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)

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

     3.5.1  In linear amides

     3.5.2  In cyclic amides

     3.5.3  In linear amidines

       3.5.3.1  arginase

       3.5.3.2  guanidinoacetase

       3.5.3.3  creatinase

       3.5.3.4  allantoicase

       3.5.3.5  formimidoylaspartate deiminase

       3.5.3.6  arginine deiminase

       3.5.3.7  guanidinobutyrase

       3.5.3.8  formimidoylglutamase

       3.5.3.9  allantoate deiminase

       3.5.3.10  D-arginase

       3.5.3.11  agmatinase

       3.5.3.12  agmatine deiminase

       3.5.3.13  formimidoylglutamate deiminase

       3.5.3.14  amidinoaspartase

       3.5.3.15  protein-arginine deiminase

       3.5.3.16  methylguanidinase

       3.5.3.17  guanidinopropionase

       3.5.3.18  dimethylargininase

       3.5.3.20  diguanidinobutanase

       3.5.3.21  methylenediurea deaminase

       3.5.3.22  proclavaminate amidinohydrolase

       3.5.3.23  N-succinylarginine dihydrolase

       3.5.3.24  N1-aminopropylagmatine ureohydrolase

       3.5.3.25  Nomega-hydroxy-L-arginine amidinohydrolase

       3.5.3.26  (S)-ureidoglycine aminohydrolase

       3.5.3.27  arginine dihydrolase

     3.5.4  In cyclic amidines

     3.5.5  In nitriles

     3.5.99  In other compounds

   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