The formation of a hydrophobic core provides a large part of the driving force for protein folding. We are investigating amyloid formation from β-lactoglobulin and are therefore interested in understanding how the dynamics of core stability are influenced by solution conditions. We have exploited the presence of a large hydrophobic binding pocket in β-lactoglobulin to encapsulate coumarin 153 (C153). Steady state spectroscopy reveals a very blue-shifted spectrum consistent with an environment similar to a combination of hexane and toluene. Time resolved fluorescence Stokes shift measurements reflect the dynamics of the hydrophobic core of β-lactoglobulin.
A transition in the dynamics of the hydrophobic core occurs at a lower temperature than does the melting of the protein as measured by circular dichroism suggesting a partitioning of  the enthalpy and entropy balance between the core structure and secondary structure.