Isomerase

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In biochemistry, an isomerase is an enzyme that catalyses the structural rearrangement of isomers. Isomerases thus catalyze reactions of the form

A → B

Contents 1 Nomenclature 2 Classification 3 References 4 External links

[edit] Nomenclature

The names of isomerases are formed as "substrate isomerase" (for example, enoyl CoA isomerase), or as "substrate type of isomerase" (for example, phosphoglucomutase).

[edit] Classification

Isomerases are classified as EC 5 in the EC number classification of enzymes. Isomerases can be further classified into six subclasses:

• EC 5.1 includes enzymes that catalyze racemization (racemases) and epimerization (epimerases)
• EC 5.2 includes enzymes that catalyze the isomerization of geometric isomers (cis-trans isomerases)
• EC 5.3 includes intramolecular oxidoreductases
• EC 5.4 includes intramolecular transferases (mutases)
• EC 5.5 includes intramolecular lyases
• EC 5.99 includes other isomerases (including topoisomerases)

[edit] References

• EC 5 Introduction from the Department of Chemistry at Queen Mary, University of London

[edit] External links

• GoPubMed: Top authors, journals, places publishing on Isomerases

v • d • e Proteins: enzymes 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

v • d • e Isomerases: Epimerase and racemases (EC 5.1) Amino-acid racemase Phenylalanine racemase (ATP-hydrolysing) - Serine racemase Other Mandelate racemase - UDP galactose epimerase - Methylmalonyl CoA epimerase

v • d • e Geometric isomerases (EC 5.2) Cyclophilin - FKBP - Parvulin - Prolyl isomerase

v • d • e Intramolecular oxidoreductases isomerases (EC 5.3) 5.3.1 - Aldoses/Ketoses Triosephosphate isomerase - Phosphopentose isomerase - Mannose phosphate isomerase - Glucose isomerase 5.3.3 - C=C Isopentenyl-diphosphate delta isomerase - Enoyl CoA isomerase 5.3.4 - S-S Protein disulfide isomerase (PDIA3) 5.3.99 - other Prostaglandin D2 synthase - Prostaglandin E synthase - Prostacyclin synthase - Thromboxane-A synthase

v • d • e Isomerase: mutases (EC 5.4) 5.4.2 Phosphomutases Phosphoglycerate mutase - Bisphosphoglycerate mutase - Phosphoglucomutase 5.4.99 Other groups Methylmalonyl-CoA mutase - Lanosterol synthase

v • d • e Isomerase: topoisomerases (EC 5.99) Type I topoisomerase - Type II topoisomerase (gyrase, topoisomerase IV)