Potencialidades do ácido 4-[(1E)etanohidrazonoil]benzóico como biomimético para a esterase da acetiltiocolina / Potencialities of [4-(1E)ethanehydrazonoyl]benzoic acid as a biomimetic for acetylthiocholine esterase

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/02/2012

RESUMO

The application of pesticides and the resulting contamination have been a matter of constant concern, being necessary to monitor these compounds by methods that are able to quantify these compounds in water and food. The chromatographic techniques are most often used for this kind of analysis, but present some drawbacks for \"in situ\" or in real time applications. Electrochemical techniques, like biosensors based on the inhibition of acetylcholinesterase, have been studied for the quantitative determination of pesticides in different samples. However, the use of enzymes is complicated due to their ability to denaturation and the possible inhibition by other species. Therefore, in this project the synthesis of [4-(1E)etanehydrazonoylbenzoic acid], a mimetic molecule for acetylcholinesterase, was carried out, aiming the catalysis of acetylcholine hydrolysis. The mimetic molecule was characterized by NMR and FTIR. The products of reaction, such as acetate and thiocholine, were identified by Ellman\ s method and FTIR. The chemical kinetic of the catalytic process was characterized as of first order with respect to the acetylthiocholine concentration with a rate constant of 0.623 s-1. The experimental data obtained with the artificial molecule were applied to the Michaelis-Menten\ s model and the kinetic parameters were determined, noting that the rate constant was calculated as 13000 times smaller than that obtained by the differential method, which indicates the inconvenience of using the enzymatic model to the mimetic catalysts. Moreover, it was found that KM has no meaning when applied to mimetic molecules.

ASSUNTO(S)

acetilcolinesterase acetylcholinesterase biomimetic molecule chemical kinetic cinética química molécula mimética

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