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

     2.8.1  Sulfurtransferases

       2.8.1.1  thiosulfate sulfurtransferase

       2.8.1.2  3-mercaptopyruvate sulfurtransferase

       2.8.1.3  thiosulfate---thiol sulfurtransferase

       2.8.1.4  tRNA uracil 4-sulfurtransferase

       2.8.1.5  thiosulfate---dithiol sulfurtransferase

       2.8.1.6  biotin synthase

       2.8.1.7  cysteine desulfurase

       2.8.1.8  lipoyl synthase

       2.8.1.9  molybdenum cofactor sulfurtransferase

       2.8.1.10  thiazole synthase

       2.8.1.11  molybdopterin synthase sulfurtransferase

       2.8.1.12  molybdopterin synthase

       2.8.1.13  tRNA-uridine 2-sulfurtransferase

       2.8.1.14  tRNA-5-taurinomethyluridine 2-sulfurtransferase

       2.8.1.15  tRNA-5-methyluridine54 2-sulfurtransferase

       2.8.1.16  L-aspartate semialdehyde sulfurtransferase

     2.8.2  Sulfotransferases

     2.8.3  CoA-transferases

     2.8.4  Transferring alkylthio groups

     2.8.5  Thiosulfotransferases

   2.9  Transferring selenium-containing groups

   2.10  Transferring molybdenum- or tungsten-containing groups

 3. Hydrolases

 4. Lyases

 5. Isomerases

 6. Ligases

 7. Translocases