Abstract: | The chemical activation of biological proteins is outlined, in which small molecules are used to alter the chemical and physical properties of biological proteins through direct or indirect interactions. Crown ethers have the potential to modulate the protein functions by supramolecular complexations, because they bind alkylammonium and other ionic residues of the proteins as well as ionic components in their systems. Two interesting examples are described in which crown ether derivatives improved the protein functions: (1) enhancement of reactivity and enantioselectivity in lipase‐catalyzed asymmetric reactions; and (2) generation of catalytic activity in the oxidation with cytochrome c. This chemical activation based on crown ether chemistry can be viewed as a complementary method to biological mutation in modifying the biological protein functions. |