Ionic strength-dependent structural transition of proteins at electrode surfaces

摘要

Using constant current chronopotentiometry we showed that in 50 mM sodium phosphate (pH 7) bovine serum albumin and some other proteins were not significantly denatured at a bare mercury electrode while at higher phosphate concentrations they underwent electric field-driven denaturation on the electrode surface.rnIn recent decades, tremendous progress has been made in the electrochemistry of proteins containing non-protein components (e.g. metals). A relatively small group of these proteins, which provide fast reversible electrode processes, has been intensively studied, while the electrochemistry of the majority of proteins has been largely ignored. Recently we have shown that practically all proteins produce a chronopotentiometric stripping peak H at solid amalgam and hanging mercury drop electrodes (HMDE) in the nanomolar and subnanomolar range. This peak, which is due to the ability of proteins to catalyze hydrogen evolution at mercury electrodes, is sensitive to changes in protein structure such as denaturation, aggregation, as well as to those related to changes in the redox state of proteins (see ESI for hydrogen evolution catalyzed by proteins).