Copper, aluminum, iron and calcium inhibit human acetylcholinesterase in vitro

• Copper, aluminum, iron and calcium have ability to inhibit acetylcholinesterase.
• No effect was caused by sodium, magnesium and potassium.
• Noncompetitive mechanism of inhibition was proved.
• Copper is the most potent inhibitor from tested metals.
• Inhibition constants Ki were calculated using Dixon plot.

Acetylcholinesterase (AChE) is an important part of cholinergic nerves where it participates in termination of neurotransmission. AChE can be inhibited by e.g. some Alzheimer disease drugs, nerve agents, and secondary metabolites. In this work, metal salts aluminum chloride, calcium chloride, cupric chloride, ferric chloride, potassium chloride, magnesium chloride and sodium chloride were tested for their ability to inhibit AChE. Standard Ellman assay based on human recombinant AChE was done and inhibition was measured using Dixon plot. No inhibition was proved for sodium, potassium and magnesium ions. However, aluminum, cupric, ferric and calcium ions were able to inhibit AChE via noncompetitive mechanism of inhibition. Though the inhibition is much weaker when compared to e.g. drugs with noncompetitive mechanism of action, biological relevance of the findings can be anticipated.