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pH Controlled Activation and Stabilization of Enzymes Using Responsive Polymer-Bioconjugates.
Monica S Rahman1, Bhagya Chandrarathne1, Katie Bender1
1Department of Chemistry and Biochemistry, Miami University, 651 E High Street, Oxford, Ohio 45056, United States.
Biomacromolecules
|June 6, 2025
Summary
Researchers developed pH-responsive bioconjugates to control enzyme activity and stability. These smart polymers offer tunable regulation of enzymes like lipase B and lysozyme, switching between high activity and stability states.
Area of Science:
- Bioconjugation Chemistry
- Enzyme Engineering
- Polymer Science
Background:
- Enzyme activity and stability are critical for biocatalysis.
- Stimuli-responsive polymers offer potential for precise control over biomolecules.
- Previous studies indicated inhibitory effects of N-isopropylacrylamide (NIPAm) polymers on enzymes.
Purpose of the Study:
- To develop stimuli-responsive bioconjugates for controlling enzymatic activity and stability.
- To investigate the pH-responsive behavior of a novel polymer conjugate with enzymes.
- To explore the potential of pH-dependent polymer-protein interactions for enzyme regulation.
Main Methods:
- Conjugation of a pH-responsive polymer (pDMAPA DP40-b-NIPAm DP10) to Candida antarctica lipase B (CalB).
- Conjugation of a similar polymer (pDMAPA DP40-b-AGA DP10) to lysozyme.
- Evaluation of enzyme activity and stability under varying pH conditions.
Main Results:
- The pDMAPA-NIPAm conjugate demonstrated pH-responsive control over CalB activity and stability.
- At low pH, the extended polymer led to high enzyme activity.
- At low pH, the polymer also occluded the active site, increasing enzyme stability.
- A similar pH-controlled activity-stability response was observed for lysozyme.
Conclusions:
- pH-responsive polymers can effectively regulate enzyme activity and stability.
- The polymer's pH-dependent interactions enable switching between active and stable enzyme states.
- This approach offers a versatile strategy for controlling enzyme performance.
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