Enzyme activity of the recombinant cysteine protease proteins from poultry red mites (PRMs, Dermanyssus gallinae) (Deg-CPR-1). The enzyme activity of the peptidase domain of Deg-CPR-1 (Deg-CPR-1(PD)-TF) and the whole region of Deg-CPR-1 without signal peptides (Deg-CPR-1(whole)-TF), including the inhibitor domain, was assessed using a SensoLyte Rh110 Cathepsin L Assay Kit (AnaSpec, Inc., Fremont, CA, USA) to measure cathepsin L activity. The concentrations of recombinant proteins used in each assay are indicated along the x-axis. TF alone was used as a negative control. Protease activity was indicated as relative fluorescence units (RFU). Error bars indicate standard deviations. Results with p < 0.01 were considered significant.