Native and denatured forms of proteins can be discriminated at edge plane carbon electrodes

Institute of Biophysics ASCR, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic.
Analytica chimica acta (Impact Factor: 4.51). 07/2012; 735:31-6. DOI: 10.1016/j.aca.2012.05.012
Source: PubMed


In an attempt to develop a label-free electrochemical method for detection of changes in protein structures based on oxidizability of tyrosine and tryptophan residues we tested different types of carbon electrodes. We found that using edge plane pyrolytic graphite electrode (EPGE) we can discriminate between native and denatured forms of human serum albumin (HSA) and of other proteins, such as bovine and chicken serum albumin, aldolase and concanavalin. Treatment of natively unfolded α-synuclein with 8 M urea resulted only in a small change in the tyrosine oxidation peak, in a good agreement with absence of highly ordered structure in this protein. Using square wave voltammetry with EPGE we were able to follow the course of HSA denaturation at different urea concentrations. The electrochemical denaturation curve agreed reasonably well with that based on intrinsic fluorescence of tyrosine and tryptophan. It can be expected that the electrochemical method will be applicable to a large number of proteins and may become useful in biomedicine and proteomics.

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Available from: Katarzyna Kurzatkowska, Sep 03, 2015
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    • "Electrochemistry of proteins boomed in the last decades, but it has focused on electroactivity of non-protein redox centers (such as metal ions) in relatively small number of conjugated proteins, being thus of little use in proteomics studying thousands of proteins [8] [9]. A couple of studies of non-conjugated proteins were done using voltammetry at graphite electrodes [10] [11] [12] [13] and impedance spectroscopy at metal electrodes [14]. We showed that chronopotentiometric stripping in combination with mercury-containing electrodes is suitable tool for label-free protein detection [13] including proteins important in biomedicine [12,15– 18]. "
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