_EC 4.3.-.- Carbon-nitrogen lyases. 238 PDB entries  
EC 4.-.-.- Lyases. [3,613 PDB entries]
EC 4.3.-.- Carbon-nitrogen lyases. [238 PDB entries]    
EC 4.3.1.- Ammonia-lyases. [104 PDB entries]
EC 4.3.2.- Lyases acting on amides, amidines, etc. [55 PDB entries]
EC 4.3.3.- Amine-lyases. [74 PDB entries]
EC 4.3.99.- Other carbon-nitrogen lyases. [5 PDB entries]