GPRP acetate is a synthetic tetrapeptide (Gly-Pro-Arg-Pro acetate) primarily used as a specific inhibitor of fibrinolysis in biochemical, hematological, and medical research. It functions by competitively binding to the kringle domains of plasminogen, preventing its activation to plasmin—a key serine protease—and thereby inhibiting the degradation of fibrin clots. This makes it invaluable in studies of blood coagulation, thrombosis, hemostasis, and vascular biology. It is commonly employed in in vitro assays to stabilize fibrin structures during experiments, in coagulation diagnostics to assess fibrinolytic activity, and in therapeutic research exploring protease involvement in cardiovascular diseases, wound healing, and inflammatory processes. Its high specificity, solubility, and stability enhance its utility in laboratory and clinical settings.