LYSIS OF CROSSLINKED HUMAN FIBRIN BY PLASMIN YIELDS INITIALLY A SINGLE MOLECULAR-COMPLEX, D DIMER-E

Physicochemical and immunological comparisons between plasmin mediated crosslinked (XL) fibrin digests made in buffer, serum and buffered Trasylol systems showed that all D dimer released from XL fibrin was associated with the fibrin E fragment in a strong, non-covalent and electrophoretically stable complex which had the empirical formula 2D-E. The complex dissociated and reassociated in presence and absence of detergent. Subunits of D dimer moiety of the complex were made up of A.alpha. chain remnants (MW 12,000), B.beta. chain remnants (42,000) and crosslinked .gamma. chain remnants (MW about 80,000). A diagram showing locations of the 3 domains of the complex in 3 distinct fibrin subunits was presented. Aggregates of the complex were found in fibrin lysates made in human serum, and their significance to fibrin lysis in vivo was discussed.