title: Design rationale, synthesis, and characterization of non-natural analogs of the cationic amino acids arginine and lysine.
abstract: A series of non-natural isosteric analogs of the cationic, ion-pairing, natural amino acids arginine and lysine have been synthesized, characterized with regard to relevant physical parameters, and protected for routine inclusion in Merrifield solid-phase synthesis. The design of these molecules is based on the concept of steric inhibition of solvation, in that judicious placement of alkyl groups can destabilize aqueous ion solvation and favor ion-pairing [see Beeson & Dix (1993) J. Am. Chem. Soc. 115, 10275]. When the residues are substituted for the natural amino acids in biologically active peptides, enhanced ion-pairing of the peptides to their receptors to increase the peptides' biological activities can result. The increased lipophilicity of the non-natural residues can also improve pharmacokinetic parameters and agonist/antagonist behaviors of peptides. While the synthesis of the L-series is described, the D-isomers were also prepared using identical chemistry.
authors.affiliation: Department of Pharmaceutical Sciences, Medical University of South Carolina, Charleston 29425-2303, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Kennedy
authors.forename: J T
authors.initials: JT
authors.lastname: Lundquist
authors.forename: T L
authors.initials: TL
authors.lastname: Simandan
authors.forename: K P
authors.initials: KP
authors.lastname: Kokko
authors.forename: C C
authors.initials: CC
authors.lastname: Beeson
authors.forename: T A
authors.initials: TA
authors.lastname: Dix
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D015195:Drug Design; D008239:Lysine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001120:Arginine; D008239:Lysine