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Lyase
From Wikipedia, the free encyclopedia
(Redirected from Lyases)
In biochemistry, a lyase is an enzyme that catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond or a new ring structure. For example, an enzyme that catalyzed this reaction would be a lyase:
Lyases differ from other enzymes in that they only require one substrate for the reaction in one direction, but two substrates for the reverse reaction.
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Systematic names are formed as "substrate group lyase." Common names include decarboxylase, dehydratase, aldolase, etc. When the reverse reaction is more important, synthase may be used in the name.
Lysases are classified as EC 4 in the EC number classification of enzymes. Lyases can be further classified into seven subclasses:
- EC 4.1 includes lyases that cleave carbon-carbon bonds, such as decarboxylases (EC 4.1.1), aldehyde lyases (EC 4.1.2), oxo acid lyases(EC 4.1.3) and others (EC 4.1.99)
- EC 4.2 includes lyases that cleave carbon-oxygen bonds, such as dehydratases
- EC 4.3 includes lyases that cleave carbon-nitrogen bonds
- EC 4.4 includes lyases that cleave carbon-sulfur bonds
- EC 4.5 includes lyases that cleave carbon-halide bonds
- EC 4.6 includes lyases that cleave phosphorus-oxygen bonds, such as adenylate cyclase and guanylate cyclase
- EC 4.99 includes other lyases, such as ferrochelatase
- EC 4 Introduction from the Department of Chemistry at Queen Mary, University of London
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| Topics | Active site - Allosteric regulation - Binding site - Catalytically perfect enzyme - Coenzyme - Cofactor - Cooperativity - EC number Enzyme catalysis - Enzyme inhibitor - Enzyme kinetics - Lineweaver-Burk plot - Michaelis-Menten kinetics - List of enzymes |
| Types | EC1 Oxidoreductases/list - EC2 Transferases/list - EC3 Hydrolases/list - EC4 Lyases/list - EC5 Isomerases/list - EC6 Ligases/list |
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| Carbonic anhydrase - Fumarase - Aconitase - Enolase (Alpha) - Enoyl-CoA hydratase/3-Hydroxyacyl ACP dehydrase - Methylglutaconyl-CoA hydratase - Tryptophan synthase - Cystathionine beta synthase - Porphobilinogen synthase - 3-isopropylmalate dehydratase - Urocanate hydratase - Uroporphyrinogen III synthase - Nitrile hydratase |
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| 4.3.1 - ammonia-lyases | Histidine ammonia-lyase - Formiminotransferase cyclodeaminase - Serine dehydratase |
| 4.3.2 - amidine-lyases | Argininosuccinate lyase - Adenylosuccinate lyase |
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| Cystathionine gamma-lyase - Cystathionine-beta-lyase - Leukotriene C4 synthase |
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| Dichloromethane dehalogenase - Halohydrin dehalogenase |
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| Adenylate cyclase - Guanylate cyclase (2D, c) |