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Haem Peroxidase
Haem peroxidases (or heme peroxidases) are haem-containing enzymes that use hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ... as the electron acceptor to catalyse a number of oxidative reactions. Most haem peroxidases follow the reaction scheme: : Fe3+ + H2O2 \rightleftharpoons e4+=O' (Compound I) + H2O : e4+=O' + substrate --> e4+=O (Compound II) + oxidized substrate : e4+=O + substrate --> Fe3+ + H2O + oxidized substrate In this mechanism, the enzyme reacts with one equivalent of H2O2 to give e4+=O' (compound I). This is a two-electron oxidation/reduction reaction in which H2O2 is reduced to water, and the enzyme is oxidized. One oxidizing equivalent resides on iron, giving the oxyferryl intermediate, and in many peroxidases the porphyrin (R) is oxidi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haem
Heme (American English), or haem (Commonwealth English, both pronounced / hi:m/ ), is a ring-shaped iron-containing molecule that commonly serves as a ligand of various proteins, more notably as a component of hemoglobin, which is necessary to bind oxygen in the bloodstream. It is composed of four pyrrole rings with 2 vinyl and 2 propionic acid side chains. Heme is biosynthesized in both the bone marrow and the liver. Heme plays a critical role in multiple different redox reactions in mammals, due to its ability to carry the oxygen molecule. Reactions include oxidative metabolism (cytochrome c oxidase, succinate dehydrogenase), xenobiotic detoxification via cytochrome P450 pathways (including metabolism of some drugs), gas sensing ( guanyl cyclases, nitric oxide synthase), and microRNA processing (DGCR8). Heme is a coordination complex "consisting of an iron ion coordinated to a tetrapyrrole acting as a tetradentate ligand, and to one or two axial ligands". The definition is lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as both a monopropellant and an oxidizer in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly into water and elemental oxygen when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a Stabilizer (chemistry), stabilizer in a weakly acidic solution in an opaque bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Heme-dependent Peroxidases
Animal heme-dependent peroxidases is a family of peroxidases. Peroxidases are found in bacteria, fungi, plants and animals. On the basis of sequence similarity, a number of animal heme peroxidases can be categorized as members of a superfamily: myeloperoxidase (MPO); eosinophil peroxidase (EPO); lactoperoxidase (LPO); thyroid peroxidase (TPO); prostaglandin H synthase (PGHS); and peroxidasin. Function Myeloperoxidase (MPO) plays a major role in the oxygen-dependent microbicidal system of neutrophils. EPO from eosinophilic granulocytes participates in immunological reactions, and potentiates tumor necrosis factor (TNF) production and hydrogen peroxide release by human monocyte-derived macrophages. MPO (and possibly EPO) primarily use Cl−ions and H2O2 to form hypochlorous acid (HOCl), which can effectively kill bacteria or parasites. In secreted fluids, LPO catalyses the oxidation of thiocyanate ions (SCN−) by H2O2, producing the weak oxidizing agent hypothiocyanite (OSCN−), wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome C Peroxidase
Cytochrome ''c'' peroxidase, or CCP, is a water-soluble heme-containing enzyme of the peroxidase family that takes reducing equivalents from cytochrome ''c'' and reduces hydrogen peroxide to water: :CCP + H2O2 + 2 ferrocytochrome ''c'' + 2H+ → CCP + 2H2O + 2 ferricytochrome ''c'' CCP can be derived from aerobically grown yeast strains and can be isolated in both native and recombinant forms with high yield from ''Saccharomyces cerevisiae.'' The enzyme’s primary function is to eliminate toxic radical molecules produced by the cell which are harmful to biological systems. It works to maintain low concentration levels of hydrogen peroxide, which is generated by the organism naturally through incomplete oxygen reduction. When glucose levels in fast growing yeast strains are exhausted, the cells turn to respiration which raises the concentration of mitochondrial H2O2. In addition to its peroxidase activity, it acts as a sensor and a signaling molecule to exogenous H2O2, which acti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascorbate Peroxidase
