Skip to main content

Research Repository

Advanced Search

A kinetic model for the metabolism of the herbicide safener fenclorim in Arabidopsis thaliana.

Liu, J.L.; Brazier-Hicks, M.; Edwards, R.


M. Brazier-Hicks

R. Edwards


Glutathione transferases (GSTs) catalyse the detoxification of a range of xenobiotics, including crop protection agents in plants. Recent studies in cultures of the model plant Arabidopsis thaliana have shown that the herbicide safener fenclorim (4,6-dichloro-2-phenylpyrimidine) is conjugated by GSTs acting in the cytosol which are induced in response to this chemical treatment. The primary glutathione conjugates are then hydrolyzed to S-(4-chloro-2-phenylpyrimidin-6-yl)-cysteine, which after accumulating transiently in the cells and medium is then metabolized by a series of competing lyases and transferases, including GSTs, to a series of polar derivatives. This system therefore represents an example of an inducible metabolic pathway, where GSTs are involved in multiple steps and where detailed information on the content of intermediates is available. Using this data, a kinetic model describing the biotransformations of differing concentrations of fenclorim in Arabidopsis has been established, which was able to quantitatively analyse fluxes and changes in metabolite levels over time as a function of the induction of GSTs by the safener. The model confirmed a regulatory role for GSTs and the hydrolytic enzymes acting on the resulting glutathione conjugates. In addition, model analysis indicated that fenclorim metabolism is capable of generating oscillations if kinetic parameters are allowed to vary. The model offers new insights into the metabolic regulation of inducible xenobiotic metabolism in plants which is important in both determining herbicide selectivity in cereal crops and the remediation of organic pollutants by plants.


Liu, J., Brazier-Hicks, M., & Edwards, R. (2009). A kinetic model for the metabolism of the herbicide safener fenclorim in Arabidopsis thaliana. Biophysical Chemistry, 143(1-2), 85-94.

Journal Article Type Article
Publication Date 2009-07
Deposit Date Oct 8, 2010
Journal Biophysical Chemistry
Print ISSN 0301-4622
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 143
Issue 1-2
Pages 85-94