Assay of acetylcholinesterase activity by potentiometric monitoring of acetylcholine.
An acetylcholine-selective electrode based on a plasticized polymeric membrane has been developed. The electrode exhibited good selectivity for acetylcholine (ACh) over choline and some common ions, low drift, and a fast response to ACh. The response was linear over an ACh concentration range of 1×10(-6) to 1×10(-3) M with a slope of 59.1±0.1 and a detection limit of 1.5×10(-7)±1.2×10(-8) M. The electrode was used to monitor enzymatic ACh hydrolysis catalyzed by acetylcholinesterase (AChE) at different substrate and enzyme concentrations. A kinetic data analysis permitted the determination of the Michaelis-Menten constant of the enzymatic hydrolysis and AChE activity in the range of 2×10(-5) to 3.8×10(-1)U ml(-1).
Department of Analytical Chemistry, University of Murcia, Murcia E-30100, Spain.
M
M
Cuartero
J A
JA
Ortuño
M S
MS
García
F
F
García-Cánovas
D000109:Acetylcholine / Q000032:analysis*; D000110:Acetylcholinesterase / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods*; D006868:Hydrolysis; D007700:Kinetics; D011199:Potentiometry / Q000379:methods*
D000110:Acetylcholinesterase; D000109:Acetylcholine