Fluorescence is the most widely used technique to study the effect of pressure on
biochemical systems. The use of pressure as a physical variable sheds light into volumetric
characteristics of reactions. Here we focus on the effect of pressure on protein solutions
using a simple unfolding example in order to illustrate the applications of the methodology.
Topics covered in this review include the relationships between practical aspects
and technical limitations; the effect of pressure and the study of protein cavities;
the interpretation of thermodynamic and relaxation kinetics; and the study of relaxation
amplitudes. Finally, we discuss the insights available from the combination of fluorescence
and other methods adapted to high pressure, such as SAXS or NMR. Because of the simplicity
and accessibility of high-pressure fluorescence, the technique is a starting point
that complements appropriately multi-methodological approaches related to understanding
protein function, disfunction, and folding from the volumetric point of view.
