Synthesis and Evaluation of Isothiocyanate-Containing Derivatives of the δ-Opioid Receptor Antagonist Tyr-Tic-Phe-Phe (TIPP) as Potential Affinity Labels for δ-Opioid Receptors
作者:Dean Y. Maeda、Fred Berman、Thomas F. Murray、Jane V. Aldrich
DOI:10.1021/jm000345s
日期:2000.12.1
Derivatives of the delta -opioid receptor-selective peptide antagonist H-Tyr-Tic-Phe-Phe-OH (TIPP) containing an isothiocyanate moiety at the para position of either Phe(3) or Phe(4) were prepared as potential affinity labels for delta -opioid receptors. The;synthesis was accomplished using a general solution-phase synthetic procedure which allows for introduction of affinity labeling groups late in the synthesis of a variety of small peptide substrates. The target peptides and their corresponding amines were then evaluated in radioligand binding experiments using Chinese hamster ovary (CHO) cells expressing delta- and mu -opioid receptors. The peptides [Phe-(P-NCS)(3)]TIPP (2) and [Phe(p-NCS)(4)]TIPP (4) showed affinity for delta -receptors comparable to the parent compound TIPP (IC50 = 12 and 5 nM, respectively, vs 6 nM for TIPP). Both peptides 2 and 4 were able to inhibit radioligand binding to d-receptors in a wash-resistant manner at a concentration of 10 nM. Therefore, the peptides [Phe(p-NCS)(3)]TIPP (2) and [Phe(p-NCS)(4)]-TIPP (4) represent two affinity labels that may prove useful in the study of delta -opioid receptors.