Abstract

Acetylcholinesterase (AChE) molecular forms were studied during mouse brain development. Mouse embryos expressed a monomeric (G(1)) and a tetrameric (G(4)) AChE form. Our results indicate that G(4) AChE expressed at embryonic day (ED) 9 and ED15 could be purified by acridinium-Sepharose chromatography and shared similar biochemical and kinetic properties with the adult form. However, the G(1) form expressed at either embryonic stage did not bind to acridinium, was not inhibited by excess substrate, and possessed higher K-m and lower V-max values than the adult G(1) form. Two peripheral anionic binding site inhibitors, fasciculin and propidium, had a significantly lower affinity for the monomeric form at ED9. Results are discussed in terms of the biological significance of the embryonic G(1) form, and its resemblance to the AChE activity found, associated with the senile plaques present in the brains of Alzheimer's patients. (C) 1998 ISDN. Published by Elsevier Science Ltd.