The catalytic efficiency of peroxidase-mimicking G-quadruplex/hemin DNAzyme when using ABTS vs. TMB as a substrate

Background: Functional nucleic acids are a group of nucleic acids with functions beyond the natural genetic materials.G-quadruplex/hemin DNAzyme can mimic the catalytic activity of horseradish peroxidase (HRP) on various organic substrates.Objective: To investigate the catalytic efficiency of G-quadruplex/hemin DNAzyme when using either ABTS or TMB as a substrate. Methods:The catalytic activity of G-quadruplex/hemin DNAzyme was studied in different types of buffer solution by absorbance measurement.Topology of G-quadruplex structure formed in Tris-HCl buffer was analyzed by circular dichroism.The kinetics parameters of the DNAzyme were determined using KaleidaGraph software. Results:The catalytic activities of G-quadruplex/hemin DNAzyme were different in different types of buffer solution.The CD analysis revealed that the parallel G-quadruplex could form in the presence of hemin even without monovalent ions.The kinetics studies, in the selected buffer, with different substrates (ABTS or TMB) showed comparable catalytic efficiency. Conclusion:G-quadruplex/hemin DNAzyme could use either ABTS or TMB as a substrate with similar catalytic efficiency.