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Selenocysteine Lyase
The enzyme selenocysteine lyase (SCL) (EC 4.4.1.16) catalyzes the chemical reaction :L-selenocysteine + reduced acceptor \rightleftharpoons selenide + L-alanine + acceptor Nomenclature This enzyme belongs to the family of 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. ...s, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is L-selenocysteine selenide-lyase (L-alanine-forming). Other names in common use include selenocysteine reductase, and selenocysteine β-lyase. Function This enzyme participates in selenoamino acid metabolism by recycling Se from selenocysteine during the degradation of selenoproteins, providing an alternate source of Se for selenocysteine biosynthesis. Structure and mechanism Mammalian SCL forms a homod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (chemistry), products, which usually have properties different from the reactants. Reactions often consist of a sequence o ... [...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] |
List Of Enzymes
This article lists enzymes by their classification in the International Union of Biochemistry and Molecular Biology's Enzyme Commission (EC) numbering system. * List of EC numbers (EC 5) * List of EC numbers (EC 6) :Oxidoreductases (EC 1) (Oxidoreductase) *Dehydrogenase * Luciferase *DMSO reductase :EC 1.1 (act on the CH-OH group of donors) * :EC 1.1.1 (with NAD+ or NADP+ as acceptor) ** Alcohol dehydrogenase (NAD) ** Alcohol dehydrogenase (NADP) **Homoserine dehydrogenase ** Aminopropanol oxidoreductase **Diacetyl reductase **Glycerol dehydrogenase **Propanediol-phosphate dehydrogenase ** glycerol-3-phosphate dehydrogenase (NAD+) ** D-xylulose reductase **L-xylulose reductase **Lactate dehydrogenase **Malate dehydrogenase **Isocitrate dehydrogenase ** HMG-CoA reductase * :EC 1.1.2 (with a cytochrome as acceptor) * :EC 1.1.3 (with oxygen as acceptor) **Glucose oxidase **L-gulonolactone oxidase **Thiamine oxidase **Xanthine oxidase * :EC 1.1.4 (with a disul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenocysteine
Selenocysteine (symbol Sec or U, in older publications also as Se-Cys) is the 21st proteinogenic amino acid. Selenoproteins contain selenocysteine residues. Selenocysteine is an analogue of the more common cysteine with selenium in place of the sulfur. Selenocysteine is present in several enzymes (for example glutathione peroxidases, tetraiodothyronine 5′ deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases, selenophosphate synthetase 2, methionine-''R''-sulfoxide reductase B1 (SEPX1), and some hydrogenases). It occurs in all three domains of life, including important enzymes (listed above) present in humans. Selenocysteine was discovered by biochemist Thressa Stadtman at the National Institutes of Health. Chemistry Selenocysteine is the Se-analogue of cysteine. It is rarely encountered outside of living tissue (and is not available commercially) because it is very susceptible to air-oxidation. More common is the oxidized derivative selenocystine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridoxal Phosphate Enzymes
Pyridoxal is one form of vitamin B6. Some medically relevant bacteria, such as those in the genera ''Granulicatella'' and ''Abiotrophia'', require pyridoxal for growth. This nutritional requirement can lead to the culture phenomenon of satellite growth. In ''in vitro'' culture, these pyridoxal-dependent bacteria may only grow in areas surrounding colonies of bacteria from other genera ("satellitism") that are capable of producing pyridoxal. Pyridoxal is involved in what is believed to be the most ancient reaction of aerobic metabolism on Earth, about 2.9 billion years ago, a forerunner of the Great Oxidation Event."Protein Domain Structure Uncovers the Origin of Aerobic Metabolism and the Rise of Planetary Oxygen", Gustavo Caetano-Anolles et al., published in Structure; paper available from University of Illinois News Bureau, 2012. See also * Pyridoxal phosphate Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6, is a coenzyme in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
