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Kinetic analysis of maize glutathione S-transferase I catalysing the detoxification from chloroacetanilide herbicides

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dc.contributor.author Labrou, NE en
dc.contributor.author Karavangeli, M en
dc.contributor.author Tsaftaris, A en
dc.contributor.author Clonis, YD en
dc.date.accessioned 2014-06-06T06:46:34Z
dc.date.available 2014-06-06T06:46:34Z
dc.date.issued 2005 en
dc.identifier.issn 00320935 en
dc.identifier.uri http://dx.doi.org/10.1007/s00425-005-1520-x en
dc.identifier.uri http://62.217.125.90/xmlui/handle/123456789/3081
dc.subject Alachlor en
dc.subject Herbicide detoxification en
dc.subject Protein engineering en
dc.subject Xenobiotics en
dc.subject.other Amino acids en
dc.subject.other Biodegradation en
dc.subject.other Catalysis en
dc.subject.other Data acquisition en
dc.subject.other Herbicides en
dc.subject.other Mutagenesis en
dc.subject.other Alachlor en
dc.subject.other Glutathione S-transferases (GST) en
dc.subject.other Herbicide detoxification en
dc.subject.other Protein engineering en
dc.subject.other Xenobiotics en
dc.subject.other Enzyme kinetics en
dc.subject.other acetamide derivative en
dc.subject.other alachlor en
dc.subject.other atrazine en
dc.subject.other glutathione transferase en
dc.subject.other herbicide en
dc.subject.other article en
dc.subject.other drug detoxification en
dc.subject.other enzymology en
dc.subject.other kinetics en
dc.subject.other maize en
dc.subject.other metabolism en
dc.subject.other protein conformation en
dc.subject.other site directed mutagenesis en
dc.subject.other Acetamides en
dc.subject.other Atrazine en
dc.subject.other Glutathione Transferase en
dc.subject.other Herbicides en
dc.subject.other Kinetics en
dc.subject.other Metabolic Detoxication, Drug en
dc.subject.other Mutagenesis, Site-Directed en
dc.subject.other Protein Conformation en
dc.subject.other Zea mays en
dc.subject.other Amino Acids en
dc.subject.other Biodegradation en
dc.subject.other Catalysts en
dc.subject.other Data en
dc.subject.other Enzymatic Activity en
dc.subject.other Herbicides en
dc.subject.other Mutagens en
dc.subject.other Zea mays en
dc.title Kinetic analysis of maize glutathione S-transferase I catalysing the detoxification from chloroacetanilide herbicides en
heal.type journalArticle en
heal.identifier.primary 10.1007/s00425-005-1520-x en
heal.publicationDate 2005 en
heal.abstract Glutathione S-transferases (GSTs, EC 2.5.1.18) are a family of multi-functional enzymes involved in biodegradation of several herbicide classes. The ability of the maize isoenzyme GST I to detoxify from the acetanilide herbicide alachlor was investigated by steady-state kinetics and site-directed mutagenesis studies. Steady-state kinetics fit well to a rapid equilibrium random sequential bi-bi mechanism with intrasubunit modulation between GSH binding site (G-site) and electrophile binding site (H-site). The rate-limiting step of the reaction is viscosity-dependent and thermodynamic data suggest that product release is rate-limiting. Three residues of GST I (Trp12, Phe35 and Ile118), which build up the xenobiotic binding site, were mutated and their functional and structural roles during alachlor conjugation were investigated. These residues are not conserved, hence may affect substrate specificity and/or product dissociation. The work showed that the key amino acid residue Phe35 modulates xenobiotic substrate binding and specificity, and participates in k cat regulation by affecting the rate-limiting step of the catalytic reaction. Trp12 and Ile118 do not seem to carry out such functions but instead, regulate the K m for alachlor by contributing to its productive orientation in the H-site. The results of the present work have practical significance since this may provide the basis for the rational design of new engineered GSTs with altered substrate specificity towards herbicides and may facilitate the design of new, more selective herbicides. © Springer-Verlag 2005. en
heal.journalName Planta en
dc.identifier.issue 1 en
dc.identifier.volume 222 en
dc.identifier.doi 10.1007/s00425-005-1520-x en
dc.identifier.spage 91 en
dc.identifier.epage 97 en


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