Title: Enantioselective in-line and off-line CE methods for the kinetic study on cimetidine and its chiral metabolites with reference to flavin-containing monooxygenase genetic isoforms
Authors: Hai, Xin
Adams, Erwin
Hoogmartens, Jos
Van Schepdael, Ann # ×
Issue Date: Apr-2009
Publisher: Wiley-v c h verlag gmbh
Series Title: Electrophoresis vol:30 issue:7 pages:1248-1257
Abstract: An in-line screening and an off-line chiral CE method were developed to determine the stereoselectivity of flavin-containing monooxygenase (FMO) isoforms using cimetidine (CIM) as a substrate. The S-oxygenation of CIM was investigated using achiral chemical oxidants and (human supersomes) enzymatic metabolism procedures. in the off-line setup, the chiral selector sulfobutylether-beta-CD was chosen to separate the CIM S-oxide (CSO) metabolites. The electrophoretic migration order of CSO was confirmed to be (+) before (-) through the use of single enantiomers obtained by preparative chromatography. For the electrophoretically mediated microanalysis method, the in-line enzymatic reaction was performed in 100 mM phosphate reaction buffer (pH 8.3), whereas 50 mM phosphate buffer with 30 mM chiral selector (pH 2.5) was used as a BGE. During the screening of FMO isoenzymes by the electrophoretically mediated microanalysis method, formation of the new chiral center on the CIM sulfur was found to be stereoselective. FMO1 produces more (-)-CSO-enantiomer, while FMO3 generates mainly (+)-CSO-enantiomer. On the other hand, FMO5 shows no activity. The kinetic constants of FMO1 and FMO3 were measured by the off-line method. A K-m = 4.31 mM for the formation of the (+)-CSO-enantiomer and a K-m = 4.56 mM for the (-)-CSO-enantiomer are reported for the first time for FMO1.
ISSN: 0173-0835
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Pharmaceutical Analysis
× corresponding author
# (joint) last author

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