Determination of the activation of fII in fII^WT and fII^MZ plasmas. To evaluate the activation potential of fII in either fII^WT or fII^MZ plasma, we used thrombin generation assays to assess fIIa/fIIa^MZ generation over time. Representative thrombin generation curves from fII^WT (A) and fII^MZ (B) plasma. Time to the start of thrombin generation was significantly delayed in fII^MZ plasma (C), as well as time to peak thrombin generation (D). Peak fIIa/fIIa^MZ generation was also significantly decreased in the fII^MZ animals (E). Of note, plasma from 4 fII^MZ animals did not have any appreciable (meizo)thrombin generation. Therefore, they were excluded from the time-to-peak (meizothrombin) analysis. Total fIIa/fIIa^MZ generation, as represented by area under the curve, was also significantly reduced in fII^MZ plasma compared with fII^WT plasma (F).