Analysis of the proteolytic activity of PC-gla/MeizoTh and APC toward HMGB1. (A) The time course of cleavage of HMGB1 by PC-gla/MeizoTh (2nM) was monitored at 37°C in the absence and presence of TM by SDS-PAGE (10% under reducing conditions) followed by immunoblotting as described in “Methods.” (B) The same as panel A except that APC (100nM) was used to monitor the cleavage of HMGB1 for 120 minutes in the absence and presence of soluble EPCR (sEPCR; 120nM); PCPSPE (25μM); sEPCR + PCPSPE; or sEPCR + PCPSPE + recombinant TM (120nM).