On the possible reaction pathway for the acylation of AChE-catalyzed hydrolysis of ACh: Semiempirical quantum chemical study

✍ Scribed by Qinmi Wang; Hualiang Jiang; Jianzhong Chen; Kaixian Chen; Ruyun Ji

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 270 KB
• Volume: 70
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1998)70:3<515::aid-qua7>3.0.co;2-x

✦ Synopsis

The acylation process in the acetylcholinesterase AChE -catalyzed Ž . hydrolysis of the neurotransmitter, acetylcholine ACh , has been determined with the semiempirical quantum chemical calculation method AM1 using the model molecules extracted from the X-ray crystal structure of Torpedo Californica AChE. For the sake of identifying the microfeatures of the mechanism of this reaction, two types of possible mechanisms, stepwise mechanism and cooperative mechanisms, were proposed and studied with AM1 methods. All the model molecules for the possible reactants, intermediates, transition states, and products in the reaction pathways of the two mechanisms were obtained. Energy profiles, the structural properties of the transition states, indicate that the acylation of AChE-catalyzed hydrolysis of ACh adopts the cooperative mechanism, i.e., the proton transfer from Ser220 of AChE to His440 occurs