Molecular forms of acetyl- and butyrylcholinesterase in normal and dystrophic mouse brain

Abstract

In searching for possible differences in the composition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) 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 BuChE activities in NB were recovered in S1, and the rest in S2, G4, G2, and G1 AChE and BuChE forms were identified in the soluble fractions obtained from NB and DB. The shift in sedimentation values of the separated AChE and BuChE 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 BuChE 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%) BuChE forms, were identified in NB. The G4A AChE and BuChE 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 BuChE 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. © 1996 Wiley‐Liss, Inc.

Glycosylation of Acetylcholinesterase Forms in Microsomal Membranes from Normal and Dystrophic Lama2dy Mouse Muscle

“…Sedimentation markers were fi-galactosidase (G), catalase (C), and alkaline phosphatase (P). The enzyme peaks were assigned to individual AChE forms according to previous reports (Cabezas-Herrera et al, 1994a,b;Moral-Naranjo et al, 1996). All AChE activity was adsorbed to immobilized Con A.…”

“…Samples were centrifuged on 5-20% sucrose gradients made with polyoxyethylene-10-oleyl ether (Brij 96) or with Triton X-l00 (Moral-Naranjo et al, 1996).…”

“…AChE components of 2.OS, 3.5S, 9.OS, lO.5S, and l6.5S were identified after centrifugation of the Triton X-100-extractable fraction (S~+ S 2 + S3) in sucrose gradients with Brij 96 (Fig. 3), which in agreement with previous results (Cabezas-Herrera et al, 1994a;Moral-Naranjo et al, 1996) corresponded to G~(amphiphilic monomers), G~(amphiphilic dimers), G( amphiphilic, detergent-interacting tetramers), G( hydrophilic, detergent-noninteracting tetramers), and asymmetric A12 forms. Sedimentation analyses in Brij 96-containing gradients allowed us to distinguish Gf rom G' forms, improving the resolution of the AChE forms with respect to previous studies in muscle extracts (Gisiger and Stephens, 1988;Skau, 1990).…”

Abundant Tissue Butyrylcholinesterase and Its Possible Function in the Acetylcholinesterase Knockout Mouse

“…Others have noted that mouse BChE is inhibited by Triton X-100. Moral-Naranjo et al (1996) and Gómez et al (1999) recovered less mouse BChE activity from sucrose gradients made with Triton X-100 than from gradients made with Brij 96 or without detergent. The inhibition was not characterized, and the extent of inhibition was not mentioned.…”

Muscular dystrophy alters the processing of light acetylcholinesterase but not butyrylcholinesterase forms in liver ofLama2dy mice

“…These changes do not occur in dystrophic mouse heart , brain (Moral-Naranjo et al, 1996), or plasma (Cabezas-Herrera et al, 1994a).…”