**5. Materials and Methods**

#### *5.1. Reagents and Chemicals*

All chemicals and reagents were purchased from Sigma-Aldrich, Merck or Fisher, unless otherwise indicated, and were analytical grade or better. Human thrombin and factor Xa were purchased from Promega (Madison, WI, USA), human Kallikrein plasma was purchased from Sigma Aldrich (Saint Louis, MO, USA), and factor XIIa was purchased from HTI (Haematologic Technologies, Essex Junction, VT, USA). The activity of both factor XIa and factor IXa was tested using BIOPHENTM factor XIa (HYPHEN biomed, Neuvillesur-Oise, France) and BIOPHEN factor IXa, respectively. The chromogenic substrates S-2238 (H-D-Phe-Pip-Arg-pNA•2HCl) for thrombin, S-2765 (Z-D-Arg-Gly-Arg-pNA•2HCl) for factor Xa and S-2302 (H-D-Pro-Phe-Arg-pNA•2HCl) for FXIIa and Kallikrein were purchased from Chromogenix (Chromogenix, Milano, Italy). All solutions and buffers were prepared with Milli-Q water (Merck Millipore, Darmstadt, Germany).
