Analysis of cetacean plasma. (A) Activated partial thromboplastin time studies. White bars show average aPTTs of pooled normal human plasma and plasma from a cetacean (a false killer whale). Gray bars show average aPTTs for plasmas from human patients lacking FXII (−XII), FXI (−XI), PK (−PK), or HK (−HK). Black bars indicate average aPTTs for mixtures of equal volumes of human factor-deficient plasmas and false killer whale plasma. Note the normal clotting times for mixtures with human plasma lacking FXI and HK. Bars represent averages of 3 runs for each plasma. (B) Plasma western blots. One-microliter samples of plasma from a false killer whale (F), a human (H), and a mouse (M) were size fractionated by SDS-PAGE and transferred to nitrocellulose. Protein controls (C) for human FXII (XII), FXI (XI), PK, or HK were included. Blots were developed with polyclonal IgGs to each human protein (left column) or monoclonal antibodies raised against mouse FXII (1D7 and 15D10, center column) or mouse FXI (14E11 and 15B4, right column). Note the absence of signals for FXII or PK, and the presence of FXI and HK, in plasma from the false killer whale.