Polarographic investigation of beta 2-microglobulin and ferritin thermal denaturation

A temperature dependence of the corresponding signals, obtained by differential pulse (d.p.) and alternating current (a.c.) polarography, from a buffered aqueous solution of ferritin and beta 2-microglobulin is used for the characterization of a protein thermal denaturation process. The method is based on the significant differences in the interaction of folded and unfolded protein forms with a dropping mercury electrode due to a different accessibility, for the redox process, of protein electroactive groups. From the analysis of the resulting current, or capacitance, signals in function of temperature the thermal transition reversibility of different protein forms in the solution, protein melting points, and the apparent activation energies of the corresponding processes were determined.