PAR4 (1-6) is a peptide agonist of proteinase-activated receptor 4 (PAR4) that corresponds to residues 1-6 of the amino terminal tethered ligand sequence of human PAR4 and residues 48-53 of the full-length sequence. It activates PAR4 and the cleavage site mutant PAR4R47A when used at a concentration of 500 μM. PAR4 (1-6) induces platelet aggregation of isolated washed human platelets when used at a concentration of 1 mM but does not affect clotting time induced by factor VIIa, soluble tissue factor, and collagen in an ex vivo coagulation assay.
