title: Synthesis and biological activity of a cyclic pseudohexapeptide analog of somatostatin.
abstract: A cyclic pseudohexapeptide analog of somatostatin, cyclo(Pro psi[ CH2S ]Phe-D-Trp-Lys-Thr-Phe) was synthesized by solid phase methods and diphenylphosphoryl azide ring closure. The resulting crystalline compound possessed 23% of the growth hormone inhibitory activity of the parent tetradecapeptide and approximately 6% of the activity of the all-amide cyclic hexapeptide analog in spite of the absence of one of two postulated intramolecular hydrogen bonds.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D013006:Growth Hormone / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000494:pharmacology; D011487:Protein Conformation; D051381:Rats; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D010446:Peptide Fragments; D013004:Somatostatin; D013006:Growth Hormone; C041362:cyclo(prolyl-thiomethyl-phenylalanyl-tryptophyl-lysyl-threonyl-phenylalanyl)