# Enhanced Diffusion of Single, Lipid-Tethered Enzymes

## TL;DR

This study shows that enzymes can move faster when active, and this enhanced movement increases when multiple enzymes are grouped together.

## Contribution

The study provides experimental validation of enhanced enzyme diffusion using single-molecule tracking on lipid bilayers.

## Key findings

- Active urease diffuses 40% faster with substrate than without or when inhibited.
- Diffusion enhancement scales with substrate concentration.
- Grouping enzymes into complexes increases diffusion enhancement.

## Abstract

Recent experimental
evidence has shown that enzymes that catalyze
exergonic reactions are able to diffuse faster during catalysis, a
process called “enhanced diffusion”. If true, enzyme
propulsion could enable the engineering of designed active materials
at the nanoscale. However, further experimental validation is needed
under well-controlled conditions. We use single-molecule tracking
of enzymes tethered to fluid lipid bilayers, which serve to constrain
motion to two dimensions, lower baseline diffusion for improved sensitivity,
and accommodate multiple tethering strategies. We find that active
urease diffuses approximately 40% faster in the presence of substrate
(urea) than in its absence or when inhibited, independent of the tethering
scheme. The degree of enhancement scales with the substrate concentration,
consistent with prior studies. Finally, we find that assembling multiple
enzymes into larger complexes results in even greater diffusion enhancement.
This work indicates that enzymes could serve as a platform to create
and study active particles at the nanoscale.