FIBRIN-RECOMBINANT HUMAN FACTOR-XIII A-SUBUNIT ASSOCIATION

The association of factor XIII a-subunits with fibrin was characterize d using recombinant human placental factor XIII (rFXIII) and native fu lly hydrated fibrin clots formed from purified fibrinogen and thrombin . Binding was assessed using small columns containing fibrin and perfu sing them with radioiodinated rFXIII. Results show that thrombin activ ation of rFXIII led to fibrin binding. The association was partially r eversible since much of the bound enzyme could be removed by percolati ng clots with more buffer. Binding was blocked by antibody directed ag ainst the COOH-terminal part of fibrinogen Aalpha-chain (Aalpha389-402 ) and also by the COOH-terminal Aalpha-chain peptide fragment Aalpha24 1-476 (Hi2-DSK).