Western blot analysis of murine plasma using an ₂-AP–specific (A) or a plasminogen-specific (B and C) antiserum. (A) Lane 1, purified murine ₂-AP; lanes 2 and 3, ₂-AP^+/+ and ₂-AP^−/− plasma. (B) Lanes 1 and 2, ₂-AP^+/+ and ₂-AP^−/− plasma after incubation with human plasmin (final concentration, 1 μmol/L) for 10 seconds at 37°C. (C) Lanes 1 and 2, ₂-AP^+/+ and ₂-AP^−/− plasma; lanes 3 and 4, ₂-AP^+/+ and ₂-AP^−/− plasma activated with tcu-PA (final concentration, 50 nmol/L) for 1 hour at 37°C; lane 5, purified murine plasminogen.