Figure 3.

(A) Schematic structures of Fe³⁺–terpyridine-modified dopamine aptamer nucleoapzymes for the catalyzed oxidation of dopamine (1) by H₂O₂ to yield dopachrome (2). (B) Rates of oxidation of dopamine (1) to dopachrome (2) in the presence of H₂O₂ using variable concentrations of dopamine (1): (a) using the nucleoapzyme in configuration I, (b) using the nucleoapzyme in configuration II, and (c) using the separated Fe³⁺–terpyridine catalyst and the dopamine aptamer. (C) Molecular dynamics energy-minimized structures of (I) the nucleoapzyme in configuration I and (II) the nucleoapzyme in configuration II.