Plasmin is a serine protease which cleaves polypeptide chains after arginyl and Iysyl residues. In addition to cleavage of fibrin, plasmin also catalyzes activation and/or degradation of compounds of the coagulation, kinin generation and complement systems. Plasmin Sepharose beads are designed for efficient cleavage and activation of various proteins containing a plasmin cleavage site, circumventing the need for chromatographic techniques to remove plasmin after completion of the cleavage reaction. BioVision’s Plasmin Sepharose is prepared by covalent coupling of bovine plasmin to activated 6% cross-linked Sepharose beads. 50 µl of the slurry is sufficient to cleave >90% of 1 mg of single-chain Pro-Urokinase (Cat # 7695) in 50 mM Tris buffer, 0.1 M NaCl, pH 7.4 within 3 h at 37°C. These beads can be regenerated for repeated use. The efficiency of reused beads depends on multiple criteria including previous usage, sample and handling of the beads.