Purification of fibrinogen using cationic detergent.

Stearyltrimethylammonium chloride was used to isolate human fibrinogen, and purified protein was obtained by removing the detergent bound to it. Medium consisting of 0.015--0.03 mM fibrinogen-detergent complex, 0.85 M NaCl, 0.03 M sodium caprylate, and 30 per cent ethanol was found to be effective for renaturation of fibrinogen from the complex. The purified fibrinogen did not form any fibrils on incubation for 15 days with Ca-2+ at pH 7.2, and 37 degrees. The clottability of the purified fibrinogen was over 99 per cent. Immunochemical studies showed that the purified fibrinogen produced one precipitation line with a mixture of anti-human fibrinogen and anti-human serum. Although highly purified, the fibrinogen preparation still contained a trace of plasminogen.