The Role of Water of Hydration in Acylation of Butyrylcholinesterase
It was found recently in our laboratory (in preparation) that the acylation of butyrylcholinesterase (acylcholine acyl-hydrolase, EC 184.108.40.206) by methanesulfonylfluoride — a reaction analogous to the acylation of butyrylcholinesterase by its natural substrate — — is accelerated by tetramethylammonium and tetraethylammonium and that the accelerators improve the binding between the enzyme and the acylating agent. The same mechanism was found in our laboratory to be operative in the acceleration of acylation of acetylcholin-esterase (acetylcholine hydrolase, EC 220.127.116.11)1,2; in this case, the acceleration was shown to result from hydration changes in the active site of acetylcholinesterase under the influence of accelerator3–5.
KeywordsNatural Substrate Viscosity Coefficient Monovalent Cation Order Rate Constant Fast Formation
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