Subject(s)
Glycoproteins/chemistry , Protein Structure, Secondary , Tissue Plasminogen Activator/chemistry , Tissue Plasminogen Activator/metabolism , Animals , CHO Cells , Circular Dichroism , Cricetinae , Enzyme Stability , Glycoproteins/metabolism , Humans , Protein Denaturation , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , TransfectionABSTRACT
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.
