Phosphatidylserine (PS) is an anionic lipid that promotes blood coagulation by directly interacting with and allowing the assembly of protein complexes of the coagulation cascade, e.g., prothrombinase (factor Xa:Va). On platelets, PS is sequestered to the cytosolic leaflet of the plasma membrane and is only exposed on the outer membrane leaflet when the platelet becomes activated. PS exposure on other membranes can also drive blood clotting. For example, the unregulated release of PS bearing microparticles from progressing tumors plays a major role in the hypercoaguable state of malignancy. Here, we examine the effects of small PS binding peptides on the assembly and enzymatic activity of coagulation factor complexes. Using a novel surface plasmon resonance (SPR) method, we directly evaluate the effect these peptides have on coagulation factor assembly. <i>In vitro</i> effects on coagulation protein complex enzymatic activity are examined with washed platelets, microparticles, and whole blood. We demonstrate that small peptides can inhibit coagulation factor complex assembly and that this activity can significantly reduce enzymatic activity.

Peptide inhibitors of coagulation factor complex assembly

249th National Meeting (2015)

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