Prevention of plasmin autodigestion by human plasma alpha2-macroglobulin.

The autodigestion of plasmin in neutral solution at 37 degrees C and prevention of plasmin autodigestion by methylamine were confirmed by using rho-Tosyl-L-Arginine-Methyl ester as a substrate of plasmin. The autodigestion of plasmin was prevented by human plasma alpha2-macroglobulin which has been reported as an antiplasmin of immediate and reversible type but was not prevented by alpha1-antitrypsin which has been reported as an antiplasmin of slow and irreversible type.