Remarks on the energy costs of insulators in enzymatic cascades

TL;DR

This paper examines the energy costs associated with insulators in enzymatic cascades, extending previous models to include proteins with active and inactive forms, highlighting the trade-off between energy consumption and insulator effectiveness.

Contribution

It introduces a new model for enzymatic insulators involving proteins with active/inactive states, analyzing energy costs in this context.

Findings

Higher energy consumption improves insulator performance.

Energy costs are a key factor in the design of biochemical network insulators.

The model extends previous work to more complex protein regulation mechanisms.

Abstract

The connection between optimal biological function and energy use, measured for example by the rate of metabolite consumption, is a current topic of interest in the systems biology literature which has been explored in several different contexts. In [J. P. Barton and E. D. Sontag, Biophys. J. 104, 6 (2013)], we related the metabolic cost of enzymatic futile cycles with their capacity to act as insulators which facilitate modular interconnections in biochemical networks. There we analyzed a simple model system in which a signal molecule regulates the transcription of one or more target proteins by interacting with their promoters. In this note, we consider the case of a protein with an active and an inactive form, and whose activation is controlled by the signal molecule. As in the original case, higher rates of energy consumption are required for better insulator performance.