Novel protein which has been identified in blood, a process for preparing the same, a process for assaying this protein and also t-PA inhibitor, and pharmaceutical compositions containing said protein.

摘要

The invention relates to a novel blood protein, called plasminogen activator binding protein (PA-BP), having a molecular mass of about 100,000 as determined by gel chromatography on Ultrogel ACA 44, an electrophoretic mobility in agarose at pH 8.6 equal to that of plasma beta -globulins, and an isoelectric point of 6.5-7.0.
The protein binds specifically and reversibly to tissue type plasminogen activator (t-PA) and to urokinase in the presence of a free active centre and specific kringle 2 of t-PA, is thermostable up to at least 56 DEG C, and is cleared from the circulation with a half-life in the order of days.
Further, the invention relates to methods for preparing the novel protein and to methods for assaying PA-BP, optionally in the presence of PA.
As PA-BP was found to control the availability of t-PA and urokinase by reversible binding of plasminogen activators, the novel protein may be used in therapy. Consequently, the invention relates to pharmaceutical compositions containing PA-BP.