Inhibition Assay: Assay buffers consist of 20 mM citric acid, 60 mM disodium hydrogen orthophosphate, 1 mM EDTA, 0.1% CHAPS, 4 mM DTT, pH 5.8 for legumain, 50 mM dihydrogen sodium orthophosphate, 1 mM EDTA, 5 mM DTT, pH 6.25 for cathepsin B and cathepsin Land 100 mM Tris, 0.1% CHAPS, 10% sucrose, 10 mM DTT, pH 7.4 for caspase-3. Concentrations of substrates during the measurement were 10 nM (legumain, cathepsin Land caspase-3) and 50 nM (cathepsin B) and concentration of enzymes were 100 nM for cathepsin Land caspase-3, 270 nM for legumain and 360 nM for cathepsin B. Each enzyme was incubated with inhibitor concentrations ranging from 1 nM to 1 mM in the presence of the substrates.