The hemin/G-Quadruplex DNAzyme consists of G-Quadruplex forming DNA that can bind the co-factor hemin (a.k.a. Fe(III)Protoporphyrin IX), forming a complex that can perform certain oxidation reaction in the presence of hydrogen peroxide. This DNAzyme can oxidize small molecules, such as dopamine and adenosine triphosphate, but can also be used for the modification of peptides and proteins by attaching small molecules.