Determining thermodynamic parameters from isothermal calorimetric isotherms of the binding of macromolecules to metal cations originally chelated by a weak ligand

Lian Hong; William D Bush; Lanying Q Hatcher; John Simon

doi:10.1021/jp075747r

Determining thermodynamic parameters from isothermal calorimetric isotherms of the binding of macromolecules to metal cations originally chelated by a weak ligand

J Phys Chem B. 2008 Jan 17;112(2):604-11. doi: 10.1021/jp075747r. Epub 2007 Nov 21.

Authors

Lian Hong¹, William D Bush, Lanying Q Hatcher, John Simon

Affiliation

¹ Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.

PMID: 18027923
DOI: 10.1021/jp075747r

Abstract

An accurate data analysis method for determining stoichiometry and thermodynamic parameters from isothermal titration calorimetry data for the binding of macromolecules to metal cations that are solubilized through an association with a weak ligand is presented. This approach is applied to determine the binding constant for the association of Cu(II) to the first 16 residues of the Alzheimer's amyloid beta peptide, Abeta(1-16) under conditions where Cu(II) is rendered soluble through weak binding to glycine. At pH 7.2 and 37 degrees C, a binding constant of 1.5 x 10(9) M-1 (Kd = 0.7 nM) is determined for the association of Cu(II) with Abeta(1-16).