title: Synthesis and binding characteristics of a novel enkephalin analogue, [3H]Tyr-D-Ala-Gly-Phe-D-Nle-Arg-Phe.
abstract: The endogenous opioid heptapeptide (Tyr-Gly-Gly-Phe-Met-Arg-Phe; MERF) has been shown to interact with multiple opioid as well as non-opioid sites in mammalian brain membranes. To increase the stability and bioavailability of MERF, new synthetic derivatives with D-amino acid substitutions were prepared and studied. One of the new compounds in this series, Tyr-D-Ala-Gly-Phe-D-Nle-Arg-Phe (DADN), had only moderate affinity in competing with [3H]MERF, whereas it displayed the highest potency in producing antinociception following intrathecal administration. DADN was radiolabeled with 41Ci/mmol specific activity. Specific binding of [3H]DADN was saturable, stereoselective and of high affinity. Chemical stability, increased micro-receptor selectivity, and hydrophobicity of the peptide all contribute to the effectiveness observed in biochemical and pharmacological studies.
authors.affiliation: Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged H-6701, Hungary.
authors.forename: Fanni
authors.initials: F
authors.lastname: Tóth
authors.forename: Judit
authors.initials: J
authors.lastname: Farkas
authors.forename: Géza
authors.initials: G
authors.lastname: Tóth
authors.forename: Mária
authors.initials: M
authors.lastname: Wollemann
authors.forename: Anna
authors.initials: A
authors.lastname: Borsodi
authors.forename: Sándor
authors.initials: S
authors.lastname: Benyhe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004745:Enkephalins / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008969:Molecular Sequence Data; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D013379:Substrate Specificity; D014316:Tritium
chemical_list: D004745:Enkephalins; D014316:Tritium