Purity >95%. A PAR-2 activating peptide (PAR-2-AP);the putative N-terminal activating peptide sequence of the rat PAR2 receptor (SLIGRL) is identical with the one previously cloned from murine tissue. We concluded that;like the thrombin receptor;the PAR2 receptor may play a pathophysiologic role in the regulation of vascular and gastric smooth muscle contractility.