In an ongoing effort to understand the thermodynamic properties of proteins, ovalbumin, lactoglobulin, lysozyme are studied
by adiabatic and differential scanning calorimetry over wide temperature ranges. The heat capacities of the samples in their
pure, solid states are linked to an approximate vibrational spectrum with the ATHAS analysis that makes use of known group
vibrations and a set of parameters, Θ1 and Θ3, of the Tarasov function for the skeletal vibrations. Good agreement is found between experiment and calculation with rms
errors mostly within ±3%. The analyses were also carried out with an empirical addition scheme using data from polypeptides
of naturally occurring amino acids. Due to space limitation, only selected results are reported.