Diffusion modifies the connectivity of kinetic schemes for multisite binding and catalysis.

Area of Science:

• Chemical Kinetics
• Biophysics
• Physical Chemistry

Background:

• Conventional chemical kinetics often assumes fast diffusion, limiting its accuracy for complex molecular interactions.
• Macromolecules with multiple reactive sites exhibit unique behaviors where local diffusion influences reaction pathways.
• Existing models struggle to capture the interplay between diffusion and reaction in multisite systems.

Purpose of the Study:

• To develop a more accurate kinetic model for multisite binding and catalysis that incorporates the influence of relative reactant diffusion.
• To provide a theoretical framework that extends beyond the limitations of conventional chemical kinetics for complex molecular systems.
• To elucidate the physical basis of diffusion's impact on reaction rates in systems with multiple binding sites.

Main Methods:

• Development and application of an exactly solvable many-particle reaction-diffusion model.
• Renormalization of phenomenological rate constants and introduction of new kinetic pathways.
• Analysis of reaction-diffusion dynamics in the context of multisite binding events.

Main Results:

• Demonstrated that diffusion's influence extends beyond simple rate scaling in multisite systems.
• Introduced new connections (reaction channels) into the kinetic scheme to account for diffusion-assisted binding.
• Quantified the relationship between chemical rates, diffusion, and binding probabilities.

Conclusions:

• The study provides a refined theoretical approach to understanding reaction kinetics in complex molecular systems.
• The developed model accurately describes how diffusion affects multisite binding and catalysis, offering new insights.
• The findings have direct applications in understanding biological processes like enzyme-substrate interactions, such as multisite substrate phosphorylation.