Aggregation kinetics of colloidal particles destabilized by enzymes

Area of Science:

• Biophysics
• Biochemistry
• Colloid Science

Background:

• Enzymatic activity is crucial in biological processes.
• Measuring enzymatic kinetics often requires sensitive detection methods.
• Colloidal particle destabilization can be indicative of enzymatic reactions.

Purpose of the Study:

• To develop and validate a method using Dynamic Light Scattering (DLS) for quantifying enzymatic activity.
• To monitor the destabilization of protein- or carbohydrate-coated colloidal particles as a measure of enzyme function.
• To analyze the kinetics of enzymatic reactions through changes in particle diffusion.

Main Methods:

• Utilizing Dynamic Light Scattering (DLS) to measure particle diffusion coefficients.
• Analyzing photon autocorrelation spectra via cumulant expansion and direct inversion methods.
• Coating colloidal particles with proteins or carbohydrates to act as enzyme substrates.
• Monitoring the time-dependent changes in particle diffusion and its distribution.

Main Results:

• Observed a decrease in both average diffusion coefficient and its standard deviation over time.
• Demonstrated that DLS is sensitive to the destabilization of coated colloidal particles.
• Successfully modeled the time-dependent changes using a kinetic model with a bimodal particle distribution.
• Showcased the sensitivity of cumulants to particle distribution details.

Conclusions:

• Dynamic Light Scattering provides a viable method for measuring enzymatic activity.
• The technique effectively quantifies enzyme-driven colloidal particle destabilization.
• Kinetic modeling of diffusion coefficient changes offers detailed insights into reaction dynamics.
• DLS is a powerful tool for studying enzyme kinetics and particle interactions.