Effect of Silver Nanoparticles on the Electron Transfer Reactivity and the Catalytic Activity of Myoglobin

✍ Scribed by Xin Gan; Tao Liu; Jun Zhong; Xinjian Liu; Genxi Li

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 262 KB
• Volume: 5
• Category: Article
• ISSN: 1439-4227
• DOI: 10.1002/cbic.200400080

✦ Synopsis

Abstract

Silver nanoparticles (11±1.5 nm) could greatly enhance the electron‐transfer reactivity of myoglobin (Mb) and its catalytic ability toward hydrogen peroxide (H~2~O~2~). Direct fast electron transfer between Mb and a pyrolytic graphite (PG) electrode was achieved, and a pair of well‐defined, quasireversible redox peaks was obtained. The cathodic and anodic peaks were located at −329 and −281 mV, respectively. Meanwhile, the catalytic ability of the protein toward the reduction of H~2~O~2~ was also studied, and a H~2~O~2~ biosensor was subsequently fabricated. Its detection limit was 1.0×10^−6^ M with a sensitivity of 0.0205 μ__A per__ μ__M of H~2~O~2~. The apparent Michaelis–Menten constant was calculated to be 1303__ μ__M. Flocculation assay showed that the protein maintained plasmon layers surrounding the surface of silver nanoparticles and avoided silver‐nanoparticle aggregation. On the other hand, UV‐visible spectroscopy studies revealed that silver nanoparticles could induce a small change of the heme‐group environment of the protein; this contributed to the enhancement of the electron‐transfer reactivity and the catalytic activity.__