[Heat denaturation of alpha-tropomyosin and its fragments].

The reasons for three heterogeneity of tropomyosin melting curves are considered. It is shown that this phenomenon is due to the molecular heterogeneity of the preparation. Different states of the SH-groups as well as the different stability of molecule regions. The melting curves of alpha-tropomyosin and two of its fragments are obtained. The thermodynamic parameters stabilizing their helical structure are determined. The existence of a thermodynamical transition at 31 degrees C is shown for alpha-tropomyosin leading to the loss of the ability of the molecule to form supra-molecular structures.