Cyclopropane-1,1-dicarboxylate is a slow-, tight-binding inhibitor of rice ketol-acid reductoisomerase

Lee, Yu-ting, Ta, Hang T. and Duggleby, Ronald G. (2005) Cyclopropane-1,1-dicarboxylate is a slow-, tight-binding inhibitor of rice ketol-acid reductoisomerase. Plant Science, 168 4: 1035-1040. doi:10.1016/j.plantsci.2004.11.020


Author Lee, Yu-ting
Ta, Hang T.
Duggleby, Ronald G.
Title Cyclopropane-1,1-dicarboxylate is a slow-, tight-binding inhibitor of rice ketol-acid reductoisomerase
Journal name Plant Science   Check publisher's open access policy
ISSN 0168-9452
1873-2259
Publication date 2005-01-01
Sub-type Article (original research)
DOI 10.1016/j.plantsci.2004.11.020
Open Access Status Not Open Access
Volume 168
Issue 4
Start page 1035
End page 1040
Total pages 6
Place of publication E. Park, Shannon, Co. Clare, Ireland
Publisher Elsevier Ireland
Language eng
Formatted abstract
Ketol-acid reductoisomerase (EC 1.1.1.86) catalyses the second reaction in the biosynthesis of the branched-chain amino acids. The reaction catalyzed consists of two stages, the first of which is an alkyl migration from one carbon atom to its neighbour. The likely transition state is therefore a cyclopropane derivative, and cyclopropane-1,1-dicarboxylate (CPD) has been reported to inhibit the Escherichia coli enzyme. In addition, this compound causes the accumulation of the substrate of ketol-acid reductoisomerase in plants. Here, we investigate the inhibition of the purified rice enzyme. The cDNA was cloned, and the recombinant protein was expressed in E. coli, purified and characterized kinetically. The purified enzyme is strongly inhibited by cyclopropane-1,1-dicarboxylate, with an inhibition constant of 90 nM. The inhibition is time-dependent and this is due to the low rate constants for formation (2.63 × 105 M−1 min−1) and dissociation (2.37 × 10−2 min−1) of the enzyme-inhibitor complex. Other cyclopropane derivatives are much weaker inhibitors while dimethylmalonate is moderately effective.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Australian Institute for Bioengineering and Nanotechnology Publications
 
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Created: Fri, 27 Jun 2014, 21:58:32 EST by Hang Ta on behalf of Aust Institute for Bioengineering & Nanotechnology