88373-72-2Relevant academic research and scientific papers
A rapid and facile method for the preparation of peptide disulfides
Maruyama, Toshihiro,Ikeo, Takayoshi,Ueki, Masaaki
, p. 5031 - 5034 (2007/10/03)
A selective and efficient method for disulfide bond formation in peptides utilizing carbon tetrachloride in dichloromethane in the presence of tetrabutylammonium fluoride (TBAF) is described. The reaction proceeded rapidly and no side reaction was observed with nucleophilic amino acids such as Met, His, Tyr or Trp. This method has been applied to three model peptides using solution and on-the-resin disulfide formation.
Probing the stereochemical requirements for receptor recognition of δ opioid agonists through topographic modifications in position 1
Qian,Shenderovich,Kover,Davis,Horvath,Zalewska,Yamamura,Porreca,Hruby
, p. 7280 - 7290 (2007/10/03)
A series of side-chain constrained tyrosine derivatives, 2',6'-dimethyl-β-methyltyrosines (TMT), has been designed and incorporated into position 1 of the highly selective δ opioid agonists DPDPE (Tyr-D-Pen2-Gly-Phe-D-Pen5-OH) and deltorphin I (DELT I, Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2). Molecular mechanics calculations on isolated TMT residues and nuclear magnetic resonance (NMR) studies of the TMT1-containing peptides in DMSO showed that each of the four stereoisomers of TMT favors one particular rotamer of the side-chain χ1 torsional angle. Therefore, substitution of four TMT isomers for Tyr1 allows us to perform a systematic conformational scan through three staggered rotamers of the aromatic side chain, gauche (-), trans, and gauche (+), and to explore specific binding requirements of the receptor in relation to the side chain conformation. The potency and selectivity of four isomers of [TMT1]DPDPE and four isomers of [TMT1]DELT I were evaluated by radioreceptor binding assays in the rat brain using μ- and δ-selective radiolabeled ligands and by bioassays with guinea pig ileum (GPI, μ receptor) and mouse vas deferens (MVD, δ receptor). In the DPDPE series only one isomer, [(2S,3R)-TMT1 ]DPDPE showed high potency and selectivity for the δ opioid receptors. The favorable side-chain rotamers found for this analogue, i.e., the trans rotamer of TMT1 and the gauche (-) rotamer of Phe4, were proposed as the most probable δ receptor-binding conformations of DPDPE analogues. Two [TMT1]DELT I isomers possessed considerable δ receptor potencies. The (2S,3R)-TMT1 isomer appeared to be a superpotent, but moderately δ-selective agonist, while the (2S,3S)-TMT1 isomer showed the highest selectivity for the δ receptors in this series. Surprisingly, [(2R,3R)TMT1]DELT I also was moderately potent at the δ receptor. These results suggest that the δ receptor requirements for the linear DELT I analogues may be satisfied with two different modes of binding of the (2S,3S)- and (2S,3R)TMT1 isomers. This study provides important guidance for the design of peptide and non-peptide ligands selective for the δ opioid receptor.
Topographically designed analogues of [D-Pen,D-Pen5]enkephalin
Hruby,Toth,Gehrig,Kao,Knapp,Lui,Yamamura,Kramer,Davis,Burks
, p. 1823 - 1830 (2007/10/02)
The conformationally restricted, cyclic disulfide-containing δ opioid receptor selective enkephalin analogue [D-Pen2,D-Pen5]enkephalin (1, DPDPE) was systematically modified topographically by addition of a methyl group at either the
