Identification of the stereoisomeric configurations of methylcitric acid produced by si-citrate synthase and methylcitrate synthase using capillary gas chromatography-mass spectrometry.
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.
van Rooyen
J P
JP
Biochemistry Department, Potchefstroom University of Christian Higher Education, South Africa.
Mienie
L J
LJ
Erasmus
E
E
De Wet
W J
WJ
Ketting
D
D
Duran
M
M
Wadman
S K
SK
D002950:Citrate (si)-Synthase / Q000378:metabolism*; D002951:Citrates / Q000096:biosynthesis / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D013237:Stereoisomerism
D002951:Citrates; C031605:2-methylcitric acid; D002950:Citrate (si)-Synthase; C092884:methylcitrate synthase