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Ivanova Ye. V., Ryabov A. D.
Enzyme-Substratum Interactions in Oxidation of (+) and (–) [Ru(phpy)(phen)2]PF6 by Hydrase
Peroxide in the Presence of Horse Radish Peroxidase
Abstract
The cyclometalated ruthenium(II) complex [Ru(phpy)(phen)2]PF6
(phpy = 2-phenylpyridine, phen = 1,10-phenanthroline) was resolved into the L and D enantiomers using
the chromatographic technique and characterized by the UV-vis and CD
spectroscopy. Since [Ru(phpy)(phen)2]PF6 is an excellent
mediator of the electron transport involving horseradish peroxidase (HRP) [1],
the ability to discriminate between the L and D enantiomers by these two
enzymes was investigated. The kinetics
of the HRP-catalyzed oxidation of the L and D enantiomers by H2O2
was studied spectrophotometrically at pH 5-9 and 25 °C. The kobsL/kobsD ratio was found to
be also pH-dependent and the highest ratio of ca. 2.5 was observed at pH around
8. Practically no selectivity is
observed at pH 5-6 suggesting that the active site of the enzyme is pH-tuned
for recognition of chiral molecules. In
general, the enantioselectivty observed here (L/D) is higher than that in the
case of planar chiral ferrocene derivatives reported by us previously [6].
Copyright (C) Chemistry Dept., Moscow State University, 2002
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