Native and denatured states of bovine serum albumin (BSA) were studied by d.c. polarographic and voltammetric Brdicka catalytic responses (BCR) in cobalt-containing solution and by constant current chronopotentiometric stripping analysis (CPSA) in borate buffer, pH 9.3. We found that 90 nM denatured BSA produced catalytic peak H (around -1.8 V vs. Ag/AgCl/3 M KCl). This peak was about 50-fold higher than the native protein under the same conditions. Qualitatively similar results were obtained also with other proteins in native and denatured states, such as human serum albumin, gamma-globulin, myoglobin and a-crystallin. 2 nM denatured BSA produced a well-developed CPS peak (at accumulation time 5 min) while native BSA yielded almost no signal under the same conditions. (c) 2006 Elsevier B.V. All rights reserved.