H-Gly-Tyr-Pro-Gly-Gln-Val-OH

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 PAR4^R47A 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.

PAR 4 (1-6) human, a hexapeptide, is a fragment of protease-activated receptor 4 (PAR4). PAR 4 (1-6) TFA acts as a PAR4-specific agonist[1].

[1] H Andersen, et al. Protease-activated receptor 1 is the primary mediator of thrombin-stimulated platelet procoagulant activity. Proc Natl Acad Sci U S A. 1999 Sep 28;96(20):11189-93. DOI:10.1073/pnas.96.20.11189
[2] E Bretschneider, et al. Evidence for functionally active protease-activated receptor-4 (PAR-4) in human vascular smooth muscle cells. Br J Pharmacol. 2001 Apr;132(7):1441-6. DOI:10.1038/sj.bjp.0703947