Paper Report for: Sepp_1991_Biochim.Biophys.Acta_1077_407
Reference
Title: Alkylation of acetylcholinesterase anionic centre with aziridinium ion accelerates the enzyme acylation step Sepp A, Jarv J Ref: Biochimica & Biophysica Acta, 1077:407, 1991 : PubMed
Affinity labelling of acetylcholinesterase (EC 3.1.1.7, acetylcholine acetylhydrolase) anionic centre with N,N-dimethyl-2-phenylaziridinium ion accelerates the hydrolysis of non-ionic acetic esters by increasing the rate of the enzyme acylation step at least 500-times while the rate of the deacylation step remains unchanged. Simultaneously, at least a 10-fold decrease of the substrate binding affinity takes place. The acceleration phenomenon can be explained by the "induced fit" mechanism as the binding of the cationic label to the enzyme anionic site brings the esteratic centre into conformation which provides extra stabilization for the transition state of the enzyme acylation reaction, probably by a more close structural fit between the substrate molecule and the enzyme active centre.
        
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Sepp A, Jarv J (1991) Alkylation of acetylcholinesterase anionic centre with aziridinium ion accelerates the enzyme acylation step Biochimica & Biophysica Acta1077: 407-12
Sepp A, Jarv J (1991) Biochimica & Biophysica Acta1077: 407-12