Evaluation of intact r_EC and its plasmic degradation products by immunoblotting. In the presence of 5 mmol/L EDTA, r_EC was digested with plasmin at either 0.5, 0.05, or 0.005 U/mL for the lengths of time indicated and run on 4% to 20% gradient SDS-PAGE under reducing conditions. Western analysis was performed using two monoclonal antibodies: 29-1, which recognizes an epitope at the domain’s C-terminus, and 3-10, which recognizes an epitope downstream in the N-terminal third of _EC.