title: On the supersecondary structure of acid proteases.
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D010450:Endopeptidases; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008958:Models, Molecular; D010405:Penicillinase; D010434:Pepsin A; D011487:Protein Conformation
chemical_list: D046911:Macromolecular Substances; D010450:Endopeptidases; D010434:Pepsin A; D010405:Penicillinase