_EC 1.6.4.- (not defined) 5 PDB entries  
EC 1.-.-.- Oxidoreductases. [3,392 PDB entries]
EC 1.6.-.- Acting on Nadh or nadph. [92 PDB entries]
EC 1.6.4.- (not defined) [5 PDB entries]    
EC 1.6.4.1 Transferred entry: 1.8.1.6. [-]
EC 1.6.4.2 Transferred entry: 1.8.1.7. [1 PDB entries]
EC 1.6.4.3 Transferred entry: 1.8.1.4. [-]
EC 1.6.4.4 Transferred entry: 1.8.1.8. [-]
EC 1.6.4.5 Transferred entry: 1.8.1.9. [4 PDB entries]
EC 1.6.4.6 Transferred entry: 1.8.1.10. [-]
EC 1.6.4.7 Transferred entry: 1.8.1.11. [-]
EC 1.6.4.8 Transferred entry: 1.8.1.12. [-]
EC 1.6.4.9 Transferred entry: 1.8.1.13. [-]
EC 1.6.4.10 Transferred entry: 1.8.1.14. [-]

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