Comparative screening of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity using spectroscopic and electrometric techniques

Human blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are useful markers to assess the effects of pesticides exposure and the potential of compounds involved in the treatment of Alzheimer disease. Therefore, there is crucial importance to establish protocols for blood cholinesterase analysis comparing different methods that can adapt to the needs of each laboratory. Thus, the objective of this study was to compare two widely used methods for analysis of blood cholinesterase activity. To achieve this objective, multiple conditions of substrate concentration, time of reaction and sample dilution were tested. Multivariate analysis involving age of the men and women volunteers, systolic and diastolic pressure, human plasma protein, AChE and BChE activity were also performed. In addition, the concentrations of four compounds able to inhibit 50% of enzymes activity (IC₅₀ value) were determined to demonstrate the differences between the two methods. Multiple conditions tested could help researchers to choose the best condition according to their purpose. Our results demonstrate the relevance of jointly evaluating AChE and BChE and suggest that the colorimetric method yields more sensitive results, while the electrometric method contributes to a faster and cheaper analysis of enzymatic activity. Ellman's method stood out for the BChE, showing lower IC₅₀ values, while Mohammad's method was more effective for the AChE. These results indicate that method selection can be guided by the target enzyme and the type of inhibitor, and that the combined use of the two techniques tends to offer a more comprehensive and reliable approach for toxicological evaluation.