104801-16-3Relevant articles and documents
Catalytic Recruitment by Phosphonyl Derivatives as Inactivators of Acetylcholinesterase and Substrates for Imidazole-Catalyzed Hydrolysis: β-Deuterium Isotope Effects
Bennet, Andrew J.,Kovach, Ildiko M.,Bibbs, Jeffrey A.
, p. 6424 - 6427 (1989)
β-Deuterium secondary isotope effects for the phosphonylation of the active site serine of acetylcholinestarase (AChE) by phosphonyl derivatives at 25 deg C and pH 7.70 in 0.05 M phosphate buffer were as follows: 3,3-dimethyl-2-butyl methylphosphonofluoridate (soman), 0.90 +/- 0.03; 2-propyl methylphosphonofluoridate (sarin), 0.91 +/- 0.04; 4-nitrophenyl 2-propyl methylphosphonate (IMN), 0.93 +/- 0.05. β-Deuterium isotope effects for the imidazole-catalyzed hydrolysis of the same three compounds and of bis(4-nitrophenyl) methylphosphonate (NMN) were similar: soman, 0.96 +/- 0.03; sarin, 0.96 +/- 0.02; IMN, 0.96 +/- 0.02 (73.0 +/- 0.01 deg C); NMN, 0.94 +/- 0.02.The results indicate an increase in the force constants for the CL (L = H,D) bonds adjacent to phosphorus at the transition state for phosphonylation.This trend is pronounced in the AChE reaction, conceivably due to a more compressed structure at the transition state for the AChE reaction in comparison to the imidazole-catalyzed hydrolysis of the phosphonyl derivatives.
