Studies on Plasminogen. IX. Purification of Human Plasminogen from Cohn Fraction III by Affinity Chromatography

Abstract

Human plasminogen was prepared from Cohn fraction III by affinity chromatography with 35-fold purification and 70% recovery. The solubility of this plasminogen at pH 7.4 depends on the pH of the solutions in which it was kept during the purification procedure. Thus, a native and an altered form can be obtained by using 0.1 M lysine at pH 7.4 and 0.1 M acetic acid at pH 3.0, respectively, as eluting agents. The altered plasminogen has high activity when suspended in acidic solution. It shows little activity when suspended in pH 7.4 buffer; its activity is partially restored with addition of 0.1 M lysine. The specific activity of these plasminogens is in the same range as that of plasminogen prepared directly from human plasma by affinity chromatography.