PeroxidasesHorseradish Peroxidase: An enzyme isolated from horseradish which is able to act as an antigen. It is frequently used as a histochemical tracer for light and electron microscopy. Its antigenicity has permitted its use as a combined antigen and marker in experimental immunology.Glutathione Peroxidase: An enzyme catalyzing the oxidation of 2 moles of glutathione in the presence of hydrogen peroxide to yield oxidized glutathione and water. EC A hemeprotein from leukocytes. Deficiency of this enzyme leads to a hereditary disorder coupled with disseminated moniliasis. It catalyzes the conversion of a donor and peroxide to an oxidized donor and water. EC Peroxidase: A hemeprotein which catalyzes the oxidation of ferrocytochrome c to ferricytochrome c in the presence of hydrogen peroxide. EC Peroxidases: Peroxidases that utilize ASCORBIC ACID as an electron donor to reduce HYDROGEN PEROXIDE to WATER. The reaction results in the production of monodehydroascorbic acid and DEHYDROASCORBIC ACID.Eosinophil Peroxidase: A 66-kDa peroxidase found in EOSINOPHIL granules. Eosinophil peroxidase is a cationic protein with a pI of 10.8 and is comprised of a heavy chain subunit and a light chain subunit. It possesses cytotoxic activity towards BACTERIA and other organisms, which is attributed to its peroxidase activity.Iodide Peroxidase: A hemeprotein that catalyzes the oxidation of the iodide radical to iodine with the subsequent iodination of many organic compounds, particularly proteins. EC Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.Guaiacol: An agent thought to have disinfectant properties and used as an expectorant. (From Martindale, The Extra Pharmacopoeia, 30th ed, p747)Catalase: An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.Selenium: An element with the atomic symbol Se, atomic number 34, and atomic weight 78.96. It is an essential micronutrient for mammals and other animals but is toxic in large amounts. Selenium protects intracellular structures against oxidative damage. It is an essential component of GLUTATHIONE PEROXIDASE.Lactoperoxidase: An enzyme derived from cow's milk. It catalyzes the radioiodination of tyrosine and its derivatives and of peptides containing tyrosine.Peroxiredoxins: A family of ubiquitously-expressed peroxidases that play a role in the reduction of a broad spectrum of PEROXIDES like HYDROGEN PEROXIDE; LIPID PEROXIDES and peroxinitrite. They are found in a wide range of organisms, such as BACTERIA; PLANTS; and MAMMALS. The enzyme requires the presence of a thiol-containing intermediate such as THIOREDOXIN as a reducing cofactor.Lignin: The most abundant natural aromatic organic polymer found in all vascular plants. Lignin together with cellulose and hemicellulose are the major cell wall components of the fibers of all wood and grass species. Lignin is composed of coniferyl, p-coumaryl, and sinapyl alcohols in varying ratios in different plant species. (From Merck Index, 11th ed)Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Superoxide Dismutase: An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC Peroxidase: An enzyme that catalyzes the chlorination of a range of organic molecules, forming stable carbon-chloride bonds. EC A phylum of fungi that produce their sexual spores (basidiospores) on the outside of the basidium. It includes forms commonly known as mushrooms, boletes, puffballs, earthstars, stinkhorns, bird's-nest fungi, jelly fungi, bracket or shelf fungi, and rust and smut fungi.Benzyl Alcohols: Alcohols derived from the aryl radical (C6H5CH2-) and defined by C6H5CHOH. The concept includes derivatives with any substituents on the benzene ring.Antioxidants: Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.Glutathione Reductase: Catalyzes the oxidation of GLUTATHIONE to GLUTATHIONE DISULFIDE in the presence of NADP+. Deficiency in the enzyme is associated with HEMOLYTIC ANEMIA. Formerly listed as EC Stress: A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).Heme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.Peroxides: A group of compounds that contain a bivalent O-O group, i.e., the oxygen atoms are univalent. They can either be inorganic or organic in nature. Such compounds release atomic (nascent) oxygen readily. Thus they are strong oxidizing agents and fire hazards when in contact with combustible materials, especially under high-temperature conditions. The chief industrial uses of peroxides are as oxidizing agents, bleaching agents, and initiators of polymerization. (From Hawley's Condensed Chemical Dictionary, 11th ed)Glutathione: A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.Histocytochemistry: Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.Lipid Peroxidation: Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Kinetics: The rate dynamics in chemical or physical systems.Phanerochaete: A genus of fungi in the family Corticiaceae, order Stereales, that degrades lignin. The white-rot fungus Phanerochaete chrysosporium is a frequently used species in research.Benzidines: Very toxic industrial chemicals. They are absorbed through the skin, causing lethal blood, bladder, liver, and kidney damage and are potent, broad-spectrum carcinogens in most species.Coprinus: A genus of black-spored basidiomycetous fungi of the family Coprinaceae, order Agaricales; some species are edible.Iodides: Inorganic binary compounds of iodine or the I- ion.Selenoproteins: Selenoproteins are proteins that specifically incorporate SELENOCYSTEINE into their amino acid chain. Most selenoproteins are enzymes with the selenocysteine residues being responsible for their catalytic functions.Lipid Peroxides: Peroxides produced in the presence of a free radical by the oxidation of unsaturated fatty acids in the cell in the presence of molecular oxygen. The formation of lipid peroxides results in the destruction of the original lipid leading to the loss of integrity of the membranes. They therefore cause a variety of toxic effects in vivo and their formation is considered a pathological process in biological systems. Their formation can be inhibited by antioxidants, such as vitamin E, structural separation or low oxygen tension.Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate: The lectin wheatgerm agglutinin conjugated to the enzyme HORSERADISH PEROXIDASE. It is widely used for tracing neural pathways.Pleurotus: A genus of basidiomycetous fungi, family POLYPORACEAE, order POLYPORALES, that grows on logs or tree stumps in shelflike layers. The species P. ostreatus, the oyster mushroom, is a choice edible species and is the most frequently encountered member of the genus in eastern North America. (Alexopoulos et al., Introductory Mycology, 4th ed, p531)Selenious Acid: A selenium compound with the molecular formula H2SO3. It used as a source of SELENIUM, especially for patients that develop selenium deficiency following prolonged PARENTERAL NUTRITION.Free Radicals: Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.Malondialdehyde: The dialdehyde of malonic acid.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Peroxiredoxin VI: A peroxiredoxin that is a cytosolic bifunctional enzyme. It functions as a peroxiredoxin via a single redox-active cysteine and also contains a Ca2+-independent acidic phospholipase A2 activity.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Thyroid Gland: A highly vascularized endocrine gland consisting of two lobes joined by a thin band of tissue with one lobe on each side of the TRACHEA. It secretes THYROID HORMONES from the follicular cells and CALCITONIN from the parafollicular cells thereby regulating METABOLISM and CALCIUM level in blood, respectively.3,3'-DiaminobenzidineAmino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.Peroxiredoxin III: A THIOREDOXIN-dependent hydroperoxidase that is localized in the mitochondrial matrix. The enzyme plays a crucial role in protecting mitochondrial components from elevated levels of HYDROGEN PEROXIDE.Selenoprotein P: An extracellular selenoprotein that contains most of the SELENIUM in PLASMA. Selenoprotein P functions as an antioxidant and appears to transport selenium from the LIVER to peripheral tissues.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Hemeproteins: Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)Selenocysteine: A naturally occurring amino acid in both eukaryotic and prokaryotic organisms. It is found in tRNAs and in the catalytic site of some enzymes. The genes for glutathione peroxidase and formate dehydrogenase contain the TGA codon, which codes for this amino acid.Polyporaceae: A family of bracket fungi, order POLYPORALES, living in decaying plant matter and timber.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Ascorbic Acid: A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant.Polyporales: An order of fungi in the phylum BASIDIOMYCOTA having macroscopic basidiocarps. The members are characterized by their saprophytic activities as decomposers, particularly in the degradation of CELLULOSE and LIGNIN. A large number of species in the order have been used medicinally. (From Alexopoulos, Introductory Mycology, 4th ed, pp504-68)Reactive Oxygen Species: Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.Thiobarbituric Acid Reactive Substances: Low-molecular-weight end products, probably malondialdehyde, that are formed during the decomposition of lipid peroxidation products. These compounds react with thiobarbituric acid to form a fluorescent red adduct.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Glucose Oxidase: An enzyme of the oxidoreductase class that catalyzes the conversion of beta-D-glucose and oxygen to D-glucono-1,5-lactone and peroxide. It is a flavoprotein, highly specific for beta-D-glucose. The enzyme is produced by Penicillium notatum and other fungi and has antibacterial activity in the presence of glucose and oxygen. It is used to estimate glucose concentration in blood or urine samples through the formation of colored dyes by the hydrogen peroxide produced in the reaction. (From Enzyme Nomenclature, 1992) EC Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.Eosinophils: Granular leukocytes with a nucleus that usually has two lobes connected by a slender thread of chromatin, and cytoplasm containing coarse, round granules that are uniform in size and stainable by eosin.Enzymes, Immobilized: Enzymes which are immobilized on or in a variety of water-soluble or water-insoluble matrices with little or no loss of their catalytic activity. Since they can be reused continuously, immobilized enzymes have found wide application in the industrial, medical and research fields.Manganese: A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)Glutathione Transferase: A transferase that catalyzes the addition of aliphatic, aromatic, or heterocyclic FREE RADICALS as well as EPOXIDES and arene oxides to GLUTATHIONE. Addition takes place at the SULFUR. It also catalyzes the reduction of polyol nitrate by glutathione to polyol and nitrite.Agaricales: An extensive order of basidiomycetous fungi whose fruiting bodies are commonly called mushrooms.tert-Butylhydroperoxide: A direct-acting oxidative stress-inducing agent used to examine the effects of oxidant stress on Ca(2+)-dependent signal transduction in vascular endothelial cells. It is also used as a catalyst in polymerization reactions and to introduce peroxy groups into organic molecules.Armoracia: A plant genus of the family BRASSICACEAE known for the root used in hot SPICES. It is also the source of HORSERADISH PEROXIDASE which is widely used in laboratories.ThyroglobulinThiocyanates: Organic derivatives of thiocyanic acid which contain the general formula R-SCN.Selenomethionine: Diagnostic aid in pancreas function determination.