Synthesis and conformational study of a cyclic hexapeptide analogue of somatostatin: cyclo(Phe‐D‐Trp‐Lys‐Thr‐o‐AMPA)

Abstract
The active sequence Phe7‐D‐Trp8‐Lys9‐Thr10 of somatostatin has been cyclized through o‐(aminomethyl)phenylacetic acid, a spacer molecule, designed to mimic a Gly‐Gly dipeptide containing a cis‐constrained peptide bond. The resulting analogue shows no GH‐inhibition. A 2D n.m.r. study reveals conformations different from the proposed bio‐active one and still sensitive to the medium (solvent).