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Photoaffinity Crosslinking of Etorphine with Opioid Binding Sites in the Bovine Adrenal Medulla
Author(s) -
Cantau P.,
Bourhim N.,
Giraud P.,
Oliver C.,
Castanas E.
Publication year - 1987
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1111/j.1470-8744.1987.tb00467.x
Subject(s) - etorphine , chemistry , covalent bond , enkephalin , adrenal medulla , endorphins , binding site , opioid , biophysics , stereochemistry , biochemistry , endocrinology , organic chemistry , biology , receptor , catecholamine , (+) naloxone
The covalent crosslinking of [3H]etorphine with opioid binding sites in the bovine adrenal medulla is reported. Of all the radiolabeled opiates tested (ethylketocyclazocine, etorphine, [D‐Ala2, D‐Leu5]enkephalin, [D‐Ala2, Me‐Phe4, Gly5‐ol]enkephalin only etorphine could be crosslinked under uv irradiation. In our conditions (black uv lamp, 160 W, peak mean 360 nm, from a distance of 10 cm) maximum covalent binding was observed after a 10‐min irradiation. Protein concentration was a crucial factor for the irreversible/total binding ratio. A good ratio (50%) was obtained at protein concentrations of about 1.0 mg/ml. Covalent binding of nonmodified opiates could be of interest for the biochemical characterization of their binding sites.