Patent ID: 8617863

Claim:
A method for preparing plasmin, the method comprising: (a) contacting a composition comprising a plasminogen with a streptokinase immobilized on a matrix thereby converting the plasminogen to a plasmin, wherein the streptokinase is a streptokinase mutant characterized as capable of activating plasminogen to plasmin, yet resistant to plasmin degradation relative to its corresponding wild-type streptokinase; and wherein the streptokinase comprises an amino acid sequence having an amino acid residue other than lysine at a position corresponding to position 85, 412, or both positions, as shown in SEQ ID NO:1; and (b) purifying the plasmin by a method comprising contacting the composition with a plasmin-binding matrix so that the plasmin is retained by the plasmin-binding matrix, the plasmin-binding matrix having a molecule disposed thereon having affinity for the plasmin.