24-458: MPO may refer to: Science and technology [ edit ] Myeloperoxidase , a peroxidase enzyme most abundantly present in neutrophil granulocytes .mpo (Multi Picture Object file extension), a 3D computer graphics image file format Medial preoptic area, a portion of the preoptic area of the hypothalamus Multi-fiber Push-On , a type of optical fiber connector Multiset path ordering ,
48-574: 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. Protein families that serve as peroxidases include: The glutathione peroxidase family consists of 8 known human isoforms. Glutathione peroxidases use glutathione as an electron donor and are active with both hydrogen peroxide and organic hydroperoxide substrates. Gpx1 , Gpx2 , Gpx3, and Gpx4 have been shown to be selenium -containing enzymes, whereas Gpx6
72-494: A homodimer of heterodimers . Both are proteolytically generated from the precursor peptide encoded by the MPO gene. The light chains are glycosylated and contain the modified iron protoporphyrin IX active site . Together, the light and heavy chains form two identical 73-kDa monomers connected by a cystine bridge at Cys153. The protein forms a deep crevice which holds the heme group at
96-604: A federally mandated and funded transportation policy-making organization in the US Master of Prosthetics and Orthotics Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title MPO . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=MPO&oldid=1188443598 " Category : Disambiguation pages Hidden categories: Short description
120-504: A now-dissolved organization previously responsible for Iran's budget Other uses [ edit ] Metal Gear Solid: Portable Ops , a 2006 video game released for the PlayStation Portable Military Post Office, a key part of a military mail system Pocono Mountains Municipal Airport (IATA code), Pennsylvania, US Most Productive Overs method , in cricket Metropolitan planning organization ,
144-450: A role in various biological processes. They are named after the fact that they commonly break up peroxides , and should not be confused with other enzymes that produce peroxide, which are often oxidases . Peroxidases typically catalyze a reaction of the form: 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
168-487: A sensitive predictor for myocardial infarction in patients presenting with chest pain . Since then, there have been over 100 published studies documenting the utility of MPO testing. The 2010 Heslop et al. study reported that measuring both MPO and CRP (C-reactive protein; a general and cardiac-related marker of inflammation) provided added benefit for risk prediction than just measuring CRP alone. Immunohistochemical staining for myeloperoxidase used to be administered in
192-695: A well-ordering in term rewriting (computer science) Matrix Product Operator, a type of tensor network central to the Density Matrix Renormalisation Group numerical technique Astronomy [ edit ] Mercury Planetary Orbiter , one component of the BepiColombo mission to Mercury Minor Planet Circulars Orbit Supplement , an astronomical publication from the Minor Planet Center Minor Planet Observer, an astronomical computer program partially based on
216-401: Is a peroxidase enzyme that in humans is encoded by the MPO gene on chromosome 17 . MPO is most abundantly expressed in neutrophils (a subtype of white blood cells ), and produces hypohalous acids to carry out their antimicrobial activity, including hypochlorous acid, the sodium salt of which is the chemical in bleach. It is a lysosomal protein stored in azurophilic granules of
240-473: Is a selenoprotein in humans with cysteine-containing homologues in rodents. Amyloid beta , when bound to heme, has been shown to have peroxidase activity. A typical group of peroxidases are the haloperoxidases . This group is able to form reactive halogen species and, as a result, natural organohalogen substances. A majority of peroxidase protein sequences can be found in the PeroxiBase database. While
264-596: Is a well-documented disease among humans resulting in impaired immune function. MPO is a member of the XPO subfamily of peroxidases and produces hypochlorous acid (HOCl) from hydrogen peroxide (H 2 O 2 ) and chloride anion (Cl ) (or hypobromous acid if Br- is present) during the neutrophil's respiratory burst . It requires heme as a cofactor . Furthermore, it oxidizes tyrosine to tyrosyl radical using hydrogen peroxide as an oxidizing agent . Hypochlorous acid and tyrosyl radical are cytotoxic , so they are used by
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#1732848170134288-424: Is different from Wikidata All article disambiguation pages All disambiguation pages Myeloperoxidase 1CXP , 1D2V , 1D5L , 1D7W , 1DNU , 1DNW , 1MHL , 1MYP , 3F9P , 3ZS0 , 3ZS1 , 4DL1 , 4EJX , 4C1M , 5FIW 4353 17523 ENSG00000005381 ENSMUSG00000009350 P05164 P11247 NM_000250 NM_010824 NP_000241 NP_034954 Myeloperoxidase ( MPO )
312-496: Is important for structure of the active site because of Asp 96's close proximity to the catalytic His95 side chain . The central heme group acts as the active site . The reaction starts when hydrogen peroxide donates an oxygen to the heme group, converting it to an activated form called "Compound I". This compound then oxidizes the chloride ions to form the hypochlorous acid and Compound II, which can be reduced back down to its original heme state. This cycle continues for as long as
