TITLE:
Capture Reagent and Strategy for Retrieving Albumin-Bound Ligands from Plasma
AUTHORS:
Megan M. Koslen, Matthew W. Eskew, Vincent Pinkert, Huyen Hoang, Fidelis Manyanga, William L. Dean, Jonathan B. Chaires, Albert S. Benight
KEYWORDS:
Human Serum Albumin (HSA), Differential Scanning Calorimetry (DSC), Protein Thermodynamic Stability, Analyte Capture
JOURNAL NAME:
Advances in Biological Chemistry,
Vol.9 No.3,
June
28,
2019
ABSTRACT: A capture strategy is described and demonstrated for
retrieving ligand entities in plasma that bind Human Serum Albumin. The method
has applications for both exogenous and endogenous ligands. Exogenous ligands
include drug candidates, performance enhancing
drugs and toxic nerve agents that also interact quite strongly with HSA.
Endogenous ligands are natural circulating compounds whose abundance corresponds to
normal hemostasis or elevated levels that could be disease-specific molecular
biomarkers. Melting curves of plasma solutions measured by differential
scanning calorimetry produce “so-called” plasma
thermograms that are physical signatures of
the plasma solution. Patterns displayed by thermograms can be sensitive
indicators of the presence of abnormal levels of exogenous and endogenous ligand
components. Effects of ligand interactions on thermodynamic stability of
proteins in plasma that they bind, primarily HSA, manifest on the plasma
thermogram. The capture strategy is
demonstrated for HSA binding in plasma of four “ideal” ligands of different
types. The particular ligands were naproxen, bromocresol green, short double
stranded and single strand DNA. Thermogram shapes and features were sensitive
to the presence of ligands as thermograms of mixtures of plasma and HSA with
these ligands were significantly different than thermograms of plasma or HSA
alone. These results demonstrated directly that significant perturbations of plasma thermograms corresponded to ligand interactions with HSA in
plasma.