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

       3.4.13.4  Xaa-Arg dipeptidase

       3.4.13.5  Xaa-methyl-His dipeptidase

       3.4.13.7  Glu-Glu dipeptidase

       3.4.13.9  Xaa-Pro dipeptidase

       3.4.13.12  Met-Xaa dipeptidase

       3.4.13.17  non-stereospecific dipeptidase

       3.4.13.18  cytosol nonspecific dipeptidase

       3.4.13.19  membrane dipeptidase

       3.4.13.20  beta-Ala-His dipeptidase

       3.4.13.21  dipeptidase E

       3.4.13.22  D-Ala-D-Ala dipeptidase

       3.4.13.23  cysteinylglycine-S-conjugate dipeptidase

     3.4.14  Dipeptidyl-peptidases and tripeptidyl-peptidases

     3.4.15  Peptidyl-dipeptidases

     3.4.16  Serine-type carboxypeptidases

     3.4.17  Metallocarboxypeptidases

     3.4.18  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