title: beta-Endorphin omission analogs: dissociation of immunoreactivity from other biological activities.
abstract: An analog of human beta-endorphine with omission of four residues at positions 11, 14, 20, and 22 has been synthesized. This analog and other synthetic analogs with deletion of a single amino acid at position 2, 5, 6, 10, 11, 12, 13, 15, or 22 have been assayed for analgesic potency, ileal opiate activity,opiate receptor-binding activity, andimmunoreactivity. Results show that deletion of a single amino acid of the beta-endorphin molecule outside of the enkephalin segment to give des-Gln11-, des-Thr12, des-Pro13-, des-Leu14-, des-Val15-, des-Asn20-, or des-Ile22-beta-endorphin markedly reduced or abolished the immunoreactivity yet gave substantial retention of opiate potencies. Deletion of a single amino acid of beta-endorphin within the enkephalin segment (des-Gly3- or des-Met5-beta-endorphin) did not markedly affect the immunoactivity; however, the opiate activities were abolished or markedly reduced. The data indicate a clear dissociation of immunoactivity from analgesic, ileal-opiate, and opiate receptor-binding activities.
mesh_terms: D000818:Animals; D004723:Endorphins / Q000276:immunology / Q000378:metabolism*; D006168:Guinea Pigs; D006801:Humans; D011957:Receptors, Opioid / Q000378:metabolism; D013329:Structure-Activity Relationship; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D011957:Receptors, Opioid; D001615:beta-Endorphin