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Ferrocyanides: Inorganic salts of the hypothetical acid ferrocyanic acid (H4Fe(CN)6).Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Oxidants: Electron-accepting molecules in chemical reactions in which electrons are transferred from one molecule to another (OXIDATION-REDUCTION).Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Laccase: A copper-containing oxidoreductase enzyme that catalyzes the oxidation of 4-benzenediol to 4-benzosemiquinone. It also has activity towards a variety of O-quinols and P-quinols. It primarily found in FUNGI and is involved in LIGNIN degradation, pigment biosynthesis and detoxification of lignin-derived products.Spectrum Analysis, Raman: Analysis of the intensity of Raman scattering of monochromatic light as a function of frequency of the scattered light.Pinocytosis: The engulfing of liquids by cells by a process of invagination and closure of the cell membrane to form fluid-filled vacuoles.Immunoenzyme Techniques: Immunologic techniques based on the use of: (1) enzyme-antibody conjugates; (2) enzyme-antigen conjugates; (3) antienzyme antibody followed by its homologous enzyme; or (4) enzyme-antienzyme complexes. These are used histologically for visualizing or labeling tissue specimens.Glutathione Disulfide: A GLUTATHIONE dimer formed by a disulfide bond between the cysteine sulfhydryl side chains during the course of being oxidized.Anisoles: A group of compounds that are derivatives of methoxybenzene and contain the general formula R-C7H7O.Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Sodium Selenite: The disodium salt of selenious acid. It is used therapeutically to supply the trace element selenium and is prepared by the reaction of SELENIUM DIOXIDE with SODIUM HYDROXIDE.Amitrole: A non-selective post-emergence, translocated herbicide. According to the Seventh Annual Report on Carcinogens (PB95-109781, 1994) this substance may reasonably be anticipated to be a carcinogen. (From Merck Index, 12th ed) It is an irreversible inhibitor of CATALASE, and thus impairs activity of peroxisomes.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Benzene DerivativesThyroiditis, Autoimmune: Inflammatory disease of the THYROID GLAND due to autoimmune responses leading to lymphocytic infiltration of the gland. It is characterized by the presence of circulating thyroid antigen-specific T-CELLS and thyroid AUTOANTIBODIES. The clinical signs can range from HYPOTHYROIDISM to THYROTOXICOSIS depending on the type of autoimmune thyroiditis.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Bromides: Salts of hydrobromic acid, HBr, with the bromine atom in the 1- oxidation state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Vitamin E: A generic descriptor for all TOCOPHEROLS and TOCOTRIENOLS that exhibit ALPHA-TOCOPHEROL activity. By virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus, these compounds exhibit varying degree of antioxidant activity, depending on the site and number of methyl groups and the type of ISOPRENOIDS.Thioredoxins: Hydrogen-donating proteins that participates in a variety of biochemical reactions including ribonucleotide reduction and reduction of PEROXIREDOXINS. Thioredoxin is oxidized from a dithiol to a disulfide when acting as a reducing cofactor. The disulfide form is then reduced by NADPH in a reaction catalyzed by THIOREDOXIN REDUCTASE.Trametes: A genus of fungi in the family Coriolaceae.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Organoselenium Compounds: Organic compounds which contain selenium as an integral part of the molecule.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Thioredoxin-Disulfide Reductase: A FLAVOPROTEIN enzyme that catalyzes the oxidation of THIOREDOXINS to thioredoxin disulfide in the presence of NADP+. It was formerly listed as EC G: A group of physiologically active prostaglandin endoperoxides. They are precursors in the biosynthesis of prostaglandins and thromboxanes. Most frequently encountered member of this group is the prostaglandin G2.Spectrum Analysis: The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Sulfhydryl Compounds: Compounds containing the -SH radical.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Phenylhydrazines: Diazo derivatives of aniline, used as a reagent for sugars, ketones, and aldehydes. (Dorland, 28th ed)Asparagus Plant: A plant genus in the family LILIACEAE (sometimes placed in Asparagaceae) that contains ECDYSTEROIDS and is an ingredient of Siotone. The shoots are used as a vegetable and the roots are used in FOLK MEDICINE.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Coumaric Acids: Hydroxycinnamic acid and its derivatives. Act as activators of the indoleacetic acid oxidizing system, thereby producing a decrease in the endogenous level of bound indoleacetic acid in plants.Biocatalysis: The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.Phenol: An antiseptic and disinfectant aromatic alcohol.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Sodium Azide: A cytochrome oxidase inhibitor which is a nitridizing agent and an inhibitor of terminal oxidation. (From Merck Index, 12th ed)Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Diiodotyrosine: A product from the iodination of MONOIODOTYROSINE. In the biosynthesis of thyroid hormones, diiodotyrosine residues are coupled with other monoiodotyrosine or diiodotyrosine residues to form T4 or T3 thyroid hormones (THYROXINE and TRIIODOTHYRONINE).Staining and Labeling: The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.