336-455: Is the first and so far only human enzyme known to break down carbon nanotubes , allaying a concern among clinicians that using nanotubes for targeted delivery of medicines would lead to an unhealthy buildup of nanotubes in tissues. The 150- kDa MPO protein is a cationic heterotetramer consisting of two 15-kDa light chains and two variable-weight glycosylated heavy chains bound to a prosthetic heme group complex with calcium ions, arranged as
360-424: The additional benefit of simultaneous detection of multiple autoantibodies relevant to vasculitis. Nonetheless, this method still requires further testing. Azide has been used traditionally as an MPO inhibitor, but 4-aminobenzoic acid hydrazide (4-ABH) is a more specific inhibitor of MPO. Peroxidase Peroxidases or peroxide reductases ( EC number 1.11.1.x ) are a large group of enzymes which play
384-407: The bottom, as well as a hydrophobic pocket at the entrance to the distal heme cavity which carries out its catalytic activity. Variation in glycosylation and the identity of the heavy chain lead to variations in molecular weight within the 135-200 kDa range. In mice, three isoforms exist, differing only by the heavy chain. One of the ligands is the carbonyl group of Asp 96. Calcium-binding
408-459: The diagnosis of acute myeloid leukemia to demonstrate that the leukemic cells were derived from the myeloid lineage. Myeloperoxidase staining is still important in the diagnosis of myeloid sarcoma , contrasting with the negative staining of lymphomas , which can otherwise have a similar appearance. In the case of screening patients for vasculitis, flow cytometric assays have demonstrated comparable sensitivity to immunofluorescence tests, with
432-482: The exact mechanisms have yet to be determined, peroxidases are known to play a part in increasing a plant's defenses against pathogens. Many members of the Solanaceae, notably Solanum melongena (eggplant/aubergine) and Capsicum chinense (the habanero/Scotch bonnet varieties of chili peppers) use Guaiacol and the enzyme guaiacol peroxidase as a defense against bacterial parasites such as Ralstonia solanacearum :
456-556: The gene expression for this enzyme commences within minutes of bacterial attack. Peroxidase can be used for treatment of industrial waste waters. For example, phenols , which are important pollutants, can be removed by enzyme-catalyzed polymerization using horseradish peroxidase . Thus phenols are oxidized to phenoxy radicals, which participate in reactions where polymers and oligomers are produced that are less toxic than phenols. It also can be used to convert toxic materials into less harmful substances. There are many investigations about
480-564: The immune system requires. Myeloperoxidase deficiency is a hereditary deficiency of the enzyme, which predisposes to immune deficiency . Antibodies against MPO have been implicated in various types of vasculitis , most prominently three clinically and pathologically recognized forms: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA); and eosinophilic granulomatosis with polyangiitis (EGPA). Antibodies are also known as anti-neutrophil cytoplasmic antibodies (ANCAs), though ANCAs have also been detected in staining of
504-436: The neutrophil and released into the extracellular space during degranulation. Neutrophil myeloperoxidase has a heme pigment, which causes its green color in secretions rich in neutrophils , such as mucus and sputum . The green color contributed to its outdated name verdoperoxidase . Myeloperoxidase is found in many different organisms including mammals, birds, fish, reptiles, and amphibians. Myeloperoxidase deficiency
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#1732848170134528-521: The neutrophil to kill bacteria and other pathogens . However, this hypochlorous acid may also cause oxidative damage in host tissue. Moreover, MPO oxidation of apoA -I reduces HDL-mediated inhibition of apoptosis and inflammation. In addition, MPO mediates protein nitrosylation and the formation of 3-chlorotyrosine and dityrosine crosslinks . Following phagocytosis, the immune cells repair and remodel tissues, which can be aided by oxidized products of myeloperoxidase function. Myeloperoxidase
552-510: The perinuclear region. Recent studies have reported an association between elevated myeloperoxidase levels and the severity of coronary artery disease . And Heslop et al. reported that elevated MPO levels more than doubled the risk for cardiovascular mortality over a 13-year period. It has also been suggested that myeloperoxidase plays a significant role in the development of the atherosclerotic lesion and rendering plaques unstable. An initial 2003 study suggested that MPO could serve as
576-647: The work of Mikko Kaasalainen Organizations [ edit ] Macedonian Patriotic Organization , a United States and Canadian organization supporting Macedonians Metropolitan planning organization , a type of transportation policy-making organization in the United States Malaysian Philharmonic Orchestra , a Malaysian orchestra based in Kuala Lumpur Managerial and Professional Officers , former British trade union Management and Planning Organization of Iran ,
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