Substrate presentation is a biological process that activates a protein. The protein is sequestered away from its substrate and then activated by release and exposure of the protein to its substrate.[1][2] A substrate is typically the substance on which an enzyme acts but can also be a protein surface to which a ligand binds. The substrate is the material acted upon. In the case of an interaction with an enzyme, the protein or organic substrate typically changes chemical form. Substrate presentation differs from allosteric regulation in that the enzyme need not change its conformation to begin catalysis. Substrate presentation is best described for domain partitioning at nanoscopic distances (<100 nm).[3]