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Studies on the Kinetic Mechanism and Salt Activation of Bovine Brain Choline Acetyltransferase
Author(s) -
Hersh Louis B.
Publication year - 1980
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.1471-4159.1980.tb09942.x
Subject(s) - choline acetyltransferase , choline , acetylcholine , chemistry , substrate (aquarium) , enzyme , salt (chemistry) , in vivo , choline chloride , non competitive inhibition , biochemistry , biophysics , biology , endocrinology , organic chemistry , microbiology and biotechnology , ecology
:The kinetic mechanism of bovine brain choline acetyltransferase has been studied using acetylaminocholine as a dead‐end inhibitor and di‐methylaminoethanol as an alternate substrate. Acetylaminocholine inhibition is competitive with respect to acetylcholine and noncompetitive with respect to choline. Dimethylaminoethanol exhibits one‐sixth the V max obtained with choline. These results suggest that the reaction obeys a sequential random kinetic mechanism. Salt activation of the enzyme is nonspecific with respect to monovalent anions, and results in a parallel increase in the K m for choline and the K i for acetylcholine. These results support the conclusion that salt activation of choline acetyltransferase is a nonspecific effect and that no specific chloride ion regulation of this enzyme occurs in vivo .