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Acetylcholinesterase and butyrylcholinesterase activity measurements by the Ellman method: II. Comparison of the procedure protocol with procedures suggested by other authors

The procedure for plasma butyrylcholinesterase (BChE ; EC 3.1.1.8) activity measurement is well established, while this is not the case for the erythrocyte acetylcholinesterase (AChE ; EC 3.1.1.7). We suggest the separation of plasma from erythrocytes by centrifugation, followed by separate measurement (with 1.0 mM acetylthiocholine as substrate) of BChE in plasma and AChE in unwashed erythrocytes. The obtained results showed that the cholinesterase activity measured in whole blood equalled the summe of the AChE activity in suspended erythrocytes plus the BChE activity in plasma, calculated upon the measured haematocrit. In blood samples from 13 individuals, the summe of activities was 97 &plusmn ; ; ; ; ; ; 7% of the activity measured in whole blood. The above procedure was compared with the method of Portmann (CBMTS, Dubrovnik 1998) based on activity measurements with acetylthiocholine and butyrylthiocholine which distinguish AChE from BChE, and with the method of Szinicz et al. (CBMTS, Dubrovnik 1998) where AChE activities are measured with acetylthiocholine in presence of ethopropazine, a BChE inhibitor. The advantage of our procedure is that both enzymes are measured with the same substrate and no inhibitor is required for the AChE and BChE assays. Further, the procedure can be performed with commercial kits for plasma activity measurements.

Cholinesterase activity measurements; protocols

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