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Heterobivalent Ligands Crosslink Multiple Cell-Surface Receptors: The Human Melanocortin-4 and δ-Opioid Receptors


  • We thank Ms. Lucinda Begay for technical assistance. The work was supported by grants R33 CA 95944 and RO1 CA 97360 from the National Cancer Institute and the National Institute of Health.


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Together we bind: A series of synthetic heterobivalent ligands containing a fragment of melanocyte stimulating hormone analogue MSH(7) and the δ-opioid ligand deltorphin-II has been prepared. These ligands bind with higher affinity and with apparent cooperativity to cells expressing both hMC4R and δ-opioid receptors. Binding affinities were evaluated using a lanthanide-based in-cyto time-resolved fluorescence binding assay.