Pyridyl-alanine as a Hydrophilic, Aromatic Element in Peptide Structural Optimization

J Med Chem. 2016 Sep 8;59(17):8061-7. doi: 10.1021/acs.jmedchem.6b00840. Epub 2016 Aug 25.

Abstract

Glucagon (Gcg) 1 serves a seminal physiological role in buffering against hypoglycemia, but its poor biophysical properties severely complicate its medicinal use. We report a series of novel glucagon analogues of enhanced aqueous solubility and stability at neutral pH, anchored by Gcg[Aib16]. Incorporation of 3- and 4-pyridyl-alanine (3-Pal and 4-Pal) enhanced aqueous solubility of glucagon while maintaining biological properties. Relative to native hormone, analogue 9 (Gcg[3-Pal6,10,13, Aib16]) demonstrated superior biophysical character, better suitability for medicinal purposes, and comparable pharmacology against insulin-induced hypoglycemia in rats and pigs. Our data indicate that Pal is a versatile surrogate to natural aromatic amino acids and can be employed as an alternative or supplement with isoelectric adjustment to refine the biophysical character of peptide drug candidates.

MeSH terms

  • Alanine / analogs & derivatives*
  • Alanine / chemistry
  • Animals
  • Cyclic AMP / biosynthesis
  • Drug Stability
  • Glucagon / analogs & derivatives*
  • Glucagon / chemical synthesis
  • Glucagon / chemistry*
  • Glucagon / pharmacology
  • HEK293 Cells
  • Humans
  • Hypoglycemia / drug therapy*
  • Male
  • Pyridines / chemistry*
  • Rats
  • Solid-Phase Synthesis Techniques
  • Solubility
  • Swine

Substances

  • 4-pyridyl-alanine
  • Pyridines
  • 3-pyridylalanine
  • Glucagon
  • Cyclic AMP
  • Alanine