroxidase (HRP) market at a global level. An assessment of the effect of the current situation and trends in the market is additionally included to provide an overview of the markets future position. The report provides the detailed information related to the global Horseradish Peroxidase (HRP) market dynamics and demonstrates superior forecast for the development of the market and its key competitors TOYOBO, Merck Millipore, Thermo Fisher, BBI Solutions, Enzybel International, Creative Enzymes, Yacoo, Xueman, Worthington, Starbio, Scripps Laboratories based on consistent information.. Apply here for the sample copy of the report @: www.99strategy.biz/request-for-sample.html?repid=24264. Furthermore, The report presents a detailed segmentation Grade?, Grade ?, Grade ?, Market Trend by Application Diagnostic ...

Background: Psoriasis is a chronic-relapsing inflammatory skin disorder, in whose pathogenesis oxidative stress is suggested to be involved. Among different enzymes that play a role in maintaining the cellular redox balance, we aimed to assess the alteration of glutathione peroxidase (GPX) activity in cutaneous lesions and its correlation with the disease severity, firstly, to support the possible candidacy of this enzyme for future topical therapeutic regimens, and secondly, to move forward in understanding the etiology of the disease and the pathogenic mechanisms involved in cutaneous lesions so as to pave the way for further investigations. Methods: The clinical severity of disease was determined according to Psoriasis Area and Severity Index (PASI) scoring system. The level of GPX activity in the skin biopsies from 20 psoriatic patients was measured using Caymans glutathione peroxidase assay kit, and its association with disease severity was assessed in each patient. Results: Tissue GPX activity

Participates as a hydrogen donor in redox reactions through the reversible oxidation of its active center dithiol to a disulfide, accompanied by the transfer of 2 electrons and 2 protons. It is involved in many cellular processes, including deoxyribonucleotide synthesis, repair of oxidatively damaged proteins, protein folding, sulfur metabolism, and redox homeostasis. Thioredoxin-dependent enzymes include phosphoadenosine-phosphosulfate reductase MET16, alkyl- hydroperoxide reductase DOT5, thioredoxin peroxidases TSA1 and TSA2, alkyl hydroperoxide reductase AHP1, and peroxiredoxin HYR1. Thioredoxin is also involved in protection against reducing stress. As part of the LMA1 complex, it is involved in the facilitation of vesicle fusion such as homotypic vacuole and ER- derived COPII vesicle fusion with the Golgi. This activity does not require the redox mechanism. Through its capacity to inactivate the stress response transcription factor YAP1 and its regulator the hydroperoxide stress sensor ...

Mono- and Stereopictres of 5.0 Angstrom coordination sphere of Iron atom in PDB 1bj9: Effect Of Unnatural Heme Substitution on Kinetics of Electron Transfer in Cytochrome C Peroxidase

Mass spectrometric evidence was obtained to confirm that the main reaction product of the horseradish peroxidase (POD)-catalyzed oxidation ofo-phenylenediamine (OPD) by hydrogen peroxide is 2,3-diaminophenazine. Although this reaction is one of the most widespread detection schemes in enzyme-linked immunosorbent assays (ELISAs), the literature data on the identity of the reaction product(s) have been strongly contradictory throughout the last few decades. Liquid chromatography with UV/Vis and mass spectrometric detection as well as exact mass measurements after LC fraction collection have led to the unambiguous identification of 2,3-diaminophenazine as main reaction product. 2,2-Diaminoazobenzene, which is frequently described in other publications to be the major reaction product, was not detected at all ...

