_EC 5.1.-.- Racemases and epimerases. 683 PDB entries  
EC 5.-.-.- Isomerases. [5,284 PDB entries]
EC 5.1.-.- Racemases and epimerases. [683 PDB entries]
EC 5.1.1.- Acting on amino acids and derivatives. [236 PDB entries]
EC 5.1.2.- Acting on hydroxy acids and derivatives. [40 PDB entries]
EC 5.1.3.- Acting on carbohydrates and derivatives. [320 PDB entries]
EC 5.1.99.- Acting on other compounds. [87 PDB entries]