Enzyme Engineering
Open Access

Abstract

N-Acetyl Cysteine Decreases Mice Brain Acetyl Cholinesterase Activity: An In Vitro Kinetic Study

Costa M, Bernardi J, Costa L, Fiuza T, Brandão R and Pereira M

Here a kinetic in vitro study of n-acetylcysteine (NAC) on mouse brain acetylcholinesterase (AChE) activity was performed, as well, few studies with the aim to improve Ellman?s methodology based on SH contain compounds. The ideal 5,5�-dithio-bis-2-nitrobenzoic acid (DTNB) concentration was of 0.3 mM and ideal medium pH=7.4. AChE demonstrated linear activity for all acetylthiocholine iodide (ATCh) tested concentrations (0.025-0.450 mM). To avoid any DTNB-NAC interaction interference, 30 sec were applied to the assay method, so-called stabilization time. No differences in Km (mM) for all NAC tested concentrations were observed. At the NAC concentrations started from 75 ?M significant differences in Vmax were achieved, characterizing a non-competitive type of AChE activity inhibition induced by NAC. In conclusion, NAC decreased AChE activity in vitro and the Ellman method was reliable for the analysis of AChE activity when inhibited by compounds that contain SH groups.