Human granulocytic ehrlichiosis agent and Ehrlichia chaffeensis reside in different cytoplasmic compartments in HL-60 cells. (1/3678)

The human granulocytic ehrlichiosis (HGE) agent resides and multiplies exclusively in cytoplasmic vacuoles of granulocytes. Double immunofluorescence labeling was used to characterize the nature of the HGE agent replicative inclusions and to compare them with inclusions containing the human monocytic ehrlichia, Ehrlichia chaffeensis, in HL-60 cells. Although both Ehrlichia spp. can coinfect HL-60 cells, they resided in separate inclusions. Inclusions of both Ehrlichia spp. were not labeled with either anti-lysosome-associated membrane protein 1 or anti-CD63. Accumulation of myeloperoxidase-positive granules were seen around HGE agent inclusions but not around E. chaffeensis inclusions. 3-(2, 4-Dinitroanilino)-3'-amino-N-methyldipropylamine and acridine orange were not localized to either inclusion type. Vacuolar-type H+-ATPase was not colocalized with HGE agent inclusions but was weakly colocalized with E. chaffeensis inclusions. E. chaffeensis inclusions were labeled with the transferrin receptor, early endosomal antigen 1, and rab5, but HGE agent inclusions were not. Some HGE agent and E. chaffeensis inclusions colocalized with major histocompatibility complex class I and II antigens. These two inclusions were not labeled for annexins I, II, IV, and VI; alpha-adaptin; clathrin heavy chain; or beta-coatomer protein. Vesicle-associated membrane protein 2 colocalized to both inclusions. The cation-independent mannose 6-phosphate receptor was not colocalized with either inclusion type. Endogenously synthesized sphingomyelin, from C6-NBD-ceramide, was not incorporated into either inclusion type. Brefeldin A did not affect the growth of either Ehrlichia sp. in HL-60 cells. These results suggest that the HGE agent resides in inclusions which are neither early nor late endosomes and does not fuse with lysosomes or Golgi-derived vesicles, while E. chaffeensis resides in an early endosomal compartment which accumulates the transferrin receptor.  (+info)

