Comparison of the initial rate of PC activation by fXa in the presence of dextran sulfate and the thrombin-rabbit TM complex on phospholipids. PC (80 nmol/L) activation was carried out on 100 μg/mL PC/PS (•, ▪) or PC/PS/PE (○, □) phospholipids with 1 nmol/L fXa in the presence of 25 μg/mL dextran sulfate (▪, □) or 1 nmol/L thrombin in complex with 100 nmol/L rabbit TM (•, ○) in TBS buffer containing 5 mmol/L Ca²⁺, 1 mg/mL BSA, and 0.1% PEG 8000. At indicated time intervals, the rate of PC activation was measured by an amidolytic activity assay as described under the Materials and Methods.