A comparison between the one-step and the two-step copper thiocholine procedure for the cytochemical localization of cholinesterases.

A comparison between the one-step and the two step copper thiocholine procedure for the subcellular localization of cholinesterases was undertaken. The results indicate that only under experimental conditions with short incubation times and precise control of the conversion into sulphide is the localization of the primary precipitate and that of the secondary precipitate identical. It was concluded that the conversion of the primary precipitate into Cu-sulphide is not necessary and can lead to artefacts.