Western blots of u-PA in platelets.

u-PA in platelet lysates (L; 5 μL) and ionophore releasates (R; 5 μL) from patients with QPD (Q) and healthy control subjects (C) was visualized with monoclonal or polyclonal antisera after 10% SDS-PAGE. (A) Nonreduced analyses indicated QPD platelet lysates and releasates contained abnormally large amounts of u-PA. The predominant form of u-PA in QPD platelets comigrated, nonreduced, with recombinant scu-PA (scuPA, 10 ng), though larger and smaller forms were also detected. When control platelet releasate was incubated (lanes *) with recombinant scu-PA (lane CR + scuPA*), high–molecular weight u-PA complexes were generated that resembled large forms of u-PA in QPD releasates (arrow indicates the most abundant large form). (B) QPD platelet releasates and lysates (R and L, 5 μL nonreduced, 20 μL reduced) contained forms of u-PA with the characteristic nonreduced/reduced mobility of purified tcu-PA (tcuPA; 4.4 ng nonreduced, 17.6 ng reduced) and LMW u-PA (LMWuPA; 3.2 ng nonreduced, 12.8 ng reduced). Arrows indicate the A chain (A*) of reduced tcu-PA, the B chain (B*) common to reduced tcu-PA and LMW u-PA, and the nonreduced form of LMW u-PA (LMW). A reduced protein with the mobility of the A chain of tcu-PA was seen in prolonged exposures of the QR and QL lanes (not shown).