Ligase
From Freepedia
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 "synthetase" (because they are used to synthesize new molecules), or "carboxylase" (when they are used to add carbon dioxide to a molecule).
Note that "synthetase" should not be confused with synthases (Synthases do not use ATP and belong to the lyase group, while synthetases do use ATP.)
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 from the Department of Chemistry at Queen Mary University of London
