_EC 1.9.6.- With a nitrogenous group as acceptor. 0 PDB entries  
EC 1.-.-.- Oxidoreductases. [8,663 PDB entries]
EC 1.9.-.- Acting on a heme group of donors. [87 PDB entries]
EC 1.9.6.- With a nitrogenous group as acceptor. [-]    
EC 1.9.6.1 Nitrate reductase (cytochrome). [-]

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