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CARBAMYLATION AND DECARBAMYLATION OF ACETYLCHOLINESTERASE: EFFECT OF CHOLINE, 3,3‐DIMETHYL‐l‐BUTANOL AND SOME ALLOSTERIC EFFECTORS
Author(s) -
Dawson M.
Publication year - 1978
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1978.tb10795.x
Subject(s) - allosteric regulation , effector , acetylcholinesterase , choline , chemistry , enzyme , biochemistry , structural similarity , aché , physostigmine , stereochemistry , biology , pharmacology , acetylcholine
— Choline is more effective than 3,3‐dimethyl‐l‐butanol (DMB) in protecting bovine erythrocyte AChE against carbamylation by physostigmine sulphate (an ester of methylcarbamic acid). Both of these alcohols bind to dimethylcarbamyl‐AChE and accelerate its decarbamylation. Choline has a higher affinity for the inhibited enzyme, and causes a more rapid reactivation than does OMB. At low ionic strength, various allosteric effectors also bind to the dimethylcarbamylenzyme and accelerate its reactivation, but not to the same extent as choline and DMB. The rate of reactivation in the presence of an allosteric effector and choline is less than the sum of the individual rates. However the rate of reactivation in the presence of an allosteric effector and DMB exceeds the sum of the individual rates. The results provide further support for a previous proposal that choline and DMB bind to different sites on the enzyme, despite their structural similarity.