title: beta-Endorphin: synthesis and properties of analogs modified in positions 8 and 31.
abstract: Four analogs of human beta-endorphin (beta h-EP) were synthesized by the solid-phase method: [Gln8,31]-beta h-EP(I), [Arg8,Gln31]-beta h-EP(II), [Ala8,Gln31]-beta h-EP (III), and [Val8, Gln31]-beta h-EP(IV). Radioreceptor binding assay with use of tritiated beta h-EP as primary ligand gave relative potencies as follows: beta h-EP, 100; I, 200;II, 150;III, 150;IV, 120. Relative potencies in an analgesic assay were: beta h-EP, 100; I,236;II, 254;III, 116;IV, 121. The side-chain of Glu-8 in beta h-EP can be replaced by a variety of structures without diminishing biological activity.
mesh_terms: D000595:Amino Acid Sequence; D000698:Analgesia; D000818:Animals; D001921:Brain / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004723:Endorphins / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D007202:Indicators and Reagents; D008722:Methods; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism; D013329:Structure-Activity Relationship; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D007202:Indicators and Reagents; D011957:Receptors, Opioid; D001615:beta-Endorphin