Berlin 2018 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 60: Anomalous Diffusion (joint session DY/BP)

DY 60.8: Talk

Thursday, March 15, 2018, 12:00–12:15, BH-N 334

Kinetics of an enzymatic reaction under anomalous diffusion - A case study — •Daniela Froemberg and Felix Höfling — Freie Universität Berlin, Department of Mathematics and Computer Science

The interior of biological cells constitutes a crowded environment in which diffusion of organelles or macromolecules is anomalous[1]. Consequently, such heterogeneous conditions also alter the kinetics of the chemical reactions taking place.

Here, we report on simulations of the reaction-diffusion dynamics of an enzyme-catalyzed reaction using a particle-based scheme. The particles diffuse in space and reactions occur with a certain microscopic propensity if the reaction partners are within a prescribed reaction distance. To mimick a crowded environment, we implement the subdiffusion by a fractional Brownian motion.

For anomalous diffusion, it is well-known that the the diffusion coefficient is a function of the lag time. Similarly, the coefficient k(t) of the effective reaction rate can adopt a timescale dependence. Preliminary results from extensive simulations suggest a power law dependence of k(t), slowing down the reaction as compared to the normal diffusive case.

We detail the behavior of k(t), elucidate the role of the subdiffusion parameter, and test for an old prediction originally made for reactions on fractals.

[1] F. Höfling, T. Franosch, Rep. Prog. Phys. 76 (2013) 046602 (50pp)