Kinetics parameters of Glutathione S-Transferase and its activation by vegetable extracts

Maria Célia Lopes Torres Nilda de Fátima Ferreira Soares June Ferreira Maia About the authors

This study was done to evaluate induction Glutathione S-Transferase, with vegetable extracts, and characterize its kinetics parameters. The aqueous, alcoholic, and hexanoic extracts were obtained from vegetables widely consumed in Brazil: eggplant (Solanum melongena L.), cauliflower (Brassica oleracea L.), cauli leaves (Brassica oleracea L.), broccoli (Brassica oleracea L.), Brussels sprout (Brassicaoleraea L.), onions (Allium cepa L.), garlic (Allium sativum L.); and bitter tasting vegetable such as jiló (Solanum gilo Raddi), guariroba (Syagrus oleracea Becc.), black mustard (Brassica nigra L.), carqueja (Cacalia spp.) and plants popularly considered as medicinal for curing certain diseases such as aloe vera (Aloe vera L.). The enzyme activity was determined using 1 chloro 2, 4 dinitrobenzene (CDNB) as substrate, in the presence of vegetable extracts. The reaction mixture, without the extract served as control. Of the botanical samples evaluated, eggplant, cauli leaves and broccoli showed highest induction of GST activity, the most being the alcoholic extract. The enzyme showed a Vmax of 0.016 abs.min-1/unit of enzyme and a Km of 0.323mM. Low Km value indicates high specificity of the enzyme with CDNB substrate and the maximum enzyme activity was in the pH range of 6.5 to 7.0.

Glutathione S-Transferase; enzyme activity; vegetable extracts

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