[The shape of fibrin-monomer molecules in solution].

Human fibrin monomers after thrombin and reptilase proteolysis can be kept in solution at pH 4.6. Using dynamic light scattering, the hydrodynamic data of these two monomer solutions and of fibrinogen in the same buffer were compared to fibrinogen at pH 7.4. The translational diffusion coefficient DT20W of fibrinogen at pH 7.4 was 1.95 +/- 3% 10(-7).cm2.sec-1 and the rotational diffusion coefficient DR20,W 50,000 +/- 30%.sec-1. The corresponding DT and DR for the two monomer solutions and fibrinogen at pH 4.6 did not significantly deviate from the above values. It is concluded that enzymatic proteolysis of fibrinogen, triggering release of the aminoterminal fibrinopeptides A and B, does not produce a major conformational change in the resulting monomers.