Cholinesterase determn. in plasma or erythrocyte samples - based on conversion of radio-labelled acetyl-choline in undiluted samples

摘要

Determn. of cholinesterase activity in undiluted plasma and erythrocyte samples is effected by (a) incubating the sample with (14C-acetyl)choline at 25 deg.C. and pH 7.4; (b) adding EtOH/HOAc to stop the reaction; (c) evaporating off any 14C-acetic acid formed; (d) measuring the difference in radioactivity between the evapd. material and residue; and (e) calculating the cholinesterase activity (in miromole/min.ml) from the radioactivity difference, the specific radioactivity of the (14C-acetyl)choline, the incubation time and the sample vol.. The sample vol. is 0.1 ml. For determn. of butyrylcholinesterase in plasma samples, the substrate concn. is 9.1 mM. For determn. of acetylcholinesterase in erythrocyte samples, the substrate concn. is 3.6 mM. USE/ADVANTAGE - The process is useful for monitoring the therapy of Alzheimer's disease using reversible cholinesterase inhibitors. Errors due to sample dilution are eliminated.