This is a negative control peptide containing the reversed sequence of the first two amino acids of the receptor-activating (tethered ligand) peptide SFLLRN-NH2. It shows no detectable affinity for the binding sites. Whereas SFLLRN-NH2 effectively displaces [3H]haTRAP, thrombin receptor-activating peptide, the same peptide with serine and phenylalanine reversed, FSLLRN-NH2, does not.
Ref: Ahn, HS. et al. Mol. Pharmacol. 51, 350 (1997).