A simple electrochemical method to monitor an azo dye reaction with a liver protein

Author(s)

Materon, Elsa Maria ^{[1, 2]} ; Marchetto, Reinaldo ^[1] ; Araujo, Angela Regina ^[1] ; Vega-Chacon, Jaime ^[1] ; Pividori, I, Maria ; Jafelicci Jr, Miguel ; Shimizu, Flavio M. ^[2] ; Oliveira Jr, Osvaldo N. ; Boldrin Zanoni, Maria Valnice ^[3]

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Chem, BR-14801970 Araraquara, SP - Brazil

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil

^[3] Jafelicci Jr, Jr., Miguel, Sao Paulo State Univ UNESP, Inst Chem, BR-14801970 Araraquara, SP - Brazil

• Document type: Journal article
• Source: Analytical Biochemistry; v. 553, p. 46-53, JUL 15 2018.
• Web of Science Citations: 2

Abstract

Disperse Orange 37 (DO37) is an efficient azo dye for dyeing synthetic textile materials owing to its resistance to degradation that may also be harmful to humans as DO37 is not entirely eliminated in wastewater treatment. In this paper, we demonstrate that DO37 is bleached by reduced glutathione (GSH) in a reaction catalyzed by glutathione-s-transferase (GST), a phase II detoxification enzyme. The reaction included a nucleophilic attack involving sulfhydryl groups, confirmed using density functional theory (DFT) calculations. DO37 also induced quenching in the fluorescence of GST through static suppression. The reaction was determined using differential pulse voltammetry (DPV) by monitoring the oxidation peak at 0.65 V of GSH sulfhydryl group. Quantitative estimation of the product reaction could be made by measuring an additional oxidation peak at 0.91 V which increased linearly with DO37 concentration. These electrochemical determinations were made possible by preconcentrating the reaction product on a graphite-epoxy electrode with immobilization of GST onto magnetite nanoparticles. Straightforward biological implications from the results are associated with the known toxicity of azo dyes such as DO37, which has been proven here to interact strongly with both GSH and the liver enzyme GST, and may induce hepatocarcinogenesis or other types of cancer. (AU)

• FAPESP's process: 13/14262-7 - Nanostructured films from biologically-relevant materials
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 12/15543-7 - Biosensors to detect Escherichia coli using the concept of an extended electronic tongue
• Grantee: FLAVIO MAKOTO SHIMIZU
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/00991-5 - Study of Detoxification Enzymes Interaction with chemotherapeutic drugs and its relationship with chemoresistance
• Grantee: Elsa María Materón Vásques
• Support Opportunities: Scholarships in Brazil - Post-Doctoral