Glucose Oxidase Initiates Radical Polymerizations by Direct Electron Transfer to Monomers

Area of Science:

• Biochemistry
• Polymer Chemistry
• Enzymology

Background:

• Glucose oxidase (GOx) is a well-established enzyme with diverse applications.
• Previously unknown catalytic activities of GOx continue to be discovered.
• Radical polymerization typically requires initiators or light energy.

Purpose of the Study:

• To investigate the potential of glucose oxidase (GOx) to initiate radical polymerization.
• To explore GOx-catalyzed polymerization under mild and biologically relevant conditions.
• To develop methods for GOx-initiated polymerization suitable for high-throughput screening and integration into biosensors.

Main Methods:

• Enzyme-catalyzed polymerization of acrylamides and methacrylates using GOx in the absence of oxygen and with high glucose concentrations.
• Computational docking studies to elucidate monomer binding and orientation within the GOx active site.
• Development of a fluorescence assay for screening GOx polymerization activity and optimization for 96-well plate format.

Main Results:

• GOx successfully initiated radical polymerization of acrylamides and methacrylates without external initiators or light.
• The mechanism involves glucose oxidation by GOx, leading to electron and proton transfer to the monomer, generating a radical species.
• Computational studies revealed specific monomer orientations within the GOx active site conducive to radical initiation.
• GOx's deoxygenation capability was leveraged to enable polymerization in non-deoxygenated conditions, facilitating high-throughput screening.

Conclusions:

• GOx possesses a novel radical polymerization initiation activity.
• This discovery enables polymer synthesis under mild, biologically compatible conditions.
• GOx-catalyzed polymerization offers potential for integration into biosensors, living systems, and synthetic cells.