Alternating antineutrophil cytoplasmic antibody specificity: drug-induced vasculitis in a patient with Wegener's granulomatosis. (2/3678)

We describe a patient who presented with Wegener's granulomatosis associated with antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) with a cytoplasmic immunofluorescence pattern (cANCA), whose ANCA type changed to antimyeloperoxidase antibodies with a perinuclear immunofluorescence pattern (pANCA) when treated with propylthiouracil, and changed back to anti-PR3 antibodies with cANCA after the medication was discontinued. The patient developed flares of vasculitis symptoms associated with rises in either type of ANCA. Tests for antimyeloperoxidase ANCA were repeatedly negative before the drug was started, strongly implicating the drug as the cause of the episode. This case demonstrates that patients with idiopathic ANCA-positive vasculitis may quickly develop a superimposed drug-associated ANCA-positive vasculitis. Iatrogenic vasculitis should be suspected when a patient with idiopathic vasculitis with one type of ANCA develops the other type of ANCA.  (+info)

Kinetics of oxidation of aliphatic and aromatic thiols by myeloperoxidase compounds I and II. (3/3678)

Myeloperoxidase (MPO) is the most abundant protein in neutrophils and plays a central role in microbial killing and inflammatory tissue damage. Because most of the non-steroidal anti-inflammatory drugs and other drugs contain a thiol group, it is necessary to understand how these substrates are oxidized by MPO. We have performed transient kinetic measurements to study the oxidation of 14 aliphatic and aromatic mono- and dithiols by the MPO intermediates, Compound I (k3) and Compound II (k4), using sequential mixing stopped-flow techniques. The one-electron reduction of Compound I by aromatic thiols (e.g. methimidazole, 2-mercaptopurine and 6-mercaptopurine) varied by less than a factor of seven (between 1.39 +/- 0.12 x 10(5) M(-1) s(-1) and 9.16 +/- 1.63 x 10(5) M(-1) s(-1)), whereas reduction by aliphatic thiols was demonstrated to depend on their overall net charge and hydrophobic character and not on the percentage of thiol deprotonation or redox potential. Cysteamine, cysteine methyl ester, cysteine ethyl ester and alpha-lipoic acid showed k3 values comparable to aromatic thiols, whereas a free carboxy group (e.g. cysteine, N-acetylcysteine, glutathione) diminished k3 dramatically. The one-electron reduction of Compound II was far more constrained by the nature of the substrate. Reduction by methimidazole, 2-mercaptopurine and 6-mercaptopurine showed second-order rate constants (k4) of 1.33 +/- 0.08 x 10(5) M(-1) s(-1), 5.25 +/- 0.07 x 10(5) M(-1) s(-1) and 3.03 +/- 0.07 x 10(3) M(-1) s(-1). Even at high concentrations cysteine, penicillamine and glutathione could not reduce Compound II, whereas cysteamine (4.27 +/- 0.05 x 10(3) M(-1) s(-1)), cysteine methyl ester (8.14 +/- 0.08 x 10(3) M(-1) s(-1)), cysteine ethyl ester (3.76 +/- 0.17 x 10(3) M(-1) s(-1)) and alpha-lipoic acid (4.78 +/- 0.07 x 10(4) M(-1) s(-1)) were demonstrated to reduce Compound II and thus could be expected to be oxidized by MPO without co-substrates.  (+info)

The inhibition of myeloperoxidase by ceruloplasmin can be reversed by anti-myeloperoxidase antibodies. (4/3678)

BACKGROUND: The purpose of this study was to characterize the recently reported inhibition of myeloperoxidase (MPO) by ceruloplasmin and to determine whether this may be disturbed in the presence of anti-MPO antibodies. METHODS: Specificity of the binding between ceruloplasmin and MPO was confirmed by Western blotting and enzyme-linked immunosorbent assay (ELISA), and the enzymatic activity of MPO was measured in the presence of ceruloplasmin, affinity-purified anti-MPO antibodies, or both. The affinity of the binding between MPO and ceruloplasmin and MPO and the anti-MPO antibodies was measured using a biosensor, with the results confirmed by chaotrope ELISA. RESULTS: Affinity-purified anti-MPO antibodies from patients with microscopic polyangiitis and florid renal vasculitis inhibited the binding between ceruloplasmin and MPO to a maximum of 72.9 +/- 12.8%, whereas those from patients with Wegener's granulomatosis and only minimal renal involvement inhibited the binding to a maximum of only 36.8 +/- 10.9% (P < 0. 001), with comparable reversal of the ceruloplasmin-mediated inhibition of MPO activity. Measurement of the affinity of the interactions demonstrated that binding between MPO and the anti-MPO antibodies is stronger than that between MPO and ceruloplasmin (1.61 x 107 to 1.33 x 108 vs. 7.46 x 106 m-1), indicating that binding to the autoantibody would be favored in vivo. CONCLUSIONS: This study confirms a role for ceruloplasmin as a physiological inhibitor of MPO, and demonstrates how the inhibition may be disrupted in the presence of anti-MPO antibodies. Because a majority (16 of 21) of the antibodies did not themselves inhibit MPO activity, their interference with the inhibition mediated by ceruloplasmin may be brought about by steric hindrance consequent upon the binding of the antibody to a dominant epitope at or near the active site.  (+info)

A cell-surface superoxide dismutase is a binding protein for peroxinectin, a cell-adhesive peroxidase in crayfish. (5/3678)

Peroxinectin, a cell-adhesive peroxidase (homologous to human myeloperoxidase), from the crayfish Pacifastacus leniusculus, was shown by immuno-fluorescence to bind to the surface of crayfish blood cells (haemocytes). In order to identify a cell surface receptor for peroxinectin, labelled peroxinectin was incubated with a blot of haemocyte membrane proteins. It was found to specifically bind two bands of 230 and 90 kDa; this binding was decreased in the presence of unlabelled peroxinectin. Purified 230/90 kDa complex also bound peroxinectin in the same assay. In addition, the 230 kDa band binds the crayfish beta-1,3-glucan-binding protein. The 230 kDa band could be reduced to 90 kDa, thus showing that the 230 kDa is a multimer of 90 kDa units. The peroxinectin-binding protein was cloned from a haemocyte cDNA library, using immuno-screening or polymerase chain reaction based on partial amino acid sequence of the purified protein. It has a signal sequence, a domain homologous to CuZn-containing superoxide dismutases, and a basic, proline-rich, C-terminal tail, but no membrane-spanning segment. In accordance, the 90 and 230 kDa bands had superoxide dismutase activity. Immuno-fluorescence of non-permeabilized haemocytes with affinity-purified antibodies confirmed that the crayfish CuZn-superoxide dismutase is localized at the cell surface; it could be released from the membrane with high salt. It was thus concluded that the peroxinectin-binding protein is an extracellular SOD (EC-SOD) and a peripheral membrane protein, presumably kept at the cell surface via ionic interaction with its C-terminal region. This interaction with a peroxidase seems to be a novel function for an SOD. The binding of the cell surface SOD to the cell-adhesive/opsonic peroxinectin may mediate, or regulate, cell adhesion and phagocytosis; it may also be important for efficient localized production of microbicidal substances.  (+info)

