_EC 5.1.1.- Acting on amino acids and derivatives. 236 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 5.1.1.1 alanine racemase. [69 PDB entries]
EC 5.1.1.2 methionine racemase. [-]
EC 5.1.1.3 glutamate racemase. [42 PDB entries]
EC 5.1.1.4 proline racemase. [5 PDB entries]
EC 5.1.1.5 lysine racemase. [2 PDB entries]
EC 5.1.1.6 threonine racemase. [-]
EC 5.1.1.7 diaminopimelate epimerase. [26 PDB entries]
EC 5.1.1.8 4-hydroxyproline epimerase. [13 PDB entries]
EC 5.1.1.9 arginine racemase. [-]
EC 5.1.1.10 amino-acid racemase. [8 PDB entries]
EC 5.1.1.11 phenylalanine racemase (ATP-hydrolyzing). [12 PDB entries]
EC 5.1.1.12 ornithine racemase. [2 PDB entries]
EC 5.1.1.13 aspartate racemase. [12 PDB entries]
EC 5.1.1.14 nocardicin-A epimerase. [-]
EC 5.1.1.15 2-aminohexano-6-lactam racemase. [4 PDB entries]
EC 5.1.1.16 protein-serine epimerase. [-]
EC 5.1.1.17 isopenicillin-N epimerase. [-]
EC 5.1.1.18 serine racemase. [14 PDB entries]
EC 5.1.1.19 O-ureido-serine racemase. [1 PDB entries]
EC 5.1.1.20 L-Ala-D/L-Glu epimerase. [11 PDB entries]
EC 5.1.1.21 isoleucine 2-epimerase. [6 PDB entries]
EC 5.1.1.22 4-hydroxyproline betaine 2-epimerase. [5 PDB entries]
EC 5.1.1.23 UDP-N-acetyl-alpha-D-muramoyl-L-alanyl-L-glutamate epimerase. [-]
EC 5.1.1.24 histidine racemase. [4 PDB entries]
EC 5.1.1.25 N-acetyl-D-glutamate racemase. [-]
EC 5.1.1.n1 Transferred entry: 5.1.1.20. [-]

[-] signifies that there are no PDB entries for the given enzyme subclass