title: Preparation and properties of tritiated human [Tyr18, Trp27]-beta-endorphin.
abstract: Tritiated [Tyr18, Trp27]-beta h-EP was prepared from the corresponding diiodotyrosine derivative by catalytic reduction in the presence of carrier free tritium gas. A photoaffinity probe for beta-endorphin (beta-EP) receptors was prepared by selective modification of [Tyr18, Trp27]-beta h-endorphin with 2-nitro-4-azidophenylsulfenyl chloride (2,4-NAPS-C1) under acidic conditions to yield [Trp18-2,4-NAPS-Trp27]-beta h-endorphin (NAPS-beta-EP). NAPS-beta-EP was purified by high performance liquid chromatography and characterized by ultraviolet absorption spectroscopy and peptide mapping. Tritiated NAPS-beta-EP was prepared from tritiated [Tyr18, Trp27]-beta h-endorphin with 2,4-NAPS-C1. The ability of NAPS-beta-EP to form covalent bonds to macromolecules due to photolysis was established using bovine serum albumin. The efficiency of photolytic cross-linking was 15% and the equilibrium dissociation constant was 1.3 X 10(-5) M.
authors.forename: R G
authors.initials: RG
authors.lastname: Hammonds
authors.forename: C H
authors.initials: CH
authors.lastname: Li
mesh_terms: D000345:Affinity Labels; D000818:Animals; D001386:Azides / Q000302:isolation & purification* / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D004723:Endorphins / Q000302:isolation & purification* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010782:Photolysis; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism; D014316:Tritium; D001615:beta-Endorphin / Q000031:analogs & derivatives
chemical_list: D000345:Affinity Labels; D001386:Azides; D004723:Endorphins; D011957:Receptors, Opioid; D014316:Tritium; D001615:beta-Endorphin; C045171:beta-endorphin, Tyr(18), Trp(27)-; C045170:beta-endorphin, 2-nitro-4-azidophenylsulfenyl-