Cloning and characterization of a cDNA encoding a novel extracellular peroxidase from Trametes versicolor. (6/3678)

The white rot basidiomycete Trametes versicolor secretes a large number of peroxidases which are believed to be involved in the degradation of polymeric lignin. These peroxidases have been classified previously as lignin peroxidases or manganese peroxidases (MnP). We have isolated a novel extracellular peroxidase-encoding cDNA sequence from T. versicolor CU1, the transcript levels of which are repressed by low concentrations of Mn2+ and induced by nitrogen and carbon but not induced in response to a range of stresses which have been reported to induce MnP expression.  (+info)

Expression of the cell adhesion molecules on leukocytes that demarginate during acute maximal exercise. (7/3678)

The pulmonary vascular bed is an important reservoir for the marginated pool of leukocytes that can be mobilized by exercise or catecholamines. This study was designed to determine the phenotypic characteristics of leukocytes that are mobilized into the circulation during exercise. Twenty healthy volunteers performed incremental exercise to exhaustion [maximal O2 consumption (VO2 max)] on a cycle ergometer. Blood was collected at baseline, at 3-min intervals during exercise, at VO2 max, and 30 min after exercise. Total white cell, polymorphonuclear leukocyte (PMN), and lymphocyte counts increased with exercise to VO2 max (P < 0.05). Flow cytometric analysis showed that the mean fluorescence intensity of L-selectin on PMN (from 14.9 +/- 1 at baseline to 9.5 +/- 1.6 at VO2 max, P < 0.05) and lymphocytes (from 11.7 +/- 1.2 at baseline to 8 +/- 0.8 at VO2 max, P < 0.05) decreased with exercise. Mean fluorescence intensity of CD11b on PMN increased with exercise (from 10.2 +/- 0.6 at baseline to 25 +/- 2.5 at VO2 max, P < 0.002) but remained unchanged on lymphocytes. Myeloperoxidase levels in PMN did not change with exercise. In vitro studies showed that neither catecholamines nor plasma collected at VO2 max during exercise changed leukocyte L-selectin or CD11b levels. We conclude that PMN released from the marginated pool during exercise express low levels of L-selectin and high levels of CD11b.  (+info)

Purification and cloning of the salivary peroxidase/catechol oxidase of the mosquito Anopheles albimanus. (8/3678)

Salivary homogenates of the adult female mosquito Anopheles albimanus have been shown previously to contain a vasodilatory activity associated with a catechol oxidase/peroxidase activity. We have now purified the salivary peroxidase using high-performance liquid chromatography. The pure enzyme is able to relax rabbit aortic rings pre-constricted with norepinephrine. The peroxidase has a relative molecular mass of 66 907 as estimated by mass spectrometry. Amino-terminal sequencing allowed us to design oligonucleotide probes for isolation of cDNA clones derived from the salivary gland mRNA from female mosquitoes. The full sequence of the cDNA demonstrated homology between A. albimanus salivary peroxidase and several members of the myeloperoxidase gene family. A close comparison of A. albimanus salivary peroxidase with canine myeloperoxidase, for which the crystal structure is known, showed that all six disulfide bridges were conserved and demonstrated identity for all five residues associated with a Ca2+-binding site. In addition, 16 of 26 residues shown to be in close proximity to the heme moiety in the canine myeloperoxidase were identical. We conclude that the salivary peroxidase of A. albimanus belongs to the myeloperoxidase gene family. Other possible functions for this molecule in blood feeding are discussed.  (+info)

