Bioimmunoassay (BIA) of Tissue Plasminogen Activator (t-PA) and Its Specific Inhibitor (t-PA/INH)

Abstract

A bioimmunoassay (BIA) for tissue plasminogen activator (t-PA) is described which depends on the binding of t-PA and its inhibitor complexes to an immobilised IgG to t-PA and the subsequent assessment of the bound t-PA using glutamic acid- plasminogen (glu-plgn) and the chromogenic substrate, S-2251. This assay indicated that neither normal plasma nor its euglobulin precipitate contain any measurable free and functionally active t-PA. The BIA was also used to measure the level of the fast acting specific t-PA inhibitor (t-PA/INH) in plasma by assessing the residual t-PA activity in the plasma euglobulin fraction (pH 5.9), following the addition of a known amount of t-PA to the plasma.