Inactivation Kinetics of G-Quadruplex/Hemin Complex and Optimization for More Reliable Catalysis

Reliable catalysis is critical for the synthesis of various chemicals, molecular sensing and biomedicine. G-quadruplex/Hemin (GQH) complex, a peroxidase-mimicking DNAzyme, has been widely used in various publications. However, a concern exists about the unstable kinetics of GQH-catalyzed peroxidation. This work investigates several factors that result in the inactivation of GQH and the signal degradation during long reaction periods, including pH, buffer component, the selection of substrate and the oxidation damage of cofactor. Using colorimetric and fluorescent assays, GQH was found to be highly unstable under basic conditions with 50 % of GQH activity lost within 2 minutes at high H2O2 concentrations. Appropriate conditions and substrates are suggested for accurately characterizing GQH-catalyzed reactions, as well as optimization to improve the catalytic reliability, such as the use of polyhistidine and cascade reactions. These results could be useful for GQH-related applications.

Automated summary

Reliable catalysis is crucial for the synthesis of chemicals, molecular sensing, and biomedicine. The G-quadruplex/Hemin (GQH) complex, a peroxidase-mimicking DNAzyme, has been widely used, but its kinetics is unstable. This study investigates the factors causing the inactivation of GQH and signal degradation during long reaction periods, proposing suggestions for optimizing GQH-catalyzed reactions and improving catalytic reliability. The results have implications for GQH-related applications.