Gold Nanoparticle-Stabilized, Tyrosine-Rich Peptide Self-Assemblies and Their Catalytic Activities in the Reduction of 4-Nitrophenol.

Peptides are suitable candidates for templates in the fabrication of various metal nanoparticles (NPs) because of their metal-binding ability and templating effect, which impart physicochemical properties to the produced nanoparticles. Peptide-binding gold nanoparticles (AuNPs) show high catalytic activity that permits their application in oxidation or reduction reactions. Herein, we prepared morphology-controllable AuNPs stabilized by self-assembled tyrosine-rich peptides (YC) by varying the pH and YC peptide/Au concentration ratio in 2-( N-morpholino)ethanesulfonic acid (MES) buffer solution. The catalytic activities of the YC peptide-stabilized AuNPs (YC@AuNPs) were tested for 4-nitrophenol (4-NP) reduction, and kinetic analysis was performed to calculate the apparent rate constants and activation energies. The relatively low activation energy of the YC@AuNPs could be explained by the hypothesis that the tyrosine-moiety of YC enriches the electron density of Au metal.