Polarographic investigation of beta(2)-microglobulin and ferritin thermal denaturation

A temperature dependence of the corresponding signals, obtained by differen tial pulse (d.p.) and alternating current (a.c.) polarography, from a buffe red aqueous solution of ferritin and beta(2)-microglobulin is used for the characterization of a protein thermal denaturation process. The method is b ased on the significant differences in the interaction of folded and unfold ed protein forms with a dropping mercury electrode due to a different acces sibility, for the redox process, of protein electroactive groups. From the analysis of the resulting current, or capacitance, signals in function of t emperature the thermal transition reversibility of different protein forms in the solution, protein melting points, and the apparent activation energi es of the corresponding processes were determined. (C) 1998 Elsevier Scienc e B.V. All rights reserved.