title: beta-Endorphin: synthesis and analgesic activity of several analogs modified in positions 2 and 5.
abstract: The solid-phase syntheses of [Sar2]-, [Ala2]-, [D-Leu2]-, [D-Lys2]-beta-endorphins and [Pro5]-, [Leu5]-, [D-Leu5]-, [D-Ala2, D-Leu5]-beta-endorphins are described. The synthetic peptides were purified by chromatography on carboxymethylcellulose and partition chromatography on Sephadex G-50. They were characterized by partition chromatography on agarose, thin-layer chromatography, paper electrophoresis, and amino acid analyses of acid and enzymic hydrolysates. Bioassay of the synthetic analogs for analgesic activity by the tail-flick method showed the D-Leu2 analog to be 48% as potent as betah-endorphin while the Ala2, D-Lys2, Leu5, and [D-Ala2, D-Leu5] analogs were 8 to 17% as active. The Sar2, D-Leu5, and Pro5 analogs were less than 1% as potent.
mesh_terms: D000595:Amino Acid Sequence; D000700:Analgesics; D000818:Animals; D001681:Biological Assay; D002845:Chromatography; D004590:Electrophoresis, Paper; D004723:Endorphins / Q000138:chemical synthesis* / Q000302:isolation & purification; D008297:Male; D051379:Mice; D008968:Molecular Conformation
chemical_list: D000700:Analgesics; D004723:Endorphins