[Interaction of fibrinogen with two forms of fibrin differing in the degree of activation by thrombin]

The inhibitory effect of fibrinogen in the clotting of two fibrin monomer species--f-desAA and f-desAABB--was studied. The concentration dependence of this effect for two fibrin forms was found to be of the same character. This fact indicates that the modifying influence of fibrinogen proposed earlier in relation to f-desAABB also takes place in the case of f-desAA. However, an equal inhibitory effect is achieved for f-desAA at much higher fibrinogen concentrations than that for f-desAABB. The inhibitory effect of fibrinogen is greater at higher ionic strengths for both fibrin forms, but in the case of f-desAA this effect is more pronounced. The role of fibrin polymerization sites formed after fibrinopeptides B removal in initial fibrin polymerization and in F-f-desAABB interaction is discussed.