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

   2.8  Transferring sulfur-containing groups

   2.9  Transferring selenium-containing groups

   2.10  Transferring molybdenum- or tungsten-containing groups

     2.10.1  Molybdenumtransferases or tungstentransferases with sulfide groups as acceptors

       2.10.1.1  molybdopterin molybdotransferase

 3. Hydrolases

 4. Lyases

 5. Isomerases

 6. Ligases

 7. Translocases