1. Oxidoreductases

 2. Transferases

 3. Hydrolases

 4. Lyases

 5. Isomerases

   5.1  Racemases and epimerases

   5.2  cis-trans-Isomerases

   5.3  Intramolecular oxidoreductases

   5.4  Intramolecular transferases

     5.4.1  Transferring acyl groups

     5.4.2  Phosphotransferases (phosphomutases)

     5.4.3  Transferring amino groups

     5.4.4  Transferring hydroxy groups

     5.4.99  Transferring other groups

       5.4.99.1  methylaspartate mutase

       5.4.99.2  methylmalonyl-CoA mutase

       5.4.99.3  2-acetolactate mutase

       5.4.99.4  2-methyleneglutarate mutase

       5.4.99.5  chorismate mutase

       5.4.99.7  lanosterol synthase

       5.4.99.8  cycloartenol synthase

       5.4.99.9  UDP-galactopyranose mutase

       5.4.99.11  isomaltulose synthase

       5.4.99.12  tRNA pseudouridine38-40 synthase

       5.4.99.13  isobutyryl-CoA mutase

       5.4.99.14  4-carboxymethyl-4-methylbutenolide mutase

       5.4.99.15  (1->4)-alpha-D-glucan 1-alpha-D-glucosylmutase

       5.4.99.16  maltose alpha-D-glucosyltransferase

       5.4.99.17  squalene---hopene cyclase

       5.4.99.18  5-(carboxyamino)imidazole ribonucleotide mutase

       5.4.99.19  16S rRNA pseudouridine516 synthase

       5.4.99.20  23S rRNA pseudouridine2457 synthase

       5.4.99.21  23S rRNA pseudouridine2604 synthase

       5.4.99.22  23S rRNA pseudouridine2605 synthase

       5.4.99.23  23S rRNA pseudouridine1911/1915/1917 synthase

       5.4.99.24  23S rRNA pseudouridine955/2504/2580 synthase

       5.4.99.25  tRNA pseudouridine55 synthase

       5.4.99.26  tRNA pseudouridine65 synthase

       5.4.99.27  tRNA pseudouridine13 synthase

       5.4.99.28  tRNA pseudouridine32 synthase

       5.4.99.29  23S rRNA pseudouridine746 synthase

       5.4.99.30  UDP-arabinopyranose mutase

       5.4.99.31  thalianol synthase

       5.4.99.32  protostadienol synthase

       5.4.99.33  cucurbitadienol synthase

       5.4.99.34  germanicol synthase

       5.4.99.35  taraxerol synthase

       5.4.99.36  isomultiflorenol synthase

       5.4.99.37  dammaradiene synthase

       5.4.99.38  camelliol C synthase

       5.4.99.39  beta-amyrin synthase

       5.4.99.40  alpha-amyrin synthase

       5.4.99.41  lupeol synthase

       5.4.99.42  tRNA pseudouridine31 synthase

       5.4.99.43  21S rRNA pseudouridine2819 synthase

       5.4.99.44  mitochondrial tRNA pseudouridine27/28 synthase

       5.4.99.45  tRNA pseudouridine38/39 synthase

       5.4.99.46  shionone synthase

       5.4.99.47  parkeol synthase

       5.4.99.48  achilleol B synthase

       5.4.99.49  glutinol synthase

       5.4.99.50  friedelin synthase

       5.4.99.51  baccharis oxide synthase

       5.4.99.52  alpha-seco-amyrin synthase

       5.4.99.53  marneral synthase

       5.4.99.54  beta-seco-amyrin synthase

       5.4.99.55  delta-amyrin synthase

       5.4.99.56  tirucalladienol synthase

       5.4.99.57  baruol synthase

       5.4.99.58  methylornithine synthase

       5.4.99.59  dTDP-fucopyranose mutase

       5.4.99.60  cobalt-precorrin-8 methylmutase

       5.4.99.61  precorrin-8X methylmutase

       5.4.99.62  D-ribose pyranase

       5.4.99.63  ethylmalonyl-CoA mutase

       5.4.99.64  2-hydroxyisobutanoyl-CoA mutase

       5.4.99.65  pre-alpha-onocerin synthase

       5.4.99.66  alpha-onocerin synthase

       5.4.99.67  4-amino-4-deoxychorismate mutase

   5.5  Intramolecular lyases

   5.6  Isomerases altering macromolecular conformation

   5.99  Other isomerases

 6. Ligases

 7. Translocases