Length and sequence relaxation of copolymers under recombination reactions

TL;DR

This paper investigates the kinetics and thermodynamics of copolymer recombination reactions, comparing infinite and finite size models, revealing conditions where sequence entropy decreases while length entropy increases.

Contribution

It introduces two modeling approaches for copolymer recombination, analyzing their predictions and exploring entropy dynamics under different reaction conditions.

Findings

Sequence entropy can decrease while length entropy increases.

Models predict different relaxation behaviors for infinite vs. finite systems.

Energetically neutral reactions dominate the studied scenarios.

Abstract

We describe the kinetics and thermodynamics of copolymers undergoing recombination reactions, which are important for prebiotic chemistry. We use two approaches: the first one, based on chemical rate equations and the mass-action law describes the infinite size limit, while the second one, based on the chemical master equation, describes systems of finite size. We compare the predictions of both approaches for the relaxation of thermodynamic quantities towards equilibrium. We find that for some choice of initial conditions, the entropy of the sequence distribution can be lowered at the expense of increasing the entropy of the length distribution. We consider mainly energetically neutral reactions, except for one simple case of non-neutral reactions.