1. Oxidoreductases

 2. Transferases

 3. Hydrolases

 4. Lyases

 5. Isomerases

   5.1  Racemases and epimerases

     5.1.1  Acting on amino acids and derivatives

       5.1.1.1  alanine racemase

       5.1.1.2  methionine racemase

       5.1.1.3  glutamate racemase

       5.1.1.4  proline racemase

       5.1.1.5  lysine racemase

       5.1.1.6  threonine racemase

       5.1.1.7  diaminopimelate epimerase

       5.1.1.8  4-hydroxyproline epimerase

       5.1.1.9  arginine racemase

       5.1.1.10  amino-acid racemase

       5.1.1.11  phenylalanine racemase (ATP-hydrolysing)

       5.1.1.12  ornithine racemase

       5.1.1.13  aspartate racemase

       5.1.1.14  nocardicin A epimerase

       5.1.1.15  2-aminohexano-6-lactam racemase

       5.1.1.16  protein-serine epimerase

       5.1.1.17  isopenicillin-N epimerase

       5.1.1.18  serine racemase

       5.1.1.19  O-ureido-serine racemase

       5.1.1.20  L-Ala-D/L-Glu epimerase

       5.1.1.21  isoleucine 2-epimerase

       5.1.1.22  4-hydroxyproline betaine 2-epimerase

       5.1.1.23  UDP-N-acetyl-alpha-D-muramoyl-L-alanyl-L-glutamate epimerase

       5.1.1.24  histidine racemase

       5.1.1.25  N-acetyl-D-glutamate racemase

     5.1.2  Acting on hydroxy acids and derivatives

     5.1.3  Acting on carbohydrates and derivatives

     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

   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)

       6.3.2.1  pantoate---beta-alanine ligase (AMP-forming)

       6.3.2.2  glutamate---cysteine ligase

       6.3.2.3  glutathione synthase

       6.3.2.4  D-alanine---D-alanine ligase

       6.3.2.5  phosphopantothenate---cysteine ligase (CTP)

       6.3.2.6  phosphoribosylaminoimidazolesuccinocarboxamide synthase

       6.3.2.7  UDP-N-acetylmuramoyl-L-alanyl-D-glutamate---L-lysine ligase

       6.3.2.8  UDP-N-acetylmuramate---L-alanine ligase

       6.3.2.9  UDP-N-acetylmuramoyl-L-alanine---D-glutamate ligase

       6.3.2.10  UDP-N-acetylmuramoyl-tripeptide---D-alanyl-D-alanine ligase

       6.3.2.11  carnosine synthase

       6.3.2.12  dihydrofolate synthase

       6.3.2.13  UDP-N-acetylmuramoyl-L-alanyl-D-glutamate---2,6-diaminopimelate ligase

       6.3.2.14  enterobactin synthase

       6.3.2.16  D-alanine---alanyl-poly(glycerolphosphate) ligase

       6.3.2.17  tetrahydrofolate synthase

       6.3.2.18  gamma-glutamylhistamine synthase

       6.3.2.20  indoleacetate---lysine synthetase

       6.3.2.23  homoglutathione synthase

       6.3.2.24  tyrosine---arginine ligase

       6.3.2.25  tubulin---tyrosine ligase

       6.3.2.26  N-(5-amino-5-carboxypentanoyl)-L-cysteinyl-D-valine synthase

       6.3.2.29  cyanophycin synthase (L-aspartate-adding)

       6.3.2.30  cyanophycin synthase (L-arginine-adding)

       6.3.2.31  coenzyme F420-0:L-glutamate ligase

       6.3.2.32  coenzyme gamma-F420-2:alpha-L-glutamate ligase

       6.3.2.33  tetrahydrosarcinapterin synthase

       6.3.2.34  coenzyme F420-1:gamma-L-glutamate ligase

       6.3.2.35  D-alanine---D-serine ligase

       6.3.2.36  4-phosphopantoate---beta-alanine ligase

       6.3.2.37  UDP-N-acetylmuramoyl-L-alanyl-D-glutamate---D-lysine ligase

       6.3.2.38  N2-citryl-N6-acetyl-N6-hydroxylysine synthase

       6.3.2.39  aerobactin synthase

       6.3.2.40  cyclopeptine synthase

       6.3.2.41  N-acetylaspartylglutamate synthase

       6.3.2.42  N-acetylaspartylglutamylglutamate synthase

       6.3.2.43  [amino-group carrier protein]---L-2-aminoadipate ligase

       6.3.2.44  pantoate---beta-alanine ligase (ADP-forming)

       6.3.2.45  UDP-N-acetylmuramate---L-alanyl-gamma-D-glutamyl-meso-2,6-diaminoheptanedioate ligase

       6.3.2.46  fumarate---(S)-2,3-diaminopropanoate ligase

       6.3.2.47  dapdiamide synthase

       6.3.2.48  L-arginine-specific L-amino acid ligase

       6.3.2.49  L-alanine---L-anticapsin ligase

       6.3.2.50  tenuazonic acid synthetase

       6.3.2.51  phosphopantothenate---cysteine ligase (ATP)

       6.3.2.52  jasmonoyl---L-amino acid ligase

       6.3.2.53  UDP-N-acetylmuramoyl-L-alanine---L-glutamate ligase

       6.3.2.54  L-2,3-diaminopropanoate---citrate ligase

       6.3.2.55  2-[(L-alanin-3-ylcarbamoyl)methyl]-3-(2-aminoethylcarbamoyl)-2-hydroxypropanoate synthase

       6.3.2.56  staphyloferrin B synthase

       6.3.2.57  staphyloferrin A synthase

       6.3.2.58  D-ornithine---citrate ligase

       6.3.2.59  3-methyl-D-ornithine---L-lysine ligase

       6.3.2.60  glutamate---[amino group carrier protein] ligase

       6.3.2.61  tubulin-glutamate ligase

       6.3.2.62  beta-tubulin-glutamate ligase

       6.3.2.63  putrebactin synthase

       6.3.2.64  bisucaberin synthase

     6.3.3  Cyclo-ligases

     6.3.4  Other carbon-nitrogen ligases

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

   6.4  Forming carbon-carbon bonds

   6.5  Forming phosphoric-ester bonds

   6.6  Forming nitrogen-metal bonds

   6.7  Forming nitrogen-nitrogen bonds

 7. Translocases