A Brownian dynamics simulation of enzyme–substrate encounters at the surface of a colloidal particle

Abstract

The numerical technique of Brownian dynamics is used to model diffusion-controlled encounters between a small spherical enzyme particle and substrate molecules (‘hot spots’) distributed randomly on the surface of a larger spherical colloidal particle. Reaction occurs when any spot gets within a certain specified distance from the enzyme's active site. Specimen results are presented for the number and distribution of reacted spots as a function of time. The simulation gives information on the effect on the kinetics of interparticle hydrodynamic interactions, the effective size of the active site, and the range of available diffusional space around the colloidal particle.