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Isothermal Titration Calorimetry for Measuring Macromolecule-Ligand Affinity
Published on: September 7, 2011
Binding isotherms for soluble immobilized affinity ligands from spectral titration
A G Mayes1, R Eisenthal, J Hubble
1Biochemistry Department, University of Bath, Claverton Down, Bath BA2 7AY, England.
Biotechnology and Bioengineering
|December 5, 1992
Summary
Spectral titration efficiently screens protein-ligand interactions. Protein binding to dye-dextran conjugates shows consistent high-affinity sites, but binding affinity increases with dye loading.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Biophysical Chemistry
Background:
- Protein-ligand interactions are crucial in biological systems and bioseparations.
- Characterizing these interactions is essential for developing affinity chromatography and extraction methods.
- Soluble immobilized ligands offer advantages for certain bioseparation techniques.
Purpose of the Study:
- To evaluate spectral titration as a method for studying protein-ligand binding equilibria.
- To characterize the binding interaction between Cibacron blue-dextran conjugates and lysozyme.
- To investigate the kinetics of protein binding to immobilized ligands.
Main Methods:
- Spectral titration was employed to analyze binding equilibria.
- Stopped-flow apparatus was utilized for kinetic investigations.
- Dye-ligand density and protein binding were quantified.
Main Results:
- Spectral titration proved to be a simple and rapid screening technique.
- A constant 28% of coupled dye was available for high-affinity protein binding at saturation, irrespective of ligand density.
- Dissociation constant decreased with increasing dye loading.
- A modified kinetic model, accounting for dye ligand transition, better described lysozyme binding data.
Conclusions:
- Spectral titration is a valuable tool for characterizing soluble adsorbents in affinity extraction and chromatography.
- Ligand density and conformation influence protein binding kinetics, impacting affinity chromatography performance.
- Understanding these binding dynamics is critical for optimizing high-performance liquid affinity chromatography.
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