[Fibrin fragment beta 15-118. Inhibitory and complex-forming properties].

Peptide beta 15-118 isolated from desAABB-NDSK preserves fibrin polymerization active site "B", inhibits polymerization process at 12 degrees C, eliminates the inhibitory properties of plasmin D-D-fragment but does not influence inhibitory properties of a D-monomer fragment. Complex formation between peptide beta 15-118 and both D- and D-D fragments was electrophoretically demonstrated. Peptide beta 15-118 forms more stable complex with the D-D fragment which does not dissociate in the medium of polymerizing fibrin as the complex of the peptide with monomer D fragment does.

[Study of the polymerization of fibrin using monoclonal antibodies 2D-2A and their Fab-fragments].

It has been shown that monAb's 2d-2a and their Fab-fragments are specific and effective inhibitors of fibrinogen clotting. Only one IgG molecule of monAb's 2d-2a can bind with one of their epitopes situated around peptide bond B beta Arg14-Gly15 in dimer fibrinogen molecule reducing the rate of protofibril lateral association and clot turbidity with only one fibrinopeptide B splitting off per fibrinogen molecule by thrombin. But two molecules of Fab-fragments of monAb's 2d-2a join to both of their epitopes and inhibit fibrinogen clotting dramatically without clot formation and with no fibrinopeptide B splitting off.

[Interaction of fibrinogen and fibrin with protamine sulfate].

Fibrinogen and fibrin sedimentation by different protamine sulphate preparations have been studied. Ionic strength and protamine sulphate concentration are found to influence the sedimentation reaction (paracoagulation). High sedimentation activity is inherent in protamine sulphate preparations with the lower electrophoretic mobility, that is with the higher molecular weight.

[Aggregation of fibrinogen molecules in a solution].

Fibrinogen is found to be able to produce highly molecular aggregates in solution. Its maximal quantity aggregates at the temperature of 4 degrees C. The pH dependence of fibrinogen aggregates production is shown.