title: Internalization of the amino terminal 1-78 sequence of the gamma chain of native fibrinogen and exposure associated with catabolism and plasmin cleavage.
abstract: Specific antibodies of the gamma 1--78 peptide of human fibrinogen were employed in binding assays and in equilibrium competitive inhibition assays to analyze the expression of gamma 1--78 antigenic determinants as an indication of the relative exposure of the gamma 1--78 sequence in the E domain of fibrinogen, high solubility fibrinogen subfractions I-8 and I-9, and plasmic cleavage fragments of fibrinogen and fibrin. A very limited exposure of gamma 1--78 sequences was found to occur concomitant with proteolytic deletions of the major carboxyterminal segment of the A alpha chains in fgI-8, fgI-9. Exposure of gamma 1--78 is not influenced by further proteolysis to fg-X which is associated with B beta 1--43 deletion. Further proteolysis to fg-Y, which is associated with deletion of beta 43--53 and of one of the D domains, is associated with additional exposure of gamma 1--78. This is not significantly influenced by further proteolysis to fg-E with deletion of the second D domain, deletion of A alpha 1--19, and proteolysis at the carboxyterminal aspects of the E domain chains.
mesh_terms: D000595:Amino Acid Sequence; D000906:Antibodies / Q000032:analysis; D000939:Epitopes; D005340:Fibrinogen / Q000276:immunology / Q000378:metabolism*; D005341:Fibrinolysin / Q000378:metabolism*; D006801:Humans; D010446:Peptide Fragments / Q000276:immunology; D011485:Protein Binding
chemical_list: D000906:Antibodies; D000939:Epitopes; D010446:Peptide Fragments; D005340:Fibrinogen; D005341:Fibrinolysin