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High affinity conformationally constrained nociceptin/orphanin FQ(1-13) amide analogues
Laksana Charoenchai1, Hongyan Wang, Jia Bei Wang
1Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Baltimore, Baltimore, Maryland 21201, USA.
Abstract:
A series of cyclic analogues with a lactam linkage were prepared by solid phase peptide synthesis to explore possible biologically active conformation(s) of nociceptin/orphanin FQ (N/OFQ). cyclo[D-Asp(7),Lys(10)]- and cyclo[Asp (6),Lys(10)]N/OFQ(1-13)NH2 exhibit high affinity (Ki = 0.27 and 0.34 nM, respectively) and high potency in the GTPgammaS assay (EC 50 = 1.6 and 4.1 nM, respectively) at human nociceptin/orphanin FQ peptide (NOP) receptors. These analogues exhibit 2- to 3-fold higher affinity and 2- to 5-fold higher potency than the parent peptide.
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