Investigating the interactions between cations, peroxidation substrates and G-quadruplex topology in DNAzyme peroxidation reactions using statistical testing

Cations affect the topology and enzymatic proficiency of most macromolecular catalysts but the role of cations in DNAzyme peroxidation reactions remains unresolved. Herein, we use statistical methods (ANOVA, t-test and Wilcoxon Mann–Whitney non-parametric test) to demonstrate that there are strong associations between cations, DNAzyme topology, peroxidation substrate and peroxidation rates of G-quadruplex peroxidises. Ammonium cation was found to be superior to all tested cations, including potassium. A t-test indicated that NH4+ was better than K+ with a p-value = 0.05. Interestingly, the nature of the peroxidation substrate employed affected the dependence of peroxidation rate on the cation present and of the three substrates tested, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), tyramine and 3,3′,5,5′-tetramethylbenzidine (TMB), ABTS was the most sensitive to the nature of cation present.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► G-quadruplex peroxidation rate depends on the cation present. ► NH4+ is best cation amongst Li+, Na+, K+, Cs+, Rb+, Sr2+, Br2+, Pb2+ and Tb3+. ► ANOVA reveals cation effect is dependent on DNAzyme topology and peroxidation substrate.