engleski

Standardization of experimental conditions for blood cholinesterase measurements

We have standardized the Ellman et al. spectrophotometric method with the thiol reagent DTNB under the following conditions: 25^0C, 0.1 M phosphate buffer pH=7.4, 1.0 mM acetylthiocholine. Under these conditions, about 92 % whole blood ChE activity corresponds to AChE and 8 % to BChE. The method is applicable over a temperature range between 10 and 40^C. A temperature conversion table has been worked out to convert activities measured at different temperatures. Inhibited blood samples containing unreacted ChE inhibitors were suggested to be stored diluted in 20 mM phosphate buffer pH=5, which did not affect the enzyme activity, but slowed down the rate of further ChE inhibition and the rate of spontaneous reactivation. We support recommendations from the current literature that AChE activities should be expressed per haemoglobin concentration, and we suggest that in individuals exposed to ChE inhibitors one should measure both, AChE and BChE activities. AChE activities are less dependent on the general state of health of an individual than BChE, while BChE is by many compounds more inhibited than AChE and is therefore a more sensitive measure of exposure to ChE inhibitors.

Human blood cholinesterase activity measurement

nije evidentirano