  • A majority of peroxidase protein sequences can be found in the PeroxiBase database. (
  • 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. (
  • One of the first aspects known of eosinophil peroxidase was that it was highly cationic, as indicated by its high isoelectric point (see Protein). (
  • The EPX gene provides instructions for making the eosinophil peroxidase protein. (
  • EPX gene mutations reduce or prevent eosinophil peroxidase production or result in a protein that is unstable and nonfunctional. (
  • The invention relates to peroxidase colloidal gold biosensors that provide a detectable electrochemical response based on direct oxidation of a redox protein at an electrode surface. (
  • Peroxidase-Conjugated Protein A is a versatile reagent which is useful in many immunological assay systems. (
  • A recombinant protein with a N-Terminal His-tag and corresponding to the amino acids 1-168 of E.coli Thiol Peroxidase The Recombinant E. coli Thiol Peroxidase Protein is derived from E. coli. (
  • The Recombinant E. coli Thiol Peroxidase Protein has been validated for the following applications: SDS-Page. (
  • The SKPO-1 protein contains the critical catalytic residues necessary for peroxidase activity, and in a whole animal assay, more H 2 O 2 was detected from the mutant compared to the wild type, consistent with the loss of an H 2 O 2 sink. (
  • The GPX3 protein is one of only a few proteins known in higher vertebrates to contain selenocysteine, which occurs at the active site of glutathione peroxidase and is coded by the nonsense (stop) codon TGA. (
  • Protein and peroxidase activities were significantly lower in salivary glands of mosquitoes after probing and feeding on blood. (
  • Both the cyclooxygenase and the peroxidase active sites are located in the catalytic domain, which accounts for approximately 80% of the protein. (
  • A total of 22 isoenzymes including allelic variants were successfully expressed in Pichia pastoris and showed peroxidase activity with at least one of the substrates tested, thus enabling their development into commercial pure isoenzymes. (
  • Tissues can contain endogenous peroxidase, pseudoperoxidase, and/or alkaline phosphatase activity that will produce background staining if an alkaline phosphatase and/or peroxidase detection system and corresponding substrates are used. (
  • The family of heme peroxidases catalyse the hydrogen peroxidase-dependent oxidation of a wide variety of different substrates. (
  • In ascorbate peroxidase, for example, (hydrophobic) aromatic substrates and (hydrophilic) ascorbate are oxidized at different sites [ 8,12 ]. (
  • COX-2 is naturally inhibited by Calcitriol (the active form of Vitamin D). Both the peroxidase and PTGS activities are inactivated during catalysis by mechanism-based, first-order processes, which means that PGHS-2 peroxidase or PTGS activities fall to zero within 1-2 minutes, even in the presence of sufficient substrates. (
  • The fold of the enzyme is known as the heme peroxidase fold, conserved among all members of this gene family. (
  • This book provides a comprehensive single source of information on the various aspects of heme peroxidase structure, function and mechanism of action. (
  • It is suggested that adult female Anopheles albimanus mosquitoes contain a salivary heme peroxidase that functions during blood finding and blood feeding by destroying hemostatically active biogenic amines released by the vertebrate host during tissue destruction. (
  • Molecular model of a tryparedoxin peroxidase molecule from the parasitic protozoa Trypanosoma cruzi, the cause of Chagas disease. (
  • Thyroid Peroxidase Human Recombinant produced in SF9 is a glycosylated, polypeptide chain containing 834 amino acids and having a molecular mass of 92,872 Dalton (excluding glycosylation), 101 kDa total mass. (
  • Soluble, ionically bound peroxidase (POD) and polyphenoloxidase (PPO) were extracted from the pulp of peach fruit during ripening at 20°C. Ionically bound form was purified 6.1-fold by DEAE-cellulose and Sephadex G-100 chromatography. (
  • In contrast, the soluble peroxidase form from tomato (Kokkinakis & Brooks, 1979) and papaya fruit (Silva et al , 1990) reach a maximum peak followed by a marked decrease at the initial levels. (
  • TMB ELISA Peroxidase Substrate will produce a soluble blue end product read at 370 nm or 655 nm. (
  • One of these proteins is called eosinophil peroxidase. (
  • Other proteins within affected eosinophils are normal, and while the cells lacking eosinophil peroxidase are smaller and may have structural changes, the loss of eosinophil peroxidase does not appear to impair the function of eosinophils. (
  • In addition, selenium is incorporated at the active site of many proteins, including glutathione peroxidase , which is particularly important for cancer protection. (
  • Many of these peroxidases are functionally associated with members of the NADPH oxidase (NOX)/dual oxidase (DUOX) family of proteins. (
  • Peroxidase/dual oxidase (duox) systems act in concert to catalyze the nonspecific formation of dityrosine bonds, which cross-link a variety of proteins. (
  • The peroxidase/duox system appears to promote dityrosine bond formation between proteins across the surface of midgut epithelial cells to form a layer that inhibits immune recognition and mediator release. (
