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Binding of synthetic fragments of β‐endorphin to nonopioid β‐endorphin receptor
Author(s) -
Navolotskaya Elena V.,
Kovalitskaya Yulia A.,
Zolotarev Yury A.,
Sadovnikov Vladimir B.
Publication year - 2008
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.1049
Subject(s) - peptide , chemistry , agonist , receptor , tritium , enkephalin , stereochemistry , (+) naloxone , oligopeptide , microbiology and biotechnology , biochemistry , antagonist , opioid , biology , physics , nuclear physics
Selective agonist of nonopioid β‐endorphin receptor decapeptide immunorphin (SLTCLVKGFY) was labeled with tritium (the specific activity of 24 Ci/mmol). [ 3 H]Immunorphin was found to bind to nonopioid β‐endorphin receptor of mouse peritoneal macrophages ( K d = 2.0 ± 0.1 n M ). The [ 3 H]immunorphin specific binding with macrophages was inhibited by unlabeled β‐endorphin ( K i = 2.9 ± 0.2 n M ) and was not inhibited by unlabeled naloxone, α‐endorphin, γ‐endorphin and [Met 5 ]enkephalin ( K i > 10 µ M ). Thirty fragments of β‐endorphin have been synthesized and their ability to inhibit the [ 3 H]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 β‐endorphin ( K i = 3.1 ± 0.3 n M ). The peptide octarphin was labeled with tritium (the specific activity of 28 Ci/mmol). [ 3 H]Octarphin was found to bind to macrophages with high affinity ( K d = 2.3 ± 0.2 n M ). The specific binding of [ 3 H]octarphin was inhibited by unlabeled immunorphin and β‐endorphin ( K i = 2.4 ± 0.2 and 2.7 ± 0.2 n M , respectively). Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.