title: Human beta-endorphin. Synthesis and biological activity of analogs with modification in residue positions 8, 27, and 9 or 11.
abstract: Three analogs of human beta-endorphin (beta h-ER) were synthesized by the solid-phase method: [Gln8,Trp27]-beta h-EP (I), [Gln8,Arg9,Trp27]-beta h-EP (II), and [Gln9,Arg11,Trp27]-beta h-EP (III). Radioreceptor binding assay with use of tritiated beta h-EP as primary ligand gave relative potencies as follows: beta h-EP, 100;I, 778;II, 467;III, 449. Relative potencies in an analgesic assay were: beta h-EP, 100;I, 114;II, 165;III, 83. The 8-11 segment of beta h-EP can tolerate a net increase in charge of +2 without diminishing analgesic potency. The substitution of Glu8 may be one of the more dependable means of designing beta-endorphin antagonists.
mesh_terms: D000595:Amino Acid Sequence; D001681:Biological Assay; D004723:Endorphins / Q000138:chemical synthesis* / Q000378:metabolism; D006801:Humans; D010146:Pain / Q000503:physiopathology; D011957:Receptors, Opioid / Q000378:metabolism; D013329:Structure-Activity Relationship; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D011957:Receptors, Opioid; D001615:beta-Endorphin