An ion-gate response of the glutathione monolayer assembly formed on a gold electrode: Part 2. The effect of alkaline earth ions

Abstract

Glutathione (y-L-glutamyl-L-cysteinyl-glycine) (GSH) is a well-known biologically active tripeptide which participates in the various functions of biological processes [ll. For example, GSH has been reported to act as a coenzyrne for ion-channel proteins and to participate in the biological redox systems 121. Longchain molecules containing thiol terminals, like n-alkanethiols, are known to form a well-ordered, densely packed and electron-insulating self-assembled monolayer film on a gold surface [3,4]. Furthermore, the ion-selective and ion-gate responses of such a monolayer assembly have also been reported by several authors [5,6]. The novel electrochemical characteristics of a GSH monolayer assembly formed on a gold surface, i.e. the ion-gate response which is controlled by the pH and the concentration of Ca*+ ion, have been reported previously [7]. In this communication we report electrochemical investigations of the effect of alkaline earth ions M*+ on the ion-gate response of the GSH monolayer assembly formed on a gold surface. The redox signal of the Fe(CN)zion was used as the marker of the ion-gate response of the GSH monolayer assembly.