Stability and noise in biochemical switches

TL;DR

This paper investigates how biological switches made of biochemical reactions maintain stability and switchability despite molecular noise, showing that small molecule numbers can still produce long-term stability and rapid switching.

Contribution

It demonstrates that biochemical switches with stability lasting years and switching times of milliseconds can be constructed from fewer than one hundred molecules, highlighting the role of noise in biological systems.

Findings

Switches stable for years can be built from fewer than 100 molecules.

Biochemical switches can switch in milliseconds despite molecular noise.

Analysis suggests feasibility of testing these predictions experimentally.

Abstract

Many processes in biology, from the regulation of gene expression in bacteria to memory in the brain, involve switches constructed from networks of biochemical reactions. Crucial molecules are present in small numbers, raising questions about noise and stability. Analysis of noise in simple reaction schemes indicates that switches stable for years and switchable in milliseconds can be built from fewer than one hundred molecules. Prospects for direct tests of this prediction, as well as implications, are discussed.