Inhibition of Fish Brain Acetylcholinesterase by Cadmium and Mercury
Industrial chemicals are known to affect the activity of cholinesterases where Se was found to have a negligible effect. It is also reported that Se reduces human cancer death rates. Such contradictory reports prompted us to study the role of Se in the inhibition of fish brain AChE caused by Cd and Hg. I 50 concentrations of Cd and Hg were found to be 20 uM and 62 nM respectively. Since Se showed no I 50, a lower (3.1 uM) and a higher (57 uM) concentration was used. Positive interaction of Se was clear when Hg was at I 50 added either before or after Se or together, and 50% inhibition was completely abolished and 100% activity was recorded. This effect of Se was observed at both the test concentrations. Interaction of Se and Cd was remarkably different recording significant inhibition at all test systems. The activation of Hg-inhibited AChE by Se may be due to acceleration of enzyme deacetylation. In the presence of Cd Se probably binds to the esteratic site more strongly to effect a conformational change thereby decreasing the AChE activity.
KeywordsAChE Activity Sodium Selenite Mercuric Chloride AChE Inhibition Cadmium Chloride
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- Albert, A., 1973, Selective toxicity, Chapman and Hall, London.Google Scholar
- Aldridge, W.N., 1959, The mechanism of inhibition of esterases by organophosphorus compounds, Arhiv za Higijenu Rada I Toksikologiju 10: 143–154.Google Scholar
- Cohen, M.H., 1980, Neurotoxic effects of heavy metals and metalloids, In Biochemistry of Brain, S Kumar, Ed. Pergamon Press, New York, pp. 453–468.Google Scholar
- Hammond, P.B., and Beliles, R.P., 1980, Metals, In Casarett and Doull’s Toxicology The Basic Science of Poisons, J.Doull, C.D.Klaassen and M.O.Amdur, Eds., Macmillan Pub.Co.Inc., New York, pp. 409-467.Google Scholar
- Lai, J.C.K., Guest, J.F., Leung, T.K.C, Lim, L., and Davison, A.N., 1980, The effect of cadmium, manganese and aluminium on sodium-potassium-activated and magnesium-activated adenosine triphosphatase activity and choline uptake in rat brain synaptosomes, Biochem. Pharmacol. 29: 141–146.PubMedCrossRefGoogle Scholar