US EPA

7429571 

Journal Article 

Carbamylation and affinity constants of some carbamate inhibitors of acetylcholinesterase and their relation to analogous substrate constants 

Hastings, FL; Main, AR; Iverson, F; , 

2002 

Yes 

Journal of Agricultural and Food Chemistry
ISSN: 0021-8561
EISSN: 1520-5118 

18 

3 

497-502 

English 

5530563 

10.1021/jf60169a022 

WOS:A1970G228400038 

https://pubs.acs.org/doi/abs/10.1021/jf60169a022
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The carbamylation (K2) and binding (Ka) constants governing inhibition of bovine erythrocyte acetylcholinesterase at 25° C, pH 7.6, by 12 methyl and dimethylcarbamates, including Temik, neostigmine, and substituted phenyl carbamates, were determined. The k2 values ranged from 146 min-1 to 0.14 min-11, while Ka, ranged from 2.4 X 10-2M to 1.0 X 10-5M, indicating that inhibitory power was as much dependent on variations in carbamylation rates as it was on initial binding. The k2 and Ka values of the ortho-, meta-, and para-substituted nitrophenyl carbamates were compared with the Km and Vmax values of related nitrophenyl acetate substrates. In each series, <wto-substitution resulted in the highest k2 or Vmax values, whereas meta- and para-substitution gave much lower values, the meta being about twice that of the para. The effect of ring orientation on Ka and Km was less dramatic, but similar. These findings suggested a fairly close analogy between the substrate and carbamate reaction, but the analogy did not hold for the comparable nitrophenyl phosphates. © 1970, American Chemical Society. All rights reserved. 

carbamic acid derivative; cholinesterase inhibitor; neostigmine; nitrobenzene derivative; pesticide; phosphoric acid; animal; article; cattle; pH; protein binding; Animal; Carbamates; Cattle; Cholinesterase Inhibitors; Hydrogen-Ion Concentration; Neostigmine; Nitrobenzenes; Pesticides; Phosphoric Acids; Protein Binding