Ligase
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In biochemistry, a ligase is an enzyme that can catalyse the joining of two molecules ("ligation" or "gluing together") by forming a new chemical bond, with accompanying hydrolysis of ATP or other similar molecules. For example, an enzyme that catalyzed this reaction would be a ligase:
- A + B → A–B
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Nomenclature
The common names of ligases often include the word "ligase," such as DNA ligase, an enzyme commonly used in molecular biology laboratories to join together DNA fragments. Other common names include "synthase" or "synthetase" (because they are used to synthesize new molecules), or "carboxylase" (when they are used to add carbon dioxide to a molecule).
Classification
Ligases are classified as EC 6 in the EC number classification of enzymes. Ligases can be further classified into six subclasses:
- EC 6.1 includes ligases used to form carbon-oxygen bonds
- EC 6.2 includes ligases used to form carbon-sulfur bonds
- EC 6.3 includes ligases used to form carbon-nitrogen bonds
- EC 6.4 includes ligases used to form carbon-carbon bonds
- EC 6.5 includes ligases used to form phosphoric ester bonds
- EC 6.6 includes ligases used to form nitrogen-metal bonds
See also
References
EC 6 Introduction (http://www.chem.qmul.ac.uk/iubmb/enzyme/EC6/intro.html) from the Department of Chemistry at Queen Mary University of Londonfr:Ligase