[Synthesis of tyrosine-related peptide and their effect on progesterone production]

Twenty peptides containing hydroxy-amino acids have been synthesized manually by stepwise solid-phase procedure. The chloromethyl resin and MBHA resin were used as solid supports. A new reagent of 0.5 mol.L-1 DDSi/1.5 mol.L-1 phenol/DCM was applied for the removal of N alpha-Boc group. TFMSA was the cleaving reagent. After purification by C-18 column; all products were assayed according to amino acid analysis. The bioactivity of synthetic peptides was tested for the effect on progesterone production in vitro. Eight peptides, GlyTyrAlaLys, (SarSer)2Lys and its methyl ester, TyrLys, HisTyr-NH2, ThrProTyrLys-NH2 TyrThrProArgLys and AspHisProThrPheLys showed significant effect on inhibiting hCG-induced progesterone production, and first three of them could also inhibit basal progesterone secretion. However, peptide GlySerTyr exhibited stimulative activity on basal progesterone secretion. So far, no reasonable relationship between structure and bioactivity was found.