Marinho_2019_Comp.Biochem.Physiol.C.Toxicol.Pharmacol_222_11

Acetylcholinesterase (AChE) plays an important role in the therapy of Alzheimer's disease and in the detection of pesticides such as organophosphates which are also widely used in chemical warfare. The aim of this study is the physicochemical and kinetic characterization of brain and muscle ChE from Danio rerio (Zebrafish). Optimal activity was found for brain ChE at alkaline pH9.0 at 30 degrees C, and for muscle ChE at alkaline pH8.5 at temperatures between 20 degrees C and 35 degrees C. The apparent kinetic constants, Km(app) and Vmax(app), for brain ChE were determined as 0.191+/-0.024mM and 0.566+/-0.028U/mg protein, and for muscle ChE as 0.230+/-0.030mM and 0.677+/-0.039U/mg protein. Both brain and muscle ChE showed inhibition at high substrate concentrations. Brain and muscle ChE showed IC50 values for physostigmine of 0.61muM and 0.37muM, respectively. The ChE activity in brain was significantly inhibited by BW254c51 in all concentrations tested, but not by Iso-OMPA, while muscle ChE presented a moderate decrease (13 to 29%) in the activity values, indicating that BuChE is present.