Noncompetitive inhibition by aluminum, scandium and yttrium of acetylcholinesterase from Electrophorus electricus.

Biochemical pharmacology

PubMedID: 7092933

Marquis JK, Lerrick AJ. Noncompetitive inhibition by aluminum, scandium and yttrium of acetylcholinesterase from Electrophorus electricus. Biochem Pharmacol. 1982;31(7):1437-40.
Measurements of altered activity of soluble acetylcholinesterase from E. electricus electric organ by the inorganic cations aluminum, scandium and yttrium demonstrate that these ions are noncompetitive enzyme inhibitors. Al3+ inhibited enzyme activity at all substrate and inhibitor concentrations studied. Inhibition by Al3+ did not appear to be sensitive to the active site-specific, competitive ligand physostigmine or to calcium, a peripheral site-binding activator cation. Inhibition by another peripheral site-binding noncompetitive inhibitor, decamethonium, was not altered by Al3+. Al3+ appears thus to have interacted with a class of peripheral anionic sites on AChE distinct from the beta- or P1 peripheral anionic sites that bind Ca2+ and C-10 and may be a useful probe of a subclass of gamma- or P2-4 peripheral anionic sites. A possible mechanism for Al3+ neurotoxicity, via alterations of the enzymes of cholinergic neurotransmission, is also suggested.