title: Bioreduction of platinum salts into nanoparticles: a mechanistic perspective.
abstract: A mechanism for the bioreduction of H2PtCl6 and PtCl2 into platinum nanoparticles by a hydrogenase enzyme from Fusarium oxysporum is proposed. Octahedral H2PtCl6 is too large to fit into the active region of the enzyme and, under conditions optimum for nanoparticle formation (pH 9, 65 degrees C), undergoes a two-electron reduction to PtCl2 on the molecular surface of the enzyme. This smaller molecule is transported through hydrophobic channels within the enzyme to the active region where, under conditions optimal for hydrogenase activity (pH 7.5, 38 degrees C) it undergoes a second two-electron reduction to Pt(0). H2PtCl6 was unreactive at pH 7.5, 38 degrees C; PtCl2 was unreactive at pH 9, 65 degrees C.
authors.affiliation: Department of Biochemistry, Microbiology & Biotechnology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
authors.forename: Yageshni
authors.initials: Y
authors.lastname: Govender
authors.forename: Tamsyn
authors.initials: T
authors.lastname: Riddin
authors.forename: Mariekie
authors.initials: M
authors.lastname: Gericke
authors.forename: Chris G
authors.initials: CG
authors.lastname: Whiteley
mesh_terms: D006864:Hydrogenase / Q000378:metabolism* / Q000648:ultrastructure; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D017671:Platinum Compounds / Q000378:metabolism*
chemical_list: D017671:Platinum Compounds; D006864:Hydrogenase