Inhibition profile of boophilin

Inhibitor samples were incubated with the nine serine proteinases listed, and the residual activity was measured after adding proteinase-specific chromogenic substrates, as follows: Pefachrome tPA (final substrate concentration 0.18 and 0.54 mM, respectively) to trypsin (final enzyme concentration 90 ng/ml) or sc-tPA (1.9 µg/ml); Chromozym X (0.36 mM) to FXa (0.11 U/ml); Pefachrome FXIIa (0.18 mM) to FXIIa (1.8 µg/ml); Chromozym PK (0.36 mM) to plasma kallikrein (0.52 µg/ml); Chromozym tPA (0.73 mM) to FVIIa (2.2 µg/ml); Chromozym PL (0.18 mM) to plasmin (91 µg/ml); Pefachrome uPA (0.18 mM) to u-PA (154 U/ml); and Chromozym TH (0.18 mM) to tryptase (0.11 µg/ml). Reactions were allowed to proceed for 2–6 min, and the effect of boophilin was estimated by setting the activity obtained without inhibitor as 100%. n.d., not determined. The concentrations used for boophilin samples were: native (n) inhibitor, 3.53 µM; recombinant (r) inhibitor (full-length), 2.36 µM; recombinant inhibitor (C-terminal domain), 15.2 µM.