Govender, Y. and Riddin, T. L. and Gericke, M. and Whiteley, C. G. (2009) On the enzymatic formation of platinum nanoparticles. Journal of Nanoparticle Research, 12 (1). pp. 261-271. ISSN 1388-0764 (Print) 1572-896X (Online)
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A dimeric hydrogenase enzyme (44.5 and 39.4 kDa sub units) was isolated in a 39.5% yield from the fungus Fusarium oxysporum and purified 4.64-fold by ion exchange chromatography on Sephacryl S-200. Characterisation of the enzyme afforded pH and temperature optima of 7.5 and 38 °C, respectively, a half-life stability of 36 min and a V max and K m of 3.57 nmol min−1 mL−1 and 2.25 mM, respectively. This enzyme was inhibited (non-competitively) by hydrogen hexachloroplatinic acid (H2PtCl6) at 1 or 2 mM with a K i value of 118 μM. Incubation of the platinum salt with the pure enzyme under an atmosphere of hydrogen and optimum enzyme conditions (pH 7.5, 38 °C) afforded <10% bioreduction after 8 h while at conditions suitable for platinum nanoparticle formation (pH 9, 65 °C) over 90% reduction took place after the same length of time. Cell-free extract from the fungal isolates produced nearly 90% bioreduction of the platinum salt under both pH and temperature conditions. The bioreduction of the platinum salt by a hydrogenase enzyme takes place by a passive process and not an active one as previously understood.
|Uncontrolled Keywords:||Platinum - Nanoparticles - Hydrogenase - Fusarium - Synthesis|
|Subjects:||Biomedical Science > Nanobiotechnology|
Material Science > Nanostructured materials
Material Science > Nanochemistry
|Deposited On:||01 Mar 2010 10:17|
|Last Modified:||01 Mar 2010 10:17|
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