Tissue plasminogen activator (t-PA) analogues have at least one substitution in the growth factor (GF) domain that at least partially reduces hepatic receptor binding without substantially jeopardising physico-chemical stability in blood or fibrinolytic activity. This results in a longer plasma half life. Substitutions in the beta-sheet encompassing residues 63-72, especially at Leu 66 and/or Tyr 67 and/or Phe 68, are particularly preferred.
