1. Oxidoreductases

 2. Transferases

   2.1  Transferring one-carbon groups

     2.1.1  Methyltransferases

     2.1.2  Hydroxymethyl-, formyl- and related transferases

     2.1.3  Carboxy- and carbamoyltransferases

       2.1.3.1  methylmalonyl-CoA carboxytransferase

       2.1.3.2  aspartate carbamoyltransferase

       2.1.3.3  ornithine carbamoyltransferase

       2.1.3.5  oxamate carbamoyltransferase

       2.1.3.6  putrescine carbamoyltransferase

       2.1.3.7  3-hydroxymethylcephem carbamoyltransferase

       2.1.3.8  lysine carbamoyltransferase

       2.1.3.9  N-acetylornithine carbamoyltransferase

       2.1.3.10  malonyl-S-ACP:biotin-protein carboxyltransferase

       2.1.3.11  N-succinylornithine carbamoyltransferase

       2.1.3.12  decarbamoylnovobiocin carbamoyltransferase

       2.1.3.15  acetyl-CoA carboxytransferase

       2.1.3.16  ureidoglycine carbamoyltransferase

     2.1.4  Amidinotransferases

     2.1.5  Methylenetransferases

   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

 3. Hydrolases

 4. Lyases

 5. Isomerases

 6. Ligases

 7. Translocases