EC 3.1 Acting on ester bonds
This subclass contains the esterase enzymes. The esterases are subdivided into: carboxylic-ester hydrolases (EC 3.1.1), thioester hydrolases (EC 3.1.2), phosphoric-monoester hydrolases, the phosphatases (EC 3.1.3), phosphoric-diester hydrolases (EC 3.1.4), triphosphoric-monoester hydrolases (EC 3.1.5), sulfuric-ester hydrolases, the sulfatases (EC 3.1.6), diphosphoric monoesterases (EC 3.1.7) and phosphoric-triester hydrolases (EC 3.1.8). The nucleases, previously included under EC 3.1.4, are now placed in a number of new sub-subclasses: the exonucleases (EC 3.1.11-16) and the endonucleases (EC 3.1.21-31).
EC 3.1.23 and EC 3.1.24
In a previous edition, site-specific endodeoxyribonucleases were set out individually in subclasses EC 3.1.23 and EC 3.1.24 (since deleted), with 113 separate entries. These are now included in three entries EC 18.104.22.168, EC 22.214.171.124 and EC 126.96.36.199. A complete listing of all of these enzymes has been produced by R.J. Roberts and is available at http://rebase.neb.com/rebase/rebase.html.