[Calorimetric study of the formation and melting of thermotropic gel in solutions of globular proteins].

Scanning calorimetry has been used for studying lysozyme water solutions of different buffer molarity (mu = 0.5 divided by 1.0) and concentrations (c = 1.5 divided by 25%) at pH 2.0. It is shown that an additional high temperature maximum (HTM) can be observed on the heating curves for lysozyme solutions during irreversible denaturation. Calorimetric and rheological studies under identical heating conditions have shown that aggregation of protein during denaturation leads to the formation of the thermotropic gel. Further increase of temperature brings up the melting of this gel which results in the appearance of HTM on thermograms. Slow cooling of lysozyme gel melt leads to its reconstruction which results in the appearance of exothermic maximum on the corresponding thermograms.