The conjugation of glutathione with herbicides and insecticides is considered to be one of the major detoxification mechanisms of plants. This conjugation is catalysed by a family of multifunctional proteins known as glutathione-s-transferases. Treatment of wheat (Triticum aestivum L. cv. Cumhuriyet-75), barley (Hordeum vulgare L. cv. Kaya), chickpea (Cicer arietinum L. cv. Ispanyol). | Turk J Biol 26 (2002) 89-94 © TÜB‹TAK Effect of Some Biocides on Glutathione-s-transferase in Barley, Wheat, Lentil and Chickpea Plants Gülseren COfiKUN, Figen Z‹HN‹O⁄LU Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova-‹zmir - TURKEY Received: Abstract: The conjugation of glutathione with herbicides and insecticides is considered to be one of the major detoxification mechanisms of plants. This conjugation is catalysed by a family of multifunctional proteins known as glutathione-s-transferases. Treatment of wheat (Triticum aestivum L. cv. Cumhuriyet-75), barley (Hordeum vulgare L. cv. Kaya), chickpea (Cicer arietinum L. cv. Ispanyol), and lentil (Lens culinaris Medik. cv. K›fll›k-k›rm›z›-51) with the selective herbicides 2,4-D (2,4-Dichloro phenoxyacetic acid) and linuron (N-(3,4-dichlorophenyl)-N´-methoxy-N´-methyl urea), and insecticides parathion methyl (O,O-dimethyl O-(4nitrophenyl) phosphorothioate) and malathion (S-1,2-bis(ethoxycarbonyl)ethyl O,O-dimethyl phosphorodithioate) caused a progressive increase in glutathione-s-transferase activity in roots and shoots. The maximum increase in enzyme activity was observed in parathion methyl treated wheat roots: 485% of control with a parathion methyl concentration of mM. A similar but lower increase in glutathione (GSH) levels was observed for roots and shoots, differing according to the origin and the type of pesticide. Key Words: Glutathione-s-transferase, detoxification, pesticide Arpa, Bu¤day, Mercimek ve Nohut Bitkilerindeki Glutation-s-transferaz Üzerine Baz› Biosidlerin Etkisi Özet: Glutationun herbisitler ve insektisitlerle konjugasyonu, bitkilerin detoksifikasyon mekanizmalar›n›n en önemlilerinden biridir. Bu konjugasyon, glutation-s-transferazlar olarak bilinen multifonksiyonel bir enzim ailesi taraf›ndan katalizlenir. Bu¤day (Triticum aestivum ), arpa (Hordeum vulgare ), nohut (Cicer arietinum .‹spanyol) ve mercime¤in .