1. A toehold exchange catalyst system comprising: a substrate molecule defining a plurality of binding sites including at least one toehold binding site; a plurality of ligand molecules, said ligand molecules having overlapping binding sites on said substrate molecule at said toehold binding site, and at least one of said ligand molecules being bound to said substrate molecule; and a catalyst molecule, said catalyst molecule being designed to bind to the substrate molecule at a position on the substrate molecule that at least partially overlaps the toehold binding site such that the binding of the catalyst molecule to the substrate molecule dislodges at least one of the bound ligand molecules to form an output molecule, while exposing a new binding site, allowing for reaction with other ligand molecules.