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Haloperoxidase
Haloperoxidases are peroxidases that are able to mediate the oxidation of halides by hydrogen peroxide. Both halides and hydrogen peroxide are widely available in the environment. The Nernst equation shows that hydrogen peroxide can oxidize chloride (E°= 1.36 V), bromide (E°= 1.09 V) and iodide (E°= 0.536 V) from a thermodynamic perspective under natural conditions, i.e., a temperature range of about 0–30 °C and a pH ranging from about 3 ( humic soil layer) to about 8 (sea water). Fluoride (E°= 2.87 V) cannot be oxidized by hydrogen peroxide. Classification The table shows the classification of haloperoxidases according to the halides whose oxidation they are able to catalyze. The classification of these enzymes by substrate-usability does not necessarily indicate enzyme substrate ''preference.'' For example, although eosinophil peroxidase is ''able'' to oxidize chloride, it preferentially oxidizes bromide. The mammalian haloperoxidases myeloperoxidase (MPO), lac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromoperoxidase
Bromide peroxidase (, ''bromoperoxidase'', ''haloperoxidase (ambiguous)'', '' eosinophil peroxidase'') is a family of enzymes with systematic name ''bromide:hydrogen-peroxide oxidoreductase''. These enzymes catalyses the following chemical reaction: : HBr + H2O2 \rightleftharpoons HOBr + H2O The HOBr is a potent brominating agent. The many organobromine compounds observed in marine environments are the products of reaction with this oxidized form of bromine. Bromo peroxidases of red and brown marine algae (''Rhodophyta'' and ''Phaeophyta'') contain vanadate (vanadium bromoperoxidase). Otherwise vanadium is unusual cofactor in biology. By virtue of this family of enzymes, a variety of brominated natural products have been isolated from marine sources. Related chloroperoxidase enzymes effect chlorination. In the nomenclature of haloperoxidase, bromoperoxidases classically are unable to oxidize chloride at all. For example, eosinophil peroxidase appears to prefer bromide o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium Bromoperoxidase
Vanadium bromoperoxidases are a kind of enzymes called haloperoxidases. Its primary function is to remove hydrogen peroxide which is produced during photosynthesis from in or around the cell. By producing hypobromous acid (HOBr) a secondary reaction with dissolved organic matter, what results is the bromination of organic compounds that are associated with the defense of the organism. These enzymes produce the bulk of natural organobromine compounds in the world. Vanadium bromoperoxidases are one of the few classes of enzymes that requires vanadium. The active site features a vanadium oxide center attached to the protein via one histidine side chain and a collection of hydrogen bonds to the oxide ligands. Occurrence and function Vanadium bromoperoxidases have been found in bacteria, fungi, marine macro algae (seaweeds), and marine microalgae (diatoms) which produce brominated organic compounds. It has not been definitively identified as the bromoperoxidase of higher eukaryotes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromoperoxidase
Bromide peroxidase (, ''bromoperoxidase'', ''haloperoxidase (ambiguous)'', '' eosinophil peroxidase'') is a family of enzymes with systematic name ''bromide:hydrogen-peroxide oxidoreductase''. These enzymes catalyses the following chemical reaction: : HBr + H2O2 \rightleftharpoons HOBr + H2O The HOBr is a potent brominating agent. The many organobromine compounds observed in marine environments are the products of reaction with this oxidized form of bromine. Bromo peroxidases of red and brown marine algae (''Rhodophyta'' and ''Phaeophyta'') contain vanadate (vanadium bromoperoxidase). Otherwise vanadium is unusual cofactor in biology. By virtue of this family of enzymes, a variety of brominated natural products have been isolated from marine sources. Related chloroperoxidase enzymes effect chlorination. In the nomenclature of haloperoxidase, bromoperoxidases classically are unable to oxidize chloride at all. For example, eosinophil peroxidase appears to prefer bromide o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peroxidases
Peroxidases or peroxide reductases ( EC numberbr>1.11.1.x are a large group of enzymes which play a role in various biological processes. They are named after the fact that they commonly break up peroxides. Functionality Peroxidases typically catalyze a reaction of the form: :ROOR' + \overset + 2H+ -> ce + R'OH Optimal substrates For many of these enzymes the optimal substrate is hydrogen peroxide, but others are more active with organic hydroperoxides such as lipid peroxides. Peroxidases can contain a heme cofactor in their active sites, or alternately redox-active cysteine or selenocysteine residues. The nature of the electron donor is very dependent on the structure of the enzyme. * For example, horseradish peroxidase can use a variety of organic compounds as electron donors and acceptors. Horseradish peroxidase has an accessible active site, and many compounds can reach the site of the reaction. * On the other hand, for an enzyme such as cytochrome c peroxidase, the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eosinophil Peroxidase
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 + Br− → HOBr + H2O Hypohalous acids formed from halides or pseudohalides are potent oxidizing agents. However, the role of eosino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactoperoxidase
