Summary
A simple new procedure is reported for the isolation of canine, bovine, porcine, and
human fibrinogen. Two molar β-alanine is used to precipitate fibrinogen from barium
sulfate adsorbed plasma. The procedure is characterized by dependability and high
yields. The material is 95% to 98% clottable protein but still contains impurities
such as plasminogen and fibrin-stabilizing factor. Plasminogen may be removed by adsorption
with charcoal. The fibrinogen preparations exhibit marked stability to freezing, lyophilization,
and dialysis. Epsilon-amino-n-caproic acid and gamma-aminobutyric acid which were
also studied have the property of precipitating proteins from plasma but lack the
specificity for fibrinogen found with β-alanine.