cymserine

Cymserine is a drug related to physostigmine, which acts as a reversible cholinesterase inhibitor, with moderate selectivity for the plasma cholinesterase enzyme butyrylcholinesterase, and relatively weaker inhibition of the better-known acetylcholinesterase enzyme.

Bisnorcymserine is a reversible inhibitor of butyrylcholinesterase. The leaving group, bisnoreseroline, interacts in a non-covalent way with Ser(200) and His(440), disrupting the existing interactions within the catalytic triad, and it stacks with Trp(84)