The Purification of Human Placental Plasminogen (Profibrinolysin)

Precipitation Methods in Plasma Fractionation

“…The purified pro-enzyme nevertheless showed high proteolytic activity after activation by streptokinase. Numerous variations of the original technique have been published [22,36,45,57], the main change being that extreme pH values have been progressively abandoned; Nitschmann and co-workers [45] extracted plasminogen from fraction 111 at pH 3 but effected purification by euglobulin precipitations, thus avoiding the dénaturation step at pH 11. Similar procedures were published by differ ent laboratories [30,57,58], certain authors using the solubilizing and stabilizing effects of lysine or e-aminocaproic acid for the extraction steps [22,51,58,61], Bergström [4] avoided the extreme acidic pH in his purifica tion of bovine plasminogen, and a similar method was used for an inter mediate-purity soluble human plasminogen [5], thus reflecting newer know ledge concerning the molecular properties of this pro-enzyme [2,61], The normal turnover and general physiological behaviour of these newer, undenatured preparations, which are soluble at physiological pH, are important from the viewpoint of substitution therapy in hyaline-membrane disease, for instance.…”