This is a negative control peptide containing the reverse sequence of the first two amino acids of the receptor activating (tethered ligand) peptide SFLLRN-NH2. It has no detectable affinity for the binding site. SFLLRN-NH2 effectively replaces [3H] haTRAP (thrombin receptor activating peptide), but the same peptide FSLLRN-NH2 that reverses serine and phenylalanine cannot.
Ref: Ahn, HS. et al. Mol. Pharmacol. 51, 350 (1997).