1. Oxidoreductases

 2. Transferases

 3. Hydrolases

   3.1  Acting on ester bonds

   3.2  Glycosylases

   3.3  Acting on ether bonds

   3.4  Acting on peptide bonds (peptidases)

     3.4.11  Aminopeptidases

     3.4.13  Dipeptidases

     3.4.14  Dipeptidyl-peptidases and tripeptidyl-peptidases

     3.4.15  Peptidyl-dipeptidases

     3.4.16  Serine-type carboxypeptidases

     3.4.17  Metallocarboxypeptidases

       3.4.17.1  carboxypeptidase A

       3.4.17.2  carboxypeptidase B

       3.4.17.3  lysine carboxypeptidase

       3.4.17.4  Gly-Xaa carboxypeptidase

       3.4.17.6  alanine carboxypeptidase

       3.4.17.8  muramoylpentapeptide carboxypeptidase

       3.4.17.10  carboxypeptidase E

       3.4.17.11  glutamate carboxypeptidase

       3.4.17.12  carboxypeptidase M

       3.4.17.13  muramoyltetrapeptide carboxypeptidase

       3.4.17.14  zinc D-Ala-D-Ala carboxypeptidase

       3.4.17.15  carboxypeptidase A2

       3.4.17.16  membrane Pro-Xaa carboxypeptidase

       3.4.17.17  tubulinyl-Tyr carboxypeptidase

       3.4.17.18  carboxypeptidase T

       3.4.17.19  carboxypeptidase Taq

       3.4.17.20  carboxypeptidase U

       3.4.17.21  glutamate carboxypeptidase II

       3.4.17.22  metallocarboxypeptidase D

       3.4.17.23  angiotensin-converting enzyme 2

       3.4.17.24  tubulin-glutamate carboxypeptidase

       3.4.17.25  glutathione-S-conjugate glycine hydrolase

     3.4.18  Cysteine-type carboxypeptidases

     3.4.19  Omega peptidases

     3.4.21  Serine endopeptidases

     3.4.22  Cysteine endopeptidases

     3.4.23  Aspartic endopeptidases

     3.4.24  Metalloendopeptidases

     3.4.25  Threonine endopeptidases

     3.4.26  Glutamic endopeptidases

   3.5  Acting on carbon-nitrogen bonds, other than peptide bonds

   3.6  Acting on acid anhydrides

   3.7  Acting on carbon-carbon bonds

   3.8  Acting on halide bonds

   3.9  Acting on phosphorus-nitrogen bonds

   3.10  Acting on sulfur-nitrogen bonds

   3.11  Acting on carbon-phosphorus bonds

   3.12  Acting on sulfur-sulfur bonds

   3.13  Acting on carbon-sulfur bonds

 4. Lyases

 5. Isomerases

 6. Ligases

 7. Translocases