P134-M Solid Phase Synthesis of C-Terminus Fluorescent Peptide: Comparison of Fmoc-Lys(5-FAM)-Resin and Fmoc-Lys[5-FAM(Trt)]-Resin

Many FRET (Fluorescent Resonance Energy Transfer) peptides require a C-terminus fluorescent label. In order to facilitate the synthesis of C-terminus fluorescent peptides, we prepared and compared two kinds of resins, Fmoc-Lys(5-FAM)-resin (I) and Fmoc-Lys5-FAM(trt)]-resin (II).¹ Resin (II) has a phenolic hydroxyl group protected with trityl group. The reason for introducing the protecting group was supposedly to prevent the phenolic hydroxyl groups from reacting with the activated amino acids during peptide synthesis.In this report, a fluorescent peptide EREQTVDLS-VKRPRTGRKKRRQ-RRRK(5-FAM)-NH₂] was synthesized using each of these resins. Syntheses were carried out under similar standard conditions. The peptides obtained showed no significant difference in purity. These results showed that resin (I) is also suitable for synthesis of C-terminus fluorescent peptide.