J. Philo, W. Sydor, T. Arakawa
2019
Citations
0
Influential Citations
4
Citations
Quality indicators
Journal
Journal of pharmaceutical sciences
Abstract
Glucagon-like peptide 1 and 2 (GLP-1 and GLP-2) and their analog peptide therapeutics are known to reversibly associate to form oligomers. Here we report the association properties of the GLP-2 analog teduglutide at concentrations up to ∼15 mg/mL. Both sedimentation equilibrium (SE-AUC) and sedimentation velocity (SV-AUC) show that teduglutide dissociates completely to monomers below 0.1 mg/mL. SE-AUC shows that the apparent weight-average molar mass increases substantially between 0.1 and 1 mg/mL, reaching a maximum of ∼14.5 kDa (∼3.9-mer) near 2 mg/mL, and then falling at higher concentrations due to strong solution non-ideality effects (highly positive second virial coefficient). Circular dichroism spectra over the range from 0.1 to 2 mg/mL show that self-association is accompanied by significant increases in alpha-helix content, and that the associated state has a distinct tertiary structure. The SV-AUC data up to 2.2 mg/mL are fitted fairly well by an ideal rapidly-reversible monomer-pentamer association. The SE-AUC modeling included thermodynamic non-ideality effects. SE-AUC data up to ∼15 mg/ml imply a monomer-pentamer association at lower concentrations, but the pentamers also appear to weakly associate to form decamers. These results illustrate the importance of directly modeling the solution non-ideality effects, which if neglected would lead to an incorrect preferred stoichiometry.