A facile method to prepare C-terminal fluorescently labelled peptides by an Fmoc strategy

Summary Spectrophotometric peptide probes, derivatized at the C-terminus, are conveniently prepared by means of an Fmoc solid-phase strategy. Using a resin such as Sasrin, the fully protected peptide can be cleaved from the resin with hydrazine, yielding the protected peptide-hydrazide which is subsequently oxidized to the azide. An amino-containing chromophore or fluorophore such as 5-(2-aminoethyl)-amino]-naphthalene sulfonic acid (EDANS) can be coupled directly to this activated carboxyl group. This allows for specific placement of the fluorophore at the C-terminal carboxyl group in the presence of trifunctional amino acids.