Studies on peptides. CXLIX Solid-phase synthesis of a rabbit stomach peptide by application of a new polymer support and a new deprotecting procedure.

A newly found rabbit stomach peptide, H-Pyr-Val-Asp-Pro-Asn-Ile-Gln-Ala-OH, was synthesized by the solid-phase method. A new polymer support, cross-linked polystyrene-polypropylene composite fiber (IONEX), was employed to facilitate multiple washing processes in chain elongation reactions. β-Cycloheptyl aspartate, Asp (OChp), was employed for the first time in this solid-phase peptide synthesis. In the final step of the synthesis, the peptide was cleaved from the resin, together with other protecting groups employed, by treatment with 1 M trimethylsilyl trifluoromethanesulfonate thioanisole in trifluoroacetic acid. The deprotected peptide was found to be identical with the sample obtained from the natural source.