Quantification of Protein–Protein Interactions Using Fluorescence Polarization

Quantitative determinations of the dissociation constants of biomolecular interactions, in particular protein–protein interactions, are essential for a detailed understanding of the molecular basis of their specificities. Fluorescence spectroscopy is particularly well suited for such studies. This article highlights the theoretical and practical aspects of fluorescence polarization and its application to the study of protein–protein interactions. Consideration is given to the nature of the different types of fluorescence probes available and the probe characteristics appropriate for the system under investigation. Several examples from the literature are discussed that illustrate different practical aspects of the technique applied to diverse systems.