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. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins A chemical bond is the physical process responsible for the attractive interactions between Atoms and Molecules and which confers stability to diatomic and polyatomic Hydrolysis is a Chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions which may go on to participate in further reactions Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state For example, an enzyme that catalyzed this reaction would be a lyase:

ATP → cAMP + PP_i

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. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Cyclic adenosine monophosphate ( cAMP, cyclic AMP or 3'-5'-cyclic Adenosine monophosphate) is a Second messenger that is important in many biological

Contents 1 Nomenclature 2 Classification 3 See also 4 References

Nomenclature

Systematic names are formed as "substrate group lyase. " Common names include decarboxylase, dehydratase, aldolase, etc. Carboxy-lyases, also known as decarboxylases, are carbon-carbon Lyases that add or remove a Carboxyl group from Organic compounds These Dehydratase is an enzyme that Catalyzes the removal of Oxygen and Hydrogen from Organic compounds in the form of water When the reverse reaction is more important, synthase may be used in the name. In Biochemistry, a synthase is an Enzyme which Catalyzes a Synthesis process

Classification

Lysases are classified as EC 4 in the EC number classification of enzymes. This article is about the Enzyme Commission codes For the European Commission system for coding chemicals see EC-No. Lyases can be further classified into seven subclasses:

• EC 4.1 includes lyases that cleave carbon-carbon bonds, such as decarboxylases (EC 4. Carboxy-lyases, also known as decarboxylases, are carbon-carbon Lyases that add or remove a Carboxyl group from Organic compounds These 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

See also

• List of EC numbers of enzymes belonging to category EC 4

References

• EC 4 Introduction from the Department of Chemistry at Queen Mary, University of London

Dehydratase is an enzyme that Catalyzes the removal of Oxygen and Hydrogen from Organic compounds in the form of water Adenylate cyclase ( also known as adenylyl cyclase or AC) is a Lyase Enzyme. Guanylate cyclase ( also known as guanylyl cyclase or GC) is a Lyase Enzyme. Ferrochelatase (FECH protoheme ferrolyase is an enzyme that catalyses the terminal (eighth step in the biosynthesis of Heme, converting Protoporphyrin IX into This list contains a list of EC numbers for the fourth group EC 4, Lyases, placed in numerical order as determined by the Nomenclature Committee of the Queen Mary University of London (known as Queen Mary and Westfield College until 2000 and still officially named as such in its charter Queen Mary incorporates several

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