title: Human beta-endorphin. Synthesis and biological activity of analogs with modifications in residue positions 3, 4 or 5.
abstract: Three analogs of human beta-endorphin (beta h-EP) have been synthesized by the solid-phase method: [Phe2, Gly4]-beta h-EP(I), [Tyr5]-beta h-EP (II), and [Trp5[-beta h-ET (III). Analogs I and II are related to the highly potent hybrid analog [dermorphin1-7]-beta c-EP (beta c-EP). Radio-receptor-binding and analgesic assays gave relative potencies as follows, respectively: beta h-FP, 100, 100; I, 51, 43; II, 64, 30; III, 15, 4. The high potency of [dermorphin 1-7]-beta c-EP is not due to any one of the following structural elements: D-Ala2, Phe3-Gly4, Tyr5, and Pro6. Increasing hydrophobicity in position 5 (Met in beta-EP) leads to decreasing biological activity.
mesh_terms: D000595:Amino Acid Sequence; D001681:Biological Assay; D004723:Endorphins / Q000138:chemical synthesis* / Q000378:metabolism; D006801:Humans; D011957:Receptors, Opioid / Q000378:metabolism; D013329:Structure-Activity Relationship; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D011957:Receptors, Opioid; D001615:beta-Endorphin