Purification of multiple glutathione transferases involved in herbicide detoxification from wheat (Triticum aestivum L.) treated with the safener fenchlorazole-ethyl
Purification of multiple glutathione transferases involved in herbicide detoxification from wheat (Triticum aestivum L.) treated with the safener fenchlorazole-ethyl
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DOI：
10.1006/pest.1997.2308
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发表时间：
1997-01-01
影响因子：
4.7
通讯作者：
Edwards, R
中科院分区：
文献类型：
--
作者：
Cummins, I;Cole, DJ;Edwards, R
从除草剂安全剂解草唑处理的小麦幼苗中纯化出多种谷胱甘肽转移酶（GST）同工酶，利用疏水作用色谱法可将其分为极性和疏水型。这两种类型的GST也可以根据它们对S-己基-谷胱甘肽-琼脂糖的亲和力来分辨。一小部分GST可以用盐洗涤从柱上洗脱下来，并且这种松散结合的级分含有被针对θ型玉米GST ZmGST I-II产生的抗血清识别的多肽。大部分只能回收使用S-己基-谷胱甘肽和这些GST的详细特征。这些同工酶催化谷胱甘肽共轭的外源性物质，包括除草剂，并显示额外的活动，谷胱甘肽过氧化物酶。每个GST由两个亚基组成，确定了四种不同的亚基。一个25-kDa的多肽，称为小麦GST 1（TaGST 1），是最丰富的亚基，并可以通过反相HPLC拆分成两个变体，TaGST Ia和TaGST Ib。该GST亚基被针对玉米GST ZmGST V-VI（其为tau型GST）产生的抗血清识别。除了TaGST 1，两个26 kDa的多肽，TaGST 2和TaGST 3，和一个24 kDa的多肽，TaGST 4，可以通过疏水相互作用色谱，SDS-PAGE和反相HPLC的组合来解决。在未处理的小麦幼苗的芽中，主要同工酶是TaGST 1a-1b，而在解草唑处理的植株的芽中，异二聚体TaGST 1-2、TaGST 1-3和TaGST 1-4也积累。值得注意的是，只有安全剂诱导的TaGST 1-2，TaGST 1-3和TaGST 1-4同工酶催化fenoxaprop-ethyl的解毒，这可能有助于解释为什么fenchlorazole-ethyl增强谷胱甘肽介导的代谢，以及小麦对这种除草剂的耐受性。所有的同工酶都具有对除草剂异丙甲草胺和氟草醚的解毒活性，但只有TaGST 1-2和TaGST 1-3对阿特拉津表现出任何活性。(C)北京：科学出版社.
Multiple isoenzymes of glutathione transferase (GST), purified from the shoots of wheat seedlings treated with the herbicide safener fenchlorazole-ethyl, could be resolved into polar and hydrophobic types using hydrophobic interaction chromatography. Both types of GSTs could also be resolved based on their affinities for S-hexyl-glutathione-agarose. A minor proportion of the GSTs could be eluted from the column with a salt wash and this loosely bound fraction contained polypeptides which were recognized by an antiserum raised against the theta-type maize GST ZmGST I-II. The major proportion could only be recovered using S-hexyl-glutathione and these GSTs were characterized in detail. These isoenzymes catalyzed the glutathione conjugation of xenobiotics, including herbicides, and showed additional activities as glutathione peroxidases. Each GST was composed of two subunits, with four distinct classes of subunit being determined. A 25-kDa polypeptide, termed Triticum aestivum GST 1 (TaGST 1), was the most abundant subunit and could be resolved into two variants, TaGST la and TaGST Ib by reversed-phase HPLC. This GST subunit was recognised by an antiserum raised against the maize GST ZmGST V-VI, which is a tau-type GST. In addition to TaGST 1, two 26-kDa polypeptides, TaGST 2 and TaGST 3, and a 24-kDa polypeptide, TaGST 4, could be resolved by a combination of hydrophobic interaction chromatography, SDS-PAGE, and reversed-phase HPLC. In the shoots of untreated wheat seedlings the major isoenzyme was TaGST la-lb, while in the shoots of fenchlorazole-ethyl-treated plants the heterodimers TaGST 1-2, TaGST 1-3, and TaGST 1-4 also accumulated. Significantly, only the safener-inducible TaGST 1-2, TaGST 1-3, and TaGST 1-4 isoenzymes catalyzed the detoxification of fenoxaprop-ethyl and this may help to explain why fenchlorazole-ethyl enhances the glutathione-mediated metabolism and also the tolerance of wheat toward this herbicide. All isoenzymes were active in detoxifying the herbicides metolachlor and fluorodifen, bur only TaGST 1-2 and TaGST 1-3 showed any activity toward atrazine. (C) 1997 Academic Press.