[Spectral study of the peripheral site of ligand binding in the active center of cholinesterases from different natural sources].

An increased ethidium bromide fluorescence at 610 nm was observed in the presence of cholinesterases from some natural sources, and a new fluorescence band appeared in the 500-570 nm region. The data obtained suggest a resonance energy transfer from the cholinesterase-ethidium bromide complex to a free ethidium bromide molecule. The structure of the peripheral ligand binding sites in the active center of bovine erythrocyte acetylcholinesterase, horse serum butyrylcholinesterase, and squid ganglia cholinesterase proved essentially similar.

[A study of the peripheral quaternary ligand binding site of cholinesterase with the use of ethidium bromide].

The peripheral binding site of horse serum cholinesterase (EC 3.1.1.