Disclosed is an enzymatic composition including:—at least one enzyme, termed plasminogenase, for converting, into plasmin, plasminogen from a blood plasma medium including plasminogen—a solid support that is insoluble in aqueous solution, the solid support having dimensions suitable for being able to be retained on a filter having a cut-off threshold of less than or equal to 0.22 μm. The plasminogenase is bound to the solid support and remains bound to this support on contact with a blood plasma medium. The composition is in the dry state. Also disclosed is a process for preparing such an enzymatic composition, to the use thereof and to a device (20) for preparing a blood plasma medium ex vivo rich in sterile plasmin and free of enzymatic composition.
