Electrochemical determination of cysteine-containing biomolecules by means of catalytic reactions on a mercury electrode
| Authors | |
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| Year of publication | 2004 |
| Type | Article in Proceedings |
| Conference | Book of Abstracts - 55th Annual Meeting of the ISE |
| MU Faculty or unit | |
| Citation | |
| Field | Electrochemistry |
| Keywords | metallothioneines; phytochelatins; glutathione; mercury electrode;catalytic reactions; Brdicka reaction;peak H |
| Description | The group cysteine-containing peptides (metallothioneines, phytochelatins, and glutathione) plays an important role in active homeostasis and detoxification of metals in animal, plant, and/or microorganism cells. In this study we describe a novel approach to electroanalysis of cys-containing peptides and proteins. This approach is based on catalytic processes (presodium wave, peak H, Brdicka current) proceeding at negative potentials (ca. 1.8 V, Ag/AgCl/3M KCl) on the hanging mercury drop electrode (HMDE). A presodium wave is current-potential response accompanied with catalytic hydrogen evolution from aqueous solutions in the presence of proteins. It was found that the sulfhydryl(SH) groups in proteins are responsible for presodium catalytic processes. The highest sensitivity in the determination was observed with derivative chronopotentiometric stripping analysis (CPSA), which monitored the catalytic signal known as peak H. The determination of the low content of Cys-peptides was successfully performed in a cobalt(III)-containing solution with ammonia buffer by differential pulse voltammetry (DPV). The CPSA (peak H) and DPV (Brdicka reaction) can be used in connection with the adsorptive transfer stripping (AdTS) technique, which is capable of determining nano/femtomole levels of metallothioneine, phytochelatin and glutathione in mL of the sample. |
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