Figure 6.

Human adhesions contain post-translationally modified fibrin

High resolution mass spectrometry analysis with subsequent peptide and post-translational modification analysis was performed on surgical samples of human adhesions.

(A) An unmodified peptide containing the thrombin cleavage site was only detected in one sample and corresponded to the thrombin cleavage site in the beta chain as indicated by the blue square.

(B) Peptides identified corresponding to the fibrinogen beta chain in different samples of human adhesions. These peptides were either unmodified (w/o, blue box), oxidized (ox, orange box), citrullinated (cit, yellow box), or carbamylated (carb, gray box). The cleavage sites for thrombin are marked in red, and the major cleavage sites for plasmin in green. Note that the adhesions contain many peptides that had been oxidized, citrullinated, and carbamylated posttranscriptionally. Many of these are clustered near the plasmin cleavage sites. ∗ samples were fixed and subjected to antigen retrieval before mass spectrometry analyses. No major differences between fixed and unfixed samples were observed in the peptide analysis.