1. Oxidoreductases

 2. Transferases

   2.1  Transferring one-carbon groups

   2.2  Transferring aldehyde or ketonic groups

   2.3  Acyltransferases

   2.4  Glycosyltransferases

   2.5  Transferring alkyl or aryl groups, other than methyl groups

   2.6  Transferring nitrogenous groups

   2.7  Transferring phosphorus-containing groups

     2.7.1  Phosphotransferases with an alcohol group as acceptor

     2.7.2  Phosphotransferases with a carboxy group as acceptor

     2.7.3  Phosphotransferases with a nitrogenous group as acceptor

     2.7.4  Phosphotransferases with a phosphate group as acceptor

     2.7.6  Diphosphotransferases

       2.7.6.1  ribose-phosphate diphosphokinase

       2.7.6.2  thiamine diphosphokinase

       2.7.6.3  2-amino-4-hydroxy-6-hydroxymethyldihydropteridine diphosphokinase

       2.7.6.4  nucleotide diphosphokinase

       2.7.6.5  GTP diphosphokinase

     2.7.7  Nucleotidyltransferases

     2.7.8  Transferases for other substituted phosphate groups

     2.7.9  Phosphotransferases with paired acceptors

     2.7.10  Protein-tyrosine kinases

     2.7.11  Protein-serine/threonine kinases

     2.7.12  Dual-specificity kinases (those acting on Ser/Thr and Tyr residues)

     2.7.13  Protein-histidine kinases

     2.7.14  Protein-arginine kinases

     2.7.99  Other protein kinases

   2.8  Transferring sulfur-containing groups

   2.9  Transferring selenium-containing groups

   2.10  Transferring molybdenum- or tungsten-containing groups

 3. Hydrolases

   3.1  Acting on ester bonds

     3.1.1  Carboxylic-ester hydrolases

     3.1.2  Thioester hydrolases

     3.1.3  Phosphoric-monoester hydrolases

     3.1.4  Phosphoric-diester hydrolases

     3.1.5  Triphosphoric-monoester hydrolases

     3.1.6  Sulfuric-ester hydrolases

     3.1.7  Diphosphoric-monoester hydrolases

       3.1.7.1  prenyl-diphosphatase

       3.1.7.2  guanosine-3',5'-bis(diphosphate) 3'-diphosphatase

       3.1.7.3  monoterpenyl-diphosphatase

       3.1.7.5  geranylgeranyl diphosphate diphosphatase

       3.1.7.6  farnesyl diphosphatase

       3.1.7.10  (13E)-labda-7,13-dien-15-ol synthase

       3.1.7.11  geranyl diphosphate diphosphatase

       3.1.7.12  (+)-kolavelool synthase

       3.1.7.13  neryl diphosphate diphosphatase

     3.1.8  Phosphoric-triester hydrolases

     3.1.11  Exodeoxyribonucleases producing 5'-phosphomonoesters

     3.1.12  Exodeoxyribonucleases producing 3'-phosphomonoesters

     3.1.13  Exoribonucleases producing 5'-phosphomonoesters

     3.1.14  Exoribonucleases producing 3'-phosphomonoesters

     3.1.15  Exonucleases that are active with either ribo- or deoxyribonucleic acids and produce 5'-phosphomonoesters

     3.1.16  Exonucleases that are active with either ribo- or deoxyribonucleic acids and produce 3'-phosphomonoesters

     3.1.21  Endodeoxyribonucleases producing 5'-phosphomonoesters

     3.1.22  Endodeoxyribonucleases producing 3'-phosphomonoesters

     3.1.25  Site-specific endodeoxyribonucleases that are specific for altered bases

     3.1.26  Endoribonucleases producing 5'-phosphomonoesters

     3.1.27  Endoribonucleases producing 3'-phosphomonoesters

     3.1.30  Endoribonucleases that are active with either ribo- or deoxyribonucleic acids and produce 5'-phosphomonoesters

     3.1.31  Endoribonucleases that are active with either ribo- or deoxyribonucleic acids and produce 3'-phosphomonoesters

   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

   3.6  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