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The effect of the experimental antitumor agent caracemide on brain choline acetyltransferase
Author(s) -
Ho B. T.,
Tansey L. W.,
Feiffer R.,
Newman R. A.,
Farquhar D.,
Field W. S.,
Krakoff I. H.
Publication year - 1988
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490190116
Subject(s) - choline acetyltransferase , acetylcholine , choline , substrate (aquarium) , acetamide , chemistry , enzyme , mixed inhibition , inhibitory postsynaptic potential , non competitive inhibition , stereochemistry , biochemistry , pharmacology , biology , endocrinology , organic chemistry , ecology
Caracemide was found to inhibit choline acetyltransferase (CAT) from rat brain. A concentration of 0.5 mM caracemide inhibited the enzyme by 93%, whereas a degradation product from caracemide, N‐(methycarbamoyloxy)acetamide, produced only a 50% inhibition. Two other degration products, N(methyl‐carbamoyloxy)‐N′‐methylurea and N‐hydroxy‐N′‐methlurea, lacked any inhibitory activity. With bovine brain CAT, caracemide showed noncompetitive inhibitio with the substrate choline, K m 337 μM, K i μM, V max 2.83 nmol acetylcholine fromed/ mg/mg protein and mixed inhibition with the substrate acetyl‐CoA, K m 21 μM, K i 146 μM, V max 3.85 noml acetylcholine formed/min/mg porotein.