The structuro-catalytic peculiarities of acetylcholinesterase (AChE) of the cerebral hemisphere of newborn, month-old, and adult rabbits were investigated. In the process of individual development, no changes were detected in the structure of the active surface of the enzyme, but differences were detected in the macromolecular organization and sensitivity to allosteric ligands. A hypothesis was advanced on the complication of the structural organization of AChE during postnatal ontogenesis. providing the possibility of the finest regulation of its activity.