A comparison of the plasminogen activator activity units of urinary-type plasminogen activator (u-PA) and tissue-type plasminogen activator (t-PA).
The earliest tissue plasminogen activator (t-PA) preparations prepared from melanoma cells were expressed in urinary-type plasminogen activator (u-PA) units of activity using the u-PA International Standard (66/46). This report describes a comparison between u-PA and t-PA units by various types of fibrin plate procedure using both human and bovine fibrin. Within the biometric limits of this procedure it was found that the potency ratio of u-PA/t-PA was 3.5 (human fibrin), 5.29 (enriched bovine fibrin) and 4.6 (crude bovine fibrin). Specific activity figures of approximately 100,000 IU/mg for pure t-PA using the urokinase standard (66/46) would convert to approximately 350,000-530,000 IU/mg using the International Standards for t-PA (83/517 and 87/670). This latter figure is compatible with the reported specific activity for purified preparations of recombinant t-PA.
Creighton-Kempsford
L J
LJ
Division of Haematology, National Institute for Biological Standards and Control, Hertfordshire, UK.
Pring
J B
JB
Gaffney
P J
PJ
D000818:Animals; D002417:Cattle; D005337:Fibrin / Q000378:metabolism; D006801:Humans; D007394:International System of Units; D010958:Plasminogen / Q000378:metabolism*; D010959:Tissue Plasminogen Activator / Q000378:metabolism*; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
D005337:Fibrin; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator