GEL-FILTRATION OF FIBRIN-I-125 AND FIBRINOGEN-I-131 AT 20 DEGREES-C AND 37 DEGREES-C

Purified rabbit 125I-fibrin was prepared in monomeric form and mixed with rabbit plasma containing 131I-fibrinogen. Using gel filtration, 125I-fibrin could be separated from 131I-fibrinogen indicating two new findings. 1. Fibrinogen was not eluted together with fibrin at 37°C and only in a small amount of 3% at 20°C. 2. Approximately 90% of the applied fibrin could not be eluted from the column at 37°C, whereas about 50% were retained on the column at 20°C. The experiments demonstrate that fibrin partially precipitated in the column when separated from fibrinogen. Thus, fibrinogen and/or other plasma proteins are necessary for keeping fibrin in solution, but fibrin does not form complexes with fibrinogen without factor-XIII action at 37°C. Furthermore, the precipitation of fibrin in the columns during gel filtration may pose problems in the quantification of fibrin in plasma. © 1979.