title: Binding of synthetic fragments of beta-endorphin to nonopioid beta-endorphin receptor.
abstract: Selective agonist of nonopioid beta-endorphin receptor decapeptide immunorphin (SLTCLVKGFY) was labeled with tritium (the specific activity of 24 Ci/mmol). [3H]Immunorphin was found to bind to nonopioid beta-endorphin receptor of mouse peritoneal macrophages (Kd = 2.0 +/- 0.1 nM). The [3H]immunorphin specific binding with macrophages was inhibited by unlabeled beta-endorphin (Ki = 2.9 +/- 0.2 nM) and was not inhibited by unlabeled naloxone, alpha-endorphin, gamma-endorphin and [Met5]enkephalin (Ki > 10 microM). Thirty fragments of beta-endorphin have been synthesized and their ability to inhibit the [3H]immunorphin specific binding to macrophages was studied. Unlabeled fragment 12-19 (TPLVTLFK, the author's name of the peptide octarphin) was found to be the shortest peptide possessing practically the same inhibitory activity as beta-endorphin (Ki = 3.1 +/- 0.3 nM). The peptide octarphin was labeled with tritium (the specific activity of 28 Ci/mmol). [3H]Octarphin was found to bind to macrophages with high affinity (Kd = 2.3 +/- 0.2 nM). The specific binding of [3H]octarphin was inhibited by unlabeled immunorphin and beta-endorphin (Ki = 2.4 +/- 0.2 and 2.7 +/- 0.2 nM, respectively).
authors.affiliation: Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Science Avenue, 6, Pushchino, Moscow Region 142290, Russia. navolots@fibkh.serpukhov.su
authors.forename: Elena V
authors.initials: EV
authors.lastname: Navolotskaya
authors.forename: Yulia A
authors.initials: YA
authors.lastname: Kovalitskaya
authors.forename: Yury A
authors.initials: YA
authors.lastname: Zolotarev
authors.forename: Vladimir B
authors.initials: VB
authors.lastname: Sadovnikov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D007127:Immunoglobulin Constant Regions / Q000378:metabolism; D007142:Immunoglobulin gamma-Chains / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D011957:Receptors, Opioid / Q000378:metabolism*; D001615:beta-Endorphin / Q000138:chemical synthesis / Q000235:genetics / Q000378:metabolism*
chemical_list: D007127:Immunoglobulin Constant Regions; D007142:Immunoglobulin gamma-Chains; D009842:Oligopeptides; D010446:Peptide Fragments; D011957:Receptors, Opioid; C445661:immunorphin; D001615:beta-Endorphin