A combined scanning dilatometric and differential scanning calorimetric study of the thermal unfolding of bovine serum albumin

Here we report the first results of combined scanning calorimetric and dilatometric investigations carried out on bovine serum albumin in aqueous solution at 30-97-degrees-C. Comparison of experimental data obtained by the two techniques suggests a ''steps'' model for the thermal denaturation of the protein. Moreover, the results in the high-temperature region, after aggregation of the unfolded chain, show a subsequent, previously unreported, spatial rearrangement of the polypeptidic chain network, during which the order of the system increases with an increase in temperature. The results indicate that scanning dilatometry is a very useful method of detecting phenomena which are not seen by calorimetry. The results also demonstrate the determinant role of water in the unfolding process.