1. Oxidoreductases

 2. Transferases

 3. Hydrolases

 4. Lyases

   4.1  Carbon-carbon lyases

   4.2  Carbon-oxygen lyases

   4.3  Carbon-nitrogen lyases

     4.3.1  Ammonia-lyases

     4.3.2  Amidine-lyases

     4.3.3  Amine-lyases

     4.3.99  Other carbon-nitrogen lyases

       4.3.99.3  7-carboxy-7-deazaguanine synthase

       4.3.99.4  choline trimethylamine-lyase

       4.3.99.5  nitrosuccinate lyase

   4.4  Carbon-sulfur lyases

   4.5  Carbon-halide lyases

   4.6  Phosphorus-oxygen lyases

   4.7  carbon-phosphorus lyases

   4.8  Nitrogen-oxygen lyases

   4.98  ATP-independent chelatases

   4.99  Other lyases

 5. Isomerases

 6. Ligases

 7. Translocases