1. Oxidoreductases

 2. Transferases

 3. Hydrolases

 4. Lyases

 5. Isomerases

   5.1  Racemases and epimerases

     5.1.1  Acting on amino acids and derivatives

     5.1.2  Acting on hydroxy acids and derivatives

     5.1.3  Acting on carbohydrates and derivatives

       5.1.3.1  ribulose-phosphate 3-epimerase

       5.1.3.2  UDP-glucose 4-epimerase

       5.1.3.3  aldose 1-epimerase

       5.1.3.4  L-ribulose-5-phosphate 4-epimerase

       5.1.3.5  UDP-arabinose 4-epimerase

       5.1.3.6  UDP-glucuronate 4-epimerase

       5.1.3.7  UDP-N-acetylglucosamine 4-epimerase

       5.1.3.8  N-acylglucosamine 2-epimerase

       5.1.3.9  N-acylglucosamine-6-phosphate 2-epimerase

       5.1.3.10  CDP-paratose 2-epimerase

       5.1.3.11  cellobiose epimerase

       5.1.3.13  dTDP-4-dehydrorhamnose 3,5-epimerase

       5.1.3.14  UDP-N-acetylglucosamine 2-epimerase (non-hydrolysing)

       5.1.3.15  glucose-6-phosphate 1-epimerase

       5.1.3.16  UDP-glucosamine 4-epimerase

       5.1.3.17  heparosan-N-sulfate-glucuronate 5-epimerase

       5.1.3.18  GDP-mannose 3,5-epimerase

       5.1.3.19  chondroitin-glucuronate 5-epimerase

       5.1.3.20  ADP-glyceromanno-heptose 6-epimerase

       5.1.3.21  maltose epimerase

       5.1.3.22  L-ribulose-5-phosphate 3-epimerase

       5.1.3.23  UDP-2,3-diacetamido-2,3-dideoxyglucuronic acid 2-epimerase

       5.1.3.24  N-acetylneuraminate epimerase

       5.1.3.25  dTDP-L-rhamnose 4-epimerase

       5.1.3.26  N-acetyl-alpha-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol 4-epimerase

       5.1.3.27  dTDP-4-dehydro-6-deoxy-D-glucose 3-epimerase

       5.1.3.28  UDP-N-acetyl-L-fucosamine synthase

       5.1.3.29  L-fucose mutarotase

       5.1.3.30  D-psicose 3-epimerase

       5.1.3.31  D-tagatose 3-epimerase

       5.1.3.32  L-rhamnose mutarotase

       5.1.3.33  2-epi-5-epi-valiolone epimerase

       5.1.3.34  monoglucosyldiacylglycerol epimerase

       5.1.3.35  2-epi-5-epi-valiolone 7-phosphate 2-epimerase

       5.1.3.36  heparosan-glucuronate 5-epimerase

       5.1.3.37  mannuronan 5-epimerase

       5.1.3.38  D-erythrulose 1-phosphate 3-epimerase

       5.1.3.40  D-tagatose 6-phosphate 4-epimerase

       5.1.3.41  fructoselysine 3-epimerase

       5.1.3.42  D-glucosamine-6-phosphate 4-epimerase

       5.1.3.43  sulfoquinovose mutarotase

       5.1.3.44  mannose 2-epimerase

     5.1.99  Acting on other compounds

   5.2  cis-trans-Isomerases

   5.3  Intramolecular oxidoreductases

   5.4  Intramolecular transferases

   5.5  Intramolecular lyases

   5.6  Isomerases altering macromolecular conformation

   5.99  Other isomerases

 6. Ligases

 7. Translocases