Lactoperoxidase is a peroxidase enzyme secreted from mammary, salivary and other mucosal glands including the lungs, bronchii and nose that functions as a natural and the first line of defense against bacteria and viruses. 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 several inorganic and organic substrates by hydrogen peroxide. These substrates include bromide and iodide and therefore lactoperoxidase can be categorised as a haloperoxidase. An other important substrate is thiocyanate. The oxidized products produced through the action of this enzyme have potent and non-specific bactericidal and antiviral activities, including destruction of the influenza virus. Lactoperoxidase together with its inorganic ion substrates, hydrogen peroxide, and oxidized products is known as the lactoperoxidase system. Hence LPO is considered a very important defense agai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environment (biophysical)
A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale from microscopic to global in extent. It can also be subdivided according to its attributes. Examples include the marine environment, the atmospheric environment and the terrestrial environment. The number of biophysical environments is countless, given that each living organism has its own environment. The term ''environment'' can refer to a singular global environment in relation to humanity, or a local biophysical environment, e.g. the UK's Environment Agency The Environment Agency (EA) is a non-departmental public body, established in 1996 and sponsored by the United Kingdom government's Department for Environment, Food and Rural Affairs, with responsibilities relating to the protection and enha .... Life-environment inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glutamate
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synthesize enough for its use. It is also the most abundant excitatory neurotransmitter in the vertebrate nervous system. It serves as the precursor for the synthesis of the inhibitory gamma-aminobutyric acid (GABA) in GABA-ergic neurons. Its molecular formula is . Glutamic acid exists in three optically isomeric forms; the dextrorotatory -form is usually obtained by hydrolysis of gluten or from the waste waters of beet-sugar manufacture or by fermentation.Webster's Third New International Dictionary of the English Language Unabridged, Third Edition, 1971. Its molecular structure could be idealized as HOOC−CH()−()2−COOH, with two carboxyl groups −COOH and one amino group −. However, in the solid state and mildly acidic water solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eosinophil
Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. Along with mast cells and basophils, they also control mechanisms associated with allergy and asthma. They are granulocytes that develop during hematopoiesis in the bone marrow before migrating into blood, after which they are terminally differentiated and do not multiply. They form about 2 to 3% of WBCs. These cells are eosinophilic or " acid-loving" due to their large acidophilic cytoplasmic granules, which show their affinity for acids by their affinity to coal tar dyes: Normally transparent, it is this affinity that causes them to appear brick-red after staining with eosin, a red dye, using the Romanowsky method. The staining is concentrated in small granules within the cellular cytoplasm, which contain many chemical mediato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutrophil
Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in different animals. They are formed from stem cells in the bone marrow and differentiated into subpopulations of neutrophil-killers and neutrophil-cagers. They are short-lived and highly mobile, as they can enter parts of tissue where other cells/molecules cannot. Neutrophils may be subdivided into segmented neutrophils and banded neutrophils (or bands). They form part of the polymorphonuclear cells family (PMNs) together with basophils and eosinophils. The name ''neutrophil'' derives from staining characteristics on hematoxylin and eosin ( H&E) histological or cytological preparations. Whereas basophilic white blood cells stain dark blue and eosinophilic white blood cells stain bright red, neutrophils stain a neutral pink. Normally, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloride Peroxidase
Chloride peroxidase () is a family of enzymes that catalyzes the chlorination of organic compounds. This enzyme combines the inorganic substrates chloride and hydrogen peroxide to produce the equivalent of Cl+, which replaces a proton in hydrocarbon substrate: :R-H + Cl− + H2O2 + H+ → R-Cl + 2 H2O In fact the source of "Cl+" is hypochlorous acid (HOCl). Many organochlorine compounds are biosynthesized in this way. This enzyme belongs to the family of oxidoreductases, specifically those acting on a peroxide as acceptors (peroxidases). The systematic name of this enzyme class is chloride:hydrogen-peroxide oxidoreductase. This enzyme is also called chloroperoxidase. It employs one cofactor which may be either heme Heme, or haem (pronounced / hi:m/ ), is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver. In biochemical terms, heme is a coordination complex "consis ... or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrian Purple
Tyrian purple ( grc, πορφύρα ''porphúra''; la, purpura), also known as Phoenician red, Phoenician purple, royal purple, imperial purple, or imperial dye, is a reddish-purple natural dye. The name Tyrian refers to Tyre, Lebanon. It is secreted by several species of predatory sea snails in the family Muricidae, rock snails originally known by the name 'Murex'. In ancient times, extracting this dye involved tens of thousands of snails and substantial labor, and as a result, the dye was highly valued. The colored compound is 6,6′-dibromoindigo. History Biological pigments were often difficult to acquire, and the details of their production were kept secret by the manufacturers. Tyrian purple is a pigment made from the mucus of several species of Murex snail. Production of Tyrian purple for use as a fabric dye began as early as 1200 BCE by the Phoenicians, and was continued by the Greeks and Romans until 1453 CE, with the fall of Constantinople. The pigment was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
