Biochemical Characterization and Kinetics of Carboxylesterase Isolated from Rabbit Liver and Lung in order to Application in the Detoxification of Environmental Pollutants

摘要

Objective: A carboxylesterase (CbE) or carboxylic-ester hydrolase (EC 3.1.1.1) is an enzyme that catalyzes the hydrolysis of carboxylesters to alcohol and carboxylate. The objective of this study is to obtain this enzyme from liver and lung of rabbit with a comparison between the effects of two specific substrates, a-naphthyl acetate (a-NA) and beta-nitrophenyl acetate (p-NPA) on the enzymes activity. The kinetic characteristics of the enzymes have been also investigated in details. Methods: CbE was obtained from rabbit liver and lung with Tris/HCl buffer (pH 7.4) extraction, ammonium sulfate precipitation, dialysis, and lyophilized. Results: The lyophilized enzyme appeared to be homogeneous on native polyacrylamide gel electrophoresis and its molecular mass was estimated to be 30 kDa suggesting a monomelic structure for the obtained enzyme. The enzyme exhibited a broad activity at different pH and temperature. The pH optimum was 7.5 and optimum temperature was 35°C.