title: Tritiated photoactivatable analogs of the native human thrombin receptor (PAR-1) agonist peptide, SFLLRN-NH2.
abstract: Six photoactivatable analogs of the human thrombin receptor activating peptide (TRAP), SFLLRN-NH2, were synthesized by substituting the photoactive amino acid, p-benzoylphenylalanine (Bpa), into each position of the peptide sequence. Platelet aggregation assays indicated that the peptides with Bpa substitutions at positions 3 to 6 retained agonist activity. These peptides were prepared in tritiated form as potential thrombin receptor photoaffinity labels. The [3H]Bpa-containing analogs were constructed by resynthesizing the peptides with the amino acid, 4-benzoyl-2',5'-dibromophenylalanine (Br2Bpa), and subjecting the purified peptides to Pd-catalyzed tritiodebromination. The radiochemical yields for the reductive tritiation were < 2% for peptides with [3H]Bpa in the third and fourth positions, and between 7 and 16% for the peptides with substitutions at the fifth and sixth positions. The low yields were due to over-reduction of the Bpa carbonyl group and nonspecific degradation during reductive tritiation. This report describes the first use of Br2Bpa for the preparation of tritiated photoactivatable peptides.
authors: Department of Physiology and Biophysics, The University of at Stony Brook, Stony Brook, New York, USA.
authors: J T
authors: JT
authors: Elliott
authors: W J
authors: WJ
authors: Hoekstra
authors: C K
authors: CK
authors: Derian
authors: M F
authors: MF
authors: Addo
authors: B E
authors: BE
authors: Maryanoff
authors: D G
authors: DG
authors: Ahern
authors: G D
authors: GD
authors: Prestwich
mesh_terms: D001792:Blood Platelets / Q000187:drug effects; D003432:Cross-Linking Reagents; D006801:Humans; D008024:Ligands; D008027:Light; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000737:chemistry; D019920:Photoaffinity Labels; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin / Q000819:agonists*; D014316:Tritium / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D008024:Ligands; D010446:Peptide Fragments; D019920:Photoaffinity Labels; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin; C082835:thrombin receptor peptide (42-47); D014316:Tritium; D010649:Phenylalanine; C053764:benzoylphenylalanine