Separation of human plasma fibrin stabilizing factor (factor XIII) from fibrinogen by fibrinogen polymer formation

Human plasma fibrin stabilizing factor (factor XIII) may be separated from fibrinogen through reversible fibrinogen polymer formation at pH 6.6, gamma/2 0.3, 0 degrees C, and subsequent Bio-Gel A 1.5m filtration. Factor XIII activity is eluted after the monomer fibrinogen peak. Polymer fractions from eight preparations, processed in duplicate, contain a mean 0.002 units factor XIII per mg fibrinogen, or about 0.7% the factor XIII content of standard plasma. Factor XIII-free fibrinogen polymers are easily dissociated (greater than 98%) to the monomer form by incubation at 37 degrees C, 18 hours. The fibrinogen preparations utilized were devoid of plasma fibronectin; thus these studies also show that reversible human fibrinogen polymer formation occurs in its absence.