Isolation and Properties of Human Vascular Plasminogen Activator

The vascular tree of cadaver legs was washed out with a detergent - glucose mixture and the soluble activator precipitated with 8%PEG 6,000. The redissolved precipitate was chromatogranhed on 4% agarose where it exhibited an apparent molecular weight of 8 × 10⁵ and was well resolved from lipids, factor VIII antigen, albumin and haemoglobin. The active material eluted in the void volume of G-200 Sephadex when using 0.15 M NaCl eluant, but was dissociated and retarded by re-chromatography in 1 M NaCl or lysine. The dissociated, purified enzyme had an apparent molecular weight of 56,000 and was a serine protease. The enzymic activity of the carrier complex was stable for several days at 4°C, but the dissociated enzyme was rapidly inactivated at 4°C.