Activation of acetyl- and butyrylcholinesterase by enzymatic removal of sialic acid from intact neuroblastoma and astroblastoma cells in culture.

Removal of sialic acid from intact mammalian nervous system cells in tissue culture is accompanied by an immediate increase in cellular cholinesterase activity. Treatment of hamster astroblast cells (clonal line NN) and mouse neuroblastoma cells (clonal lines S21, N18, and N115) for brief periods with a low level of Clostridium perfringens sialidase, 5 X 10(-3) units/ml, removed 1-15 mug of sialic acid per mg of cell protein and brought about a large increase in v0 and Vmax of cellular acetylcholinesterase (EC 3.1.1.7). Butyrylcholinesterase (EC 3.1.1.8) activities also increased upon careful enzymatic removal of cellular sialic acid, and cells with characteristically low butyrylcholinesterase activity, e.g., adrenergic clonal line N115 neuroblasts displayed relatively high activity after treatment with sialidase. These findings open the possibility that adaptive regulation of cholinesterases in mammalian cells may be mediated rapidly through changes in their sialic acid content.