Figure 9. Time course for trypsin digestion of PR-B in NaCl vs KCl and mapped proteolytic fragments.
1 μM PR-B was digested using trypsin at 500:1 protein to enzyme mass ratio. Reactions were carried out at 4°C in 20 mM Tris, pH 8.0, 2.5 mM MgCl2, 1 mM CaCl2, 1 mM DTT, 10−5 M progesterone and 300 mM MCl. Reactions were allowed to proceed for 90 minutes with samples taken as a function of time. Resultant peptides were probed using immunoblot analysis, and detected using anti-HBD antibody. (*) fragment lengths are estimated using immunoblot analysis and apparent molecular mass.