2.1.1. Chemicals. Chromogenic substrates S2238 (H-D-Phe-
Pip-Arg-pNA) and S2236 (p-Glu-Pro-Arg-pNa) were purchased
from BIOPHEN, and APTT-reagent was from
Renam(Russia). Ecamulin purified fromEchis multisquamatis
venom was kindly donated by Dr. Korolova. Factor X
activator from Russell’s viper venom (RVV) and ADP were
purchased from Sigma (US).