The capabilities of contemporary differential scanning and isothermal titration
microcalorimetry for studying the thermodynamics of protein unfolding/refolding and their
association with partners, particularly target DNA duplexes, are considered. It is shown that
the predenaturational changes of proteins must not be ignored in studying the
thermodynamics of formation of their native structure and their complexes with partners,
particularly their cognate DNA duplexes.