Ascorbate peroxidase is a bifunctional peroxidase that catalyzes the H(2)O(2)-dependent oxidation of both ascorbate and various aromatic substrates. The ascorbate binding site was recently identified as being close to the gamma-heme edge [Sharp, K. H., Mewies, M., Moody, P. C. E., and Raven, E. L. (2003)Nat. Struct. Biol. 10, 303-307]. In this work, the X-ray crystal structure of recombinant soybean cytosolic ascorbate peroxidase (rsAPX) in complex with salicylhydroxamic acid (SHA) has been determined to 1.46 A. The SHA molecule is bound close to the delta-heme edge in a cavity that connects the distal side of the heme to the surface of the protein. There are hydrogen bonds between the phenolic hydroxide of the SHA and the main chain carbonyl of Pro132, between the carbonyl oxygen of SHA and the side chain guanadinium group of Arg38, and between the hydroxamic acid group and the indole nitrogen of Trp41. The structure provides the first information about the location of the aromatic binding site ...

There is a peroxidase quench that will block ALL forms of peroxidase, totally. This is the glucose oxidase method. Hsu H-M, et al Am J Pathology 188:209-217,1984 Andrew SM and Jasani G Histchem J 19:426-430, 1987 Vector provided me with the exact protocol ,Date: Mon, 10 Jul 2000 14:43:03 -0400 ,From: Jeff Crews ,[email protected], ,Subject: Re: IH on Liver Tissue ,To: [email protected], [email protected] , , With extremely bloody tissue like spleen or liver, it is sometimes , impossible to quench all of the peroxidase present in the blood. Try , an alkaline-phoshatase detection system. , , Jeffrey Crews, HTL (ASCP) , Organogenesis, Inc. , , ,______________________________ Reply Separator _________________________________ ,Subject: IH on Liver Tissue ,Author: ,[email protected], at internet ,Date: 07/10/2000 11:03 AM , , ,How can you successfully perform immunohistochemistry on slides of liver ,tissue using horse-radish peroxidase and DAB? How do you quench the ,endogenous peroxidase ...

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Etienne, Florence ; Linard, Dominique ; Knoops, Bernard. Regulation of human peroxiredoxin 5 expression and identification of phosphorylation sites..187th meeting of the Belgian Society of Biochemistry and Molecular Biology (Liège, Belgique, 14/05/2004 ...

p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.,/p> ,p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.,/p> ,p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).,/p> ,p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x,sup>64,/sup> + x,sup>4,/sup> + x,sup>3,/sup> + x + 1. The algorithm is described in the ISO 3309 standard. ,/p> ,p class=publication>Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.,br /> ,strong>Cyclic redundancy and other checksums,/strong>,br /> ,a href=http://www.nrbook.com/b/bookcpdf.php>Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993),/a>),/p> Checksum:i ...

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Colorimetric assay kit used to test for glutathione peroxidase (GPX) activity in multiple species and sample types. Glutathione peroxidase is the catalyst for glutathione (GSH) converting hydrogen peroxide (H2O2). to water (H2O).

0048] This is a colorimetric enzyme immunoassay for the quantitative determination of retroviral reverse transcriptase activity by incorporation of dioxigenein- and biotin-labeled dUTP into DNA. The Reverse Transcriptase Assay, colorimetric takes advantage of the ability of reverse transcriptase to synthesize DNA, starting from the template/primer hybrid poly (A)×oligo (dT)15. Digoxigenin- and biotin-labeled nucleotides in an optimized ratio are incorporated into one and the same DNA molecule, which is freshly synthesized by the RT. The detection and quantification of synthesized DNA as a parameter for RT activity follows a sandwich ELISA protocol: Biotin-labeled DNA binds to the surface of microtiter plate (MTP) modules that have been precoated with streptavidin. In the next step, an antibody to digoxigenin, conjugated to peroxidase (anti-DIG-POD), binds to the digoxigenin-labeled DNA. In the final step, the peroxidase substrate ABTS is added. The peroxidase enzyme catalyzes the cleavage of ...

