The effect of tetrabutylammonium ion on chicken brain acetylcholinesterase activity in vitro

The effect of tetrabutylammonium ion on chicken brain acetylcholinesterase activity was investigated. Tetrabutylammonium ion (1-4mM) reversibly inhibited acetylcholinesterase activity of chicken brain (34-73%) in a concentration dependent manner, the IC50 being about 1.1mM. A Lineweaver-Burk plot, as well as a Dixon plot, indicated that the nature of inhibition is noncompetitive with a Km value of 0.134mM and a Ki value of 1.58mM at 37 degrees C. An Arrhenius plot showed that the transition temperature is significantly reduced in the presence of tetrabutylammonium ion.