Abstract
1. The kinetics of acetylcholinesterase (EC 3.1.1.7) activity and its inhibition by eserine or by Sevin (1-naphthyl N-methylcarbamate) have been studied over the substrate concentration range 5×10−8 to 2·5×10−2m. 2. Equations are given for inhibition as a function of time, substrate and inhibitor concentrations, and the relevant parameters determined at 25° and 37°. 3. The observed and calculated effects of time, dilution, substrate addition and enzyme concentration were in good agreement and consistent with a steady-state carbamylation by eserine or by Sevin in the presence of excess of inhibitor. 4. The quantitative destruction of either inhibitor at high enzyme concentrations implied by the carbamylation hypothesis has been confirmed experimentally. 5. The importance and possibility of allowing quantitatively for dilution and substrate effects when estimating carbamate inhibition are demonstrated.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Disney R. W. A comparison of two methods for the measurement of cholinesterase inhibition in human blood. Biochem Pharmacol. 1966 Mar;15(3):361–366. doi: 10.1016/0006-2952(66)90307-8. [DOI] [PubMed] [Google Scholar]
- JENSEN-HOLM J. The cholinesterase activity, alone and in the presence of inhibitors, at low substrate concentrations. Acta Pharmacol Toxicol (Copenh) 1961;18:379–397. doi: 10.1111/j.1600-0773.1961.tb01680.x. [DOI] [PubMed] [Google Scholar]
- Reiner E., Simeon-Rudolf V. The kinetics of inhibition of erythrocyte cholinesterase by monomethylcarbamates. Biochem J. 1966 Feb;98(2):501–505. doi: 10.1042/bj0980501. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WILSON I. B., HARRISON M. A., GINSBURG S. Carbamyl derivatives of acetylcholinesterase. J Biol Chem. 1961 May;236:1498–1500. [PubMed] [Google Scholar]
- WILSON I. B., HATCH M. A., GINSBURG S. Carbamylation of acetvlcholinesterase. J Biol Chem. 1960 Aug;235:2312–2315. [PubMed] [Google Scholar]
- Winteringham F. P., Disney R. W. A radiometric study of cholinesterase and its inhibition. Biochem J. 1964 Jun;91(3):506–514. doi: 10.1042/bj0910506. [DOI] [PMC free article] [PubMed] [Google Scholar]