Immobilized acetylcholinesterase in magnetic nanoparticles for in-line inhibition studies using a capillary electrophoresis system.

Enzyme assays can be performed with the capillary electrophoresis technique (CE) in many approaches, such as the immobilized enzyme micro-reactor. Acetylcholinesterase is a promising enzyme to be used when pursuing such a method, as it has already been explored in the proposal of similar methods of miniaturizing enzyme assays. The present work proposes a novel enzyme micro-reactor, based on the anchorage of the enzyme on magnetic nanoparticles of MnFe ₂ O _4, with chitosan and glutaraldehyde as the cross-linker in the capillary by means of an arrange of neodymium magnets. The calculated K _m of the enzyme evaluated by this method was 1.12 mmol L ^-1 , comparable to other studies in the literature that utilizes immobilized enzymes. Also, IC ₅₀ for neostigmine was assessed in 3 different micro-reactors, with an average of 29.42 ± 3.88 μmol L ^-1 . In terms of the micro-reactor stability, it was possible to perform at least 25 experiments with assembled micro-reactor. The method was applied to hydroalcoholic extracts of 7 plant species. Plinia cauliflora had the best result, with 42.31 ± 6.81% of enzyme inhibition in a concentration of 100 mg L ^-1 .
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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