[Thermal properties of collagen-water system. 1. Increments of heat capacity during denaturation and glass transition].

The absolute values of heat capacity of the collagen-water systems with different relative content of the components in both native and denatured state were studied by the method of differential scanning calorimetry in a wide temperature range (-40 +/- 140 degrees C) which includes the region of the denaturation phase transition as well as the region of the relaxation glass transition. From the experimental data the values of denaturation increment delta Cpnd-0.42 +/- 0.04 J/(g.K) at the collagen content 10-50% and the values of glass transition increment delta Cpg-0.54 +/- 0.12 J/(g.K) for moist denatured protein were calculated. Different processes influencing the increment values are analysed. The nonequilbrium character of the glass-like state of moist proteins was clearly demonstrated in the study of glass transition.