Switchable Biocatalytic Reactions Controlled by Interfacial pH Changes Produced by Orthogonal Biocatalytic Processes

Area of Science:

• Biotechnology
• Enzyme Engineering
• Nanotechnology

Background:

• Enzyme activity is often sensitive to local environmental conditions, such as pH.
• Controlling enzyme activity dynamically is crucial for complex biocatalytic systems.
• Immobilization techniques offer methods to stabilize enzymes and control their microenvironment.

Purpose of the Study:

• To develop a method for switching enzyme activity using localized pH changes generated by co-immobilized enzymes.
• To demonstrate reversible activation and inhibition of target enzymes (amyloglucosidase and trypsin) via pH modulation.
• To explore the potential for controlling complex biocatalytic cascades using orthogonal enzymatic reactions.

Main Methods:

• Immobilizing pairs of enzymes (actuator and target) onto a nano-structured surface.
• Utilizing urease or esterase as actuator enzymes to generate local pH changes.
• Employing amyloglucosidase and trypsin as target enzymes, sensitive to pH variations.
• Applying substrate addition and removal to reversibly control actuator enzyme activity and, consequently, target enzyme states.

Main Results:

• Demonstrated reversible switching between active and inactive states for immobilized amyloglucosidase and trypsin.
• Showcased how urease and esterase, as actuator enzymes, could modulate local pH to control target enzyme activity.
• Confirmed the orthogonality of biocatalytic reactions while enabling coupled pH-dependent operation.
• Established a system where external signals (substrates) trigger pH-mediated enzyme activity modulation.

Conclusions:

• Developed a novel approach for pH-dependent, switchable enzyme activity using co-immobilized enzymes on nanostructures.
• This method allows for the reversible control of enzyme function, with potential applications in complex biocatalytic systems.
• The findings pave the way for designing sophisticated, signal-responsive biocatalytic cascades with tunable outputs.