Water induced effects on the thermal response of a protein

The effects of water induced on the thermal response of a protein were discussed. An anomalous compression of the protein near the freezing point of water such as a compression not related to the negative thermal expansion of the solvent was detected. It was found that the physiological protein working temperature (T=300 K) appeared to be related to the activation of exchange of vicinal water with the bulk and the concomitant absorption of heat by hydrophilic amino acids. The interpretation of the inferred activation was done on the basis of degenerate tetrahedral order between the hydration shell and the bulk.