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Phosphate Monoester Hydrolysis by Trinuclear Alkaline Phosphatase; DFT Study of Transition States and Reaction Mechanism
Author(s) -
Chen ShiLu,
Liao RongZhen
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402016
Subject(s) - chemistry , hydrolysis , phosphate , hydroxide , alkoxide , transition state , phenol , reaction mechanism , alkaline phosphatase , aryl , density functional theory , alkyl , medicinal chemistry , catalysis , stereochemistry , computational chemistry , organic chemistry , enzyme
Alkaline phosphatase (AP) is a trinuclear metalloenzyme that catalyzes the hydrolysis of a broad range of phosphate monoesters to form inorganic phosphate and alcohol (or phenol). In this paper, by using density functional theory with a model based on a crystal structure, the AP‐catalyzed hydrolysis of phosphate monoesters is investigated by calculating two substrates, that is, methyl and p ‐nitrophenyl phosphates, which represent alkyl and aryl phosphates, respectively. The calculations confirm that the AP reaction employs a “ping‐pong” mechanism involving two chemical displacement steps, that is, the displacement of the substrate leaving group by a Ser102 alkoxide and the hydrolysis of the phosphoseryl intermediate by a Zn2‐bound hydroxide. Both displacement steps proceed via a concerted associative pathway no matter which substrate is used. Other mechanistic aspects are also studied. Comparison of our calculations with linear free energy relationships experiments shows good agreement.