Effect of dichlorvos on the acetylcholinesterase from tambaqui (Colossoma macropomum) brain
Assis, C.R.D.1,2; Amaral, I.P.G.1; Castro, P.F.1,3; Carvalho Jr., L.B.1; Bezerra, R.S.1
1 - Laboratório de Enzimologia – LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami, Universidade Federal de Pernambuco, Recife-PE, Brazil.
2 – Escola Politécnica de Pernambuco, Universidade de Pernambuco, Recife-PE, Brazil.
3 – Empresa Brasileira de Pesquisa Agropecuária – Embrapa Meio-Norte, Parnaíba-PI, Brazil
Dichlorvos is an acute toxic organophosphorous pesticide, which is known as a classical acetylcholinesterase (AChE; EC 3.1.1.7) inhibitor. Here, tambaqui (Colossoma macropomum), an important Amazonian fish, is proposed as a source of brain AChE to be used in dichlorvos in vitro assay. AChE activity was determined using acetylcholine as substrate and 5,5' Ditiobis (2-nitrobenzoic) acid (DTNB) as colour-developing agent. The inhibitory effect of dichlorvos on AChE activities was determined at concentrations from 0.01 to 10 ppm and compared with those without the pesticide. The effect of dichlorvos on AChE activity followed an exponential decay model (R2 = 0.9999, Y = 26.5074 + 73.49259 e (-X/0.01104)). The IC50 calculated was 0.0126 ppm, which is lower than those reported for AChE extracted from other fish species. These results suggest that tambaqui brain AChE is a very sensitive biomarker to dichlorvos and can be used as a tool to aquatic environment monitoring.
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