MOLECULAR FORMS OF ACETYLCHOLINESTERASE: THEIR DE NOVO SYNTHESIS IN MOUSE NEUROBLASTOMA CELLS

Abstract

Rat mouse AChE [acetylcholinesterase] molecular forms were indistinguishable with respect to their sedimentation coefficients and their evolutive proportions during brain maturation. Among rat or mouse erythrocytes, rat C6 glial cells and mouse 2A and NS 20 neuroblastoma cells, only neuroblastoma cells showed both the ES and HS molecular forms with a 1:1 proportion for NS 20 cells. All these cells lacked a 3rd molecular form (16S) present in rat and mouse superior cervical ganglia. After irreversible inhibition or pre-existing NS 20 neuroblastoma AchE the ES form was first synthesized (de novo synthesis). The HS form began to appear after a lag time of several hours and represented, 24 h after inhibition, only 15% of the total recovered activity, which is near the initial level. The initial relative proportions returned by 2-3 days after inhibition. The recovery of the HS form was, for the most part, blocked by actinomycin D, which did not block the recovery of activity itself, which remained as an ES form. Integration of the ES form into the HS form probably depends on the synthesis of a new mRNA, which is required for the synthesis of either new AChE polypeptide chain, polymerization initiating protein or activating enzyme.