title: Effect of silver nanoparticles on the electron transfer reactivity and the catalytic activity of myoglobin.
abstract: 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, quasi-reversible 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 x 10(-6) M with a sensitivity of 0.0205 microA per microM of H2O2. The apparent Michaelis-Menten constant was calculated to be 1303 muM. 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.
authors.affiliation: Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Gan
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Zhong
authors.forename: Xinjian
authors.initials: X
authors.lastname: Liu
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques; D002384:Catalysis; D004579:Electron Transport; D006861:Hydrogen Peroxide / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry*; D049329:Nanostructures; D010084:Oxidation-Reduction; D012834:Silver / Q000737:chemistry*
chemical_list: D009211:Myoglobin; D012834:Silver; D006861:Hydrogen Peroxide