  • Calculated ionisation potentials to determine the oxidation of vanillin precursors by lignin peroxidase. (
  • In view of the biocatalytic production of vanillin, this research focused on the lignin peroxidase (LiP) catalysed oxidation of naturally occurring phenolic derivatives: O-methyl ethers, O-acetyl esters, and O-glucosyl ethers. (
  • Dr Robert Mason, Research Associate in the Department of Genetics, and first author of the study, said: 'In addition to glutathione peroxidase, this study has identified many genes that improve Huntington's 'symptoms' in yeast. (
  • Sequence databases, ORF finding and ORF characterization were utilized to identify peroxidase genes from the 14871 isotigs generated by de novo assembly. (
  • Animals exposed to RNA interference (RNAi) of the putative peroxidase genes were screened for susceptibility to the human pathogen Enterococcus faecalis . (
  • In the current study, we functionally analysed these three catalase-peroxidase genes and found that MgCatD-1, encoding a secreted catalase-peroxidase, plays an important role in the pathogenicity of Z. tritici. (
  • These results show that secreted catalase-peroxidase is an important pathogenicity factor for successful pathogenesis of Z. tritici. (
  • Eosinophil peroxidase is an enzyme found within the eosinophil granulocytes, innate immune cells of humans and mammals. (
  • The open reading frame of human eosinophil peroxidase was found to have a length of 2,106 base pairs (bp). (
  • The promoter sequence for human eosinophil peroxidase is an unusually strong promoter. (
  • Eosinophil peroxidase is a predominately α-helical heme-containing enzyme. (
  • Eosinophil peroxidase has not been characterized by X-ray crystallography. (
  • Eosinophil peroxidase deficiency is a condition that affects certain white blood cells called eosinophils but causes no health problems in affected individuals. (
  • In eosinophil peroxidase deficiency, eosinophils have little or no eosinophil peroxidase. (
  • Because eosinophil peroxidase deficiency does not cause any health problems, this condition is often diagnosed when blood tests are done for other reasons or when a family member has been diagnosed with the condition. (
  • Approximately 100 individuals with eosinophil peroxidase deficiency have been described in the scientific literature. (
  • Eosinophil peroxidase deficiency is estimated to occur in 8.6 in 1,000 Yemenite Jews, in 3 in 1,000 North-African Jews, and in 1 in 1,000 Iraqi Jews. (
  • and in Luxembourg, eosinophil peroxidase deficiency is thought to occur in 1 in 100,000 people. (
  • During an immune response, activated eosinophils release eosinophil peroxidase at the site of injury. (
  • As a result, eosinophils have severely reduced amounts of eosinophil peroxidase or none at all. (
  • Kutter D, Mueller-Hagedorn S, Forges T, Glaesener R. A case of eosinophil peroxidase deficiency. (
  • Romano M, Patriarca P, Melo C, Baralle FE, Dri P. Hereditary eosinophil peroxidase deficiency: immunochemical and spectroscopic studies and evidence for a compound heterozygosity of the defect. (
  • an oxidase layer atop the deposited colloidal gold adsorbed peroxidase wherein direct electron transfer to the conducting surface occurs in the presence of an analyte when the bioelectrode is suitably coupled with a reference/counter electrode. (
  • The variations in direct peroxidase bioelectrocatalysis when coming from carbon/graphite to metal electrodes and oxides, as well as modified electrodes, are analyzed regarding the variations in adsorption/orientation of peroxidase at the electrodes, interfacial electron transfer rates and mechanism of catalysis. (
  • The sequences were manually reviewed and verified with Sanger sequencing of PCR amplified genomic fragments, resulting in the discovery of 28 secretory peroxidases, 23 of them previously unknown. (
  • Since progesterone was found to inhibit peroxidase induction due to both estrone and diethylstilbestrol, as well as estradiol, it is considered unlikely that this antagonism relates to progestin-induced increases in uterine 17 β -hydroxysteroid dehydrogenase. (
  • Isoflavones also inhibit thyroid peroxidase , which produces the thyroid hormones T3 and T4. (
  • Research at Iowa State University shows that the addition of soybean peroxidase to pig manure can reduce its environmental impacts in terms both of odours and harmful gases. (
  • Soybean peroxidase is an enzyme derived from soybean hulls. (
  • Commodity soybean cultivars contain various amounts of active peroxidase enzyme. (
  • This study evaluates alternative supply chain arrangements for moving soybean hulls containing peroxidase from producer to processor. (
  • Results suggest at current peroxidase levels in soybeans, supply chain arrangements involving soybean segregation offer cost advantages over the standard commodity supply chain. (
  • A. Mika, F. Buck, and S. Lüthje, "Membrane-bound class III peroxidases: identification, biochemical properties and sequence analysis of isoenzymes purified from maize ( Zea mays L.) roots," Journal of Proteomics , vol. 71, no. 4, pp. 412-424, 2008. (
  • While breakthroughs in peroxidase-like nanozymes have been made recently, most studies are based on trial-and-error strategies to identify and synthesize suitable peroxidase mimics. (