Recombinant PbICP is a potent inhibitor of cysteine proteases but not of cathepsin B.

Substrate hydrolysis was measured in the presence of the control protein MBP (1 µM or 100 nM) or in the presence of MBP-PbICP (1 µM or 100 nM) or PbICP (100 nM). Experiments were performed in triplicate. Protease activity in the presence of 1 µM and 100 nM MBP, respectively was considered as 100% and the percentage of residual protease activity in the presence of the inhibitor was calculated. n.d. not done.