title: The role of the N-terminus in the active conformation of the substance P analogues.
abstract: The role of the N-terminus in the activity of substance P analogues was studied with the isolated rat spinal cord and the guinea-pig ileum. When the C-terminal Leu10 or Met11 was replaced by the D-isomer, the analogues without the N-terminal tetrapeptide were 40-100 times less potent than those with the N-terminus in both motoneuron-depolarizing and ileum-contracting actions. These results that the N-terminus may stabilize the active conformation of the substance P analogues.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D055598:Chemical Phenomena; D002621:Chemistry; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D011487:Protein Conformation; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism; D018040:Receptors, Neurokinin-1; D013116:Spinal Cord / Q000187:drug effects; D013329:Structure-Activity Relationship; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D011956:Receptors, Cell Surface; D018040:Receptors, Neurokinin-1; D013373:Substance P