G Protein-coupled receptors

 Ion channels

 Nuclear receptors

 Protein kinases

 Cytokines and receptors

 Cell surface molecules and ligands

 Transporters

 Enzymes

   Oxidoreductases (EC1)

   Transferases (EC2)

   Hydrolases (EC3)

   Lyases (EC4)

     Carboxy-lyases [EC:4.1.1.-]

       GAD [HSA:2571 2572] [KO:K01580]

       ODC1 [HSA:4953] [KO:K01581]

       HDC [HSA:3067] [KO:K01590]

       DDC [HSA:1644] [KO:K01593]

       DDC* [HSA_VAR:1644v1] [HSA:1644] [KO:K01593]

       AMD1 [HSA:262] [KO:K01611]

       GGCX [HSA:2677] [KO:K10106]

     Aldehyde-lyases [EC:4.1.2.-]

     Hydro-lyases [EC:4.2.1.-]

     Phosphorus-oxygen lyases [EC:4.6.1.-]

     Moco biosynthesis enzyme [EC:4.1.99.2 4.6.1.17]

   Isomerases (EC5)

   Ligases (EC6)

 Nucleic acids

 Not elsewhere classified