Electrochemistry of and redox-induced metal release from metallothioneins at a nafion-coated bismuth film electrode

摘要

Nafion-coated bismuth film electrodes (NCBiFEs) were used to investigate the redox behavior of and metal release from rabbit liver metallothioneins (MTs) in an acetate buffer. Owing to the permselective exchange between positively charged MT molecules and cations in Nafion and the absence of detectable MT adsorption at bismuth surface, a diffusion-controlled Nernstian redox wave of MTs (E-pc =-0.869 V) was observed for the first time. The Nernstian behavior of the diffusing MTs is in contrast to the voltammetric responses of MTs at thin mercury films or Nafion-coated mercury film electrodes, which either result in the replacement of the metals originally present in MTs by mercury or lead to a noticeable MT adsorption. By avoiding these undesirable features, the NCBiFE provides an excellent milieu for voltammetric studies of different types of MTs and related isoforms, paving the way for studying the redox-modulated metal transfer of MTs and understanding the biological role of MTs in heavy metal detoxification and essential metal regulations.