FXIIIa-mediated cross-linking of α
AP and XL5-HSA to fibrinogen. FXIII was pre-activated to fXIIIa by thrombin, the thrombin inactivated with FPRck, and the fXIIIa then combined with fibrinogen and α2AP (A) or XL5-HSA (B) in transglutamination reactions probed, after reducing SDS-polyacrylamide electrophoresis, with either (A) anti-α2AP or (B) anti-HSA antibodies. The position of pre-stained molecular mass markers is indicated to the left of the panels. Reactions containing only FXIII, only fibrinogen, or only α2AP are also shown.