Synthesis of dermorphin-(1–4) derivatives catalyzed by proteases in organic solvents.

In order to extend the use of proteases to organic synthesis and seek the rules of enzymatic reactions in organic media, we focused on unnatural substrates for proteases to form amide bonds. In this paper, the study ofunnatural substrates containingd-amino acid residue, which act as acyl acceptors as well as acyl donors for proteases in organic media, is reported. Dermorphin is a heptapeptide (H-Tyr-d-Ala-Phe-Gly-Tyr-Pro-Ser-NH2) with potent analgesic activity. The N-terminal tetrapeptide is the minimum sequence that retains dermorphin activity, and is selected as the model compound in our study. Two dermorphin-(1–4) derivatives, Boc-Tyr-d-Ala-Phe-Gly-N2H2Ph and Boc-Tyr-d-Ala-Phe-Gly-NH2, which contained ad-amino acid residue, were synthesized by proteases in organic media for the first time. The synthesis of these two dermorphin-(1–4) derivatives could be catalyzed by subtilisin with Boc-Tyr-d-Ala-OCH2CF3 as an acyl donor substrate in AcOEt. The synthesis of dermorphin-(1–2) derivative Boc-Tyr-d-Ala-N2H2Ph was catalyzed byα-chymotrypsin in different organic solvents andd-Ala-N2H2Ph was used as an acyl acceptor substrate. Factors influencing the above enzymatic reactions were systematically studied. [ABSTRACT FROM AUTHOR]