title: Identification of the stereoisomeric configurations of methylcitric acid produced by si-citrate synthase and methylcitrate synthase using capillary gas chromatography-mass spectrometry.
abstract: The absolute separation of the four stereoisomeric configurations of methylcitric acid can be achieved on a nonchiral stationary phase SE30 capillary column using the corresponding O-acetylated (tri-(-)-2-butyl ester derivatives. Identification of the separated isomers was done using methylcitric acid produced by si-citrate synthase and methylcitrate synthase of Candida lipolitica. si-Citrate synthase produces the (2S,3S)-, (2S,3R)- and a small amount of the (2R,3S)-isomers. Methylcitrate synthase produces the (2R,3S)-isomer, indicating that this enzyme is more stereospecific than the animal citrate synthase enzyme. The (2R,3R)-isomer may act as an inhibitor of aconitase.
authors.affiliation: Biochemistry Department, Potchefstroom University of Christian Higher Education, South Africa.
authors.forename: J P
authors.initials: JP
authors.lastname: van Rooyen
authors.forename: L J
authors.initials: LJ
authors.lastname: Mienie
authors.forename: E
authors.initials: E
authors.lastname: Erasmus
authors.forename: W J
authors.initials: WJ
authors.lastname: De Wet
authors.forename: D
authors.initials: D
authors.lastname: Ketting
authors.forename: M
authors.initials: M
authors.lastname: Duran
authors.forename: S K
authors.initials: SK
authors.lastname: Wadman
mesh_terms: D002950:Citrate (si)-Synthase / Q000378:metabolism*; D002951:Citrates / Q000096:biosynthesis / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D013237:Stereoisomerism
chemical_list: D002951:Citrates; C031605:2-methylcitric acid; D002950:Citrate (si)-Synthase; C092884:methylcitrate synthase