Moral-Naranjo_1996_J.Neurosci.Res_43_224

In searching for possible differences in the composition of acetylcholinesterase (AChE) and butyrylcholinesterase (BCHE) forms in dystrophic brain, the distribution of various enzyme molecules in normal (NB) and dystrophic (DB) 129B6F1/J mouse brain has been investigated. The tissue was sequentially extracted with saline (S1) and with saline-Triton X-100 buffers (S2) to release soluble and membrane-bound cholinesterases. About 15% of the AChE and 35% of the BCHE activities in NB were recovered in S1, and the rest in S2. G4, G2, and G1 AChE and BCHE forms were identified in the soluble fractions obtained from NB and DB. The shift in sedimentation values of the separated AChE and BCHE species in sucrose gradients made with and without detergents revealed the occurrence of hydrophilic (H) and amphiphilic (A) variants of cholinesterases in the extracts. The amphiphilic properties of the several AChE and BCHE molecules were analyzed by Triton X-114 phase-partitioning and by phenyl-agarose chromatography. A12 (1%), G4A (72%), G4H (8%), and G2A + G1A (19%) AChE molecules, and G4A (34%), G4H (19%), and G2A + G1A (47%) BCHE forms, were identified in NB. The G4A AChE and BCHE isoforms differed in their interaction with Triton X-114 and with a hydrophobic matrix. Neither the extent of cholinesterase solubilization, nor the distribution of individual enzyme forms, was significantly altered in DB. The lack of specific differences in the distribution of AChE and BCHE forms between NB and DB suggests that the biosynthetic pathway leading to the various enzyme forms is altered in muscle but not in dystrophic mouse brain.