DNA flexible chain modified MOFs as a versatile platform for chemoenzymatic cascade reactions in glucose catalysis.

Glucose oxidase (GOD) is widely used in the pharmaceutical industry, fermentation products and glucose biosensors for its essential role in catalyzing the conversion of glucose to gluconic acid and hydrogen peroxide (HO). As HO is the by-product and will have a toxic effect on glucose oxidase, so introducing another enzyme that could consume HO to form an enzymatic cascade reaction is a practical solution. However, this decision will lead to extra expenses and complex condition optimization such as the specific mass ratio, temperature and pH to improve the activity, stability and recyclability. Herein, we describe a mild and versatile strategy by anchoring GOD on carboxyl-activated MOF (Cu-TCPP(Fe)) through DNA-directed immobilization (DDI) technology. Robust MOF nanosheets were utilized as not only the carrier for the immobilization of GOD, but also a peroxidase-like catalyst for the decomposition of HO to reduce its harmful impacts. In this work, the immobilized GOD retained 55.78% of its initial activity after being used for 7 times. More than 60% of the immobilized enzyme's catalytic activity was still maintained after 96 h of being stored at 50 ℃. This study provides a new idea for preparing immobilized enzymes with enhanced stability, fast diffusion and high activity, which can be used in fields such as biocatalysis and biotechnology.