Design and Synthesis of Motilin Antagonists Derived from the [1−4] Fragment of Porcine Motilin
作者:Masayuki Haramura、Akira Okamachi、Kouichi Tsuzuki、Kenji Yogo、Makoto Ikuta、Toshiro Kozono、Hisanori Takanashi、Eigoro Murayama
DOI:10.1021/jm010332u
日期:2002.1.1
A series of cyclic peptides having the general structure H-Phe-c[-N-epsilon-Lys-X-NH-(CH2)(n)-CO-] were designed on the basis of structure-activity relationship studies of motilin. All were motilin antagonists. The cyclic peptides, in which X is a 3-tert-butyl-substituted tyrosine residue (H-Phe-c[-N-epsilon-Lys-Tyr(3-tBu)-betaAla-] (3), H-Phe-c[-N-epsilon-Lys-Tyr(3-tBu)-Gly-] (6), H-Phe-c[-N-epsilon-Lys-Tyr(3-tBu)-Abu-] (7), and H-Phe-c[-N-epsilon-Lys-Tyr(3-tBu)-Ahx-] (8)) showed potent motilin receptor antagonistic activity in the rabbit smooth muscle (pA(2) > 7). The 3-tert-butyl Tyr was found to be the moiety responsible for enhanced binding to the motilin receptor, while the size of the ring had little importance.