Ala-parafluoroPhe-Arg-Cha-Cit-Tyr-NH2 is a biologically active peptide functioning as a selective agonist for Protease Activated Receptor 1 (PAR-1), a subtype of G-protein coupled receptors involved in mediating thrombin's cellular effects. Exhibiting high specificity for PAR-1 over PAR-2, its selectivity was assessed via cell-based calcium signaling assays in HEK293 cells. As an agonist, it is instrumental for in vivo investigations of PAR-1 activation. PAR-1 also collaborates with PAR-4, influencing thrombin-induced hepatocellular carcinoma within 'coagulation type' tumor environments where thrombin generation occurs.