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"Charge Relay from Molybdate Oxyradicals
to Palladium Lipoic Complex to DNA"
(Garnett and Garnett, Conference on Oxygen Intermediates in Nonheme Metallobiochemistry,
1996)
Wade A. Garnett and Merrill Garnett, Garnett McKeen Lab
University Campus, 25 East Loop Road
Stony Brook, New York 11790 USA
Among the blue heteropolymolybdates ß-Mo8O26 is of special interest
in that it can be dissected in alkali to yield superoxide
1. This is represented: ß-Mo8O26=>0 2
-1 + (Mo4012)2.
After confirming identity and purity of this lattice structure by X-Ray crystallography (Molecular Structures Corp),
these crystals were solubilized in NaOH. The blue solution was assayed electrochemically in a background electrolyte
of Na acetate-acetic acid at pH 5.0 to allow protonation and formation of some perhydroxy radical. The mixture
of oxyradicals gave a strong reducing signal at 925. mv by cyclic voltammetry with a Hg electrode.
Palladium-lipoic complex trimerizes under the influence of thiamine (2) to produce a pseudoreversible strong reducing
signal by the same method. The complex is characterized as a synthetic DNA reductase.
The molybdata and palladium signals do not overlap. When the two materials are combined and scanned together,
their original signals disappear and a new intermediate signal appears. This is consistent with oxidation of the
oxyradicals, and reduction of the palladium complex. The further addition of calf thymus of the palladium complex.
The further addition of calf thymus DNA then regenerates (oxidizes) the signal.
Under defined conditions therefore, DNA and palladium-lipoic complex constitute a system capable of scavenging
oxyradicals.
1.V.W. Day, M.F> Fredrich, W.G. Klemperer, W. Shum, J.Am. Chem. Soc., 99: 2, p.952, Feb 2, 1977
2.M. Garnettm, J.Inorg.Biochem., 59 :2&3, p.231, Aug.1995
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