SYNTHESIS OF α‐ AND β‐MELANOCYTE STIMULATING HORMONES*

The solid phase synthesis of α‐melanocyte stimulating hormone (α‐MSH) using the benzhydrylamine resin and a number of recently described side chain protecting groups is given. The carboxamide terminal peptide was obtained directly by treatment of the peptide resin with liquid hydrogen fluoride at 0 in the presence of carbonium ion scavengers. The solid phase synthesis of the C‐terminal carboxylate hormone, porcine β‐melanocyte stimulating hormone (β_p‐MSH), using a 1% cross‐linked Merrifield resin and the same side chain protecting groups as in the α‐MSH synthesis also is presented. Purification of both peptides was carried out by conventional chromatographic techniques. Both hormones were fully active and β_p‐MSH was slightly more potent than previously reported in the literature.