Ascorbate peroxidase (or L-ascorbate peroxidase, APX or APEX) () is an enzyme that catalyzes the chemical reaction :L-ascorbate + H2O2 \rightleftharpoons dehydroascorbate + 2 H2O It is a member of the family of heme-containing peroxidases. Heme peroxidases catalyse the H2O2-dependent oxidation of a wide range of different, usually organic, substrates in biology. This enzyme belongs to the family of oxidoreductases, specifically those acting on a peroxide as acceptor (peroxidases). The systematic name of this enzyme class is L-ascorbate:hydrogen-peroxide oxidoreductase. Other names in common use include L-ascorbic acid peroxidase, L-ascorbic acid-specific peroxidase, ascorbate peroxidase, and ascorbic acid peroxidase. This enzyme participates in ascorbate and aldarate metabolism. Overview Ascorbate-dependent peroxidase activity was first reported in 1979,, more than 150 years after the first observation of peroxidase activity in horseradish plants and almost 40 years after the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
α Helix
An alpha helix (or α-helix) is a sequence of amino acids in a protein that are twisted into a coil (a helix). The alpha helix is the most common structural arrangement in the secondary structure of proteins. It is also the most extreme type of local structure, and it is the local structure that is most easily predicted from a sequence of amino acids. The alpha helix has a right-handed helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid that is four residues earlier in the protein sequence. Other names The alpha helix is also commonly called a: * Pauling–Corey–Branson α-helix (from the names of three scientists who described its structure) * 3.613-helix because there are 3.6 amino acids in one ring, with 13 atoms being involved in the ring formed by the hydrogen bond (starting with amidic hydrogen and ending with carbonyl oxygen) Discovery In the early 1930s, William Astbury showed that there were dras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DyP-type Peroxidase Family
In molecular biology, the DyP-type peroxidase family is a family of haem peroxidase enzymes. Haem peroxidases were originally divided into two superfamilies, namely, the animal peroxidases and the plant peroxidases (which are subdivided into class I, II and III), which include fungal (class II) and bacterial peroxidases. The DyP (for dye de-colourising peroxidase) family constitutes a novel class of haem peroxidase. Because these enzymes were derived from fungal sources, the DyP family was thought to be structurally related to the class II secretory fungal peroxidases. However, the DyP family exhibits only low sequence similarity to classical fungal peroxidases, such as LiP and MnP, and does not contain the conserved proximal and distal histidines and an essential arginine found in other plant peroxidase superfamily members. DyP proteins have several characteristics that distinguish them from all other peroxidases, including a particularly wide substrate specificity, a lack of homo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Domains
In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of several domains, and a domain may appear in a variety of different proteins. Molecular evolution uses domains as building blocks and these may be recombined in different arrangements to create proteins with different functions. In general, domains vary in length from between about 50 amino acids up to 250 amino acids in length. The shortest domains, such as zinc fingers, are stabilized by metal ions or disulfide bridges. Domains often form functional units, such as the calcium-binding EF hand domain of calmodulin. Because they are independently stable, domains can be "swapped" by genetic engineering between one protein and another to make chimeric proteins. Background The concept of the domain was first proposed in 1973 by Wetlaufer after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EC 1
EC or ec may refer to: Arts and entertainment * EC Comics, an American publisher of comic books * '' Electric Circus'', a Canadian television program * Eric Clapton Stratocaster, signature model guitars by Fender Businesses and organisations Government * Environment and Climate Change Canada, a Canadian federal government department * European Commission, the executive body of the European Union * European Council, the European Union institution comprising the college of heads of state of government * European Communities, one of the three pillars of the EU * European Community, a significant component of the European Union from 1993 to 2009, renamed European Economic Community Transportation * EuroCity, a train service of the European inter-city rail network * EasyJet Europe (IATA code: EC) * Avialeasing (former IATA code: EC), a cargo airline * East Coast (train operating company), a train operating company in the UK * EC, the aircraft registration prefix for Spain Ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
