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Dehydratase
Dehydratases are a group of lyase enzymes that form double and triple bonds in a substrate through the removal of water. They can be found in many places including the mitochondria, peroxisome and cytosol. There are more than 150 different dehydratase enzymes that are classified into four groups. Dehydratases can act on hydroxyacyl-CoA with or without cofactors, and some have a metal and non-metal cluster act as their active site. A dehydratase deficiency in the body can lead to a less severe condition of hyperphenylalaninemia Hyperphenylalaninemia is a medical condition characterized by mildly or strongly elevated concentrations of the amino acid phenylalanine in the blood. Phenylketonuria (PKU) can result in severe hyperphenylalaninemia. Phenylalanine concentrations ( ..., which involves an over presence of phenylalanine in the blood. It is caused by a genetic recessive disorder in the autosomal DNA. Common dehydratases include: Delta-aminolevulinic acid dehydratase is found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lyase
In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chemical bonds by means other than hydrolysis (a substitution reaction) and oxidation, often forming a new double bond or a new ring structure. The reverse reaction is also possible (called a Michael reaction). For example, an enzyme that catalyzed this reaction would be a lyase: : ATP → cAMP + PPi Lyases differ from other enzymes in that they require only one substrate for the reaction in one direction, but two substrates for the reverse reaction. Nomenclature Systematic names are formed as "''substrate group-lyase''." Common names include decarboxylase, dehydratase, aldolase, etc. When the product is more important, synthase may be used in the name, e.g. phosphosulfolactate synthase (EC 4.4.1.19, Michael addition of sulfite to phosphoenolpyruvate). A combination of both an elimination and a Michael addition is seen in O-succinylhomoserine (thiol)-lyase (MetY or MetZ) which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperphenylalaninemia
Hyperphenylalaninemia is a medical condition characterized by mildly or strongly elevated concentrations of the amino acid phenylalanine in the blood. Phenylketonuria (PKU) can result in severe hyperphenylalaninemia. Phenylalanine concentrations ( he are routinely screened in newborns by the neonatal heel prick (Guthrie test), which takes a few drops of blood from the heel of the infant. Standard heconcentrations in unaffected persons are about 60 µM: heconcentrations in persons with untreated phenylketonuria may be many times that (600µM to 2400µM), which indicate that the child is at risk for severe intellectual disability. Phenylketonuria is classed as an autosomal recessive condition: in heterozygous form, heshows a moderate elevation, perhaps two-fold over that of unaffected homozygotes, which is classified as hyperphenylalaninemia ('' hyper-'' + ''phenylalanine'' + '' -emia'' = high hein blood). Symptoms and signs The coloration of the skin, hair, and eyes is different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Object Identifier
A digital object identifier (DOI) is a persistent identifier or handle used to uniquely identify various objects, standardized by the International Organization for Standardization (ISO). DOIs are an implementation of the Handle System; they also fit within the URI system ( Uniform Resource Identifier). They are widely used to identify academic, professional, and government information, such as journal articles, research reports, data sets, and official publications. DOIs have also been used to identify other types of information resources, such as commercial videos. A DOI aims to resolve to its target, the information object to which the DOI refers. This is achieved by binding the DOI to metadata about the object, such as a URL where the object is located. Thus, by being actionable and interoperable, a DOI differs from ISBNs or ISRCs which are identifiers only. The DOI system uses the indecs Content Model for representing metadata. The DOI for a document remains fixed over t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Standard Serial Number
An International Standard Serial Number (ISSN) is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is especially helpful in distinguishing between serials with the same title. ISSNs are used in ordering, cataloging, interlibrary loans, and other practices in connection with serial literature. The ISSN system was first drafted as an International Organization for Standardization (ISO) international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard. When a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in print and electronic media. The ISSN system refers to these types as print ISSN (p-ISSN) and electronic ISSN (e-ISSN). Consequently, as defined in ISO 3297:2007, every serial in the ISSN system is also assigned a linking ISSN ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
