Summary
Fibrinogen and fibrin related chains in reduced human plasma as well as the bonds
interlinking partially cross-linked fibrin from plasma clots have been studied by
means of 1D- and 2D electrophoresis and Western blotting. Immunovisualization of reduced
plasma or partially cross-linked fibrin with monoclonal antibodies specific for the
α-chains or the γ-chains have shown that several bands represent material belonging
to both chains. In order to decide whether these bands constitute αγ-chain hybrids
or superimposed α- and γ-chain dimers, the cross-linked material was separated according
to both isoelectric point (pI) and molecular weight (MW) using Pharmacia’s Multiphor
II system. Western blotting of the second dimension gels revealed that partially cross-linked
fibrin contains αsγt-chain hybrids and γ- polymers, in addition to the well-known γ-dimers and α-polymers.
The main αsγt-chain hybrid has a pI between that of the α- and the γ-chains, a MW of about 200
kDa and contains Aα-chains with intact fibrinopeptide A (FPA). It was also observed
that soluble fibrinogen/fibrin complexes as well as partially cross-linked fibrin
contain degraded α-dimers with MWs close to the γ-dimers. These findings demonstrate
that factor XIII-catalyzed cross-linking of fibrin is a more complex phenomenon than
earlier recognized.
