[Fibrin-fragment D-protector equilibrium system. Quantitative determination of protector activity].

Equilibrium distribution of fibrin between clot fibres and liquid phase was studied as affected by the protector fraction of fibrinogen tryptic hydrolyzate in the presence of fragment D. It was found that in such a system the protector counteracting the solubilizing fibrin-effect of fragment D evokes an increase in the content of the fibrin solid phase. The effect is suggested to be used as a quantitative index of the protector activity. The presence of equilibrium between the protector--fragment D complex and products of its dissociation is shown. This equilibrium is a part of a more complex fibrin--fragment D-protector equilibrium system.