AWV #17B: In this experiment, you will Use a Gas Pressure Sensor to measure the production of oxygen gas as hydrogen peroxide is destroyed by the enzyme catalase or peroxidase at various enzyme concentrations. Measure and compare the initial rates of reaction for this enzyme when different concentrations of enzyme react with H2O2. Measure the production of oxygen gas as hydrogen peroxide is destroyed by the enzyme catalase or peroxidase at various temperatures. Measure and compare the initial rates of reaction for the enzyme at each temperature. Measure the production of oxygen gas as hydrogen peroxide is destroyed by the enzyme catalase or peroxidase at various pH values. Measure and compare the initial rates of reaction for the enzyme at each pH value.

Glutathione peroxidase activity in seminal plasma is related to semen quality but has no relation to in vitro fertilization outcome.

Peroxidases may be important in the mechanism of toxicity of a number of compounds including benzene, a chemical that has been associated with bone marrow toxicity and leukemia after chronic exposure. The major peroxidase in bone marrow is myeloperoxidase (MPO), which has been previously thought to be expressed at the promyelocytic stage of differentiation. Hematopoietic progenitor cells are important potential cellular targets of bone marrow toxins and leukemogens. We therefore examined peroxidase activity in both murine and human progenitor cells. Murine progenitor populations were purified as lineage-negative cells (, 99% enriched) and human progenitor populations were purified as CD34+ cells (, 95% enriched). Using conventional biochemical assays for peroxidase activity, murine and human progenitor cells were found to have 30% and 11% of the peroxidase activity of murine and human unpurified marrow, respectively. Peroxidase activity was confirmed in purified murine and human progenitor ...

Peroxiredoxin 5 gene is mapped on chromosome on 11q13.1 that displays mitochondrial presequence and 3 cysteines involved in antioxidant activity with C-terminal peroxisomal sequence. It localizes in fibroblasts of normal tendon and endothelial cells of degenerative tendon. It also interacts with peroxisome receptor 1 which used translation initiation sites to produced mitochondrial forms. Its crystal structure has been resolved to 1.5 angstrom resolution and contains three transcript variants isoforms. Peroxiredoxin 5 reduces hydrogen peroxide and alkyl hydroperoxides that acts as antioxidant on different tissues under normal conditions and inflammatory processes through thioredoxin system. It has an antioxidant capacity equivalent to CAT that involved in intracellular redox signaling. Peroxiredoxin 5 a peroxidase that lessen hydrogen peroxides 10 times faster than free cysteine that shows hydrogen bonds in the active sites which makes two possible catalysis such as enhancement of thiolate ...

The Peroxiredoxin (Prdx) family of genes encodes thiol-specific antioxidant proteins that protect cells from oxidative stress. Mammalian cells express six different Prdx proteins, and these proteins play a role in cell signaling, proliferation and apoptosis. Recent studies have shown that Prdx levels are elevated in many cancers, suggesting that Prdx upregulation may be an advantageous adaptation to the cancerous state. In the present study we investigated the expression and function of different Prdx proteins in untreated and doxorubicin-treated MCF-7 breast cancer cells, as well as noncancerous MCF-10A cells. We used real-time PCR and western blotting to examine Prdx expression in both cell lines, and also measured Prdx protein expression in doxorubicin-treated MCF-7 cells. In addition, we suppressed Prdx expression using transiently transfected siRNA and measured cell proliferation and apoptosis. Our results show that MCF-7 cells are significantly more resistant to cell death induced by the ...

Peroxidase Conjugated Affinity Purified Anti-SHEEP IgG F(ab)2 (RABBIT) (Min X Human Serum Proteins), Peroxidase Conjugated Affinity Purified anti-Sheep IgG F(ab)2 [Rabbit] Minimum Cross Reactivity to Human Serum Proteins; N/A Peroxidase Conjugated Affin

The mostly conjugated reporter enzymes are horseradish peroxidase (HRP) from the horseradish plant Armoracia rusticana, and alkaline phosphatase (AP) from calf intestines, though Glucose oxidase (GOD) and ß-D-Galactosidase from E.coli will also be used. HRP and AP each provide totally different advantages relying on the appliance necessities. HRP is a small 40 kDa molecule which often binds to an antibody in a ratio of 4:1. Its small dimension means good intracellular penetration and its much less more likely to trigger steric hindrance with the antigen/antibody complicated. AP is barely bigger (86 kDa) which can trigger steric interference however the substrate-converting response is linear, which can imply the detection incubation might be prolonged and probably be extra delicate. AP additionally removes the potential for non-specific staining of tissues with excessive ranges of endogenous peroxidases - a limiting think about HRP.. ...

