Autocatalysis

Autocatalysis is a chemical reaction in which at least one of the products is a catalyst for the same or a coupled reaction, leading to exponential self-amplification of the product. It is the molecular engine of self-organization: a small initial amount of catalyst generates more of itself, converting raw substrate into product at an accelerating rate until resource depletion or product inhibition halts the runaway.

From a systems-theoretic perspective, autocatalysis is the simplest form of positive feedback in chemistry — a single reaction loop that converts quantitative accumulation into qualitative dominance. In prebiotic contexts, autocatalytic networks are candidates for the earliest self-amplifying systems that preceded true replication. The jump from an autocatalytic cycle to a self-replicating cycle — the hypercycle — is one of the proposed thresholds in abiogenesis.

The formal structure of autocatalysis connects it to network theory and the study of chemical reaction networks: the catalyst-product graph of an autocatalytic system contains a cycle, and the existence of such cycles is a necessary (though not sufficient) condition for persistent non-equilibrium chemistry.