(Invited) Electrochemical Studies of Zinc/L-Cysteine Interactions in Aqueous Buffers. (25th October 2017)

• Record Type: Journal Article
• Authors: Cheek, Graham T.; Worosz, Matthew A.; Doan, Michelle Y; Clark, Dexter C.
• Is Part Of: ECS transactions. Volume 80:Number 10(2017)
• Page Start: 1159
• Page End: 1166
• Publication Date: 2017-10-25
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/08010.1159ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : The electrochemical behavior of L-cysteine has been investigated in pH 11.0 phosphate buffer at both gold and glassy carbon. Cyclic voltammetric responses show similar behavior to that in pH 7.4 phosphate and pH 4.7 acetate buffers. There is a positive 60 mV L-cysteine peak potential shift with decreasing pH, consistent with a one-electron/one-proton L-cysteine oxidation mechanism. Electrochemical impedance spectroscopic (EIS) studies of L-cysteine suggested involvement of significant surface interactions between gold and L-cysteine and/or its oxidation products. Studies of glutathione, a tripeptide incorporating L-cysteine, showed an oxidation process for the L-cysteine moiety, although little interaction with the gold oxide layer was observed by cyclic voltammetry. In a pH 4.7 acetate buffer, only minimal voltammetric changes at gold were noted upon addition of ZnSO4 to L-cysteine, showing that L-cysteine is not extensively complexed by Zn 2+ at pH 4.7.