The synthesis of neurotensin.

A tridecapeptide having the amino acid sequence, less than Glu-Leu-Tyr-Glu-Asn-Pro-Arg-Arg-Pro-Tyr-Iie-Leu-OH, (The nomenclature and symbols follow the suggestions of the IUPAC-IUB Commission on Biochemical Nomenclature (1972) J. Biol. Chem. 247, 977).) has been synthesized by the Merrifield solid-phase procedure. The synthetic scheme chosen involved synthesis of the peptide in the (Gln) form and cyclization to the less than Glu) form. After purification, the (Gln) peptide was obtained in a 7% yield and the (greater than Glu) peptide was obtained in a 35% yield. The (greater than Glu) was found to be chemically and biologically indistinguishable from the tridecapeptide, neurotensin, recently isolated from bovine hypothalami.