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

• Published in: Chembiochem : a European journal of chemical biology Vol. 5; no. 12; pp. 1686 - 1691
• Main Authors: Gan, Xin, Liu, Tao, Zhong, Jun, Liu, Xinjian, Li, Genxi
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley-VCH Verlag 03.12.2004; WILEY-VCH Verlag; WILEY‐VCH Verlag
• Subjects: Biosensing Techniques; Catalysis; electrochemistry; electrodes; Electron Transport; Hydrogen Peroxide - chemistry; myoglobin; Myoglobin - chemistry; nanoparticles; Nanostructures; Oxidation-Reduction; silver; Silver - chemistry
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.200400080

Silver nanoparticles (11±1.5 nm) could greatly enhance the electron-transfer reactivity of myoglobin (Mb) and its catalytic ability toward hydrogen peroxide (H₂O₂). 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 H₂O₂ was also studied, and a H₂O₂ biosensor was subsequently fabricated. Its detection limit was 1.0×10⁻⁶ M with a sensitivity of 0.0205 μA per μM of H₂O₂. The apparent Michaelis-Menten constant was calculated to be 1303 μM. 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.