期刊
EUROPEAN JOURNAL OF BIOCHEMISTRY
卷 268, 期 1, 页码 132-138出版社
WILEY
DOI: 10.1046/j.1432-1327.2001.01856.x
关键词
enantioselective sulfoxidation; selective oxygen-transfer; vanadium bromoperoxidase; vanadium chloroperoxidase
We have previously shown that vanadium bromoperoxidase from Ascophyllum nodosum mediates production of the (R)-enantiomer of methyl phenyl sulfoxide with 91% enantiomeric excess. Investigation of the intrinsic selectivity of vanadium bromoperoxidase reveals that the enzyme catalyzes the sulfoxidation of methyl phenyl sulfide in a purely enantioselective manner. The K-m of the enzyme for methyl phenyl sulfide was determined to be approximate to 3.5 mM in the presence of 25% methanol or tert-butanol, The selectivity of the sulfoxidation of methyl phenyl sulfide is optimal in the temperature range 25-30 degreesC and can be further optimized by increasing the enzyme concentration, yielding selectivities with up to 96% enantiomeric excess. Furthermore, we established for the first time that vanadium bromoperoxidase is functional at temperatures up to 70 degreesC. A detailed investigation of the sulfoxidation activity of this enzyme using O-18-labeled hydrogen peroxide shows that vanadium bromoperoxidase mediates the direct transfer of the peroxide oxygen to the sulfide. A schematic model of the vanadium haloperoxidase sulfoxidation mechanism is presented.
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