Abstract: A fibrinolytically active plasminogen activator of the tissue type, wherein the growth factor (G) domain has been deleted, and wherein also the K1 domain has been deleted and additionally has been modified in one or more of the following sites or region: the sites of amino acid residues 177, 184, 277 and 448 and the F domain, the F domain modification if present being a deletion of part or all of said domain; DNA-sequence comprising a nucleotide sequence coding for said plasminogen activator; expression vector which in a transformed host cell can express said DNA-sequence; host cell transformed using such vector; pharmaceutical composition comprising the fibrinolytically active plasminogen activator; plasminogen activator for use in treating thrombotic disease; a process for the manufacture of such fibrinolytically active plasminogen activator; a process for the treatment of thrombotic disorder; and a process of localizing thrombi while using such plasminogen activator.