Fibrin--recombinant human factor XIII a-subunit association.

The association of factor XIII a-subunits with fibrin was characterized using recombinant human placental factor XIII (rFXIII) and native fully hydrated fibrin clots formed from purified fibrinogen and thrombin. Binding was assessed using small columns containing fibrin and perfusing them with radioiodinated rFXIII. Results show that thrombin activation of rFXIII led to fibrin binding. The association was partially reversible since much of the bound enzyme could be removed by percolating clots with more buffer. Binding was blocked by antibody directed against the COOH-terminal part of fibrinogen A alpha-chain (A alpha 389-402) and also by the COOH-terminal A alpha-chain peptide fragment A alpha 241-476 (Hi2-DSK).