On Thu, 12 Oct 2000, Gayle Brosnan-Watters wrote: , Can anyone tell me if it is okay to perfuse mice with a perfusate containing , glutaraldehyde when I am going to do the Tago technique for cholinesterase , staining? Yes. The original paper (Tago, Kimura & Maeda 1986 J Histochem Cytochem 34: 1431-1438) says fix for 1 to 4 days in 1 to 4% formaldehyde, with or without 0.5 to 2% glutaraldehyde. Alternatively, fix in 4% formaldehyde and 0.2% picric acid in 0.1M phosphate buffer, pH 7.4. The principle of this method is that you use a 100X diluted medium of the Karnovsky-Roots type. The reaction product (copper ferrocyanide) has a peroxidase-like activity, and is amplified by a DAB-H2O2 incubation. It is sometimes necessary to inhibit endogenous peroxidase activity, especially in unfixed cryostat sections, by putting them in 0.1% H2O2 for 30 minutes before starting the AChE incubation. John A. Kiernan, Department of Anatomy & Cell Biology, The University of Western Ontario, LONDON, Canada N6A 5C1 ...

One of the most widely used enzymes for chromogenic detection in immunoassays is horseradish peroxidase (HRP), a highly stable enzyme (Clin. Chim. Acta 81:1,1977). The compound 3,3-diaminobenzidine (DAB) is a highly sensitive HRP substrate.

TY - JOUR. T1 - Metabolism of 1- and 3-Fluorobenzo[a]pyrene by Cytochrome P450 and Horseradish Peroxidase. AU - Cavalieri, Ercole. AU - Devanesan, Prabhakar. AU - Mulder, Patrick. AU - Ramakrishna, N. V S. AU - Rogan, Eleanor G. PY - 1994/8/1. Y1 - 1994/8/1. N2 - Benzo[a]pyrene (BP) is a good model for elucidating the mechanism of oxygen transfer for substrates that are considered good electron donors. Fluoro substitution of BP represents a suitable probe for studying mechanisms of oxygen transfer in the metabolic formation of BP quinones and BP phenols. By using this strategy with 6-fluoroBP (6-FBP), we have previously demonstrated that the BP quinones are formed metabolically via an initial one-electron oxidation of BP catalyzed by cytochrome P450. Now we have synthesized 1-FBP and 3-FBP with the purpose of elucidating the mechanism of phenol formation. If formation of 3-hydroxyBP (3-OHBP) (major metabolite of BP) and 1-OHBP (minor metabolite of BP) occurs via an initial electron transfer from ...

The pathophysiology of recurrent pregnancy loss (RPL) is still unknown in 50% of the cases. Herein we measure the expression of beta3 integrin subunit, a well-known implantation marker, in women with or without RPL and correlate it with the histological dating of the endometrial tissue. LH-timed endometrial biopsies were obtained from cases (RPL; n = 21, age 33.9+/-4.7) and healthy controls (n = 29; age 29.8+/-4.1) during the mid-secretory phase (post ovulatory day: 8 to 10). Endometrial samples were timed histologically according to Noyes criteria and underwent immunohistochemical staining for beta3 integrin expression. For statistical analysis the semi-quantitative HSCORE was assessed. Type I (beta3 negative in an out-of-phase endometrium) and Type II defect (beta3 negative in an in-phase endometrium) were also analysed. Statistical analysis was done with Student t-test, Mann Whitney U test, ANCOVA and chi square for trend. Significance was set as P < 0.05. The mean (SD) age in controls was lower