Partial purification and properties of an esterase from tomato cell suspension cultures hydrolysing the pyrethroid insecticide cyfluthrin

Abstract

AbstractAn esterase which hydrolyses the pyrethroid insecticide cyfluthrin, was isolated from tomato cell suspension cultures and purified 10‐fold. The apparent molecular weight of the enzyme was estimated to be 32 000 Dalton, the pH‐optimum 8‐0, and the temperature optimum 35°C. The esterase showed a low substrate specificity and hydrolysed certain esters, e. g. ethyl 4‐nitrobenzoate, p‐nitrophenyl acetate and dinoseb acetate, whereas ethyl butyrate and the organophosphates demeton‐S‐methyl sulfoxide and paraoxon could not be hydrolysed. Because of the additional strong inhibition of the enzyme by these organophosphates the cyfluthrin hydrolase is suggested to belong to the B‐esterase type. An apparent Km‐value of 6‐25 × 10−4 mol litre−1 was obtained for p‐nitrophenyl acetate as substrate.