_EC 3.4.23.- Aspartic endopeptidases. 1,519 PDB entries  
EC 3.-.-.- Hydrolases. [22,196 PDB entries]
EC 3.4.-.- Acting on peptide bonds (peptide hydrolases). [7,186 PDB entries]
EC 3.4.23.- Aspartic endopeptidases. [1,519 PDB entries]    
EC 3.4.23.1 Pepsin A. [13 PDB entries]
EC 3.4.23.2 Pepsin B. [-]
EC 3.4.23.3 Gastricsin. [2 PDB entries]
EC 3.4.23.4 Chymosin. [7 PDB entries]
EC 3.4.23.5 Cathepsin D. [6 PDB entries]
EC 3.4.23.6 Transferred entry: 3.4.21.103, 3.4.23.18, 3.4.23.19, 3.4.23.20, [-]
EC 3.4.23.7 Transferred entry: 3.4.23.20. [-]
EC 3.4.23.8 Transferred entry: 3.4.23.25. [-]
EC 3.4.23.9 Transferred entry: 3.4.23.21. [-]
EC 3.4.23.10 Transferred entry: 3.4.23.22. [-]
EC 3.4.23.11 Deleted entry. [-]
EC 3.4.23.12 Nepenthesin. [-]
EC 3.4.23.13 Deleted entry. [-]
EC 3.4.23.14 Deleted entry. [-]
EC 3.4.23.15 Renin. [72 PDB entries]
EC 3.4.23.16 HIV-1 retropepsin. [895 PDB entries]
EC 3.4.23.17 Pro-opiomelanocortin converting enzyme. [-]
EC 3.4.23.18 Aspergillopepsin I. [3 PDB entries]
EC 3.4.23.19 Aspergillopepsin Ii. [2 PDB entries]
EC 3.4.23.20 Penicillopepsin. [14 PDB entries]
EC 3.4.23.21 Rhizopuspepsin. [8 PDB entries]
EC 3.4.23.22 Endothiapepsin. [69 PDB entries]
EC 3.4.23.23 Mucorpepsin. [3 PDB entries]
EC 3.4.23.24 Candidapepsin. [11 PDB entries]
EC 3.4.23.25 Saccharopepsin. [12 PDB entries]
EC 3.4.23.26 Rhodotorulapepsin. [-]
EC 3.4.23.27 Transferred entry: 3.4.21.103. [-]
EC 3.4.23.28 Acrocylindropepsin. [-]
EC 3.4.23.29 Polyporopepsin. [1 PDB entries]
EC 3.4.23.30 Pycnoporopepsin. [-]
EC 3.4.23.31 Scytalidopepsin A. [-]
EC 3.4.23.32 Scytalidopepsin B. [4 PDB entries]
EC 3.4.23.33 Transferred entry: 3.4.21.101. [-]
EC 3.4.23.34 Cathepsin E. [2 PDB entries]
EC 3.4.23.35 Barrierpepsin. [-]
EC 3.4.23.36 Signal peptidase Ii. [-]
EC 3.4.23.37 Transferred entry: 3.4.21.100. [-]
EC 3.4.23.38 Plasmepsin I. [5 PDB entries]
EC 3.4.23.39 Plasmepsin Ii. [21 PDB entries]
EC 3.4.23.40 Phytepsin. [1 PDB entries]
EC 3.4.23.41 Yapsin 1. [-]
EC 3.4.23.42 Thermopsin. [-]
EC 3.4.23.43 Prepilin peptidase. [-]
EC 3.4.23.44 Nodavirus endopeptidase. [12 PDB entries]
EC 3.4.23.45 Memapsin 1. [12 PDB entries]
EC 3.4.23.46 Memapsin 2. [309 PDB entries]
EC 3.4.23.47 HIV-2 retropepsin. [27 PDB entries]
EC 3.4.23.48 Plasminogen activator Pla. [4 PDB entries]
EC 3.4.23.49 Omptin. [1 PDB entries]
EC 3.4.23.50 Human endogenous retrovirus K endopeptidase. [-]
EC 3.4.23.51 HycI peptidase. [2 PDB entries]
EC 3.4.23.52 Preflagellin peptidase. [1 PDB entries]

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