Structure activity deltorphins

The N-terminal tetrapeptides of D-Met-deltorphin and D-Ala-deltor-phins did not show preference for delta receptors over mu receptors. The common determinants concurring to the remarkably efficient targeting of deltorphins towards the delta receptors were identified through structure-activity relationship studies conducted on an extensive series of synthetic analogues. The following structural requirements explain why the deltorphins are such potent and selective delta agonists a phenolic side chain (Tyr) and a... [Pg.178]

In related studies, Mosberget al. (230-232) carefully evaluated the cyclic truncated deltorphin analog H-Tyr-c-[D-Cys-Phe-D-Pen]-OH (JOM-13)in a series of structure-activity and conformational studies that used the j3-MePhe constraint (230) and alternative constraints for the position (see ref 231 for an excellent review). These studies led to the conclusion of the gauche (-) side-chain conformation for Xi in Phe and the trans side-chain conformation for the Tyr Xi (232). As expected the backbone conformations of... [Pg.70]

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