[Calorimetric study of the mechanism of uncoiling the collagen molecule in the presence of ions].

Calorimetric and polarimetric studies of partially denaturated collagen in the presence and absence of one and two valence ions were performed. It is shown that in the presence of salt in partial denaturation of renaturated collagen the denaturation enthalpy is changed upon two steps. Both stages are followed by the conformational alteration. The denaturation enthalpy of the renaturated collagen is less than that of the native one, but in the presence of salts it is rather higher than in its absence. The study made possible to indicate that two-stage alteration of denaturation enthalpy is occurrence of denaturation products with partially reconstructed structure in which the salts take an active part.