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

   6.1  Forming carbon-oxygen bonds

   6.2  Forming carbon-sulfur bonds

   6.3  Forming carbon-nitrogen bonds

     6.3.1  Acid-D-ammonia (or amine) ligases (amide synthases)

     6.3.2  Acid-D-amino-acid ligases (peptide synthases)

     6.3.3  Cyclo-ligases

     6.3.4  Other carbon-nitrogen ligases

     6.3.5  Carbon-nitrogen ligases with glutamine as amido-N-donor

       6.3.5.1  NAD+ synthase (glutamine-hydrolysing)

       6.3.5.2  GMP synthase (glutamine-hydrolysing)

       6.3.5.3  phosphoribosylformylglycinamidine synthase

       6.3.5.4  asparagine synthase (glutamine-hydrolysing)

       6.3.5.5  carbamoyl-phosphate synthase (glutamine-hydrolysing)

       6.3.5.6  asparaginyl-tRNA synthase (glutamine-hydrolysing)

       6.3.5.7  glutaminyl-tRNA synthase (glutamine-hydrolysing)

       6.3.5.9  hydrogenobyrinic acid a,c-diamide synthase (glutamine-hydrolysing)

       6.3.5.10  adenosylcobyric acid synthase (glutamine-hydrolysing)

       6.3.5.11  cobyrinate a,c-diamide synthase

       6.3.5.12  Ni-sirohydrochlorin a,c-diamide synthase

       6.3.5.13  lipid II isoglutaminyl synthase (glutamine-hydrolysing)

   6.4  Forming carbon-carbon bonds

   6.5  Forming phosphoric-ester bonds

   6.6  Forming nitrogen-metal bonds

   6.7  Forming nitrogen-nitrogen bonds

 7. Translocases