Solution syntheses of two enkephalin-containing peptides, peptide E and dynorphin(1-24), using Nin-(2,4,6-triisopropylphenylsulfonyl)tryptophan

Two enkephalin-containing peptides, peptide E and dynorphin(1-24), were synthesized by conventional solution methods employing a new Trp derivative, Nin-(2,4,6-triisopropylphenylsulfonyl)tryptophan Trp(Tps)]. All protecting groups employed including the Tps group were removed by treatment with 1 M trifluoromethanesulfonic acid (TFMSA)-thioanisole in trifluoroacetic acid (TFA) at the final steps of these syntheses. Subsequent purifications by Sephadex G-25 chromatography, CM-Biogel A ion exchange chromatography, and reversed-phase high-performance liquid chromatography afforded highly purified samples. Both synthetic peptide E and dynorphin(1-24) exhibited high in vitro opioid activity. The usefulness of this new tryptophan derivative for practical peptide synthesis was established through these syntheses of complex Trp-containing peptides.