Fig. 3.

Effect of calcium on the chymotrypsin C-mediated degradation of human cationic trypsin. Wild-type cationic trypsin (A) or the E82A mutant (B) were incubated at 2 μM concentration with 300 nM chymotrypsin C (final concentration) in 0.1 M Tris·HCl (pH 8.0) and the indicated CaCl₂ concentrations. At the given times, residual trypsin activity was determined as described in Fig. 1A.