| Abstract
| - Potential energy surfaces for the phosphonylation of sarin and acetylcholinesterase (AChE) have beentheoretically studied at the B3LYP/6-311G(d,p) level of theory. The obtained results show that thephosphonylation process involves a two-step addition−elimination mechanism, with the first step (additionprocess) being the rate-determining step, while by comparison, the ensuing steps are very rapid. Stable trigonalbipyramidal intermediates are formed in the studied pathways. It is also revealed that the catalytic triad ofacetylcholinesterase plays the catalytic role in the reaction by speeding up the phosphonylation process, as itdoes in the acylation reaction of ACh and AChE. The effect of aqueous solvation was accounted for via thepolarizable continuum model. It is concluded that the enzymatic reaction here is influenced strongly by thesolvent environment.
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