Acetylcholinesterase in Mouse Neuroblastoma Cells: Intracellular and Released Enzyme

Mouse neuroblastoma cells in cultures release acetylcholinesterase into the growth medium. The released enzyme, as well as the intracellular activity, separate on a density gradient into two molecular forms, sedimenting as 4.5S and 10.5S entities. The relative amounts of these forms are different in the two cases: whereas the slower sedimenting form is the major one in the cellular extract, the 10.5S form predominates in the released activity. The cellular and released proteins were labelled by [3H]diisopropylphosphofluoridate and analysed on polyacrylamide‐SDS gels. The results suggest that the intracellular as well as the extracellular molecules are oligomers of similar subunits.