Low frequency dynamics of lysozyme: A Raman scattering and low temperature specific heat study

Raman scattering and low temperature specific heat (C p ) measurements have been performed to investigate the low frequency vibrational dynamics of hen egg white dry lysozyme. The occurrence of low energy extra excitations have been revealed both in the light scattering spectrum and in the C p / T 3 vs. T plot. A perfect agreement in the frequency and temperature position of the Boson Peak in this protein has been observed. At temperature below 3 K it has been found a contribution to the specific heat similar to that revealed in glassy systems. This, together with the other analogies discovered between thermal properties of amorphous and biological systems, suggests the possibility of making the most of the knowledge about the former in order to understand some glassy-like behaviours of proteins.