SDS-PAGE analysis of purified fibrinogen. Fibrinogen was purified from citrated plasma obtained from the patient (P) and healthy subjects (N) and was studied for the apparent molecular mass, the release of fibrinopeptides A and B by thrombin, and cross-linking of γ and α chains. (A) SDS-PAGE analyses (SDS-PAGE) of purified fibrinogen and identification of the γ chain by Western blotting using the γ chain–specific monoclonal antibody (Western blot). (B) Conversion of Aα and Bβ chains to α and β chains by thrombin treatment in the absence of calcium. (C) Formation of γ dimer (γ-γ) and α polymer (α-poly) upon thrombin treatment in the presence of FXIII and 2 mM calcium was analyzed by SDS-PAGE.