[Thermostability of DNA and its connection with the glassing process].

Using differential scanning calorimetry, the thermal denaturation of calf thymus DNA with different content of water (from 12 to 92%) was investigated. Dependences of melting temperature and enthalpy on the biopolymer hydration degree were established. Within the range of water concentrations from 92 to 50% the values of thermodynamic parameters of denaturation were obtained being in good agreement with the published data.

[Formation and melting of ordered structures in denatured myoglobin with differing water content: differential scanning calorimetry method].

The possibility of superstructure formation in denatured globular proteins has been studied through the temperature dependence of the absolute values of heat capacity in the myoglobin-water system with water content from 80 to 25% in the temperature range 20-160 degrees C. For all the composition range studied it is found that after the denaturation of myoglobin the new regular structures with reversible melting are formed. These structures are similar in properties to the thermotropic gels in concentrated myoglobin solutions.

[Thermal characteristics of a collagen-water system. II. Conformationalmobility of macromolecules in native and denatured states].

By calorimetric study of the collagen-water systems with 10-100% content of protein in the temperature range 20 + 90 degrees C we have measured the proper heat capacity of protein in native and denatured state. It is shown that S-like dependence of heat capacity on the water content for both native and denatured samples is caused by glass transition. At temperatures above the glass transition in moist collagen or above the denaturation of native collagen the translational mobility of segments in protein molecules appears.

[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.