alpha-chymotrypsin and dermorphin

A series of novel cyclic ureidopeptides, analogues of dermorphine/deltorphine tetrapeptide, were synthesized by solid phase peptide synthesis and/or in solution. The antinociceptive activity of N-substituted amides 1-10 was evaluated using hot-plate and tail-flick tests. Analogue 1 showed significant, stronger than morphine, antinociceptive effect after systemic applications. All analogues were also tested for their in vitro resistance to proteolysis by means of mass spectroscopy and it was found that all substituted amides 1-10 showed full stability during incubation with large excess of chymotrypsin and pepsin. Compound 1 is a lead molecule for further evaluation.

Topics: Analgesics, Opioid; Animals; Chymotrypsin; Hot Temperature; Hydrolysis; Hyperalgesia; Indoles; Male; Mice; Mice, Inbred BALB C; Models, Chemical; Molecular Structure; Oligopeptides; Opioid Peptides; Pepsin A; Proteolysis; Spectrometry, Mass, Electrospray Ionization; Styrenes

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 of unnatural substrates containing D-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-NH(2)) 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-N(2)H(2)Ph and Boc-Tyr-D-Ala-Phe-Gly-NH(2), which contained a d-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-OCH(2)CF(3) as an acyl donor substrate in AcOEt. The synthesis of dermorphin-(1-2) derivative Boc-Tyr-D-Ala-N(2)H(2)Ph was catalyzed by alpha-chymotrypsin in different organic solvents and D-Ala-N(2)H(2)Ph was used as an acyl acceptor substrate. Factors influencing the above enzymatic reactions were systematically studied.

Topics: Catalysis; Chromatography, High Pressure Liquid; Chymotrypsin; Molecular Structure; Oligopeptides; Opioid Peptides; Organic Chemicals; Solvents; Subtilisin