1. Oxidoreductases

 2. Transferases

 3. Hydrolases

   3.1  Acting on ester bonds

   3.2  Glycosylases

     3.2.1  Glycosidases, i.e. enzymes that hydrolyse O- and S-glycosyl compounds

     3.2.2  Hydrolysing N-glycosyl compounds

       3.2.2.1  purine nucleosidase

       3.2.2.2  inosine nucleosidase

       3.2.2.3  uridine nucleosidase

       3.2.2.4  AMP nucleosidase

       3.2.2.5  NAD+ glycohydrolase

       3.2.2.6  ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase

       3.2.2.7  adenosine nucleosidase

       3.2.2.8  ribosylpyrimidine nucleosidase

       3.2.2.9  adenosylhomocysteine nucleosidase

       3.2.2.10  pyrimidine-5'-nucleotide nucleosidase

       3.2.2.11  beta-aspartyl-N-acetylglucosaminidase

       3.2.2.12  inosinate nucleosidase

       3.2.2.13  1-methyladenosine nucleosidase

       3.2.2.14  NMN nucleosidase

       3.2.2.15  DNA-deoxyinosine glycosylase

       3.2.2.16  methylthioadenosine nucleosidase

       3.2.2.17  deoxyribodipyrimidine endonucleosidase

       3.2.2.19  [protein ADP-ribosylarginine] hydrolase

       3.2.2.20  DNA-3-methyladenine glycosylase I

       3.2.2.21  DNA-3-methyladenine glycosylase II

       3.2.2.22  rRNA N-glycosylase

       3.2.2.23  DNA-formamidopyrimidine glycosylase

       3.2.2.24  ADP-ribosyl-[dinitrogen reductase] hydrolase

       3.2.2.25  N-methyl nucleosidase

       3.2.2.26  futalosine hydrolase

       3.2.2.27  uracil-DNA glycosylase

       3.2.2.28  double-stranded uracil-DNA glycosylase

       3.2.2.29  thymine-DNA glycosylase

       3.2.2.30  aminodeoxyfutalosine nucleosidase

       3.2.2.31  adenine glycosylase

   3.3  Acting on ether bonds

   3.4  Acting on peptide bonds (peptidases)

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

   3.6  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