Purification and partial characterization of a glutathione S-transferase from the two-spotted spider mite, Tetranychus urticae

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• 作者：Konanz ; Stefanie ; Nauen ; Ralf
• 关键词：Tetranychus urticae ; Glutathione S-transferases ; Monochlorobimane ; Acaricide resistance ; Two-spotted spider mite
• 刊名：Pesticide Biochemistry and Physiology
• 出版年：2004
• 出版时间：June, 2004
• 年：2004
• 卷：79
• 期：2
• 页码：49-57
• 全文大小：257 K

文摘

Glutathione S-transferases (GSTs) are known to catalyze conjugations by facilitating the nucleophilic attack of the sulfhydryl group of endogenous reduced glutathione on electrophilic centers of a vast range of xenobiotic compounds, including insecticides and acaricides. Elevated levels of GSTs in the two-spotted spider mite, Tetranychus urticae Koch, have recently been associated with resistance to acaricides such as abamectin [Pestic. Biochem. Physiol. 72 (2002) 111]. GSTs from acaricide susceptible and resistant strains of T. urticae were purified by glutathione–agarose affinity chromatography and characterized by their Michaelis–Menten kinetics towards artificial substrates, i.e., 1-chloro-2,4-dinitrobenzene and monochlorobimane. The inhibitory potential of azocyclotin, dicumarol, and plumbagin was low (IC₅₀ values>100μM), whereas ethacrynic acid was much more effective, exhibiting an IC₅₀ value of 4.5μM. GST activity is highest in 2–4-day-old female adults and dropped considerably with progressing age. Furthermore, molecular characteristics were determined for the first time of a GST from T. urticae, such as molecular weight (SDS–PAGE) and N-terminal amino acid sequencing (Edman degradation). Glutathione–agarose affinity purified GST from T. urticae strain WI has a molecular weight of 22.1kDa. N-terminal amino acid sequencing revealed a homogeneity of 50 % to insect GSTs closely related to insect class I GSTs (similar to mammalian Delta class GSTs).