To calculate binding kinetics between PLY and PB-molecules (PB-2 and PB-3), FortèBio Octet K2 system and FortèBio Ni-NTA biosensors were employed. The experiment was executed in a black flat bottom 96-well plate and biosensors were equilibrated in recommended kinetic buffer (PBS, 0.02 % tween 20, 0.05 % NaN3) for 1 h before proceeding. All DMSO stock solutions of inhibitor and reference (DMSO) were dissolved in kinetic buffer, the total concentration of DMSO was with less than 5 %. PLY and PLYC428A (reference) both were 10x-histidine tagged, those were diluted in PBS with a final concentration 100 µg/ml. At room temperature, all samples including PLY, PLYC428A (reference), multiple concentrations of inhibitor and respective buffer control samples were transferred to 96-well plate, a working volume of 200 µl was used for each well. The layout of assay was designed in FortèBio data acquisition9 software, the experiment was carried out in following steps: 1 st initial baseline for 60 s, 2 nd protein loading for 400 s, 3 rd inhibitor baseline for 60 s, 4 th association of inhibitor for 120 s and 5 th dissociation for 200 s. Last three steps (3rd, 4th and 5th) were repeated for each concentrations of inhibitor.