Immunological Monitoring of Fenton Fragmentation of Fibrinogen

Fibrinogen is transformed into insoluble "neofibe" by reaction with up to 100 microM Cu(II) and 1.5 mM ascorbate. The soluble peptides which are released during the reaction can be monitored by amino acid analysis and by measuring released keto-carbonyl (with DNPH). Immunologic characterization of the soluble peptides, with antibodies directed against fibrino-peptide A (FPA) clearly show the release of this epitope, optimally at 50 microM Cu(II). Anti-FPB gives no evidence of that epitope. However, N-terminal amino acid analyses reveals the presence of 3 peptides terminating in ALA (alpha chain FPA), GLU (beta chain FPB) and SER/ASP (unknown). The release of fibrinopeptides is interpreted within the context of a general mechanism for OH'-induced peptide chain cleavage via intermediate Schiff-base hydrolysis.