F-104 epitope expression during fibrinogenolysis. (A) Purified system. Purified fibrinogen was digested with plasmin for increasing periods of time and residual F-104 immunoreactivity quantified by solution phase competitive ELISA. The T0F-104 immunoreactivity observed (16,346 ± 47 pmol Aα chain equivalents/mL) was 136% of the expected value based on amino acid analysis. Inset. SDS-PAGE was conducted on 12.5% gels under nonreducing conditions followed by transfer to nitrocellulose and F-104 immunoblotting as described in Materials and Methods. A total of 10 μg (74.1 pmol Aα chain equivalents, determined immunologically) of intact or plasmin-treated fibrinogen was applied to each lane. The migration of standard molecular weight markers is indicated at the extreme right for reference. (B) Plasma system. Fibrinogenolysis was initiated in a single donor normal plasma and F-104 immunoreactivity monitored over the course of digestion by solution phase competitive ELISA. Results are expressed as for (A). F-104 immunoreactivity in the T0 plasma (31,671 ± 2,063 pmol Aα chain equivalents/mL) was 156% of the expected value based on clottability determination. Inset. SDS-PAGE and immunoblotting were conducted as for (A). Approximately 3.5 μg clottable plasma fibrinogen (31.7 pmol Aα chain equivalents, determined immunologically) were applied to each lane.
