“…Further, we confirmed the proposed pose is basically similar to that for the same ligands and papain in our previous docking study (R 1 is also accommodated in the S 1 pocket of papain) 33. The protonation states of titratable residues (Arg, Lys, Asp, Glu, and His) were determined according to their calculated p K a values at pH 8.0, the optimum for the trypsin activity34 by using the PDB2PQR server 36. We treated the protonation states of the side‐chains of His57, Asp102, and Ser195 in the catalytic triad as neutral (N δ H), anionic, and neutral (O γ H) forms, respectively.…”