Quasielastic light‐scattering studies on human fibrinogen and fibrin. I. Fibrinogen

A quasielastic light‐scattering system has been constructed to study human fibrinogen. The first phase of the investigation was an attempt to clarify the shape of the firbinogen molecule using diffusion methods. The translational diffusion coefficient was measured as 2.04 ± 0.09 × 10−7 cm2 sec−1. Aggregation is suggested as the reason for a lower value previously obtained using this technique. Diffusion indicated the molecule was rigid and did not dissociate at low concentration, low ionic strength, or 37°C. Thermal denaturation was observed at 40°C. At 3°C, a second thermal instability was discovered.