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Updated: Jun 19, 2026

Simple Elimination of Background Fluorescence in Formalin-Fixed Human Brain Tissue for Immunofluorescence Microscopy
Published on: September 3, 2017
Inactivation of acetylcholinesterase by various fluorophores
Lilu Guo1, Alirica I Suarez, Charles M Thompson
1Department of Biomedical and Pharmaceutical Sciences, Center for Structural and Functional Neuroscience, The University of Montana, Missoula, MT 59812, USA. lilu.guo@ateristech.com
Abstract:
The inhibition of recombinant mouse acetylcholinesterase (rMAChE) and electric eel acetylcholinesterase (EEAChE) by seven, structurally different chromophore-based (dansyl, pyrene, dabsyl, diethylamino- and methoxycoumarin, Lissamine rhodamine B, and Texas Red) propargyl carboxamides or sulfonamides was studied. Diethylaminocoumarin, Lissamine, and Texas Red amides inhibited rMAChE with IC50 values of 1.00 microM, 0.05 microM, and 0.70 microM, respectively. Lissamine and Texas Red amides inhibited EEAChE with IC50 values of 3.57 and 10.4 microM, respectively. The other chromophore amides did not inhibit either AChE. The surprising inhibitory potency of Lissamine was examined in further detail against EEAChE and revealed a mixed-type inhibition with Ki = 11.7 microM (competitive) and Ki' = 24.9 microM (noncompetitive), suggesting that Lissamine binds to free enzyme and enzyme-substrate complex.
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