Figure 3
Activation of ferret trypsinogens and human cationic trypsinogen (PRSS1) by enteropeptidase. (A) Trypsinogens at 2 µM concentration were incubated with 28 ng/mL human enteropeptidase (final concentration) at 37 °C, in 0.1 M Tris-HCl (pH 8.0), 1 mM CaCl2 and 0.05% Tween 20 (final concentrations) in a final volume of 100 µL. Aliquots of 2 µL were withdrawn at the indicated times and trypsin activity was measured with the N-CBZ-Gly-Pro-Arg-p-nitroanilide substrate. Mean values with S.D. are shown. (B) Samples (90 µL) were precipitated with 10% trichloroacetic acid (final concentration) at the indicated times and analyzed by SDS-PAGE and Coomassie Blue staining, as described in Methods. A representative gel from two experiments is shown.
