Diffusion-controlled effects in reversible enzymatic fast reaction systems--critical spherical shell and proximity...

Area of Science:

• Biochemistry
• Chemical Kinetics
• Physical Chemistry

Background:

• Enzyme kinetics are crucial for understanding biological processes.
• Fast reaction systems, particularly reversible enzymatic ones, present unique kinetic challenges.
• Diffusion-controlled effects can significantly alter observed reaction rates.

Purpose of the Study:

• To investigate diffusion-controlled effects in reversible enzyme fast reaction systems.
• To establish relationships between theoretical and experimental kinetic parameters.
• To provide a framework for accurately calculating rate constants and activation energy.

Main Methods:

• Derivation of an expression relating proximity and experimental second-order rate constants.
• Development of a joint relation for activation energy calculations.
• Formulation of a formula to determine the experimental upper limit for second-order rate constants.

Main Results:

• Proximity and experimental second-order rate constants are generally unequal unless reactions are very slow.
• Absolute reaction rate theory is not always valid for calculating activation energy in these systems.
• The upper limit of second-order rate constants depends on diffusion coefficients, active surface area, and equilibrium concentrations.

Conclusions:

• Diffusion limitations must be considered in fast reversible enzymatic reactions.
• New theoretical approaches are needed for accurate kinetic analysis beyond traditional methods.
• The findings offer a more precise method for quantifying reaction rates and limits in complex enzymatic systems.